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000
FXUS66 KOTX 152325 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
325 PM PST THU JAN 15 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
UPDATED AVIATION DISCUSSION.
TONIGHT THROUGH SUNDAY...FOG AND STRATUS STILL DOMINATE THE BULK
OF THE LOWER ELEVATIONS OF THE FORECAST AREA THIS AFTERNOON.
OUTSIDE OF A LITTLE DOWNSLOPE FROM EASTERLY FLOW OFF THE CENTRAL
PANHANDLE MOUNTAINS INTO THE PULLMAN AREA AND EASTERN
PALOUSE...LARGELY CLOUDY CONDITIONS PREVAIL OVER MOST LOCATIONS
BELOW 3500 FEET OR SO...WHICH LINES UP NICELY WITH THE 12Z KOTX
SOUNDING. NEARLY THIS EXACT SAME PATTERN LOOKS PERSIST FOR
SEVERAL DAYS.
THE GFS AND NAM BOTH GRADUALLY MOVE SURFACE HIGH PRESSURE UNDER
THE LARGE SCALE RIDGE TOWARD THE IDAHO PANHANDLE...WHICH SHOULD
WORK TO CONTINUE AND STRENGTHEN THE EAST TO WEST GRADIENT THAT HAS
BEEN DEVELOPING ACROSS THE AREA. EASTERLY FLOW SHOULD KEEP THE
PALOUSE RELATIVELY CLEAR...WHILE LOWER BOUNDARY LAYER RH VALUES
LOOK TO GRADUALLY ADVECT INTO THE CWA FROM THE NORTHEAST BY THE
SECOND HALF OF THE WEEKEND. EXAMINING BUFKIT SOUNDINGS FROM BOTH
THE NAM AND GFS IN CONJUNCTION WITH THE BOUNDARY LAYER RH
LOWERING...IT SEEMS THE BASIN WILL BE THE LIKELY CANDIDATE TO STAY
TOTALLY CLOUDY THROUGHOUT THE SHORT TERM OF THE FORECAST...WITH
THE WEST PLAINS OF SPOKANE LIKELY ALSO STAYING LARGELY CLOUDY.
ELSEWHERE...LOWER BOUNDARY LAYER RH SHOULD ALLOW AT LEAST SOME
REDUCTION IN CLOUD COVER.
WHILE CLOUDS WILL BE REDUCING SOME THROUGH THE WEEKEND...INVERSION
STRENGTH DOES NOT EVEN LOOK TO WAVER. SURFACE TO 850 MB
TEMPERATURE DIFFERENTIALS STILL RUNNING ON THE ORDER OF 10C WITH
NO DISCERNIBLE VERTICAL MIXING WOULD STILL RESULT IN A DECENT
AMOUNT OF STRATUS...EVEN WITH LOWER BOUNDARY LAYER RH VALUES
BECOMING LESS AND LESS SUPPORTIVE OF FOG. BECAUSE OF THIS...THE
AIR STAGNATION ADVISORY WILL CONTINUE THROUGH EARLY NEXT WEEK.
UNDER THE STRATUS AND IN THE FOG...DIURNAL TEMPERATURE CHANGES
WILL BE VERY SMALL...PROBABLY ONLY A DEGREE OR TWO PER DAY.
HOWEVER...IN THE MOUNTAINS...WITH 850 MB TEMPERATURES SURPASSING
+10C...TEMPERATURES WILL COMMONLY BE IN THE 50S IN THE CASCADES
AND OKANOGAN HIGHLANDS BEFORE WARMER AIR ADVECTS EASTWARD TOWARD
THE IDAHO PANHANDLE WITH THE RIDGE AXIS BY THE END OF THE WEEKEND.
/FRIES
SUNDAY NIGHT THROUGH THURSDAY...THE UPPER LEVEL RIDGE AXIS WILL BE
NUDGED EAST TO EASTERN IDAHO AND WESTERN MONTANA BY AN APPROACHING
PACIFIC TROUGH AT THE START OF THE WORK WEEK. AS THE TROUGH NEARS
THE NORTHWEST COAST THE UPPER FLOW SPLITS...WITH A SHORTWAVE SLIDING
ACROSS CENTRAL BC AND THE REMAINDER OF THE ENERGY DROPPING INTO A
CLOSED LOW OFF THE CALIFORNIA COAST. THE INLAND NORTHWEST WILL BE
LEFT BETWEEN THE TWO SYSTEMS. MODELS ARE IN MUCH BETTER AGREEMENT
WITH THE SPLIT FLOW AS THE 12Z GFS HAS MOVED TOWARD THE ECMWF
SOLUTION. POPS HAVE BEEN REMOVED FROM THE TUESDAY/TUESDAY NIGHT
PERIOD AND REDUCED TO A SLIGHT CHANCE IN THE MOUNTAINS FOR THE END
OF THE FORECAST PERIOD. THE CLOSED LOW WILL MOVE ASHORE TO OUR SOUTH
ON WEDNESDAY BUT MAY TRACK CLOSE ENOUGH TO ALLOW SOME WRAP AROUND
MOISTURE TO AFFECT THE FORECAST AREA. PERSISTENT LOW LEVEL
INVERSIONS WILL KEEP FOG AND LOW STRATUS TRAPPED OVER MOST OF THE
VALLEYS THROUGH MIDWEEK. DIURNAL TEMPERATURE SWINGS WILL CONTINUE
TO BE QUITE SMALL FOR MOST VALLEYS. ANY AREAS THAT SEE SUNSHINE
WILL WARM UP SIGNIFICANTLY COMPARED TO THOSE STUCK IN THE GLOOM.
/KELCH
&&
.AVIATION...
A STRENGTHENING RIDGE ALOFT WITH A WEAK HIGH PRESSURE AT THE SURFACE
WILL ALLOW THE PERSISTENCE OF A STRONG INVERSION OVER THE VALLEYS
AND COLUMBIA BASIN. NORTH OF INTERSTATE 90 INCLUDING THE KGEG
VCNTY TAF SITES...KEAT...AND KMWH...LIFR AND VLIFR VISIBILITIES
AND CEILINGS WILL PERSIST WITH LITTLE OR NO IMPROVEMENT THROUGH
00Z SATURDAY. FOG AND LOW STRATUS IS SPREADING EAST TO THE PULLMAN AREA
THIS AFTERNOON AND MAY AFFECT THE KPUW TAF SITE AFTER 03Z FRIDAY.
VFR CONDITIONS AT KLWS ARE EXPECTED TO DETERIORATE TONIGHT AS LOW
STRATUS DEVELOPS AGAIN. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 26 31 27 31 25 31 / 0 0 0 0 0 0
COEUR D`ALENE 29 32 29 32 27 32 / 0 0 0 0 0 0
PULLMAN 31 43 31 40 30 39 / 0 0 0 0 0 0
LEWISTON 33 38 33 38 30 39 / 0 0 0 0 0 0
COLVILLE 26 34 27 33 23 33 / 0 0 0 0 0 0
SANDPOINT 28 32 29 32 23 32 / 0 0 0 0 0 0
KELLOGG 30 39 30 35 29 31 / 0 0 0 0 0 0
MOSES LAKE 23 33 24 35 26 31 / 0 0 0 0 0 0
WENATCHEE 25 33 26 33 27 32 / 0 0 0 0 0 0
OMAK 25 30 26 30 25 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST TUESDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST TUESDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST FRIDAY FOR SPOKANE AREA...
UPPER COLUMBIA BASIN.
&&
$$
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000
FXUS66 KSEW 152323
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 PM PST THU JAN 15 2009
.SYNOPSIS...A STRONG UPPER LEVEL RIDGE RIDGE WILL REMAIN OVER THE
PACIFIC NORTHWEST THROUGH THE WEEKEND. A WARM DRY AIR MASS ALOFT
WILL CONTINUE TO GIVE A STRONG INVERSION. AREAS OF LOW CLOUDS AND
FOG WILL PERSIST OVER THE INTERIOR LOWLANDS WHILE CLEAR SKIES AND
MILD TEMPERATURES ARE ON TAP FOR THE COAST AND MOUNTAINS. OFFSHORE
FLOW WILL PERSIST...MAINLY NEAR THE WESTERN STRAIT OF JUAN DE FUCA
AND NEAR THE COAST.
&&
.SHORT TERM...A STRONG INVERSION WILL CONTINUE TO KEEP STAGNANT AIR
IN MUCH OF THE LOWLANDS INTO THE WEEKEND. BOTH THE PROFILER AND
ACARS OBS SHOW TEMPS WARMING FROM THE UPPER 30S JUST BELOW 1000FT TO
THE LOWER 60S JUST ABOVE 2000FT. DESPITE THIS UNUSUALLY WARM AIR
THERE HAS BEEN LITTLE MIXING FOR THE INTERIOR LOWLANDS SO FAR...AND
EACH DAY I HAVE HAD TO PUSH OUR MAX TEMPS FCSTS IN THE PUGET SOUND
BASIN BACK DOWN BELOW GUIDANCE. HAVE EXTENDED THE AIR STAGNATION
ADVISORY THRU MONDAY FOR THE INTERIOR LOWLANDS IN COORD WITH LOCAL
AIR QUALITY METS.
FOR TEMPS...ALONG THE WEST SLOPES OF THE CASCADES I AM KEEPING SOME
WARMTH IN THE FCST...BUT STILL ARND 5 DEGREE COOLER THAN THE 4KM
WRFGFS. OF COURSE IT WAS WARM ABOVE THE INVERSION IN THE MOUNTAINS
AND ON THE COAST TODAY AND THE FCST TEMPS LOOKS LIKE THEY WERE OKAY
TDY. CROSS CASCADE GRADIENT IS -7MB (EASTERLY) SO DRY AIR WILL TEND
TO EAT AWAY AT THE STRATUS FROM ABOVE AND TO SOME DEGREE MAY PUNCH
IN AT THE COOL DAMP AIR IN PLACE LIKE GOLD BAR/NORTH BEND ETC. AT
3PM HERE IN NORTH SEATTLE THE STRATUS IS TRYING TO SCATTER OUT...AND
IT MAY THIN AND BE PARTLY SUNNY TIL SUNSET. BUT ANY AREAS THAT CLEAR
INTO THE EVENING ARE SURE TO BE FOLLOWED BY FOG AND LOW STRATUS
QUICKLY REDEVELOPING. IT IS GETTING TOO LATE IN THE DAY AND
INSOLATION THIS TIME OF YEAR WILL NOT OVERTURN THE MURKY BOUNDARY
LAYER. IF STRONGER EASTERLY WINDS THRU THE CASCADES DEVELOP BY SAT
THEN THE FOGGY CLOUDY FORECAST MAY HAVE TO ADJUSTED AND WE MAY
IMPROVE...BUT THAT DOES NOT LOOK LIKELY RIGHT NOW.
THE SKY AND WEATHER GRIDS HAVE BEEN TWEAKED A LITTLE TO MATCH UP
WITH THE AFTERNOON VISIBLE SATELLITE IMAGE. SO FAR IT HAS BEEN MORE
HAZY AND MISTY THAN FOGGY...BUT THE TREND HAS BEEN FOR THE INVERSION
TO LOWER AND AREAS OF GENUINE FOG OUGHT TO DEVELOP. AT THE LEAST THE
STRATUS WILL JUST KEEP LOWERING DOWN FROM THE HILL TOPS. A DENSE FOG
ADVISORY MAY HAVE TO BE ISSUED FOR A FEW AREAS AS THE INVERSION
APPROACHES THE SURFACE...BUT WE ARE NOT THERE YET...OVER SEATTLE IT
STAYED ARND 400M THIS AFTERNOON. FCST IS CLOSE TO PERSISTENCE THRU
SUNDAY...AND SHUD ONLY NEED TO BE ADJUSTED IN A FEW AREAS AFTER THE
MAX TEMP ANALYSIS IS IN. ABOVE THE INVERSION ALONG THE WEST SLOPES
CASCDS THERE WILL SURELY HAVE BEEN SOME ERRORS TDY...THE MESO FCST
SOUNDINGS STARTED OUT TOO DRY THIS MORNING ARND PUGET SOUND AND THAT
COULD MEAN THE WRFGFS IS TOO WARM IN SOME AREAS. MAYBE WE NEED A FEW
WEATHER BALLOONS OR ACARS DEW POINTS TO HELP INITIALIZE THE MODEL
WITH THIS LOW STRATUS AND FOG ARND PGTSND. IT HAS BEEN A LONG TIME
SINCE I FILLED WEATHER BALLOONS AND SENT THEM OFF...MISS THAT. 19
.LONG TERM...DESPITE A SLOWER WEAKER 12Z GFS IN BREAKING DOWN THE
RIDGE I ONLY DELAYED THE TREND TOWARD CLIMO A LITTLE. BY MIDWEEK OUR
POPS RANGE FROM 30PCT IN THE LOWLANDS TO 50PCT IN THE MTNS...AND
EVEN ON THE WEAK 12Z RUN HEIGHTS STILL FALL INTO THE 560S BY TUE
WHICH SUGGESTS THE RIDGE WILL NOT PERSIST AS STRONG AS OVER THE
WEEKEND AND MAY EITHER PROGRESS EAST OR MAYBE RETROGRADE SOMETIME
NEXT WEEK. AT THE LEAST A LOT OF MID AND HIGH CLOUDS AND SOME
PERSISTENT AREAS OF STRATUS COULD KEEP THE MOSTLY CLOUDY FORECAST IN
THE BALLPARK IF NOT THE POP FCST. A SHORTWAVE MOVING THRU B.C. SUCH
AS THE ONE IN THE 18Z GFS WOULD GIVE ONSHORE FLOW INTO WRN WA AS
HIGH PRES OVER ERN WA IS REPLACED BY WEAK LOW PRES. THAT 18Z RUN HAS
A SHARP LITTLE UPPER TROF OVER WRN WA 12Z WED...AND ALTHOUGH HEIGHTS
ONLY FALL TO ABOUT 552DAM OVER SEATTLE A CHANCE OF SHOWERS SEEMS
REASONABLE. BEHIND THAT TROF THE 18Z GFS BUILDS A 1042MB COOL HIGH
OVER ERN B.C. AND ALTA WHILE THE UPPER TROF DRIFTS SW TO THE OREGON
OFFSHORE WATERS LATER WED AND BECOMES A SMALL CUT OFF LOW. THAT
COULD RESULT IN A BIT OF A COOLING TREND AND FREEZING LEVELS WOULD
PROBABLY BE BACK CLOSER TO SEASONABLE NORMS IF THAT VERIFIES. 19
&&
.AVIATION...A MASSIVE SUBSIDENCE INVERSION WILL REMAIN INTACT OVER
WESTERN WASHINGTON FOR THE NEXT 24 HOURS...CAUSING STRATUS AND CIGS
BENEATH THE INVERSION TO REMAIN STUBBORNLY LOW AND WIDESPREAD. JUST
IN TIME FOR SUNSET...A FEW HOLES HAVE DEVELOPED IN THE STRATUS NEAR
SEATTLE AND IN AN AREA CENTERED ON THE SAN JUANS. THIS SHOULD
ACTUALLY AID IN RADIATIONAL COOLING AFTER SUNSET AND HELP WITH
RE-DEVELOPMENT OF SURFACE-BASED FOG...SO BASICALLY A CONTINUATION OF
IFR/LIFR CONDITIONS IN THE LOWLANDS WELL INTO FRIDAY. IN CONTRAST...
THE COAST AND MOUNTAINS HAVE EXPERIENCED THE BENEFITS OF UPPER
RIDGING IN THE FORM OF P6SM SKC.
KSEA...SOME THINNING AND PATCHES OF BLUE SKY ARE THE BEST WE COULD
DO TODAY AS LOW-LEVEL MOISTURE REMAINS TRAPPED BENEATH A MASSIVE
SUBSIDENCE INVERSION. WHETHER IT BE BY RADIATIONAL COOLING OR SIMPLE
LOWERING OF THE EXISTING STRATUS DECK...FOG IS EXPECTED TO RE-FORM
TONIGHT WITH MOST OF THE DEGRADATION IN CONDITIONS TAKING PLACE
BETWEEN 04Z AND 08Z. ON FRIDAY AFTERNOON...THERE MAY BE A LITTLE
MORE THINNING AND SCATTERING OF CLOUDS THAN TODAY...BUT STRENGTH OF
THE SUBSIDENCE INVERSION AND MERE PERSISTENCE WOULD SUGGEST IT WILL
BE SLOW AND LATE ON FRI AFTN. HANER
&&
.MARINE...MODERATE OFFSHORE FLOW OVER WESTERN WASHINGTON WILL
CONTINUE WITH PERSISTENT HIGH PRES EAST OF THE CASCADES. OBSERVED
KUIL-KBLI GRADIENT BETWEEN -4 AND -5 MB HAVE PERSISTED ALL DAY...AND
NO CHANGE IN THE LARGE-SCALE PATTERN IS EXPECTED THROUGH SATURDAY.
HAVE THEREFORE GONE WITH A PERSISTENCE FORECAST THROUGH
SATURDAY...WHICH REQUIRES EXTENDING THE CURRENT ROUND OF GALE
WARNINGS AND SMALL CRAFT ADVISORIES. OFFSHORE FLOW WILL BE STRONGEST
IN THE VICINITY OF CAPE FLATTERY AND GRAYS HARBOR...WHERE LOCAL
TERRAIN INFLUENCES CHANNEL THE EASTERLY WIND. HANER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...AIR STAGNATION ADVISORY FOR THE LOWLANDS OF WESTERN WA
EXCEPT FOR THE COAST AND WESTERN STRAIT THRU MON.
FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER AT RENTON
IN KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...GALE WARNING WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY FOR THE COAST AND CENTRAL STRAIT.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KOTX 152206
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
206 PM PST THU JAN 15 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
TONIGHT THROUGH SUNDAY...FOG AND STRATUS STILL DOMINATE THE BULK
OF THE LOWER ELEVATIONS OF THE FORECAST AREA THIS AFTERNOON.
OUTSIDE OF A LITTLE DOWNSLOPE FROM EASTERLY FLOW OFF THE CENTRAL
PANHANDLE MOUNTAINS INTO THE PULLMAN AREA AND EASTERN
PALOUSE...LARGELY CLOUDY CONDITIONS PREVAIL OVER MOST LOCATIONS
BELOW 3500 FEET OR SO...WHICH LINES UP NICELY WITH THE 12Z KOTX
SOUNDING. NEARLY THIS EXACT SAME PATTERN LOOKS PERSIST FOR
SEVERAL DAYS.
THE GFS AND NAM BOTH GRADUALLY MOVE SURFACE HIGH PRESSURE UNDER
THE LARGE SCALE RIDGE TOWARD THE IDAHO PANHANDLE...WHICH SHOULD
WORK TO CONTINUE AND STRENGTHEN THE EAST TO WEST GRADIENT THAT HAS
BEEN DEVELOPING ACROSS THE AREA. EASTERLY FLOW SHOULD KEEP THE
PALOUSE RELATIVELY CLEAR...WHILE LOWER BOUNDARY LAYER RH VALUES
LOOK TO GRADUALLY ADVECT INTO THE CWA FROM THE NORTHEAST BY THE
SECOND HALF OF THE WEEKEND. EXAMINING BUFKIT SOUNDINGS FROM BOTH
THE NAM AND GFS IN CONJUNCTION WITH THE BOUNDARY LAYER RH
LOWERING...IT SEEMS THE BASIN WILL BE THE LIKELY CANDIDATE TO STAY
TOTALLY CLOUDY THROUGHOUT THE SHORT TERM OF THE FORECAST...WITH
THE WEST PLAINS OF SPOKANE LIKELY ALSO STAYING LARGELY CLOUDY.
ELSEWHERE...LOWER BOUNDARY LAYER RH SHOULD ALLOW AT LEAST SOME
REDUCTION IN CLOUD COVER.
WHILE CLOUDS WILL BE REDUCING SOME THROUGH THE WEEKEND...INVERSION
STRENGTH DOES NOT EVEN LOOK TO WAVER. SURFACE TO 850 MB
TEMPERATURE DIFFERENTIALS STILL RUNNING ON THE ORDER OF 10C WITH
NO DISCERNIBLE VERTICAL MIXING WOULD STILL RESULT IN A DECENT
AMOUNT OF STRATUS...EVEN WITH LOWER BOUNDARY LAYER RH VALUES
BECOMING LESS AND LESS SUPPORTIVE OF FOG. BECAUSE OF THIS...THE
AIR STAGNATION ADVISORY WILL CONTINUE THROUGH EARLY NEXT WEEK.
UNDER THE STRATUS AND IN THE FOG...DIURNAL TEMPERATURE CHANGES
WILL BE VERY SMALL...PROBABLY ONLY A DEGREE OR TWO PER DAY.
HOWEVER...IN THE MOUNTAINS...WITH 850 MB TEMPERATURES SURPASSING
+10C...TEMPERATURES WILL COMMONLY BE IN THE 50S IN THE CASCADES
AND OKANOGAN HIGHLANDS BEFORE WARMER AIR ADVECTS EASTWARD TOWARD
THE IDAHO PANHANDLE WITH THE RIDGE AXIS BY THE END OF THE WEEKEND.
/FRIES
SUNDAY NIGHT THROUGH THURSDAY...THE UPPER LEVEL RIDGE AXIS WILL BE
NUDGED EAST TO EASTERN IDAHO AND WESTERN MONTANA BY AN APPROACHING
PACIFIC TROUGH AT THE START OF THE WORK WEEK. AS THE TROUGH NEARS
THE NORTHWEST COAST THE UPPER FLOW SPLITS...WITH A SHORTWAVE SLIDING
ACROSS CENTRAL BC AND THE REMAINDER OF THE ENERGY DROPPING INTO A
CLOSED LOW OFF THE CALIFORNIA COAST. THE INLAND NORTHWEST WILL BE
LEFT BETWEEN THE TWO SYSTEMS. MODELS ARE IN MUCH BETTER AGREEMENT
WITH THE SPLIT FLOW AS THE 12Z GFS HAS MOVED TOWARD THE ECMWF
SOLUTION. POPS HAVE BEEN REMOVED FROM THE TUESDAY/TUESDAY NIGHT
PERIOD AND REDUCED TO A SLIGHT CHANCE IN THE MOUNTAINS FOR THE END
OF THE FORECAST PERIOD. THE CLOSED LOW WILL MOVE ASHORE TO OUR SOUTH
ON WEDNESDAY BUT MAY TRACK CLOSE ENOUGH TO ALLOW SOME WRAP AROUND
MOISTURE TO AFFECT THE FORECAST AREA. PERSISTENT LOW LEVEL
INVERSIONS WILL KEEP FOG AND LOW STRATUS TRAPPED OVER MOST OF THE
VALLEYS THROUGH MIDWEEK. DIURNAL TEMPERATURE SWINGS WILL CONTINUE
TO BE QUITE SMALL FOR MOST VALLEYS. ANY AREAS THAT SEE SUNSHINE
WILL WARM UP SIGNIFICANTLY COMPARED TO THOSE STUCK IN THE GLOOM.
/KELCH
&&
.AVIATION...
A STRENGTHENING RIDGE ALOFT WITH A WEAK HIGH PRESSURE AT THE SURFACE
WILL ALLOW THE PERSISTENCE OF A STRONG INVERSION OVER THE VALLEYS
AND COLUMBIA BASIN THROUGH 18Z FRIDAY. NORTH OF INTERSTATE 90
INCLUDING THE KGEG VCNTY TAF SITES AND KEAT LIFR AND VLIFR
VISIBILITIES AND CEILINGS WILL PERSIST WITH LITTLE OR NO
IMPROVEMENT THROUGH 12Z FRIDAY. AROUND KMWH...WHILE CONDITIONS
HAVE IMPROVED...SOME -SN OR -FZDZ MAY CAUSE SOME ICING THROUGH
20Z. /FRIES
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 26 31 27 31 25 31 / 0 0 0 0 0 0
COEUR D`ALENE 29 32 29 32 27 32 / 0 0 0 0 0 0
PULLMAN 31 43 31 40 30 39 / 0 0 0 0 0 0
LEWISTON 33 38 33 38 30 39 / 0 0 0 0 0 0
COLVILLE 26 34 27 33 23 33 / 0 0 0 0 0 0
SANDPOINT 28 32 29 32 23 32 / 0 0 0 0 0 0
KELLOGG 30 39 30 35 29 31 / 0 0 0 0 0 0
MOSES LAKE 23 33 24 35 26 31 / 0 0 0 0 0 0
WENATCHEE 25 33 26 33 27 32 / 0 0 0 0 0 0
OMAK 25 30 26 30 25 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST TUESDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST TUESDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST FRIDAY FOR SPOKANE AREA...
UPPER COLUMBIA BASIN.
&&
$$
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000
FXUS66 KPQR 152144
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
143 PM PST THU JAN 15 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE FLOW ALSO CONTINUES...THE MAIN
EFFECT IS WINDS THROUGH THE GORGE. THE DRY OFFSHORE FLOW IN THE
HIGHER TERRAIN AND ALONG THE COAST IS CAUSING UNSEASONABLY WARM AND
DRY CONDITIONS THAT WILL LIKELY CONTINUE INTO THE UPCOMING WEEKEND.
MEANWHILE...THE CENTRAL AND SOUTHERN WILLAMETTE VALLEY WILL LIKELY
REMAIN UNDER A STRONG INVERSION...WITH MUCH COOLER TEMPERATURES AND
PERSISTENT FOG.
&&
.SHORT TERM...MODELS CONTINUE TO KEEP THE STRONG RIDGE OVER THE
REGION THROUGH SAT..BEFORE BEGINNING TO SHIFT INLAND SUN. WITH THE
STABLE PATTERN...CONFIDENCE IN MODELS IS HIGH THROUGH THE SHORT TERM.
NAM IS PREFERRED FOR DEPICTING OFFSHORE PRESSURE GRADIENTS RESULTING
FROM THE STRONG SURFACE HIGH E OF THE CASCADES. AS THE UPPER RIDGE
SHIFTS E SUN...SURFACE STRENGTHENS SOME...INCREASING THE ALREADY
STRONG GORGE GRADIENT UP TO AROUND 10 MB. SUNDAY MAY ALSO SEE A BIT
OF AN INCREASE IN CROSS COAST RANGE GRADIENTS WHICH WOULD ALLOW FOR
MORE WARMING ALONG THE COAST. OTHERWISE EXPECT PERSISTENCE TO BE THE
BEST FORECAST OVER THE NEXT FEW DAYS...COOL DAYS IN THE VALLEYS WITH
FOG AND LOW CLOUDS IN WIND PROTECTED AREAS...AND WARM TEMPERATURES IN
THE MOUNTAINS. WILL EXTEND AIR STAGNATION ADVISORY THROUGH SUN.
&&
.LONG TERM...MODELS CONTINUE TREND IN SHOWING THE RIDGE MOVING E
EARLY NEXT WEEK. VARIOUS MODEL RUNS HAVE SHOWN AN ASSORTMENT OF
SOLUTIONS AFTER TUE...BUT MOST RECENT RUNS OF GFS AND ECMWF HAVE BEEN
TRENDING TOWARDS A CLOSED LOW UNDERCUTTING THE LONGWAVE RANGE. THIS
WOULD SUGGEST ONLY A LIMITED CHANCE FOR RAIN THROUGH MIDWEEK...SO
WILL CUT POPS BACK BELOW CLIMATOLOGICAL VALUES. WEAKENING RIDGE EARLY
IN THE WEEK WILL TEND TO REDISTRIBUTE TEMPERATURES A LITTLE MORE
NORMALLY...COOLING MOUNTAINS SOME AND ALLOWING VALLEYS TO WARM A
LITTLE.
&&
.AVIATION...STRONG UPPER HIGH ALONG THE COAST WILL CONTROL THE
WEATHER TONIGHT AND FRIDAY. SURFACE HIGH PRESSURE OVER IDAHO WILL
GIVE MODERATELY STRONG OFFSHORE FLOW TO THE AREA. VFR CONDITIONS
OVER MOST OF THE AREA TONIGHT AND FRIDAY. THE EXCEPTION WILL BE THE
SOUTHERN WILLAMETTE VALLEY AND PORTIONS OF THE CENTRAL WILLAMETTE
VALLEY AND EAST COLUMBIA GORGE THIS AFTERNOON AND EVENING. THESE
AREAS STRATUS AND FOG PATCHES WILL CONTINUE GIVING IFR CONDITIONS
WITH LIFR IN THE SOUTHERN WILLAMETTE. THE FOG WILL REFORM IN THE
CENTRAL VALLEY LATER THIS EVENING AND SPREAD INTO PORTIONS OF THE
NORTH AND ALONG THE COLUMBIA RIVER WEST OF PORTLAND LATER TONIGHT
AND FRIDAY MORNING. FOG AND STRATUS WILL CLEAR IN THE NORTH VALLEY
AND PART OF THE CENTRAL VALLEY BY EARLY FRIDAY AFTERNOON. FAIRLY
STRONG EAST WINDS WILL BLOW THROUGH THE WESTERN COLUMBIA GORGE
TONIGHT AND FRIDAY. WIND GUSTS WILL REACH 50 MPH ALONG THE WEST END
OF THE GORGE.
KPDX AND APPROACHES...VFR CONDITIONS IN THE KPDX AREA THIS AFTERNOON
AND EVENING. EAST WINDS NEAR THE COLUMBIA GORGE WILL SPREAD AROUND
KPDX THIS EVENING THEN DECREASE AT KPDX LATE TONIGHT. WIND GUSTS TO
25 KT ARE POSSIBLE TO KPDX WITH STRONGER WINDS NEAR THE GORGE. AFTER
THE WINDS DECREASE LATE TONIGHT FOG PATCHES FROM THE WEST WILL
SPREAD CLOSE TO KPDX GIVING A 50 PERCENT THREAT OF IFR CONDITIONS AT
KPDX FRIDAY MORNING. ALL FOG PATCHES WILL CLEAR BY MIDDAY FRIDAY.
&&
.MARINE...STRONG HIGH PRESSURE WELL INLAND TONIGHT AND FRIDAY. WINDS
WILL REMAIN BELOW SMALL CRAFT TONIGHT AND FRIDAY AND SEAS WILL
REMAIN BELOW 10 FEET.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY THROUGH SUN FOR THE LOWER INTERIOR
VALLEYS OF NW OREGON AND SW WA.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 151802
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1002 AM PST THU JAN 15 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
UPDATE FOR TODAY...12Z KOTX SOUNDING SHOWS THE SAME PERSISTING
INVERSION THAT HAS BEEN OVER THE AREA FOR THE PAST COUPLE OF DAYS.
SURFACE TO 850 MB TEMPERATURE DIFFERENTIALS ARE CURRENTLY RUNNING
ABOUT 7C OVER SPOKANE...WHICH OBSERVATIONS AND A PERUSAL OF THE
KUIL SOUNDING INDICATING MUCH WARMER AIR ALOFT LIKELY BEING
PRESENT OVER THE WESTERN CWA. AS A RESULT...INVERSIONS ARE
PROBABLY EVEN STRONGER OVER THE WESTERN CWA...WHICH IS PROBABLY
THE CAUSE FOR THE DETERIORATED AIR QUALITY INDICATED BY SENSORS
NEAR TWISP AND WINTHROP. BECAUSE THE MODELS PERSIST THE INVERSION
THROUGH NEXT WEEK...THE AIR STAGNATION ADVISORY HAS BEEN EXTENDED
THROUGH TUESDAY.
UNDER THE INVERSION...FOG HAS PERSISTED AROUND SPOKANE GEIGER AND
ALONG THE HIGHWAY TWO CORRIDOR. ELSEWHERE...SUCH AS DOWNTOWN
SPOKANE...POST FALLS...COEUR D`ALENE...AND MOSES
LAKE...VISIBILITIES HAVE INCREASED ENOUGH TO ALLOW THE DENSE FOG
ADVISORIES TO BE PARED BACK SOME. FOR THE REST OF THE DAY...DENSE
FOG IS GENERALLY ONLY EXPECTED FROM SPOKANE AIRPORT WEST ALONG
HIGHWAY TWO INTO THE UPPER COLUMBIA BASIN.
ONE LAST UPDATE...OBSERVATIONS FROM MOSES LAKE TO HANFORD HAS BEEN
REPORTING SOME FLURRIES THIS MORNING...AND REPORTS OF SOME SLICK
SPOTS HAVE BEEN COMING IN. AS A RESULT...FLURRIES THROUGH THE NOON
HOUR HAVE BEEN ADDED TOT HE FORECAST BEFORE IT SEEMS THE STRATUS
LAYER SHOULD WARM ENOUGH TO END ICE NUCLEATION IN THE STRATUS.
/FRIES
&&
.AVIATION...
A STRENGTHENING RIDGE ALOFT WITH A WEAK HIGH PRESSURE AT THE SURFACE
WILL ALLOW THE PERSISTENCE OF A STRONG INVERSION OVER THE VALLEYS
AND COLUMBIA BASIN THROUGH 18Z FRIDAY. NORTH OF INTERSTATE 90
INCLUDING THE KGEG VCNTY TAF SITES AND KEAT LIFR AND VLIFR
VISIBILITIES AND CEILINGS WILL PERSIST WITH LITTLE OR NO
IMPROVEMENT THROUGH 12Z FRIDAY. AROUND KMWH...WHILE CONDITIONS
HAVE IMPROVED...SOME -SN OR -FZDZ MAY CAUSE SOME ICING THROUGH
20Z. /FRIES
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 31 30 31 28 31 28 / 0 0 0 0 0 0
COEUR D`ALENE 32 29 32 27 32 28 / 0 0 0 0 0 0
PULLMAN 43 32 41 30 39 33 / 0 0 0 0 0 0
LEWISTON 38 32 37 31 38 33 / 0 0 0 0 0 0
COLVILLE 34 28 34 29 33 24 / 0 0 0 0 0 0
SANDPOINT 34 27 34 31 32 26 / 0 0 0 0 0 0
KELLOGG 40 30 36 28 33 29 / 0 0 0 0 0 0
MOSES LAKE 35 31 36 28 35 28 / 0 0 0 0 0 0
WENATCHEE 33 29 32 28 33 30 / 0 0 0 0 0 0
OMAK 30 29 30 27 30 28 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST TUESDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL NOON PST TODAY FOR COEUR D`ALENE AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST TUESDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST FRIDAY FOR SPOKANE AREA...
UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KSEW 151731
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
930 AM PST THU JAN 15 2009
.SYNOPSIS...A STRONG UPPER LEVEL RIDGE RIDGE WILL REMAIN OVER THE
PACIFIC NORTHWEST THROUGH THIS WEEKEND. A WARM DRY AIR MASS ALOFT
WILL CONTINUE TO GIVE A STRONG INVERSION. AREAS OF LOW CLOUDS AND
FOG WILL PERSIST OVER THE LOWLANDS WHILE CLEAR SKIES AND MILD
TEMPERATURES CAN BE EXPECTED AT THE COAST AND IN THE MOUNTAINS.
OFFSHORE FLOW WILL PERSIST...MAINLY NEAR THE WESTERN STRAIT OF JUAN
DE FUCA AND NEAR THE COAST.
&&
.SHORT TERM...STRATUS CONTINUES TO SLOWLY LOWER...AIR MASS IS MURKY
IN THE LOWLANDS. CLEAR AND GOOD MIXING COAST AND WESTERN STRAIT OF
JUAN DE FUCA...OFFSHORE GRADIENTS HAVE INCREASED...AT 9AM SEA-EAT WAS
-6.2MB AND UIL-BLI -4.7MB...BUT IT WILL STILL BE A BIT OF A STRUGGLE
FOR THE WARM AIR ALOFT AND EASTERLY FLOW TO START MIXING OUT THE
PUGET SOUND BASIN...MAYBE A COUPLE HOURS OF IMPROVEMENT AND ONLY IN
A FEW AREAS...THEN FOG OR STRATUS WILL SET UP QUICKLY AGAIN EVENING.
THE WEST SLOPES OF THE CASCADES CONTINUE TO HAVE A GOOD CHANCE OF
AFTERNOON SUNSHINE. OUR MAX TEMP FCSTS WERE TOO WARM YESTERDAY ALL
ALONG THE WEST SLOPES OF THE CASCADES AND ON THE EAST SIDE...BUT IT
IS SO WARM ALOFT THAT JUST A LITTLE MIXING WILL MAKE A SPECTACULAR
DIFFERENCE. THE FCST FOR THE MOUNTAINS AND COAST IS EASY
ENUF...SUNNY...AND THE INVERSION IS ONLY VERY SHALLOW ON THE COAST
SO WARM TEMPS ABOVE (IT IS 60F ON THE UIL SOUNDING AT ONLY 1200FT)
ARE CERTAIN TO MIX DOWN TO SOME DEGREE IN MANY AREAS OUT THERE. THE
PROFILER HERE SHOWS THE TEMP JUMPING FROM +2C BELOW THE INVERSION AT
300M TO +15C UP ABOVE THE STRATUS IN THE WARM AIR...THAT IS QUITE A
JUMP. WHETHER THE 10-15KT EAST WIND SKIMMING ACROSS THE TOP OF THE
STRATUS CAN ENTRAIN DRY AIR INTO THE LAYER AND THEN ALLOW SOME
MIXING THIS AFTERNOON REMAINS TO BE SEEN. BUT EVEN IF WE DO MIX UP
TO SOME DEGREE THIS AFTERNOON THE STRONG INVERSION IS SURE TO
QUICKLY REESTABLISH RIGHT AWAY EACH EVENING...AND AN INVERSION EVER
GETTING CLOSER TO THE SURFACE WILL TRAP POLLUTANTS EVEN MORE
EFFECTIVELY. OUR TEMP FCSTS ARE A MIX OF STATISTICAL GUIDANCE AND
THE MODELS WITH COOLEST TEMPS IN THE LOWLANDS...AND WARMTH IN THE
MOUNTAINS AND ON AND COAST...AS WELL AS SOME OPTIMISM FOR THE WEST
SLOPES OF THE CASCADES WITH THIS OFFSHORE FLOW AND BETTER CHANCE OF
MIXING THERE. 19
.LONG TERM...MAY HAVE TO PUSH BACK THE TREND TO MORE CLIMO LOOKING
FCSTS WITH THE CHANCE OF SHOWERS...THE LATEST RUNS OF THE GFS DO
UNDERCUT THE RIDGE SOMEWHAT BUT A SYSTEM GOES INTO CALIF BY MIDWEEK
WHILE A WEAKER CUT OFF UPPER HIGH REMAINS CENTERED NEAR VANCOUVER
ISLAND...SO THE RIDGE MAY TAKE A COUPLE OF EXTRA DAYS TO BREAK DOWN
NEXT WEEK. 19
&&
.AVIATION...A STRONG SUBSIDENCE INVERSION WILL REMAIN INTACT OVER
WESTERN WASHINGTON FOR THE NEXT 24 HOURS. THE INVERSION APPEARS TO
HAVE LOWERED SOME IN THE PAST 24 HOURS...TODAY`S 12Z KUIL SOUNDING
SHOWED THE WARM NOSE ABOVE THE INVERSION NEAR 900 MB...COMPARED TO
YESTERDAY`S 850 MB. THIS HAS CAUSED STRATUS AND CEILINGS BENEATH THE
INVERSION TO LOWER A BIT. PRETTY STEADY CEILING AROUND 600 FT MSL
OVER THE CENTRAL AND SOUTH SOUND THIS MORNING. KSEA-KEAT EASTERLY
GRADIENTS HAVE STRENGTHENED FROM NON-EXISTENT YESTERDAY MORNING INTO
THE MODERATE CATEGORY THIS MORNING. AM COUNTING ON THIS ERODING THE
ERN EDGE OF THE STRATUS ALONG THE FOOTHILLS WITH SOME TEMPORARY
SCATTERING GETTING AS FAR WEST AS I-5 FROM TCM-PAE-BLI LATE THIS
AFTERNOON. STRATUS NEAR KOLM AND ALONG THE NORTH AND EAST SIDE OF
THE OLYMPICS SHOULD REMAIN FIRMLY IN PLACE TODAY.
KSEA...STRATUS DECK HAS JUST ABOUT LOWERED ONTO THE AIRFIELD AS OF
17Z. STRATUS MAY LIFT A FEW HUNDRED FEET DURING THE COURSE OF THE
DAY...BUT CIGS SHOULD REMAIN BELOW 010 THROUGH AT LEAST 22Z.
INCREASING DRY EASTERLY FLOW FROM THE CASCADES INTO THE FOOTHILLS
MAY PUSH SOME SCATTERING OF THE STRATUS AS FAR WEST AS KSEA SOMETIME
AFTER 22Z. BELIEVE ENOUGH SCATTERING WILL TAKE PLACE TO SET THE
STAGE FOR SURFACE-BASED FOG FORMING OVER THE AIRFIELD THIS EVENING
AFTER ABOUT 04Z. HANER
&&
.MARINE...STRENGTHENING HIGH PRES EAST OF THE CASCADES WILL CONTINUE
THE MODERATE OFFSHORE FLOW OVER WESTERN WASHINGTON. KUIL-KBLI
GRADIENT OF -4.7 AT 16Z WILL CONTINUE TO SUPPORT EASTERLY GALES AT
THE WEST ENTRANCE TODAY. LOOKING FOR PEAK WIND SPEEDS DURING THE
DIURNALLY FAVORED PERIOD AROUND 11 AM OR NOON. BASED ON OBS FROM
YESTERDAY AND FAIRLY PERSISTENT GRADIENTS OVER WRN WA...OPTED TO GO
WITH SMALL CRAFT ADVISORIES FOR THE COAST AND CENTRAL STRAIT AS
WELL. WITH LITTLE CHANGE IN THE PATTERN FOR THE NEXT FEW DAYS...GALE
WARNING AND SCA MAY NEED TO BE EXTENDED OR RE-ISSUED LATER
TODAY. HANER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...AIR STAGNATION ADVISORY FOR THE LOWLANDS OF WESTERN WASHINGTON
EXCEPT FOR THE COAST AND WESTERN STRAIT.
FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER AT RENTON
IN KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...GALE WARNING WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY FOR THE COAST AND CENTRAL STRAIT.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KPQR 151651
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
850 AM PST THU JAN 15 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE FLOW CONTINUE INTO FRIDAY WITH
THE MAIN EFFECT IS WINDS ACROSS THE CASCADE PASSES AND THROUGH THE
GORGE. EAST WINDS ARE ALREADY BECOMING QUITE GUSTY THROUGH
GORGE...AND SHOULD PUSH INTO TROUTDALE AND PORTLAND LATER TONIGHT AND
THURSDAY. THE DRY OFFSHORE FLOW IN THE HIGHER TERRAIN AND ALONG THE
COAST IS CAUSING UNSEASONABLY WARM AND DRY CONDITIONS THAT WILL
LIKELY CONTINUE INTO THE UPCOMING WEEKEND. MEANWHILE...THE CENTRAL
AND SOUTHERN WILLAMETTE VALLEY WILL LIKELY REMAIN UNDER A STRONG
INVERSION...WITH MUCH COOLER TEMPERATURES AND PERSISTENT FOG.
&&
.SHORT TERM...WATER VAPOR PICTURES SHOW STRONG UPPER RIDGE NEAR
130W...WHILE SLE 12Z SOUNDING SHOWED STRONG INVERSION AROUND 1500 FT.
STRONG SURFACE HIGH E OF CASCADES HAS SETUP A STRONG CROSS GORGE
PRESSURE GRADIENT NEAR 8 MB. MODELS CONTINUE WITH A PERSISTENT
PATTERN THROUGH THE END OF THE WEEK...SO MORE OF THE SAME IS IN
STORE. THIS ENTAILS WARM TEMPS IN THE MOUNTAINS WITH PLENTY OF
SUN...COLDER AIR IN WIND PROTECTED VALLEYS WITH LOW CLOUDS AND
FOG...AND WINDY CONDITIONS IN THE WEST END OF THE GORGE. SURFACE
OBSERVATIONS INDICATE SOME PATCHY DENSE FOG REMAINS IN THE WILLAMETTE
VALLEY...MAINLY IN THE N. WILL DROP THE DENSE FOG ADVISORY BUT STILL
NEED TO INCLUDE A MENTION OF DENSE FOG THROUGH MIDDAY.
&&
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
GFS...ECMWF AND CANADIAN ALL INDICATING THE UPPER RIDGE TO BEGIN
SHIFTING E AROUND SUNDAY...BUT THE DETAILS OF WHAT IS TO FOLLOW
REMAIN UP IN THE AIR. GIVEN CURRENT MODEL SOLUTIONS...WILL STICK WITH
A DRY FORECAST THROUGH MON...THEN TREND TOWARDS CLIMATOLOGY POPS TUE
TO WED. TEMPERATURES WILL MODERATE TOWARDS A MORE EVENLY DISTRIBUTED
MARITIME PATTERN...COOLER FOR THE MOUNTAINS AND A BIT WARMER FOR THE
VALLEYS.
&&
.AVIATION...STRONG UPPER HIGH ALONG THE COAST WILL CONTROL THE
WEATHER TODAY AND TONIGHT. SURFACE HIGH PRESSURE OVER IDAHO WILL
GIVE MODERATELY STRONG OFFSHORE FLOW TO THE AREA. VFR CONDITIONS
OVER MOST OF THE AREA TODAY AND TONIGHT. THE EXCEPTION IS THE
WILLAMETTE VALLEY AREAS ALONG THE COLUMBIA RIVER FROM PORTLAND TO
KELSO AND THE EAST END OF THE COLUMBIA GORGE. IN THESE AREAS
WIDESPREAD STRATUS AND FOG IS OCCURRING. THERE IS WIDESPREAD
IFR/LIFR CONDITIONS IN THESE AREAS. THE AREAS ALONG THE COLOMBIA
RIVER AND THE NORTHERN END OF THE WILLAMETTE VALLEY WILL CLEAR BY
EARLY AFTERNOON. THE REMAINDER OF THE WILLAMETTE VALLEY WILL REMAIN
CLOUDY WITH SOME FOG THROUGH THE AFTERNOON. FOG WILL INCREASE IN THE
CENTRAL AND SOUTH VALLEY TONIGHT AND SPREAD INTO PART OF THE NORTH
VALLEY AND ALONG THE COLUMBIA RIVER. FAIRLY STRONG EAST WINDS WILL
BLOW THROUGH THE WESTERN COLUMBIA GORGE THROUGH TONIGHT WITH WIND
GUSTS REACHING 50 MPH ALONG THE WEST END OF THE GORGE.
KPDX AND APPROACHES...WIDESPREAD IFR/LIFR CONDITIONS IN THE KPDX
AREA THIS MORNING EXCEPT NEAR THE COLUMBIA GORGE. FOG AND STRATUS
WILL CLEAR BY EARLY AFTERNOON WITH VFR CONDITIONS. AREAS OF FOG WEST
OF KPDX WILL DEVELOP LATER TONIGHT. EAST WINDS WILL INCREASE NEAR
THE GORGE TO KPDX BY MIDDAY WITH WIND GUSTS TO 40 MPH NEAR THE
GORGE.
&&
.MARINE...STRONG HIGH PRESSURE WELL INLAND TODAY AND TONIGHT. WINDS
WILL REMAIN BELOW SMALL CRAFT TODAY AND TONIGHT AND SEAS WILL REMAIN
BELOW 10 FEET.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY THROUGH SAT FOR THE LOWER INTERIOR
VALLEYS OF NW OREGON AND SW WA.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 151131
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
325 AM PST THU JAN 15 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
TODAY AND TONIGHT...LATEST MODELS ARE SIMILAR AND IN GOOD
AGREEMENT WITH SATELLITE EXTRAPOLATION. THE STRONG UPPER LEVEL
RIDGE JUST OFF THE COAST WILL SHIFT INTO THE REGION AND BECOME
WELL ESTABLISHED DURING THE NEXT 24 HOURS. WHILE WEAK SLUGS OF
UPPER LEVEL MOISTURE AND EVEN A MODERATE SHORT WAVE WILL CREST THE
RIDGE TODAY AND TONIGHT...NOTHING HAPPENING ALOFT WILL BE ABLE TO
SHAKE LOOSE THE INVERSION LID ON THE LOW LEVEL BOUNDARY LAYER.
INVERSION WILL STRENGTHEN TODAY AND TONIGHT WITH GENERALLY STATIC
CONDITIONS BELOW 4000 FEET FEATURING CONTINUED WIDESPREAD FOG AND
STRATUS WITH LITTLE DIURNAL CHANGE TO TEMPERATURES. ONLY MARGINAL
CONFIDENCE IN ANY SORT OF OBVIOUS AFTERNOON BREAK OUT
ANYWHERE...WITH BEST CHANCE OF BRIEF FOG LIFT AND STRATUS BREAK UP
SOUTH OF INTERSTATE 90 IN THE DEEP BASIN TODAY...FOLLOWED BY A
RETURN TO THE MURK AFTER DARK TONIGHT. ONLY THE PALOUSE WHERE WEAK
DOWNSLOPING WILL KEEP PULLMAN DRY AND ESSENTIALLY CLEAR...AND THE
ELEVATIONS ABOVE THE INVERSION LAYER WILL EXPERIENCE ANY SUNSHINE
TODAY. CURRENT DENSE FOG AND AIR STAGNATION HIGHLIGHTS REMAIN
VALID. /FUGAZZI
FRIDAY THROUGH MONDAY...THE UNSEASONABLY WARM 588 DAM HIGH
PRESSURE SYSTEM WILL REMAIN DOMINATE OVER THE NORTHWEST.
GFS/EURO/NAM ARE PICKING UP ON A SHORTWAVE CURRENTLY AT 140W
ROUNDING THE RIDGE ON FRIDAY WITH THE HEART OF ITS ENERGY DROPPING
WELL EAST THROUGH THE DAKOTAS. AS THE WAVE PASSES THE EAST...THE
RIDGE AXIS PUSHES INLAND AND THE EMBEDDED CLOSED 588 DAM HIGH WILL
WOBBLE TO EAST/NORTHEAST OVER THE CWA. A WEAK SOUTHERN BRANCH OF
THE SHORTWAVE IS EXPECTED TO PEEL OFF FROM THE MAIN SHORTWAVE
SNEAKING UNDER THE CLOSED HIGH OVER EASTERN WA ON SATURDAY. THIS
WILL CONTINUE TO FOLLOW A CIRCULAR PATH THROUGH CENTRAL
IDAHO...OREGON...AND BACK NORTH THROUGH WESTERN WA ON SUNDAY. ALL
GUIDANCE APPEARS TO PICK UP ON THIS FEATURE BUT DO SHOW SOME
DIFFERENCES IN THE STRENGTH AND EXACT TRACK. WITH SUCH DRY AIR IN
PLACE...WE DO NOT EXPECT ANYMORE THAN SCATTERED HIGH CLOUDS. THE
ONE IMPACT I WANTED TO FOCUS ON IS NOTED BY ALL GUIDANCE IN THE
850MB WINDS. AS THE MAIN SHORTWAVE TRACKS DOWN ALONG THE SPINE OF
THE DIVIDE FRIDAY MORNING.. THERE IS A SHORT-LIVED MID LEVEL W/SW
PRESSURE GRADIENT AT THE 850MB SURFACE...THEN AS THE RIPPLE EJECTS
AND CIRCLES TO THE SOUTH...WE SEE 850MB FLOW WEAKLY FOLLOW SUITE.
WITH STRONG LOW- LEVEL INVERSION ACROSS THE LOWER-
ELEVATIONS...THIS WILL HAVE NO IMPACT. NAM12/GFS DO SHOW 10-15KTS
W/SW ROUGHLY AT 4-5K FT WHICH WOULD BE ALONG THE BLUE MTS FRIDAY
MORNING INTO THE AFTERNOON WHICH MAY PLAY A ROLE IN POTENTIAL
MIXING WARMER TEMPERATURES DOWN FOR SURROUNDING FOOTHILLS. AS THE
WAVE PASSES TO THE SOUTH AND WEST SATURDAY AFTERNOON/SUNDAY... THE
WINDS TREND NNE/E WITH LITTLE NO EFFECTS.
TUESDAY...GLOBAL MODEL SOLUTIONS APPEAR TO HAVE COME IN
SOMEWHAT BETTER AGREEMENT THAT THE RIDGE AXIS WILL TRACK EAST
ACROSS THE DIVIDE AS A POTENT SHORTWAVE APPROACHES THE COAST. IN
ADDITION...AS THE SHORTWAVE RUNS INTO THE RIDGE...THE WAVE WILL
WEAKEN...AND SPLIT. CONFIDENCE REALLY GOES DOWN TRYING TO FIGURE
OUT THE DETAILS WITH PART OF THE FORECAST. THE GFS AND ITS
ENSEMBLE MEMBERS ARE MUCH MORE PROGRESSIVE WITH THE WAVE CROSSING
INTO THE NORTHWEST BEFORE THE SOUTHERN FLANK BRANCHES OFF AND
RETROGRADES TO THE S/SW. THIS WOULD BRING CHANCE FOR PRECIPITATION
WITH THE PASSAGE OF A STRONGER COLD FRONT. THE EUROPEAN AND ITS
ENSEMBLE MEMBERS HAVE BEEN SLIGHTLY MORE CONSISTENT AND INDICATE
THE WAVE WILL SPLIT BEFORE REACHING THE COAST PUTTING OUR CWA INTO
A COL CREATING A MUCH WARMER AND STAGNANT EXTENDING INTO TUESDAY.
WEDNESDAY AND THURSDAY...THERE IS DECENT AGREEMENT WITH THE
00Z FORECAST PACKAGES THAT HIGH PRESSURE WILL QUICKLY REBUILD OUT
BETWEEN 130-140W BEHIND WHAT EVER BECOMES OF TUESDAYS WAVE. THIS
WILL STEER A COOLER CANADIAN AIRMASS THROUGH THE CWA BRINGING
SLIGHT CHANCE FOR PRECIPITATION AND COOLER
TEMPERATURES...ESPECIALLY FOR THE MTNS. /BODNAR
&&
.AVIATION...
A STRENGTHENING RIDGE ALOFT WITH A WEAK HIGH PRESSURE AT THE SURFACE
WILL ALLOW THE PERSISTENCE OF A STRONG INVERSION OVER THE VALLEYS
AND COLUMBIA BASIN THROUGH 12Z FRIDAY. NORTH OF INTERSTATE 90
INCLUDING THE KGEG VCNTY TAF SITES AND KEAT LIFR AND VLIFR
VISIBILITIES AND CEILINGS WILL PERSIST WITH LITTLE OR NO IMPROVEMENT
THROUGH 12Z FRIDAY. AT KLWS MODERATE IMPROVEMENT TO IFR CONDITIONS
IS POSSIBLE BY 18Z TODAY WITH A RETURN TO LIFR CONDITIONS AFTER 04Z.
AT KMWH VFR CONDITIONS ARE EXPECTED AFTER 18Z...WITH A RETURN TO
LIFR VIS AND CIGS AFTER 06Z TONIGHT. STRATUS LAYER TOPS WILL REMAIN
AROUND 4000 FT MSL THROUGH 12Z FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 31 30 31 28 31 28 / 0 0 0 0 0 0
COEUR D`ALENE 32 29 32 27 32 28 / 0 0 0 0 0 0
PULLMAN 43 32 41 30 39 33 / 0 0 0 0 0 0
LEWISTON 38 32 37 31 38 33 / 0 0 0 0 0 0
COLVILLE 34 28 34 29 33 24 / 0 0 0 0 0 0
SANDPOINT 34 27 34 31 32 26 / 0 0 0 0 0 0
KELLOGG 40 30 36 28 33 29 / 0 0 0 0 0 0
MOSES LAKE 35 31 36 28 35 28 / 0 0 0 0 0 0
WENATCHEE 33 29 32 28 33 30 / 0 0 0 0 0 0
OMAK 30 29 30 27 30 28 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL NOON PST TODAY FOR COEUR D`ALENE AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL NOON PST TODAY FOR MOSES LAKE AREA...
SPOKANE AREA...UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KSEW 151122
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
320 AM PST THU JAN 15 2009
.SYNOPSIS...A STRONG UPPER LEVEL RIDGE RIDGE WILL REMAIN OVER THE
PACIFIC NORTHWEST THROUGH THIS WEEKEND. A SURFACE RIDGE EAST OF THE
CASCADES WILL MAINTAIN OFFSHORE FLOW THROUGH THE PERIOD. THE RIDGE
WILL PRODUCE A WARM AND DRY AIR MASS ALOFT AND A VERY STRONG LOW
LEVEL INVERSION. AREAS OF LOW CLOUDS AND FOG WILL PERSIST OVER THE
LOWLANDS...WITH MOSTLY CLEAR AND MILD CONDITIONS FOR THE COAST AND
MOUNTAINS.
&&
.SHORT TERM...STRONG UPPER LEVEL RIDGING ALONG THE WEST COAST WILL
CONTINUE TO EXPAND AND SLOWLY SHIFT NORTHWARD INTO THE WEEKEND. A
STRONG LOW LEVEL INVERSION REMAINS IN PLACE ACROSS WESTERN
WASHINGTON THIS MORNING AND WILL BE THE MAIN PLAYER IN THE FORECAST
FOR THE NEXT THREE DAYS OR SO. SOME HIGH LEVEL MOISTURE SLIDING
THROUGH THE STRONG RIDGE IS OBSCURING FOG IMAGERY...BUT SURFACE OBS
ACROSS THE AREA SHOW SOLID STRATUS BLANKETING MUCH OF THE REGION.
THE KSEW PROFILER AND ACARS DATA SHOW TEMPERATURES IN THE 925-850 MB
LAYER HAVE WARMED CONSIDERABLY OVER THE PAST 24 HOURS...WITH
TEMPERATURES APPROACHING 60F NEAR 925MB. IN ADDITION...VERY DRY AIR
HAS MOVED IN ALOFT...14 PERCENT HUMIDITY AT HURRICANE RIDGE AT 2 AM.
THIS HAS SUPPRESSED THE STRATUS LAYER RESULTING IN THE LOWER
CEILINGS OBSERVED THIS MORNING. PROFILER DATA SEEMS TO SUGGEST THAT
TOPS OF THE STRATUS ARE IN THE NEIGHBORHOOD OF 1200-1500 FEET.
DESPITE OFFSHORE GRADIENTS...INTERIOR LOWLANDS WILL SEE LITTLE
BENEFIT WITH THE STRONG INVERSION IN PLACE. SOME LOWLAND LOCATIONS
MAY SEE SOME BRIEF CLEARING THE NEXT 2 OR 3 AFTERNOONS...BUT THE
MOUNTAINS AND COAST WILL BE THE PLACE TO SEE SOME SUN AND
UNSEASONABLY MILD TEMPERATURES. AIR STAGNATION WILL BE A PROBLEM
OVER THE INTERIOR AND AN ADVISORY FOR THIS REMAINS IN EFFECT THROUGH
SATURDAY.
.LONG TERM...THE EXTENDED MODELS CONTINUE TO SHOW A CHANGE IN THE
PATTERN EARLY NEXT WEEK AS THE RIDGE EVENTUALLY SHIFTS INTO THE
ROCKIES AND WEAKENS. THE EURO/GFS SEEM TO AGREE ON SOME SORT OF
SPLIT PATTERN DEVELOPING...BUT DISAGREE ON UPSTREAM DEVELOPMENTS
OVER THE NORTHEAST PACIFIC. I CERTAINLY WOULDNT PLACE ANY CONFIDENCE
ON EITHER SOLUTION THIS EARLY IN THE GAME. 27
&&
.AVIATION...A STRONG SUBSIDENCE INVERSION WILL REMAIN INTACT OVER
WESTERN WASHINGTON FOR THE NEXT 24 HOURS. SANDPOINT PROFILER SHOWS
THE INVERSION HAS NOT LOWERED MUCH IN THE LAST FEW HOURS WITH THE
BASE OF THE INVERSION STILL NEAR 1500 FEET. STRATUS DECK HAS SLOWLY
LOWERED OVERNIGHT WITH THE BASE OF THE DECK IN THE 500 TO 800 MSL
RANGE. VISIBILITIES BELOW A MILE SO FAR HAVE BEEN CONFINED TO KBLI.
HAZY CONDITIONS HERE AT SANDPOINT BUT VISIBILITIES STILL GOOD.
MODELS CONTINUE TO SHOW THE INVERSION LOWERING TODAY INTO TONIGHT
BUT WITH THE PROFILER OBS WILL BACK THE 1/4 MILE VISIBILITIES AT
KSEA BUT KEEP THEM AT THE HIGHEST TERMINAL...KPAE. LITTLE MIXING
TODAY AND TONIGHT. MODELS CONTINUE TO SHOW A BREAKOUT OF THE STRATUS
IN MOST PLACES TODAY BUT THE MODEL SOUNDINGS VERIFYING AT 09Z HAVE
THE BASE OF THE INVERSION IN THE 500 TO 1000 FOOT RANGE. WITH THE
MODELS A LITTLE AHEAD OF THE GAME WILL ALSO BACK OFF ON THE AMOUNT
OF SCATTERING OUT THIS AFTERNOON INTO THIS EVENING. THE EXCEPTION OT
ALL THIS WILL CONTINUE TO BE THE COAST WITH JUST SCATTERED CLOUDS AT
BEST FOR KHQM.
KSEA...CEILING AND VISIBILITIES HAVE BEEN SLOWLY LOWERING OVERNIGHT
AND THIS TREND WILL CONTINUE THIS MORNING. CEILINGS REMAINING BELOW
5000 FEET. WILL BACK OFF THE 1/4 MILE VISIBILITY WITH THE BASE OF
THE STRATUS REMAINING JUST OFF THE DECK AND INDICATE A TEMPO 1/2
MILE VISIBILITY MID MORNING TO EARLY AFTERNOON. SOME SLIGHT CLEARING
AROUND 00Z BEFORE EVERYTHING CLOSES BACK IN AROUND 03Z. LIGHT NORTH
WIND THROUGH FRIDAY MORNING. FELTON
&&
.MARINE...STRENGTHENING HIGH PRES EAST OF THE CASCADES WILL CONTINUE
THE LIGHT TO MODERATE OFFSHORE FLOW OVER WESTERN WASHINGTON.
KUIL-KBLI GRADIENT UP TO NEAR -5 MB AT 10Z. WILL EXTEND THE GALE AT
THE WEST ENTRANCE THROUGH THE AFTERNOON. SOME OF THE OTHER AREAS
ALONG THE COAST WITH GAPS IN THE COASTAL TERRAIN COULD SEE SOME
SLIGHTLY STRONGER WINDS...UP TO 20 KNOTS THROUGH TONIGHT. FOR THE
INTERIOR LIGHT NORTH WINDS THROUGH FRIDAY. LITTLE CHANGE IN THE
OVERALL PATTERN IS EXPECTED INTO THE EARLY PART OF NEXT WEEK. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...AIR STAGNATION ADVISORY FOR THE LOWLANDS OF WESTERN WASHINGTON
EXCEPT FOR THE COAST AND WESTERN STRAIT.
FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER
IN KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...GALE WARNING WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KSEW 151122
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
320 AM PST THU JAN 15 2009
.SYNOPSIS...A STRONG UPPER LEVEL RIDGE RIDGE WILL REMAIN OVER THE
PACIFIC NORTHWEST THROUGH THIS WEEKEND. A SURFACE RIDGE EAST OF THE
CASCADES WILL MAINTAIN OFFSHORE FLOW THROUGH THE PERIOD. THE RIDGE
WILL PRODUCE A WARM AND DRY AIR MASS ALOFT AND A VERY STRONG LOW
LEVEL INVERSION. AREAS OF LOW CLOUDS AND FOG WILL PERSIST OVER THE
LOWLANDS...WITH MOSTLY CLEAR AND MILD CONDITIONS FOR THE COAST AND
MOUNTAINS.
&&
.SHORT TERM...STRONG UPPER LEVEL RIDGING ALONG THE WEST COAST WILL
CONTINUE TO EXPAND AND SLOWLY SHIFT NORTHWARD INTO THE WEEKEND. A
STRONG LOW LEVEL INVERSION REMAINS IN PLACE ACROSS WESTERN
WASHINGTON THIS MORNING AND WILL BE THE MAIN PLAYER IN THE FORECAST
FOR THE NEXT THREE DAYS OR SO. SOME HIGH LEVEL MOISTURE SLIDING
THROUGH THE STRONG RIDGE IS OBSCURING FOG IMAGERY...BUT SURFACE OBS
ACROSS THE AREA SHOW SOLID STRATUS BLANKETING MUCH OF THE REGION.
THE KSEW PROFILER AND ACARS DATA SHOW TEMPERATURES IN THE 925-850 MB
LAYER HAVE WARMED CONSIDERABLY OVER THE PAST 24 HOURS...WITH
TEMPERATURES APPROACHING 60F NEAR 925MB. IN ADDITION...VERY DRY AIR
HAS MOVED IN ALOFT...14 PERCENT HUMIDITY AT HURRICANE RIDGE AT 2 AM.
THIS HAS SUPPRESSED THE STRATUS LAYER RESULTING IN THE LOWER
CEILINGS OBSERVED THIS MORNING. PROFILER DATA SEEMS TO SUGGEST THAT
TOPS OF THE STRATUS ARE IN THE NEIGHBORHOOD OF 1200-1500 FEET.
DESPITE OFFSHORE GRADIENTS...INTERIOR LOWLANDS WILL SEE LITTLE
BENEFIT WITH THE STRONG INVERSION IN PLACE. SOME LOWLAND LOCATIONS
MAY SEE SOME BRIEF CLEARING THE NEXT 2 OR 3 AFTERNOONS...BUT THE
MOUNTAINS AND COAST WILL BE THE PLACE TO SEE SOME SUN AND
UNSEASONABLY MILD TEMPERATURES. AIR STAGNATION WILL BE A PROBLEM
OVER THE INTERIOR AND AN ADVISORY FOR THIS REMAINS IN EFFECT THROUGH
SATURDAY.
.LONG TERM...THE EXTENDED MODELS CONTINUE TO SHOW A CHANGE IN THE
PATTERN EARLY NEXT WEEK AS THE RIDGE EVENTUALLY SHIFTS INTO THE
ROCKIES AND WEAKENS. THE EURO/GFS SEEM TO AGREE ON SOME SORT OF
SPLIT PATTERN DEVELOPING...BUT DISAGREE ON UPSTREAM DEVELOPMENTS
OVER THE NORTHEAST PACIFIC. I CERTAINLY WOULDNT PLACE ANY CONFIDENCE
ON EITHER SOLUTION THIS EARLY IN THE GAME. 27
&&
.AVIATION...A STRONG SUBSIDENCE INVERSION WILL REMAIN INTACT OVER
WESTERN WASHINGTON FOR THE NEXT 24 HOURS. SANDPOINT PROFILER SHOWS
THE INVERSION HAS NOT LOWERED MUCH IN THE LAST FEW HOURS WITH THE
BASE OF THE INVERSION STILL NEAR 1500 FEET. STRATUS DECK HAS SLOWLY
LOWERED OVERNIGHT WITH THE BASE OF THE DECK IN THE 500 TO 800 MSL
RANGE. VISIBILITIES BELOW A MILE SO FAR HAVE BEEN CONFINED TO KBLI.
HAZY CONDITIONS HERE AT SANDPOINT BUT VISIBILITIES STILL GOOD.
MODELS CONTINUE TO SHOW THE INVERSION LOWERING TODAY INTO TONIGHT
BUT WITH THE PROFILER OBS WILL BACK THE 1/4 MILE VISIBILITIES AT
KSEA BUT KEEP THEM AT THE HIGHEST TERMINAL...KPAE. LITTLE MIXING
TODAY AND TONIGHT. MODELS CONTINUE TO SHOW A BREAKOUT OF THE STRATUS
IN MOST PLACES TODAY BUT THE MODEL SOUNDINGS VERIFYING AT 09Z HAVE
THE BASE OF THE INVERSION IN THE 500 TO 1000 FOOT RANGE. WITH THE
MODELS A LITTLE AHEAD OF THE GAME WILL ALSO BACK OFF ON THE AMOUNT
OF SCATTERING OUT THIS AFTERNOON INTO THIS EVENING. THE EXCEPTION OT
ALL THIS WILL CONTINUE TO BE THE COAST WITH JUST SCATTERED CLOUDS AT
BEST FOR KHQM.
KSEA...CEILING AND VISIBILITIES HAVE BEEN SLOWLY LOWERING OVERNIGHT
AND THIS TREND WILL CONTINUE THIS MORNING. CEILINGS REMAINING BELOW
5000 FEET. WILL BACK OFF THE 1/4 MILE VISIBILITY WITH THE BASE OF
THE STRATUS REMAINING JUST OFF THE DECK AND INDICATE A TEMPO 1/2
MILE VISIBILITY MID MORNING TO EARLY AFTERNOON. SOME SLIGHT CLEARING
AROUND 00Z BEFORE EVERYTHING CLOSES BACK IN AROUND 03Z. LIGHT NORTH
WIND THROUGH FRIDAY MORNING. FELTON
&&
.MARINE...STRENGTHENING HIGH PRES EAST OF THE CASCADES WILL CONTINUE
THE LIGHT TO MODERATE OFFSHORE FLOW OVER WESTERN WASHINGTON.
KUIL-KBLI GRADIENT UP TO NEAR -5 MB AT 10Z. WILL EXTEND THE GALE AT
THE WEST ENTRANCE THROUGH THE AFTERNOON. SOME OF THE OTHER AREAS
ALONG THE COAST WITH GAPS IN THE COASTAL TERRAIN COULD SEE SOME
SLIGHTLY STRONGER WINDS...UP TO 20 KNOTS THROUGH TONIGHT. FOR THE
INTERIOR LIGHT NORTH WINDS THROUGH FRIDAY. LITTLE CHANGE IN THE
OVERALL PATTERN IS EXPECTED INTO THE EARLY PART OF NEXT WEEK. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...AIR STAGNATION ADVISORY FOR THE LOWLANDS OF WESTERN WASHINGTON
EXCEPT FOR THE COAST AND WESTERN STRAIT.
FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER
IN KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...GALE WARNING WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KPQR 151059 COR
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
258 AM PST THU JAN 15 2009
CORRECTED ADVISORIES
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE FLOW CONTINUE INTO FRIDAY WITH
THE MAIN EFFECT IS WINDS ACROSS THE CASCADE PASSES AND THROUGH THE
GORGE. EAST WINDS ARE ALREADY BECOMING QUITE GUSTY THROUGH
GORGE...AND SHOULD PUSH INTO TROUTDALE AND PORTLAND LATER TONIGHT AND
THURSDAY. THE DRY OFFSHORE FLOW IN THE HIGHER TERRAIN AND ALONG THE
COAST IS CAUSING UNSEASONABLY WARM AND DRY CONDITIONS THAT WILL
LIKELY CONTINUE INTO THE UPCOMING WEEKEND. MEANWHILE...THE CENTRAL
AND SOUTHERN WILLAMETTE VALLEY WILL LIKELY REMAIN UNDER A STRONG
INVERSION...WITH MUCH COOLER TEMPERATURES AND PERSISTENT FOG.
&&
.SHORT TERM...UNSEASONABLY STRONG UPPER LEVEL RIDGE CONTINUES TO
DOMINATE THE WEST COAST OF NORTH AMERICA...EXTENDING FROM SOUTHERN
CALIFORNIA TO THE SOUTHERN YUKON TERRITORY. STRONG SUBSIDENCE
ASSOCIATED WITH THE RIDGING IS LEADING TO VERY WARM AND DRY
CONDITIONS ALOFT...WITH 850 MB TEMPERATURES IN MID-TEENS DEG C ACROSS
MUCH OF WESTERN OREGON. TEMPERATURES ON WEDNESDAY IN THE HIGHER
TERRAIN SOARED INTO THE 50S AND 60S...WITH SOME RAWS SITES IN THE
CENTRAL OREGON COAST RANGE REACHING THE LOWER 70S. MEANWHILE...A
STRONG INVERSION KEPT COOLER AIR ACROSS WILLAMETTE VALLEY, THIS
PATTERN WILL CONTINUE FOR AT LEAST THE NEXT SEVERAL DAYS.
THE INVERSION IS EVEN SHALLOWER THU WITH FOG AND LOW CLOUDS OVER MOST
OF THE AREA WITH AREAS OF DENSE FOG THROUGH OUT THE LOWLANDS. AT THE
SAME TIME THE OFFSHORE FLOW THROUGH THE GORGE HAS BEEN INCREASING. AT
2 AM THE PRESSURE GRADIENT FROM TROUTDALE TO THE DALLES WAS -7.8 MB.
BUT WINDS AREA GENERALLY IN THE 10 TO 20 MPH RANGE IN THE WESTERN
PART OF THE GORGE...BUT IN CORBETT - A FAVORITE EAST WIND LOCATION -
HAS BEEN GUSTING TO AROUND 40 MPH. EVENTUALLY THE EAST WINDS WILL
REACH KTTD/KPDX...BUT IT MAY TAKE A WHILE DUE TO THE STRONG
INVERSION.
THE INVERSION AND TIMING OF FOG DEVELOPMENT/CLEARING WILL MAKE
TEMPERATURE FORECASTS QUITE CHALLENGING IN THE VALLEYS THE NEXT
COUPLE DAYS. NEAR KEUG...THE FOG/LOW CLOUDS ARE LIKELY TO HANG IN THE
LONGEST. AROUND THE PORTLAND METRO AREA...MOS GUIDANCE VARIES WILDLY
BETWEEN MID 40S AND UPPER 50S FOR HIGHS THE NEXT COUPLE DAYS.
HOWEVER...WITH A GOOD DEAL OF SUNSHINE AFTER EXPECTED BREAKOUT OF
FOG...HIGHS AROUND 50 DEGREES EACH DAY APPEAR REASONABLE.
MEANWHILE...THE COAST AND HIGHER TERRAIN WILL BE PUSHING INTO THE
UPPER 50S AND 60S EACH DAY...EXCEPT FOR THE HIGHER CASCADE PEAKS AND
SNOW COVERED AREAS SHELTERED FROM THE SUN. WEAGLE
&&
.LONG TERM...GFS...ECMWF AND CANADIAN ALL INDICATING THE UPPER RIDGE
TO BEGIN SHIFTING E AROUND SUNDAY...BUT THE DETAILS OF WHAT IS TO
FOLLOW REMAIN UP IN THE AIR. GIVEN CURRENT MODEL SOLUTIONS...WILL
STICK WITH A DRY FORECAST THROUGH MON...THEN TREND TOWARDS
CLIMATOLOGY POPS TUE TO WED. TEMPERATURES WILL MODERATE TOWARDS A
MORE EVENLY DISTRIBUTED MARITIME PATTERN...COOLER FOR THE MOUNTAINS
AND A BIT WARMER FOR THE VALLEYS.
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
CONTINUE ACROSS THE REGION WILL MAINTAIN A STRONG INVERSION BELOW
1500 FT...TRAPPING MOISTURE IN THE INLAND VALLEYS. AN EXTENSIVE AREA
OF IFR/LIFR CONDITIONS IN FOG AND LOW STRATUS IS EXPECTED TO
CONTINUE IN VALLEY LOCATIONS THROUGH TONIGHT...WITH LITTLE IF ANY
AFTERNOON IMPROVEMENT EXPECTED. ELSEWHERE...VFR CONDITIONS WILL
PREVAIL.
KPDX AND APPROACHES...IFR/LIFR CONDITIONS EXPECTED UNTIL AROUND
20Z...THEN VFR CONDITIONS SHOULD DEVELOP AS EASTERLY GORGE WINDS
ERODE THE FOG LAYER.
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER OVER THE
COASTAL WATERS...RESULTING IN LIGHT WINDS AND SEAS IN THE 3 TO
4 FOOT RANGE THROUGH TONIGHT. SWELL WILL INCREASE TO THE 9 TO 10
FOOT RANGE FRI AND SAT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY THROUGH SAT FOR THE LOWER INTERIOR
VALLEYS OF NW OREGON AND SW WA.
DENSE FOG ADVISORY THROUGH 10 AM THU FOR THE WILLAMETTE
VALLEY...CLARK COUNTY...LOWER COLUMBIA AND I-5 CORRIDOR
IN COWLITZ COUNTY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KPQR 151059 COR
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
258 AM PST THU JAN 15 2009
CORRECTED ADVISORIES
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE FLOW CONTINUE INTO FRIDAY WITH
THE MAIN EFFECT IS WINDS ACROSS THE CASCADE PASSES AND THROUGH THE
GORGE. EAST WINDS ARE ALREADY BECOMING QUITE GUSTY THROUGH
GORGE...AND SHOULD PUSH INTO TROUTDALE AND PORTLAND LATER TONIGHT AND
THURSDAY. THE DRY OFFSHORE FLOW IN THE HIGHER TERRAIN AND ALONG THE
COAST IS CAUSING UNSEASONABLY WARM AND DRY CONDITIONS THAT WILL
LIKELY CONTINUE INTO THE UPCOMING WEEKEND. MEANWHILE...THE CENTRAL
AND SOUTHERN WILLAMETTE VALLEY WILL LIKELY REMAIN UNDER A STRONG
INVERSION...WITH MUCH COOLER TEMPERATURES AND PERSISTENT FOG.
&&
.SHORT TERM...UNSEASONABLY STRONG UPPER LEVEL RIDGE CONTINUES TO
DOMINATE THE WEST COAST OF NORTH AMERICA...EXTENDING FROM SOUTHERN
CALIFORNIA TO THE SOUTHERN YUKON TERRITORY. STRONG SUBSIDENCE
ASSOCIATED WITH THE RIDGING IS LEADING TO VERY WARM AND DRY
CONDITIONS ALOFT...WITH 850 MB TEMPERATURES IN MID-TEENS DEG C ACROSS
MUCH OF WESTERN OREGON. TEMPERATURES ON WEDNESDAY IN THE HIGHER
TERRAIN SOARED INTO THE 50S AND 60S...WITH SOME RAWS SITES IN THE
CENTRAL OREGON COAST RANGE REACHING THE LOWER 70S. MEANWHILE...A
STRONG INVERSION KEPT COOLER AIR ACROSS WILLAMETTE VALLEY, THIS
PATTERN WILL CONTINUE FOR AT LEAST THE NEXT SEVERAL DAYS.
THE INVERSION IS EVEN SHALLOWER THU WITH FOG AND LOW CLOUDS OVER MOST
OF THE AREA WITH AREAS OF DENSE FOG THROUGH OUT THE LOWLANDS. AT THE
SAME TIME THE OFFSHORE FLOW THROUGH THE GORGE HAS BEEN INCREASING. AT
2 AM THE PRESSURE GRADIENT FROM TROUTDALE TO THE DALLES WAS -7.8 MB.
BUT WINDS AREA GENERALLY IN THE 10 TO 20 MPH RANGE IN THE WESTERN
PART OF THE GORGE...BUT IN CORBETT - A FAVORITE EAST WIND LOCATION -
HAS BEEN GUSTING TO AROUND 40 MPH. EVENTUALLY THE EAST WINDS WILL
REACH KTTD/KPDX...BUT IT MAY TAKE A WHILE DUE TO THE STRONG
INVERSION.
THE INVERSION AND TIMING OF FOG DEVELOPMENT/CLEARING WILL MAKE
TEMPERATURE FORECASTS QUITE CHALLENGING IN THE VALLEYS THE NEXT
COUPLE DAYS. NEAR KEUG...THE FOG/LOW CLOUDS ARE LIKELY TO HANG IN THE
LONGEST. AROUND THE PORTLAND METRO AREA...MOS GUIDANCE VARIES WILDLY
BETWEEN MID 40S AND UPPER 50S FOR HIGHS THE NEXT COUPLE DAYS.
HOWEVER...WITH A GOOD DEAL OF SUNSHINE AFTER EXPECTED BREAKOUT OF
FOG...HIGHS AROUND 50 DEGREES EACH DAY APPEAR REASONABLE.
MEANWHILE...THE COAST AND HIGHER TERRAIN WILL BE PUSHING INTO THE
UPPER 50S AND 60S EACH DAY...EXCEPT FOR THE HIGHER CASCADE PEAKS AND
SNOW COVERED AREAS SHELTERED FROM THE SUN. WEAGLE
&&
.LONG TERM...GFS...ECMWF AND CANADIAN ALL INDICATING THE UPPER RIDGE
TO BEGIN SHIFTING E AROUND SUNDAY...BUT THE DETAILS OF WHAT IS TO
FOLLOW REMAIN UP IN THE AIR. GIVEN CURRENT MODEL SOLUTIONS...WILL
STICK WITH A DRY FORECAST THROUGH MON...THEN TREND TOWARDS
CLIMATOLOGY POPS TUE TO WED. TEMPERATURES WILL MODERATE TOWARDS A
MORE EVENLY DISTRIBUTED MARITIME PATTERN...COOLER FOR THE MOUNTAINS
AND A BIT WARMER FOR THE VALLEYS.
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
CONTINUE ACROSS THE REGION WILL MAINTAIN A STRONG INVERSION BELOW
1500 FT...TRAPPING MOISTURE IN THE INLAND VALLEYS. AN EXTENSIVE AREA
OF IFR/LIFR CONDITIONS IN FOG AND LOW STRATUS IS EXPECTED TO
CONTINUE IN VALLEY LOCATIONS THROUGH TONIGHT...WITH LITTLE IF ANY
AFTERNOON IMPROVEMENT EXPECTED. ELSEWHERE...VFR CONDITIONS WILL
PREVAIL.
KPDX AND APPROACHES...IFR/LIFR CONDITIONS EXPECTED UNTIL AROUND
20Z...THEN VFR CONDITIONS SHOULD DEVELOP AS EASTERLY GORGE WINDS
ERODE THE FOG LAYER.
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER OVER THE
COASTAL WATERS...RESULTING IN LIGHT WINDS AND SEAS IN THE 3 TO
4 FOOT RANGE THROUGH TONIGHT. SWELL WILL INCREASE TO THE 9 TO 10
FOOT RANGE FRI AND SAT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY THROUGH SAT FOR THE LOWER INTERIOR
VALLEYS OF NW OREGON AND SW WA.
DENSE FOG ADVISORY THROUGH 10 AM THU FOR THE WILLAMETTE
VALLEY...CLARK COUNTY...LOWER COLUMBIA AND I-5 CORRIDOR
IN COWLITZ COUNTY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KPQR 151030
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
229 AM PST THU JAN 15 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE FLOW CONTINUE INTO FRIDAY WITH
THE MAIN EFFECT IS WINDS ACROSS THE CASCADE PASSES AND THROUGH THE
GORGE. EAST WINDS ARE ALREADY BECOMING QUITE GUSTY THROUGH
GORGE...AND SHOULD PUSH INTO TROUTDALE AND PORTLAND LATER TONIGHT AND
THURSDAY. THE DRY OFFSHORE FLOW IN THE HIGHER TERRAIN AND ALONG THE
COAST IS CAUSING UNSEASONABLY WARM AND DRY CONDITIONS THAT WILL
LIKELY CONTINUE INTO THE UPCOMING WEEKEND. MEANWHILE...THE CENTRAL
AND SOUTHERN WILLAMETTE VALLEY WILL LIKELY REMAIN UNDER A STRONG
INVERSION...WITH MUCH COOLER TEMPERATURES AND PERSISTENT FOG.
&&
.SHORT TERM...UNSEASONABLY STRONG UPPER LEVEL RIDGE CONTINUES TO
DOMINATE THE WEST COAST OF NORTH AMERICA...EXTENDING FROM SOUTHERN
CALIFORNIA TO THE SOUTHERN YUKON TERRITORY. STRONG SUBSIDENCE
ASSOCIATED WITH THE RIDGING IS LEADING TO VERY WARM AND DRY
CONDITIONS ALOFT...WITH 850 MB TEMPERATURES IN MID-TEENS DEG C ACROSS
MUCH OF WESTERN OREGON. TEMPERATURES ON WEDNESDAY IN THE HIGHER
TERRAIN SOARED INTO THE 50S AND 60S...WITH SOME RAWS SITES IN THE
CENTRAL OREGON COAST RANGE REACHING THE LOWER 70S. MEANWHILE...A
STRONG INVERSION KEPT COOLER AIR ACROSS WILLAMETTE VALLEY, THIS
PATTERN WILL CONTINUE FOR AT LEAST THE NEXT SEVERAL DAYS.
THE INVERSION IS EVEN SHALLOWER THU WITH FOG AND LOW CLOUDS OVER MOST
OF THE AREA WITH AREAS OF DENSE FOG THROUGH OUT THE LOWLANDS. AT THE
SAME TIME THE OFFSHORE FLOW THROUGH THE GORGE HAS BEEN INCREASING. AT
2 AM THE PRESSURE GRADIENT FROM TROUTDALE TO THE DALLES WAS -7.8 MB.
BUT WINDS AREA GENERALLY IN THE 10 TO 20 MPH RANGE IN THE WESTERN
PART OF THE GORGE...BUT IN CORBETT - A FAVORITE EAST WIND LOCATION -
HAS BEEN GUSTING TO AROUND 40 MPH. EVENTUALLY THE EAST WINDS WILL
REACH KTTD/KPDX...BUT IT MAY TAKE A WHILE DUE TO THE STRONG
INVERSION.
THE INVERSION AND TIMING OF FOG DEVELOPMENT/CLEARING WILL MAKE
TEMPERATURE FORECASTS QUITE CHALLENGING IN THE VALLEYS THE NEXT
COUPLE DAYS. NEAR KEUG...THE FOG/LOW CLOUDS ARE LIKELY TO HANG IN THE
LONGEST. AROUND THE PORTLAND METRO AREA...MOS GUIDANCE VARIES WILDLY
BETWEEN MID 40S AND UPPER 50S FOR HIGHS THE NEXT COUPLE DAYS.
HOWEVER...WITH A GOOD DEAL OF SUNSHINE AFTER EXPECTED BREAKOUT OF
FOG...HIGHS AROUND 50 DEGREES EACH DAY APPEAR REASONABLE.
MEANWHILE...THE COAST AND HIGHER TERRAIN WILL BE PUSHING INTO THE
UPPER 50S AND 60S EACH DAY...EXCEPT FOR THE HIGHER CASCADE PEAKS AND
SNOW COVERED AREAS SHELTERED FROM THE SUN. WEAGLE
&&
.LONG TERM...GFS...ECMWF AND CANADIAN ALL INDICATING THE UPPER RIDGE
TO BEGIN SHIFTING E AROUND SUNDAY...BUT THE DETAILS OF WHAT IS TO
FOLLOW REMAIN UP IN THE AIR. GIVEN CURRENT MODEL SOLUTIONS...WILL
STICK WITH A DRY FORECAST THROUGH MON...THEN TREND TOWARDS
CLIMATOLOGY POPS TUE TO WED. TEMPERATURES WILL MODERATE TOWARDS A
MORE EVENLY DISTRIBUTED MARITIME PATTERN...COOLER FOR THE MOUNTAINS
AND A BIT WARMER FOR THE VALLEYS.
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
CONTINUE ACROSS THE REGION WILL MAINTAIN A STRONG INVERSION BELOW
1500 FT...TRAPPING MOISTURE IN THE INLAND VALLEYS. AN EXTENSIVE AREA
OF IFR/LIFR CONDITIONS IN FOG AND LOW STRATUS IS EXPECTED TO
CONTINUE IN VALLEY LOCATIONS THROUGH TONIGHT...WITH LITTLE IF ANY
AFTERNOON IMPROVEMENT EXPECTED. ELSEWHERE...VFR CONDITIONS WILL
PREVAIL.
KPDX AND APPROACHES...IFR/LIFR CONDITIONS EXPECTED UNTIL AROUND
20Z...THEN VFR CONDITIONS SHOULD DEVELOP AS EASTERLY GORGE WINDS
ERODE THE FOG LAYER.
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER OVER THE
COASTAL WATERS...RESULTING IN LIGHT WINDS AND SEAS IN THE 3 TO
4 FOOT RANGE THROUGH TONIGHT. SWELL WILL INCREASE TO THE 9 TO 10
FOOT RANGE FRI AND SAT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY THROUGH SAT FOR THE LOWER INTERIOR
VALLEYS OF NW OREGON AND SW WA.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 151019
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
219 AM PST THU JAN 15 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
TODAY AND TONIGHT...LATEST MODELS ARE SIMILAR AND IN GOOD
AGREEMENT WITH SATELLITE EXTRAPOLATION. THE STRONG UPPER LEVEL
RIDGE JUST OFF THE COAST WILL SHIFT INTO THE REGION AND BECOME
WELL ESTABLISHED DURING THE NEXT 24 HOURS. WHILE WEAK SLUGS OF
UPPER LEVEL MOISTURE AND EVEN A MODERATE SHORT WAVE WILL CREST THE
RIDGE TODAY AND TONIGHT...NOTHING HAPPENING ALOFT WILL BE ABLE TO
SHAKE LOOSE THE INVERSION LID ON THE LOW LEVEL BOUNDARY LAYER.
INVERSION WILL STRENGTHEN TODAY AND TONIGHT WITH GENERALLY STATIC
CONDITIONS BELOW 4000 FEET FEATURING CONTINUED WIDESPREAD FOG AND
STRATUS WITH LITTLE DIURNAL CHANGE TO TEMPERATURES. ONLY MARGINAL
CONFIDENCE IN ANY SORT OF OBVIOUS AFTERNOON BREAK OUT
ANYWHERE...WITH BEST CHANCE OF BRIEF FOG LIFT AND STRATUS BREAK UP
SOUTH OF INTERSTATE 90 IN THE DEEP BASIN TODAY...FOLLOWED BY A
RETURN TO THE MURK AFTER DARK TONIGHT. ONLY THE PALOUSE WHERE WEAK
DOWNSLOPING WILL KEEP PULLMAN DRY AND ESSENTIALLY CLEAR...AND THE
ELEVATIONS ABOVE THE INVERSION LAYER WILL EXPERIENCE ANY SUNSHINE
TODAY. CURRENT DENSE FOG AND AIR STAGNATION HIGHLIGHTS REMAIN
VALID. /FUGAZZI
FRIDAY THROUGH MONDAY...THE UNSEASONABLY WARM 588 DAM HIGH
PRESSURE SYSTEM WILL REMAIN DOMINATE OVER THE NORTHWEST.
GFS/EURO/NAM ARE PICKING UP ON A SHORTWAVE CURRENTLY AT 140W
ROUNDING THE RIDGE ON FRIDAY WITH THE HEART OF ITS ENERGY DROPPING
WELL EAST THROUGH THE DAKOTAS. AS THE WAVE PASSES THE EAST...THE
RIDGE AXIS PUSHES INLAND AND THE EMBEDDED CLOSED 588 DAM HIGH WILL
WOBBLE TO EAST/NORTHEAST OVER THE CWA. A WEAK SOUTHERN BRANCH OF
THE SHORTWAVE IS EXPECTED TO PEEL OFF FROM THE MAIN SHORTWAVE
SNEAKING UNDER THE CLOSED HIGH OVER EASTERN WA ON SATURDAY. THIS
WILL CONTINUE TO FOLLOW A CIRCULAR PATH THROUGH CENTRAL
IDAHO...OREGON...AND BACK NORTH THROUGH WESTERN WA ON SUNDAY. ALL
GUIDANCE APPEARS TO PICK UP ON THIS FEATURE BUT DO SHOW SOME
DIFFERENCES IN THE STRENGTH AND EXACT TRACK. WITH SUCH DRY AIR IN
PLACE...WE DO NOT EXPECT ANYMORE THAN SCATTERED HIGH CLOUDS. THE
ONE IMPACT I WANTED TO FOCUS ON IS NOTED BY ALL GUIDANCE IN THE
850MB WINDS. AS THE MAIN SHORTWAVE TRACKS DOWN ALONG THE SPINE OF
THE DIVIDE FRIDAY MORNING.. THERE IS A SHORT-LIVED MID LEVEL W/SW
PRESSURE GRADIENT AT THE 850MB SURFACE...THEN AS THE RIPPLE EJECTS
AND CIRCLES TO THE SOUTH...WE SEE 850MB FLOW WEAKLY FOLLOW SUITE.
WITH STRONG LOW- LEVEL INVERSION ACROSS THE LOWER-
ELEVATIONS...THIS WILL HAVE NO IMPACT. NAM12/GFS DO SHOW 10-15KTS
W/SW ROUGHLY AT 4-5K FT WHICH WOULD BE ALONG THE BLUE MTS FRIDAY
MORNING INTO THE AFTERNOON WHICH MAY PLAY A ROLE IN POTENTIAL
MIXING WARMER TEMPERATURES DOWN FOR SURROUNDING FOOTHILLS. AS THE
WAVE PASSES TO THE SOUTH AND WEST SATURDAY AFTERNOON/SUNDAY... THE
WINDS TREND NNE/E WITH LITTLE NO EFFECTS.
TUESDAY...GLOBAL MODEL SOLUTIONS APPEAR TO HAVE COME IN
SOMEWHAT BETTER AGREEMENT THAT THE RIDGE AXIS WILL TRACK EAST
ACROSS THE DIVIDE AS A POTENT SHORTWAVE APPROACHES THE COAST. IN
ADDITION...AS THE SHORTWAVE RUNS INTO THE RIDGE...THE WAVE WILL
WEAKEN...AND SPLIT. CONFIDENCE REALLY GOES DOWN TRYING TO FIGURE
OUT THE DETAILS WITH PART OF THE FORECAST. THE GFS AND ITS
ENSEMBLE MEMBERS ARE MUCH MORE PROGRESSIVE WITH THE WAVE CROSSING
INTO THE NORTHWEST BEFORE THE SOUTHERN FLANK BRANCHES OFF AND
RETROGRADES TO THE S/SW. THIS WOULD BRING CHANCE FOR PRECIPITATION
WITH THE PASSAGE OF A STRONGER COLD FRONT. THE EUROPEAN AND ITS
ENSEMBLE MEMBERS HAVE BEEN SLIGHTLY MORE CONSISTENT AND INDICATE
THE WAVE WILL SPLIT BEFORE REACHING THE COAST PUTTING OUR CWA INTO
A COL CREATING A MUCH WARMER AND STAGNANT EXTENDING INTO TUESDAY.
WEDNESDAY AND THURSDAY...THERE IS DECENT AGREEMENT WITH THE
00Z FORECAST PACKAGES THAT HIGH PRESSURE WILL QUICKLY REBUILD OUT
BETWEEN 130-140W BEHIND WHAT EVER BECOMES OF TUESDAYS WAVE. THIS
WILL STEER A COOLER CANADIAN AIRMASS THROUGH THE CWA BRINGING
SLIGHT CHANCE FOR PRECIPITATION AND COOLER
TEMPERATURES...ESPECIALLY FOR THE MTNS. /BODNAR
&&
.AVIATION...
A STRONG RIDGE OF HIGH PRESSURE WILL KEEP A NEAR PERSISTENT
PATTERN THROUGH 06Z/16TH. THIS MEANS VLIFR CONDITIONS WITH DENSE
FOG PERSISTING AT KGEG. VLIFR CONDITIONS WILL ALSO LIKELY PERSIST
THROUGH 18-20Z TOMORROW AT KEAT/KSFF/KCOE BUT OCCASIONAL IMPROVEMENT
TO LIFR IS POSSIBLE IF CLOUD LAYER BRIEFLY LIFTS ABOVE THE SURFACE.
CLEARING THIS EVENING AT KMWH MAY LEAD TO THE DEVELOPMENT OF DENSE
FOG AROUND 06Z. FOR KLWS...SLIGHTLY BETTER CONDITIONS EXPECTED
WITH STRATUS LAYER JUST ABOVE THE TERMINAL. AND FOR KPUW...FOG MAY
APPROACH THE TERMINAL BTWN 09Z-18Z SO WILL KEEP VCFG IN TAF. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 31 30 31 28 31 28 / 0 0 0 0 0 0
COEUR D`ALENE 32 29 32 27 32 28 / 0 0 0 0 0 0
PULLMAN 43 32 41 30 39 33 / 0 0 0 0 0 0
LEWISTON 38 32 37 31 38 33 / 0 0 0 0 0 0
COLVILLE 34 28 34 29 33 24 / 0 0 0 0 0 0
SANDPOINT 34 27 34 31 32 26 / 0 0 0 0 0 0
KELLOGG 40 30 36 28 33 29 / 0 0 0 0 0 0
MOSES LAKE 35 31 36 28 35 28 / 0 0 0 0 0 0
WENATCHEE 33 29 32 28 33 30 / 0 0 0 0 0 0
OMAK 30 29 30 27 30 28 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL NOON PST TODAY FOR COEUR D`ALENE AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL NOON PST TODAY FOR MOSES LAKE AREA...
SPOKANE AREA...UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KOTX 150625
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1025 PM PST WED JAN 14 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
THE DENSE FOG ADVISORY HAS BEEN EXPANDED TO INCLUDE THE MOSES LAKE
AREA. CAMERAS SHOW FOG AT WARDEN WITH VISIBILITY AS MOSES LAKE AT
10 PM DOWN TO A QUARTER MILE. WITH BREAKS IN THE STRATUS STILL
PRESENT NORTH OF MOSES LAKE AROUND EPHRATA ADDITIONAL DENSE FOG
WILL LIKELY FORM THROUGH THE OVERNIGHT HOURS INTO THURSDAY
MORNING. OTHERWISE CURRENT FORECAST GRIDS AND TEXT PRODUCTS LOOK
IN GOOD SHAPE. JW
&&
.AVIATION...
A STRONG RIDGE OF HIGH PRESSURE WILL KEEP A NEAR PERSISTENT
PATTERN THROUGH 06Z/16TH. THIS MEANS VLIFR CONDITIONS WITH DENSE
FOG PERSISTING AT KGEG. VLIFR CONDITIONS WILL ALSO LIKELY PERSIST
THROUGH 18-20Z TOMORROW AT KEAT/KSFF/KCOE BUT OCCASIONAL IMPROVEMENT
TO LIFR IS POSSIBLE IF CLOUD LAYER BRIEFLY LIFTS ABOVE THE SURFACE.
CLEARING THIS EVENING AT KMWH MAY LEAD TO THE DEVELOPMENT OF DENSE
FOG AROUND 06Z. FOR KLWS...SLIGHTLY BETTER CONDITIONS EXPECTED
WITH STRATUS LAYER JUST ABOVE THE TERMINAL. AND FOR KPUW...FOG MAY
APPROACH THE TERMINAL BTWN 09Z-18Z SO WILL KEEP VCFG IN TAF. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 27 31 30 35 29 36 / 0 0 0 0 0 0
COEUR D`ALENE 27 31 29 38 30 37 / 0 0 0 0 0 0
PULLMAN 29 42 30 39 33 40 / 0 0 0 0 0 0
LEWISTON 32 38 32 38 34 39 / 0 0 0 0 0 0
COLVILLE 28 33 28 34 25 33 / 0 0 0 0 0 0
SANDPOINT 29 32 27 34 27 35 / 0 0 0 0 0 0
KELLOGG 28 40 30 36 30 36 / 0 0 0 0 0 0
MOSES LAKE 24 35 31 36 31 37 / 0 0 0 0 0 0
WENATCHEE 28 32 29 36 30 37 / 0 0 0 0 0 0
OMAK 26 30 29 32 30 34 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR COEUR D`ALENE
AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR MOSES LAKE
AREA...SPOKANE AREA...UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KSEW 150458
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST WED JAN 14 2009
.SYNOPSIS...A STRONG UPPER LEVEL RIDGE RIDGE WILL REMAIN PARKED OVER
THE PACIFIC NORTHWEST THROUGH THIS WEEKEND. A SURFACE RIDGE EAST OF
THE CASCADES WILL MAINTAIN OFFSHORE FLOW THROUGH THE PERIOD. THE
RIDGE WILL PRODUCE A WARM AND DRY AIR MASS ALOFT AND A VERY STRONG
LOW LEVEL INVERSION...MAKING THE AIR MASS STAGNANT AND COOL NEAR THE
SURFACE AND ALLOWING AREAS OF LOW CLOUDS AND FOG TO PERSIST OVER THE
LOWLANDS. MUCH OF THE PUGET SOUND BASIN AND ALL ALONG THE I-5
CORRIDOR WILL SEE STAGNANT AIR THROUGH SATURDAY.
&&
.SHORT TERM...THE STRONG UPPER LEVEL RIDGE WILL REMAIN PARKED OVER
THE PACIFIC NORTHWEST THROUGH THE WEEKEND. AIR STAGNATION IS THE
MAIN PROBLEM AND AN ADVISORY FOR THIS REMAINS IN EFFECT THROUGH
SATURDAY. MAIN FORECAST PROBLEMS WILL BE COVERAGE OF LOW CLOUDS AND
FOG AND TEMPERATURE RANGES IN THE FOGGY AREAS VS THE SUNNY AREAS.
THE STRONG UPPER LEVEL RIDGE HAS PRODUCED A MASSIVE LOW LEVEL
INVERSION OVER THE AREA WHICH IS CREATING THE STAGNANT CONDITIONS.
OFFSHORE FLOW ISN`T STRONG ENOUGH TO PRODUCE MUCH IN THE WAY OF
VENTILATION. MODELS SHOW THE INVERSION SLOWLY LOWERING TO THE
SURFACE OVERNIGHT...AND THE NAM BOUNDARY LAYER RH AND SOUNDINGS BOTH
SHOW THE LOW LEVEL RH DECREASING THURSDAY AFTERNOON...IMPLYING
CLEARING. GFSLAMP AND NAM-MOS AVIATION GUIDANCE ALSO SHOWS THIS.
CURRENT CONDITIONS SHOW THE CIGS AND VIS LOWERING AT MANY
STATIONS...WHICH INDICATES THE INVERSION IS LOWERING. CURRENT
FORECASTS MAINTAIN AREAS OF FOG AROUND PUGET SOUND THURSDAY
AFTERNOON WHICH IS PESSIMISTIC COMPARED TO THE MODEL FORECASTS...BUT
FREQUENTLY CORRECT IN THIS TYPE OF REGIME. NOT ENOUGH CONFIDENCE IN
THE MODELS AT THIS POINT TO UPDATE THE FORECAST SO WILL LET THE
MIDSHIFT TAKE THEIR HACKS ON THE REGULAR MORNING PACKAGE. IF IT DOES
CLEAR OUT...MAX TEMPS WILL BE A GOOD BIT WARMER THAN TODAY...46 AT
KSEA PER GFSLAMP AND GFS...AND 51 PER NAM-MOS. KAM
.LONG TERM...BOTH GFS/ECMWF INDICATE A CHANGE IN THE PATTERN EARLY
NEXT WEEK. GFS BRINGS A WEAK UPPER LEVEL TROUGH OVER THE AREA LATE
TUESDAY BEFORE BUILDING ANOTHER BIG RIDGE A LITTLE FURTHER OFFSHORE.
ECMWF KEEPS THE THE AREA DRY...BUT DEVELOPS SOME SORT OF SPLIT FLOW
PATTERN. GFS SEEMS MORE REASONABLE AT THIS POINT...BUT THIS IS MUCH
TOO FAR OUT IN THE FUTURE FOR ANY SORT OF CONFIDENCE. KAM
&&
.AVIATION...A STRONG SUBSIDENCE INVERSION WILL REMAIN INTACT OVER
WESTERN WASHINGTON FOR THE NEXT 24 HOURS. SANDPOINT PROFILER SHOWS
THE INVERSION LOWERING WITH THE BASE OF THE INVERSION NOW DOWN TO
AROUND 1500 FEET AND THIS CORRESPONDS WELL TO THE CLOUD TOP REPORTS
OUT OF KSEA AND KBFI THIS EVENING. THE INVERSION WILL CONTINUE TO
SLOWLY LOWER THROUGH THURSDAY WHICH WILL RESULT IN A THINNER LAYER
OF LOW LEVEL MOISTURE TRAPPED NEAR THE SURFACE. THIS WILL INCREASE
THE CHANCES FOR BREAKOUT THURSDAY AFTERNOON ESPECIALLY AT THE HIGHER
TERMINALS...KSEA AND KPAE. ON THE FLIP SIDE IT ALSO MEANS THAT
OVERNIGHT THE CEILINGS WILL SLOWLY LOWER PUTTING THE HIGHER
TERMINALS IN THE MIDDLE OF THE CLOUDS. WILL PUT BOTH KPAE AND KSEA
VISIBILITIES DOWN BELOW A HALF MILE IN FOG BY THURSDAY MORNING WITH
THE LOWER INTERIOR TERMINALS IN GENERAL AROUND OVC005 WITH POSSIBLE
VISIBILITIES 3-5SM IN FOG. EXPECT BREAKOUT FOR ALL THE INTERIOR
TERMINALS DURING THE AFTERNOON HOURS BUT WITH THE INVERSION INTACT
EXPECT FOG TO REFORM THURSDAY EVENING. THE EXCEPTION TO ALL THIS
WILL BE KHQM WHERE THERE IS ENOUGH MIXING TO KEEP SKIES CLEAR
THROUGH THURSDAY.
KSEA...SANDPOINT PROFILER TELLS THE STORY WITH THE TREND OF THE
INVERSION LOWERING. THIS WILL CONTINUE INTO THURSDAY MORNING.
CEILINGS AT KRNT ALREADY DOWN TO 500 FEET SO ITS SHOULD BE JUST A
MATTER OF TIME BEFORE THE CEILINGS LOWER DOWN TO THE DECK AT KSEA.
WILL STAY WITH THE CURRENT TIMING OF 1/4 MILE VISIBILITIES BEGINNING
AT 13Z. THE CLOUD LAYER CURRENTLY IS LESS THAN 1000 FEET THICK AND
WITH THE INVERSION LOWERING DURING THE DAY ON THURSDAY THE LAYER
SHOULD THIN OUT ENOUGH TO ALLOW KSEA TO BREAK OUT INTO THE SUNSHINE
IN THE EARLY AFTERNOON. FELTON
&&
.MARINE...STRENGTHENING HIGH PRES EAST OF THE CASCADES WILL CONTINUE
THE LIGHT TO MODERATE OFFSHORE FLOW OVER WESTERN WASHINGTON.
KUIL-KBLI GRADIENTS HANGING AROUND -4 TO -4.5 MB OVERNIGHT INTO
THURSDAY MORNING. WILL GO AHEAD AND UPGRADE THE SMALL CRAFT ADVISORY
TO A GALE WARNING THERE UNTIL MIDDAY THURSDAY. SOME OF THE OTHER
AREAS ALONG THE COAST WITH GAPS IN THE COASTAL TERRAIN COULD SEE
SOME SLIGHTLY STRONGER WINDS...UP TO 20 KNOTS THROUGH THURSDAY. FOR
THE INTERIOR NORTH WINDS TO 10 KNOTS WILL SLOWLY DIMINISH TONIGHT
INTO THURSDAY. LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED
THROUGH THE WEEKEND. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...AIR STAGNATION ADVISORY FOR THE LOWLANDS OF WESTERN WASHINGTON
EXCEPT FOR THE COAST AND WESTERN STRAIT.
FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER
IN KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...GALE WARNING WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KPQR 150445
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
844 PM PST WED JAN 14 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE FLOW WILL INCREASE TONIGHT AND
THURSDAY...EXCEPT IN WIND SHELTERED VALLEYS. EAST WINDS ARE ALREADY
BECOMING QUITE GUSTY THROUGH GORGE...AND SHOULD PUSH INTO TROUTDALE
AND PORTLAND LATER TONIGHT AND THURSDAY. THE DRY OFFSHORE FLOW IN THE
HIGHER TERRAIN AND ALONG THE COAST IS CAUSING UNSEASONABLY WARM AND
DRY CONDITIONS THAT WILL LIKELY CONTINUE INTO THE UPCOMING WEEKEND.
MEANWHILE...THE CENTRAL AND SOUTHERN WILLAMETTE VALLEY WILL LIKELY
REMAIN UNDER A STRONG INVERSION...WITH MUCH COOLER TEMPERATURES AND
PERSISTENT FOG.
&&
.SHORT TERM...THE WEATHER STORY REMAINS A TALE OF TWO DISTINCT
WEATHER REGIMES ACROSS THE DISTRICT. AN UNSEASONABLY STRONG UPPER
LEVEL RIDGE CONTINUES TO DOMINATE THE WEST COAST OF NORTH
AMERICA...EXTENDING FROM SOUTHERN CALIFORNIA TO THE SOUTHERN YUKON
TERRITORY. STRONG SUBSIDENCE ASSOCIATED WITH THE RIDGING IS LEADING
TO VERY WARM AND DRY CONDITIONS ALOFT...WITH 850 MB TEMPERATURES IN
MID-TEENS DEG C ACROSS MUCH OF WESTERN OREGON. AS A RESULT...
TEMPERATURES IN THE HIGHER TERRAIN SOARED INTO THE 50S AND 60S
TODAY...WITH SOME RAWS SITES IN THE CENTRAL OREGON COAST RANGE
REACHING THE LOWER 70S. MEANWHILE...A STRONG INVERSION KEPT COOLER
AIR AND STRATUS IN PLACE ACROSS THE CENTRAL AND SOUTHERN WILLAMETTE
VALLEY...WHERE AREAS SOUTH OF ABOUT KEIZER AND MCMINNVILLE NEVER
REALLY CLEARED OUT TODAY AND TEMPERATURES STAYED AROUND 40 DEGREES.
EVEN IN PORTLAND...WHERE THE LOW CLOUDS AND FOG DID CLEAR...THE
INVERSION NEVER MIXED OUT AND TEMPERATURES STAYED BELOW 50 DEGREES IN
MOST SPOTS.
THIS EVENING...OFFSHORE PRESSURE GRADIENTS ARE BEGINNING TO INCREASE
AS HIGH PRESSURE BUILDS EAST OF THE CASCADES AND A THERMAL TROUGH
BUILDS UP THE OREGON COAST. THIS IS CAUSING EAST WINDS TO INCREASE
THROUGH THE GORGE...AND WITHIN THE PAST HOUR A MESOWEST SITE AT
CORBETT GUSTED TO ABOUT 40 MPH. EVENTUALLY THE EAST WINDS WILL REACH
KTTD/KPDX...POSSIBLY KEEPING THESE AREAS CLEAR OF FOG MUCH OF THE
NIGHT. ELSEWHERE...LOW CLOUDS IN THE CENTRAL/SOUTH WILLAMETTE VALLEY
WILL EVENTUALLY LOWER INTO A FOG LAYER...AND AREAS THAT CLEARED (SUCH
AS HILLSBORO AND SCAPPOOSE) SHOULD DEVELOP SOME LOCALLY DENSE FOG
OVERNIGHT.
THE INVERSION AND TIMING OF FOG DEVELOPMENT/CLEARING WILL MAKE
TEMPERATURE FORECASTS QUITE CHALLENGING IN THE VALLEYS THE NEXT
COUPLE DAYS. NEAR KEUG...THE FOG/LOW CLOUDS ARE LIKELY TO HANG IN THE
LONGEST...WITH CLOUD COVER HOLDING TEMPERATURES UP NEAR OR SLIGHTLY
ABOVE FREEZING AT NIGHT...THEN HOLDING TEMPERATURES DOWN TO AROUND 40
DEGREES EACH DAY. AROUND THE PORTLAND METRO AREA...MOS GUIDANCE
VARIES WILDLY BETWEEN MID 40S AND UPPER 50S FOR HIGHS THE NEXT COUPLE
DAYS. SINCE THE GORGE WIND WILL LIKELY BE A COOL...MOIST...SUB-
INVERSION LAYER WIND...WILL TEND TOWARD THE COOLER GUIDANCE FOR HIGHS
AND MILDER GUIDANCE FOR MIN TEMPERATURES. HOWEVER...WITH A GOOD DEAL
OF SUNSHINE...HIGHS AROUND 50 DEGREES EACH DAY APPEAR REASONABLE.
MEANWHILE...THE COAST AND HIGHER TERRAIN WILL BE PUSHING INTO THE
UPPER 50S AND 60S EACH DAY...EXCEPT FOR THE HIGHER CASCADE PEAKS AND
SNOW COVERED AREAS SHELTERED FROM THE SUN. WEAGLE
&&
.LONG TERM...GFS...ECMWF AND CANADIAN ALL INDICATING THE UPPER RIDGE
TO BEGIN SHIFTING E AROUND SUNDAY...BUT THE DETAILS OF WHAT IS TO
FOLLOW REMAIN UP IN THE AIR. GIVEN CURRENT MODEL SOLUTIONS...WILL
STICK WITH A DRY FORECAST THROUGH MON...THEN TREND TOWARDS
CLIMATOLOGY POPS TUE TO WED. TEMPERATURES WILL MODERATE TOWARDS A
MORE EVENLY DISTRIBUTED MARITIME PATTERN...COOLER FOR THE MOUNTAINS
AND A BIT WARMER FOR THE VALLEYS.
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
CONTINUE ACROSS THE REGION THROUGH THURSDAY WHICH WILL MAINTAIN A
STRONG INVERSION TRAPPING MOISTURE IN THE INLAND VALLEYS. AN
EXTENSIVE AREA OF IFR TO MVFR CONDITIONS IS EXPECTED IN VALLEY
LOCATIONS TONIGHT THROUGH THURSDAY MORNING AS FOG FORMS IN LOW LYING
VALLEYS. ELSEWHERE...VFR CONDITIONS WILL PREVAIL.
KPDX AND APPROACHES...IFR CONDITIONS EXPECTED TO REFORM AFTER
MIDNIGHT WITH LIFR BY 12Z. CONDITIONS WILL IMPROVE TO VFR AROUND 20Z.
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER OVER THE
COASTAL WATERS...RESULTING IN LIGHT WINDS AND SEAS IN THE 3 TO
4 FOOT RANGE THROUGH THURSDAY. SWELL WILL INCREASE TO THE 9 TO 10
FOOT RANGE FRI AND SAT. TW
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY THROUGH SAT FOR THE LOWER INTERIOR
VALLEYS OF NW OREGON AND SW WA.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 150442
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
842 PM PST WED JAN 14 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
MINOR FORECAST UPDATES HAVE BEEN SENT OUT FOR THE REST OF TONIGHT
INTO TOMORROW. GFS AND NAM SHOW A NEAR PERSISTENT FORECAST FOR
TOMORROW WITH LITTLE CHANGE IN 850MB TEMPERATURES AND BOUNDARY
LAYER MOISTURE AS STRONG HIGH PRESSURE REMAINS PARKED OVER THE AREA.
LOOKS LIKE STRATUS WILL HANG IN ALL DAY IN THE VALLEYS FROM
HIGHWAY TWO NORTH...WITH ONLY BRIEF BREAKS POSSIBLE SOUTH OF HERE
AS BOUNDARY LAYER STAYS FAIRLY MOIST. BASED ON THIS NEAR
PERSISTENT PATTERN ADJUSTED TOMORROW HIGH TEMPS CLOSE TO WHAT WAS
OBSERVED TODAY. IN ADDITION...THE DENSE FOG ADVISORIES LOOK ON
TRACK FOR THE UPPER COLUMBIA BASIN...SPOKANE...AND COEUR D`ALENE
AREAS THROUGH NOON TOMORROW. AT SOME POINT TONIGHT THE MOSES LAKE
AREA MIGHT BE ADDED AS BREAKS IN THE STRATUS THIS EVENING MAY LEAD
TO DENSE FOG FORMATION. OTHER CHANGE WAS TO INCREASE CLOUD COVER
AND FOG COVERAGE FOR THE POMEROY AND LA CROSSE AREA BASED ON
CURRENT FOG PRODUCT SATELLITE. JW
&&
.AVIATION...
A STRONG RIDGE OF HIGH PRESSURE WILL KEEP A NEAR PERSISTENT
PATTERN THROUGH 06Z/16TH. THIS MEANS VLIFR CONDITIONS WITH DENSE
FOG PERSISTING AT KGEG. VLIFR CONDITIONS WILL ALSO LIKELY PERSIST
THROUGH 18-20Z TOMORROW AT KEAT/KSFF/KCOE BUT OCCASIONAL IMPROVEMENT
TO LIFR IS POSSIBLE IF CLOUD LAYER BRIEFLY LIFTS ABOVE THE SURFACE.
CLEARING THIS EVENING AT KMWH MAY LEAD TO THE DEVELOPMENT OF DENSE
FOG AROUND 06Z. FOR KLWS...SLIGHTLY BETTER CONDITIONS EXPECTED
WITH STRATUS LAYER JUST ABOVE THE TERMINAL. AND FOR KPUW...FOG MAY
APPROACH THE TERMINAL BTWN 09Z-18Z SO WILL KEEP VCFG IN TAF. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 27 31 30 35 29 36 / 0 0 0 0 0 0
COEUR D`ALENE 27 31 29 38 30 37 / 0 0 0 0 0 0
PULLMAN 29 42 30 39 33 40 / 0 0 0 0 0 0
LEWISTON 32 38 32 38 34 39 / 0 0 0 0 0 0
COLVILLE 28 33 28 34 25 33 / 0 0 0 0 0 0
SANDPOINT 29 32 27 34 27 35 / 0 0 0 0 0 0
KELLOGG 28 40 30 36 30 36 / 0 0 0 0 0 0
MOSES LAKE 24 35 31 36 31 37 / 0 0 0 0 0 0
WENATCHEE 28 32 29 36 30 37 / 0 0 0 0 0 0
OMAK 26 30 29 32 30 34 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR COEUR D`ALENE
AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR SPOKANE AREA...
UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KOTX 142337 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
337 PM PST WED JAN 14 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
UPDATED AVIATION DISCUSSION.
TONIGHT...THE DENSE FOG ADVISORY FOR THE SPOKANE AND COEUR D`ALENE
AREAS AS WELL AS LINCOLN COUNTY HAS BEEN EXTENDED THROUGH NOON
THURSDAY. FOR DOWNTOWN SPOKANE...AND FOR SPOTS ALONG THE COLUMBIA
RIVER...VISIBILITIES WILL BE A BIT BETTER. THERE HAS BEEN ENOUGH
RADIATIVE TRANSFER IN THE BOUNDARY LAYER TO MIX THE LOWEST
ELEVATIONS...BUT ELEVATIONS ABOVE 2000 FEET REMAIN IN THICK FOG
AS THE UPPER RIDGE REMAINS STRONG. LITTLE TO NO IMPROVEMENT IN THE
VISIBILITY HAS OCCURRED THIS AFTERNOON FOR ELEVATIONS ABOVE 2000
FEET. THE HIGHWAY 2 CORRIDOR FROM AIRWAY HEIGHTS THROUGH WILBUR
AND COULEE CITY REMAINS FOGGY AS WELL.
FOR THE REST OF THE UPPER COLUMBIA BASIN AND THE WATERVILLE
PLATEAU...THE STRATUS WILL LIKELY EXPAND INTO THE RITZVILLE...
ODESSA...AND MOSES LAKE AREAS THIS EVENING AND OVERNIGHT. /GKOCH
THURSDAY THROUGH SATURDAY...RIDGE STILL INFLUENCING THE AREA ALONG
WITH THE NUISANCE ISSUES ASSOCIATED WITH ITS POSITIONING
...PRIMARILY LOWLAND AND VALLEY FOG AND AIR STAGNATION ISSUES.
THE AXIS PLACEMENT OF THE RIDGE ALOFT IS OVER THE COAST AND THE
RIDGE IS NARROW ENOUGH TO ALLOW MINOR DISTURBANCE TO RIPPLE DOWN
ITS EAST EDGE AND BRUSH EXTREME EASTERN WASHINGTON AND NORTHERN
IDAHO AT INTERVALS INTO SATURDAY...BUT NONE OF THESE DISTURBANCES
IS EXPECTED TO BE STRONG ENOUGH TO GENERATE ANY MEASURABLE
PRECIP...PERHAPS LATER RUNS MIGHT SUGGEST SOME LEAKAGE OF TRACE
PRECIP SUCH AS DRIZZLE AND SNOW FLURRIES OUT OF THE STRATUS/FOG
AND PERHAPS FREEZING FOG MIGHT BE ADDED TO ADDRESS SIGNIFICANT
DEPOSITION OF ICE ON SURFACE FEATURES...BUT CURRENTLY THE FORECAST
LOOKS STEERED IN THE RIGHT DIRECTION AS FAR AS CLOUDS AND FOG OVER
MOST LOWLAND POPULATED AREAS WITH MOUNTAINS REMAINING FAIRLY
CLEAR. FORECAST TEMPERATURES CHANGE LITTLE SHOWING NOT MUCH OF ANY
TREND INTO SATURDAY WITH THIS STAGNANT WEATHER PATTERN. /PELATTI
SATURDAY NIGHT THROUGH WEDNESDAY...THE UPPER LEVEL RIDGE AND STRONG
SURFACE INVERSIONS WILL PERSIST OVER THE INLAND NORTHWEST THROUGH
AT LEAST MONDAY...THEN THE RIDGE AXIS WILL START TO MOVE EAST.
MEDIUM RANGE MODELS DISAGREE ON THE TIMING OF THE BREAKDOWN OF THE
RIDGE SO NO BIG CHANGES TO THE EXTENDED FORECAST AT THIS TIME. FOR
TUESDAY POPS HAVE BEEN TWEAKED A BIT HIGHER ALONG THE CASCADE
CREST BUT LOWER ALONG THE IDAHO BORDER AS THE RIDGE MAY HANG ON A
BIT LONGER OVER OUR EASTERN ZONES. ON WEDNESDAY POPS HAVE BEEN
TRENDED SLIGHTLY TOWARD CLIMO. NO BIG CHANGES TO TEMPERATURES FROM
PREVIOUS FORECAST PACKAGE. VALLEYS WILL CONTINUE TO HAVE SMALL
DIURNAL SWINGS AS FOG AND LOW STRATUS PERSIST. BY MIDWEEK MODEL
DIFFERENCE IN 850MB TEMPERATURES OVER THE SPOKANE AREA SWING FROM
-2C ON THE GFS TO +6C FROM THE ECMWF. CONFIDENCE REMAINS LOW FOR
THIS PORTION OF THE FORECAST. /KELCH
&&
.AVIATION...
LOW CLOUDS AND FOG WILL IMPACT AVIATION OPERATIONS IN SPOKANE...
COEUR D`ALENE...WENATCHEE...MOSES LAKE...AND LEWISTON. MOISTURE WILL
REMAIN TRAPPED UNDER A STRONG LOW LEVEL TEMPERATURE INVERSION FOR
THE NEXT SEVERAL DAYS. BRIEF VFR CONDITIONS AT MOSES LAKE THIS
EVENING WILL DETERIORATE AS FOG AND LOW STRATUS REDEVELOPS
TONIGHT. LITTLE IMPROVEMENT IS EXPECTED AT KGEG THROUGH 21Z
THURSDAY. VFR CONDITIONS SHOULD CONTINUE IN THE PULLMAN AREA IN
LIGHT SOUTHEAST DOWNSLOPE FLOW. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 27 35 32 35 29 36 / 0 0 0 0 0 0
COEUR D`ALENE 27 38 33 38 30 37 / 0 0 0 0 0 0
PULLMAN 29 41 30 39 33 40 / 0 0 0 0 0 0
LEWISTON 32 36 32 38 34 39 / 0 0 0 0 0 0
COLVILLE 30 35 26 34 25 33 / 0 0 0 0 0 0
SANDPOINT 29 34 27 34 27 35 / 0 0 0 0 0 0
KELLOGG 28 36 32 36 30 36 / 0 0 0 0 0 0
MOSES LAKE 26 36 31 36 31 37 / 0 0 0 0 0 0
WENATCHEE 28 36 29 36 30 37 / 0 0 0 0 0 0
OMAK 26 32 29 32 30 34 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR COEUR D`ALENE
AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR SPOKANE AREA...
UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KSEW 142313
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
313 PM PST WED JAN 14 2009
.SYNOPSIS...A STRONG RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE
REGION INTO THE WEEKEND. THE AIR MASS WILL BE WARM AND DRY ALOFT
WITH A PRONOUNCED INVERSION...MAKING THE AIR MASS STAGNANT IN THE
LOWEST LEVELS. MUCH OF THE PUGET SOUND BASIN AND ALL ALONG THE I-5
CORRIDOR WILL SEE STAGNANT AIR THROUGH SATURDAY. SOME AREAS OF DENSE
FOG WILL LIKELY DEVELOP TONIGHT...WITH A BETTER CHANCE OF DENSE FOG
BY FRIDAY NIGHT. THE WEATHER IN AND NEAR THE MOUNTAINS WILL BE WARM
AND SUNNY.
&&
.SHORT TERM...CARVED SOME OF THE STRATUS OFF OUR SKY COVER GRIDS
THIS MORNING...AND THAT WAS REWARDED WITH A LOW STRATUS OVERCAST
THAT STILL PERSISTS AS I WRITE THIS HERE IN NORTH SEATTLE. NO MATTER
THE TIME OF YEAR...MARINE STRATUS UNDER AN INVERSION IS HARD TO
SHAKE. STILL...IT IS A VERY GOOD BET THAT THE STRATUS WILL BECOME
SHALLOWER AND POSSIBLY LESS EXTENSIVE. LOOKING AT THE TEMPS AT JUST
1000FT OFF THE UW MESOSCALE MODEL SHOWS VERY WARM TEMPS NEAR 60F IN
SOME SPOTS THU AND FRI. IF YOU`RE UNDER STRATUS OR FOG...MUCH
COOLER. THE AREAS THAT WERE CLOUDY OR FOGGY TODAY ARE LIKELY TO BE
THE AREAS THAT STAY ESPECIALLY STAGNANT THRU SATURDAY...WITH A TREND
TO FOG OR VERY LOW CIGS RIGHT ON THE DECK. THE COAST...SOME OF THE
EAST SIDE ZONES...AND NEARLY EVERYWHERE IN THE MOUNTAINS WILL BE
CLEAR AND UNUSUALLY WARM THRU SAT FOR SOME SPRING SKIING. AREAS THAT
ARE ON THE BORDERLINE BETWEEN THE LOW STRATUS OR FOG OVER PUGET
SOUND/NORTHERN WATERS/STRAIT AND THE CLEARING JUST INLAND OR CLOSER
TO THE MTNS...WELL THOSE AREAS WILL PROBABLY SEE THE DENSEST FOG
DEVELOP...AND THEN A GOOD CHANCE FOR AFTERNOON CLEARING...FOLLOWED
BY A QUICK DROP BACK INTO THE FOG EACH EVENING. THE SAN JUANS WILL
PROBABLY STAY UNDER FOG AND STRATUS...AT LEAST BELOW 1000FT BUT A
TRIP UP MT CONSTITUTION SHUD BE REWARDED BY MIDDAY THU. ANY TRIP TO
THE MOUNTAINS WILL CERTAINLY BE REWARDED WITH UNUSUALLY WARM TEMPS
AND CLEAR SKIES. I ONCE AGAIN PUSHED OUR TEMP GRIDS COOLER NEAR THE
WATER AND BETWEEN TACOMA AND OLYMPIA...AND NUDGED THEM TOWARD THE
4KM WRFGFS TO ADD A LITTLE MORE WARMTH FOR THE WEST SLOPES OF THE
CASCADES. OUR FCST IS NOT AS WARM AS THAT MODEL AND IS CLOSER TO THE
STATISTICAL GUIDANCE BUT STILL KEEPS SOME OF THE LOOK OF THE
MESOSCALE MODEL. I DID NOT WORK OVER THE MINIMUM TEMPS...MAYBE
SOMETHING FOR THE EVENING SHIFT TO ADDRESS...SOME SPOTS THAT ARE THE
MORE SHELTERED AREAS...BUT ALSO REMAIN CLEAR CLOSER TO THE CASCADES
AND OUT ON THE COAST HAVE A GOOD CHANCE OF FROST...FINDING THOSE
POCKETS AND DROPPING OUR MIN TEMP GRID CAN BE A CHALLENGE. 19
.LONG TERM...OUR FORECAST SHOWS A TREND TO NORMAL WEATHER FOR
WINTERTIME...CLIMO...WITH TEMPS NEAR NORMAL AND HIGHER POPS BY
MIDWEEK. THE GFS HAS A SIGNIFICANT BUT NOT ESPECIALLY STRONG UPPER
TROF OVER THE AREA BY MIDWEEK...AT LEAST ON THE 12Z RUN...SO IT IS
NOT A BAD BET BY THAT TIME THAT NORMAL WEATHER FOR JANUARY WILL
RETURN. THE ECMWF SPLITS THIS SYSTEM AND BREAKS THE RIDGE DOWN ONLY
SLOWLY. WHETHER IT HAPPENS MIDWEEK OR TOWARD THE END OF NEXT
WEEK...CERTAINLY TOWARD THE END OF THE MONTH THE FAR EXTENDED
PORTION OF THE GFS RETURNS THE REGION TO THE SAME PATTERN WE SAW SET
UP SEVERAL WEEKS AGO. THE 6-10 AND 8-14 DAY OUTLOOKS CALL FOR BELOW
NORMAL TEMPS SO A COOLING TREND FOR THE AIR MASS IN GENERAL LOOKS
LIKE A GOOD BET SOME TIME NEXT WEEK. AT FIRST...FOR SUN-TUE IF FOG
HAS PERSISTED IN SOME AREAS...FOR INSTANCE SRN PGTSND/ARND
OLYMPIA...THEN AT FIRST TEMPS IN THOSE AREAS WILL WARM FOR A COUPLE
DAYS AS THE STAGNATION COMES TO AN END. I DID NOT TRY TO CHASE DOWN
MUCH DETAIL HOWEVER IN THE EXTENDED FCST YET...MERELY TRENDED TO
CLIMO AND MATCHED UP THE PDX FCST. 19
&&
.AVIATION...A STRONG SUBSIDENCE INVERSION HAS PLACED A SOLID
METEOROLOGICAL LID OVER THE STRATUS COVERING MUCH OF THE WR WA
INTERIOR TODAY. THIS FEATURE WILL REMAIN IN PLACE...BUT THE DEPTH OF
LOW-LEVEL MOISTURE IS FORECAST TO VERY SLOWLY BECOME MORE AND MORE
SHALLOW OVER THE NEXT 24 HOURS. THIS MEANS WE MAY SLOWLY THIN OR
SCATTER THE CURRENT BKN006-018 DECK FROM THE TOP THROUGH THU. WOULD
EXPECT THE GENERAL COVERAGE OF STRATUS ON THU AFTN TO BE ABOUT HALF
WHAT IT IS TODAY. FOR TONIGHT...LOWLAND LOCATIONS WITHOUT STRATUS
THIS AFTERNOON COULD EASILY FOG IN AFTER SOME COOLING THIS EVENING
BUT WOULD BURN OFF EARLY THU AFTN.
KSEA...LATEST SATELLITE TRENDS AND MODEL BOUNDARY LAYER R.H.
FORECASTS SUGGEST THE CURRENT ROUND OF OVC008-012 STRATUS WILL HANG
IN TOUGH THROUGH THU MORNING...LOWERING SLIGHTLY OVERNIGHT. THE GOOD
NEWS IS THAT THIS STUBBORN LAYER WOULD LIMIT SURFACE-BASED FOG
DEVELOPMENT TONIGHT...SO LOW CEILINGS ARE A GOOD BET BUT REDUCED
VISIBILITIES ARE NOT NEARLY SO CERTAIN TONIGHT. STILL COUNTING ON
THE INCREASING SHALLOWNESS OF THE LOW-LEVEL MOIST LAYER TO SCATTER
OUT THE STRATUS AT KSEA ON THU AFTN...GIVING WAY TO HAZY SUNSHINE.
HANER
&&
.MARINE...STRENGTHENING HI PRES EAST OF THE CASCADES WILL CONTINUE
THE LIGHT TO MODERATE OFFSHORE FLOW OVER WRN WA. LATEST 22Z UIL-BLI
GRADIENT OF -3.8 MB MAKES ME WONDER OF THE CURRENT FORECAST OF 15-25
KT AT THE WEST ENTRANCE IS TOO WEAK. A SMALL CRAFT ADVISORY IS OUT
FOR THE WEST ENTRANCE...THOUGH SOME LOW-END SMALL CRAFT WINDS ARE
ALSO POSSIBLE OVER THE WATERS ADJACENT TO GRAYS HARBOR WITH OFFSHORE
FLOW FUNNELING THROUGH THERE. LIGHT WINDS OVER THE INTERIOR. HANER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...AIR STAGNATION ADVISORY FOR THE LOWLANDS OF WESTERN WASHINGTON
EXCEPT FOR THE COAST AND WESTERN STRAIT.
FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER
IN KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...SMALL CRAFT ADVISORY AT THE WEST ENTRANCE.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KOTX 142246
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
246 PM PST WED JAN 14 2009
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE PACIFIC
NORTHWEST THROUGH EARLY NEXT WEEK. THE MOUNTAINS WILL LIKELY
EXPERIENCE PERIODS OF CLEAR SKIES...WHILE THE LOW ELEVATIONS WILL
BE TRAPPED IN LOW CLOUDS AND FOG. AIR STAGNATION WILL BE A PROBLEM
FOR VALLEY LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A
PROLONGED STRONG LOW LEVEL INVERSION.
&&
.DISCUSSION...
TONIGHT...THE DENSE FOG ADVISORY FOR THE SPOKANE AND COEUR D`ALENE
AREAS AS WELL AS LINCOLN COUNTY HAS BEEN EXTENDED THROUGH NOON
THURSDAY. FOR DOWNTOWN SPOKANE...AND FOR SPOTS ALONG THE COLUMBIA
RIVER...VISIBILITIES WILL BE A BIT BETTER. THERE HAS BEEN ENOUGH
RADIATIVE TRANSFER IN THE BOUNDARY LAYER TO MIX THE LOWEST
ELEVATIONS...BUT ELEVATIONS ABOVE 2000 FEET REMAIN IN THICK FOG
AS THE UPPER RIDGE REMAINS STRONG. LITTLE TO NO IMPROVEMENT IN THE
VISIBILITY HAS OCCURRED THIS AFTERNOON FOR ELEVATIONS ABOVE 2000
FEET. THE HIGHWAY 2 CORRIDOR FROM AIRWAY HEIGHTS THROUGH WILBUR
AND COULEE CITY REMAINS FOGGY AS WELL.
FOR THE REST OF THE UPPER COLUMBIA BASIN AND THE WATERVILLE
PLATEAU...THE STRATUS WILL LIKELY EXPAND INTO THE RITZVILLE...
ODESSA...AND MOSES LAKE AREAS THIS EVENING AND OVERNIGHT. /GKOCH
THURSDAY THROUGH SATURDAY...RIDGE STILL INFLUENCING THE AREA ALONG
WITH THE NUISANCE ISSUES ASSOCIATED WITH ITS POSITIONING
...PRIMARILY LOWLAND AND VALLEY FOG AND AIR STAGNATION ISSUES.
THE AXIS PLACEMENT OF THE RIDGE ALOFT IS OVER THE COAST AND THE
RIDGE IS NARROW ENOUGH TO ALLOW MINOR DISTURBANCE TO RIPPLE DOWN
ITS EAST EDGE AND BRUSH EXTREME EASTERN WASHINGTON AND NORTHERN
IDAHO AT INTERVALS INTO SATURDAY...BUT NONE OF THESE DISTURBANCES
IS EXPECTED TO BE STRONG ENOUGH TO GENERATE ANY MEASURABLE
PRECIP...PERHAPS LATER RUNS MIGHT SUGGEST SOME LEAKAGE OF TRACE
PRECIP SUCH AS DRIZZLE AND SNOW FLURRIES OUT OF THE STRATUS/FOG
AND PERHAPS FREEZING FOG MIGHT BE ADDED TO ADDRESS SIGNIFICANT
DEPOSITION OF ICE ON SURFACE FEATURES...BUT CURRENTLY THE FORECAST
LOOKS STEERED IN THE RIGHT DIRECTION AS FAR AS CLOUDS AND FOG OVER
MOST LOWLAND POPULATED AREAS WITH MOUNTAINS REMAINING FAIRLY
CLEAR. FORECAST TEMPERATURES CHANGE LITTLE SHOWING NOT MUCH OF ANY
TREND INTO SATURDAY WITH THIS STAGNANT WEATHER PATTERN. /PELATTI
SATURDAY NIGHT THROUGH WEDNESDAY...THE UPPER LEVEL RIDGE AND STRONG
SURFACE INVERSIONS WILL PERSIST OVER THE INLAND NORTHWEST THROUGH
AT LEAST MONDAY...THEN THE RIDGE AXIS WILL START TO MOVE EAST.
MEDIUM RANGE MODELS DISAGREE ON THE TIMING OF THE BREAKDOWN OF THE
RIDGE SO NO BIG CHANGES TO THE EXTENDED FORECAST AT THIS TIME. FOR
TUESDAY POPS HAVE BEEN TWEAKED A BIT HIGHER ALONG THE CASCADE
CREST BUT LOWER ALONG THE IDAHO BORDER AS THE RIDGE MAY HANG ON A
BIT LONGER OVER OUR EASTERN ZONES. ON WEDNESDAY POPS HAVE BEEN
TRENDED SLIGHTLY TOWARD CLIMO. NO BIG CHANGES TO TEMPERATURES FROM
PREVIOUS FORECAST PACKAGE. VALLEYS WILL CONTINUE TO HAVE SMALL
DIURNAL SWINGS AS FOG AND LOW STRATUS PERSIST. BY MIDWEEK MODEL
DIFFERENCE IN 850MB TEMPERATURES OVER THE SPOKANE AREA SWING FROM
-2C ON THE GFS TO +6C FROM THE ECMWF. CONFIDENCE REMAINS LOW FOR
THIS PORTION OF THE FORECAST. /KELCH
&&
.AVIATION...
LOW CLOUDS AND FOG WILL IMPACT AVIATION OPERATIONS IN SPOKANE...
COEUR D`ALENE...WENATCHEE...MOSES LAKE...AND LEWISTON. MOISTURE
WILL REMAIN TRAPPED UNDER A STRONG LOW LEVEL TEMPERATURE INVERSION
FOR THE NEXT SEVERAL DAYS. SOME IMPROVEMENT IS EXPECTED IN
WENATCHEE AFTER 21Z WITH FOG LIFTING INTO A LOW STRATUS DECK...BUT
FOG WILL LIKELY REDEVELOP AGAIN THIS EVENING. LITTLE IMPROVEMENT IS
EXPECTED AT KGEG. VISIBILITIES MAY RISE ABOVE A MILE THIS
AFTERNOON...BUT THICK FOG IS EXPECTED TO REDEVELOP THIS EVENING.
/GKOCH
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 27 35 32 35 29 36 / 0 0 0 0 0 0
COEUR D`ALENE 27 38 33 38 30 37 / 0 0 0 0 0 0
PULLMAN 29 41 30 39 33 40 / 0 0 0 0 0 0
LEWISTON 32 36 32 38 34 39 / 0 0 0 0 0 0
COLVILLE 30 35 26 34 25 33 / 0 0 0 0 0 0
SANDPOINT 29 34 27 34 27 35 / 0 0 0 0 0 0
KELLOGG 28 36 32 36 30 36 / 0 0 0 0 0 0
MOSES LAKE 26 36 31 36 31 37 / 0 0 0 0 0 0
WENATCHEE 28 36 29 36 30 37 / 0 0 0 0 0 0
OMAK 26 32 29 32 30 34 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR COEUR D`ALENE
AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST THURSDAY FOR SPOKANE AREA...
UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KPQR 142244
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
243 PM PST WED JAN 14 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE LOW-LEVEL FLOW SHOULD BEGIN TO
DEVELOP TODAY...AND THEN INTENSIFY TONIGHT AND THURSDAY. EXPECT THE
OFFSHORE FLOW TO LAST THROUGH SUNDAY. STRONG VALLEY INVERSIONS WILL
RESULT IN UNSEASONABLY WARM DAYTIME TEMPERATURES IN THE COAST RANGE
AND CASCADES FOR THE NEXT FEW DAYS.
&&
.SHORT TERM...LOW CLOUDS HAVE HUNG IN THROUGH EARLY AFTERNOON OVER
THE SOUTHERN HALF OF THE WILLAMETTE VALLEY...AS OTHER AREAS HAVE SEEN
A SLOW DECREASE IN CLOUD COVERAGE. EVEN WITH SOME SUN THOUGH...LOW
VALLEYS HAVE REMAINED COOL DUE TO THE STRONG INVERSION. ABOVE THE
INVERSION...IN THE FOOTHILLS AND COAST RANGE...TEMPS HAVE SOARED AT
MANY LOCATIONS INTO THE 60S. THE NEXT FEW DAYS PROMISE MUCH OF THE
SAME AS THE UPPER RIDGE CONTINUES TO SHIFT CLOSER TO THE COAST. MOS
VALLEY LOWS ARE LIKELY TOO COLD NEXT FEW NIGHTS AS CLOUDS AND FOG
WILL LIMIT RADIATIONAL COOLING. OFFSHORE FLOW OVER THE NEXT FEW DAYS
SHOULD TEND TO KEEP MOST BEACHES CLEAR OF FOG AND LOW CLOUDS...WITH
MILD TEMPS RESULTING FROM DOWNSLOPE BREEZES OFF THE COAST RANGE. WEST
WINDS NEAR THE WEST END OF THE GORGE WILL TEND TO MIX AIR MASS UP A
BIT THERE...BUT OTHER VALLEYS WILL TEND TO BE STAGNANT UNDER THE
INVERSION WITH LIGHT WINDS. HAVE ADDED THE UPPER HOOD RIVER VALLEY
AND THE WESTERN GORGE EAST OF CASCADES LOCKS TO THE AIR STAGNATION
ADVISORY.
&&
.LONG TERM...GFS...ECMWF AND CANADIAN ALL INDICATING THE UPPER RIDGE
TO BEGIN SHIFTING E AROUND SUNDAY...BUT THE DETAILS OF WHAT IS TO
FOLLOW REMAIN UP IN THE AIR. GIVEN CURRENT MODEL SOLUTIONS...WILL
STICK WITH A DRY FORECAST THROUGH MON...THEN TREND TOWARDS
CLIMATOLOGY POPS TUE TO WED. TEMPERATURES WILL MODERATE TOWARDS A
MORE EVENLY DISTRIBUTED MARITIME PATTERN...COOLER FOR THE MOUNTAINS
AND A BIT WARMER FOR THE VALLEYS.
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
CONTINUE ACROSS THE DISTRICT THROUGH THURSDAY MAINTAINING A STRONG
INVERSION TRAPPING MOISTURE IN THE INLAND VALLEYS. SOME INCREASE IN
OFFSHORE FLOW TONIGHT WILL ALLOW FOR LESS EXTENSIVE FOG AND LOW
CLOUDS NEAR THE MOUTH OF THE GORGE. WITH EXTENSIVE IFR AND MVFR
CONDITIONS NIGHT AND MORNING IN THE VALLEYS...VFR CONDITIONS WILL
PREVAIL ELSEWHERE.
KPDX AND APPROACHES...IFR CONDITIONS EXPECTED TO REFORM THIS AFTER
MIDNIGHT WITH LIFR BY 12Z. CONDITIONS WILL IMPROVE TO VFR AROUND 20Z.
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE
COASTAL WATERS...RESULTING IN RATHER LIGHT WINDS AND SEAS THROUGH
THE WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY THROUGH SAT FOR THE LOWER INTERIOR
VALLEYS OF NW OREGON AND SW WA.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 141916
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1116 AM PST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEK AND DOMINATE
THE WEATHER PATTERN INTO THE WEEKEND. WARM AND DRY CONDITIONS IN
THE MOUNTAINS AND WIDESPREAD LOW CLOUDS AND FOG ACROSS THE LOW
LANDS FOR THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
THE DENSE FOG ADVISORY HAS BEEN CANCELLED FOR THE WENATCHEE AND
MOSES LAKE AREAS...AS WELL AS OVER THE WATERVILLE PLATEAU. 18Z
VISIBLE SATELLITE IMAGERY SHOWS THE FOG AND STRATUS BROKEN ALONG
THE INTERSTATE 90 CORRIDOR WEST OF SPRAGUE. TRAFFIC CAMERAS IN
WENATCHEE SUGGEST THAT THE DENSE FOG IS PATCHY. FOG IS THICK OVER
THE DEEP BASIN AROUND THE TRI-CITIES...BUT LESS PROLIFIC AROUND
MOSES LAKE AND RITZVILLE. SOME OF THIS DEEP BASIN FOG MAY ERODE
THIS AFTERNOON...BUT GIVEN THE LOW SUN ANGLE THIS TIME OF YEAR...I
WOULDN`T EXPECT IT TO COMPLETELY DISSIPATE.
ANOTHER AREA OF THICK FOG AND LOW STRATUS IS ALONG AND NORTH OF
HIGHWAY 2 FROM SPOKANE TO COULEE CITY. THIS MORE NORTHERN BAND OF
FOG WILL PROBABLY BE HARDER TO MIX OUT SINCE IT IS OVER SNOW
COVER. THEN THIS EVENING...IT IS REASONABLE TO EXPECT THE STRATUS
AROUND THE TRI-CITIES TO EXPAND NORTH AND FILL THE UPPER BASIN.
/GKOCH
&&
.AVIATION...
LOW CLOUDS AND FOG WILL IMPACT AVIATION OPERATIONS IN SPOKANE...
COEUR D`ALENE...WENATCHEE...MOSES LAKE...AND LEWISTON. MOISTURE
WILL REMAIN TRAPPED UNDER A STRONG LOW LEVEL TEMPERATURE INVERSION
FOR THE NEXT SEVERAL DAYS. SOME IMPROVEMENT IS EXPECTED IN
WENATCHEE AFTER 21Z WITH FOG LIFTING INTO A LOW STRATUS DECK...BUT
FOG WILL LIKELY REDEVELOP AGAIN THIS EVENING. LITTLE IMPROVEMENT IS
EXPECTED AT KGEG. VISIBILITIES MAY RISE ABOVE A MILE THIS
AFTERNOON...BUT THICK FOG IS EXPECTED TO REDEVELOP THIS EVENING.
/GKOCH
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 34 30 35 32 35 29 / 0 0 0 0 0 0
COEUR D`ALENE 34 27 38 33 38 30 / 0 0 0 0 0 0
PULLMAN 44 33 41 30 39 33 / 0 0 0 0 0 0
LEWISTON 38 34 36 32 38 34 / 0 0 0 0 0 0
COLVILLE 35 29 35 26 34 25 / 0 0 0 0 0 0
SANDPOINT 35 27 34 27 34 27 / 0 0 0 0 0 0
KELLOGG 37 25 36 32 36 30 / 0 0 0 0 0 0
MOSES LAKE 33 29 36 31 36 31 / 0 0 0 0 0 0
WENATCHEE 36 30 36 29 36 30 / 0 0 0 0 0 0
OMAK 31 27 32 29 32 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR COEUR
D`ALENE AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR SPOKANE
AREA...UPPER COLUMBIA BASIN.
&&
$$
000
FXUS66 KSEW 141725
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
915 AM PST WED JAN 14 2009
.SYNOPSIS...A STRONG RIDGE OF HIGH PRESSURE WILL BUILD OVER THE
REGION INTO THE WEEKEND. THE AIR MASS WILL WARM AND DRY ALOFT AND A
PRONOUNCED INVERSION WILL MAKE THE AIR MASS STAGNANT IN THE PUGET
SOUND BASIN AND ALONG THE I-5 CORRIDOR BY THURSDAY. AREAS OF DENSE
FOG WILL LIKELY DEVELOP TONIGHT...AND MAY PERSIST IN SOME
AREAS...ESPECIALLY NEAR THE WATER...INTO THE WEEKEND. THE WEATHER IN
THE MOUNTAINS WILL BE WARM AND SUNNY.
&&
.SHORT TERM...TRIMMED THE SKY COVER AND FOG BACK A BIT THIS MORNING
AND SENT THE ZONES OUR FOR A LITTLE MORE SUN...ESPECIALLY THE
EASTERN LOWLAND ZONE. AREAS OF OF FOG AND LOW CLOUDS ARE IN THE
STRAIT...THE NORTHERN WATERS AND WESTERN SKAGIT...WHATCOM...AND
SNOHOMISH COUNTIES. AREAS OF LOW CLOUDS AND PATCHY FOG EXTEND SOUTH
THRU MNLY PUGET SOUND. THERE ISN`T A WHOLE LOT OF LOW STUFF YET IN
THE SOUTHWEST. COAST IS MOSTLY CLEAR...MAYBE SOME CIRRUS AND A FEW
PATCHES OF FOG THIS MORNING. THE INVERSION ON THE PROFILER IS DOWN
TO AROUND 800M...BUT THERE IS STILL A NICE MIXED LAYER WITH SOME
10-15KT NORTHERLIES. NOT UNTIL TONIGHT SHOULD THE VENTILATION REALLY
DROP OFF...THE UW MESO MODEL SUGGESTS THAT AROUND MIDNIGHT THE AIR
MASS ALL ALONG THE I-5 CORRIDOR WILL BECOME CALM AND IT IS ALMOST A
CERTAINTY THAT WE WILL SEE PERSISTENT FOG AND LOW CLOUDS OVER THE
WATER THAT PERSISTS THRU ALL DAY THU AND FRI...AND PROBABLY INTO
SAT...WITH AREAS OF FOG OVER THE LOWLAND LAND AREAS AS WELL...THO
MAINLY IN THE NIGHT AND MORNING HOURS. ANY MIX OUT IN THE AFTERNOON
WILL BE PRETTY LIMITED NEAR THE WATER AND BELOW 500FT...BUT THE
MOUNTAINS AND THE COAST AND THE WEST SLOPES OF THE CASCADES WILL BE
WARM AND SUNNY. WILL SEND AN AIR STAGNATION ADVISORY FOR THE I-5
CORRIDOR AND LOWLANDS BUT NOT THE COAST AND MOUNTAINS AND ALSO NOT
THE WEST PART OF THE STRAIT...AROUND 2PM. 19
.LONG TERM...PREVIOUS DISCUSSION...RIDGING REMAINS OVER THE REGION
THROUGH THE WEEKEND WITH AREAS OF FOG STICKING AROUND...ESPECIALLY
INTERIOR AREAS. THE EXTENDED MODELS CONTINUE TO SHOW A CHANGE IN THE
PATTERN EARLY NEXT WEEK AS UPPER LEVEL RIDGING SHIFTS EASTWARD INTO
THE ROCKIES AND FLATTENS. THERE IS PLENTY OF VARIATION IN THE MODEL
SOLUTIONS...BUT RECENT RUNS OF THE GFS AND EURO MODELS SHOW UPPER
LEVEL RIDGING RETROGRADING BACK TO 140W TO 150W...WITH CUT OFF
SYSTEMS HEADING INTO OUR SOUTH. THIS DOES NOT LOOK PARTICULARLY
WET...BUT CERTAINLY LOOKS MORE UNSETTLED BEYOND THE MIDDLE OF NEXT
WEEK. 27
&&
.AVIATION...A STRONG SUBSIDENCE INVERSION WILL BE IN PLACE FOR THE
NEXT 24 HOURS AND BEYOND. 12Z KUIL SOUNDING SHOWED THE STRONG
INVERSION IN PLACE BETWEEN 1900 AND 3800 FEET. THIS WILL MAKE IT
TOUGH TO MIX OUT THE MOISTURE AND STRATUS TRAPPED BENEATH THE
INVERSION. HOWEVER...LIGHT OFFSHORE FLOW AT THE TOP OF THE BOUNDARY
LAYER SHOULD HELP TO THIN THE BKN013-018 LAYER AROUND THE EAST AND
NORTH SIDE OF THE OLYMPIC MTNS...BUT THIS WILL BE SLOW. NOW THAT THE
SUN HAS RISEN...THE SUN SHOULD SLOWLY BURN OFF THE REMAINING PATCHES
OF SURFACE-BASED FOG LATE THIS MORNING.
KSEA...WILL CONTINUE TO FLIRT WITH THE EASTERN EDGE OF A BKN012-015
DECK TO YOUR WEST AND SOME LOWER STRATUS DRIFTING IN FROM THE EAST
THIS MORNING. CONDITIONS ALONG THE LANDING APPROACHES COULD BE
VARIABLE THROUGH 20Z AS THESE DIFFERENT LAYERS MORPH IN AND OUT.
THIS MEANS SOME AMOUNT OF TIME WHERE THE APPROACHES COULD ALSO BE
CLEAR. AFTER ABOUT 20Z...FURTHER DRYING ALOFT SHOULD THIN OUT OR
PUSH BACK THE HIGHER BKN012-015 DECK WHILE THE SUN SHOULD MELT ANY
FOG IN THE VICINITY INTO A MERE HAZE. LOOKING AT PREDOMINANT VFR
CONDITIONS AFTER 21Z. COULD BE SOME MORE FOG DEVELOPMENT
TONIGHT...BUT IT WOULD BE QUITE SHALLOW AND ITS EVOLUTION IS HIGHLY
UNCERTAIN AT THIS POINT. HANER
&&
.MARINE...OBJECTIVE SURFACE ANALYSIS SHOWS THAT HIGH PRESSURE HAS
NOW SHIFTED EAST OF THE CASCADES. LIGHT TO MODERATE OFFSHORE FLOW IS
NOW PRESENT WITH THE 16Z UIL-BLI GRADIENT AT -2.8 MB. AS A
RESULT...SMALL CRAFT WINDS HAVE DEVELOPED AT TATOOSH ISLAND. LITTLE
CHANGE IN THIS GENERAL PATTERN IS EXPECTED FROM NOW THROUGH SUNDAY.
HANER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER IN
KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...SMALL CRAFT ADVISORY AT THE WEST ENTRANCE.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KPQR 141625
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 AM PST WED JAN 14 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE LOW-LEVEL FLOW SHOULD BEGIN TO
DEVELOP TODAY...AND THEN INTENSIFY TONIGHT AND THURSDAY. EXPECT THE
OFFSHORE FLOW TO LAST THROUGH SUNDAY. STRONG VALLEY INVERSIONS WILL
RESULT IN UNSEASONABLY WARM DAYTIME TEMPERATURES IN THE COAST RANGE
AND CASCADES FOR THE NEXT FEW DAYS.
&&
.SHORT TERM...SLE SOUNDING SHOWED A STRONG INVERSION AROUND 950 MB
THIS MORNING AS THE UPPER RIDGE SHIFTS SLOWLY E TOWARDS THE COAST.
MODEL SOUNDINGS CONTINUE TO SHOW THE STRONG INVERSION PERSISTING
THROUGH THE END OF THE WEEK...MEANING WARM TEMPS IN THE FOOTHILLS AND
COAST RANGE...WITH COLDER AIR TRAPPED IN INLAND VALLEYS. FOG AND LOW
CLOUDS SHOULD BE PERSISTENT IN WIND PROTECTED VALLEYS...ESP S HALF OF
WILLAMETTE VALLEY. AS SURFACE HIGH BUILDS DOWN E OF THE CASCADES...
WILL SEE OFFSHORE WINDS THROUGH THE GORGE PICK UP TONIGHT. OFFSHORE
FLOW OVER THE NEXT FEW DAYS SHOULD TEND TO KEEP MOST BEACHES CLEAR OF
FOG AND LOW CLOUDS...WITH MILD TEMPS RESULTING FROM DOWNSLOPE BREEZES
OFF THE COAST RANGE.
&&
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
STRONG WARM CORE HIGH PRESSURE OVER THE WESTERN USA WILL KEEP REGION
DRY SO KEPT POPS AT OR NEAR ZERO ON MANY DAYS IN EXTENDED.
TEMPERATURES SHOULD MODERATE NICELY DURING THE AFTERNOON IN THE
MOUNTAINS THOUGH INVERSION SHOULD KEEP STRATUS/FOG AROUND MOST OF DAY
WITH LITTLE MIXING THUS LOWERED VALLEY TEMPS. MAY GET SOME MIXING
AFTER SATURDAY AS OFFSHORE FLOW BEGINS ALSO MODELS NOT IN AGREEMENT
THEREAFTER SO FOR NOW KEEPING IT DRY. WOLFE
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE LEADING TO
VERY STABLE CONDITIONS ACROSS THE DISTRICT. MOISTURE TRAPPED UNDER
THE INVERSION HAS LED TO ANOTHER ROUND OF IFR CONDITIONS IN THE
INTERIOR THIS MORNING. ALONG THE COAST...OFFSHORE FLOW WILL ALLOW
VFR CONDITIONS TO CONTINUE. VFR CONDITIONS WILL RETURN ACROSS THE
INTERIOR THIS AFTERNOON AS LOW LEVEL OFFSHORE DEVELOPS.
KPDX AND APPROACHES...IFR CONDITIONS EXPECTED TO CONTINUE THIS
MORNING WITH CONDITIONS IMPROVING TO VFR BY 20Z. CONDITIONS WILL
LIKELY REMAIN VFR TONIGHT WITH STRONGER OFFSHORE FLOW.
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE
COASTAL WATERS...RESULTING IN RATHER LIGHT WINDS AND SEAS THROUGH
THE WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY WILLAMETTE VALLEY...CLARK COUNTY AND
LOWLANDS OF SOUTHWEST WASHINGTON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 141136
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
330 AM PST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEK AND DOMINATE
THE WEATHER PATTERN INTO THE WEEKEND. WARM AND DRY CONDITIONS IN
THE MOUNTAINS AND WIDESPREAD LOW CLOUDS AND FOG ACROSS THE LOW
LANDS FOR THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
TODAY AND TONIGHT...A STRONG UPPER LEVEL RIDGE WILL CONTINUE TO
BUILD OVER THE REGION TODAY. SPOKANE RAOBS OVER THE LAST 24 HOURS
INDICATE A STRENGTHENING INVERSION TREND. GFS AND NAM MODELS ARE
SIMILAR WITH THE UPPER LEVEL FIELD OF MOTION ADVERTISING A GENERAL
STATIC FLOW REGIME TODAY FOLLOWED BY A STRENGTHENING AND SHIFTING OF
THE RIDGE INTO THE REGION FROM IT`S CURRENT AXIS POSITION OFF THE
COAST. THIS BODES ILL FOR ANY RELIEF FROM THE MUSHY AND FOGGY
VALLEY/BASIN CONDITIONS CURRENTLY BEDEVILING THE REGION. AN
ALREADY WEAK SURFACE PRESSURE GRADIENT WILL REMAIN WEAK AS AN AXIS
OF SURFACE HIGH PRESSURE BECOMES ESTABLISHED OVER THE IDAHO
PANHANDLE. WITH LITTLE IN THE WAY OF WEATHER SYSTEMS TO SHAKE
LOOSE THE INVERSION AND STIR UP THE LOW LEVELS...A GENERAL
PERSISTENCE FORECAST OF MUCH OF THE SAME FOR THE NEXT 24 HOURS AS
OCCURRED IN THE LAST 24 HOURS IS PLAUSIBLE AND WELL WARRANTED.
THUS ALL CURRENT DENSE FOG ADVISORIES AND THE AIR STAGNATION
ADVISORY WILL REMAIN VALID. GENERALLY FOGGY AND COOL LOWER
ELEVATION CONDITIONS EXPECTED TODAY AND TONIGHT...WITH ONLY THE
PALOUSE REGION EXPERIENCING ANY MIXING AT ALL WITH THE SURFACE HIGH
OVER IDAHO ALLOWING A WEAK DRYING DOWNSLOPE BREEZE THROUGH
PULLMAN AND INTO THE BASIN. ON THE SKI SLOPES ABOVE 4000 FEET OR
SO GENERALLY SUNNY CONDITIONS. MUCH OF THE SAME TONIGHT AS IS
OCCURRING NOW...WITH WIDESPREAD FOG AND FREEZING FOG CONTINUING.
/FUGAZZI
THURSDAY THROUGH SUNDAY...ONLY CHANGE TO THE PREVIOUS
FORECAST PACKAGE WAS TO INCREASE TEMPERATURES ACROSS THE NORTHERN
BLUE MTS...CAMAS PRAIRIE AND PANHANDLE MOUNTAINS. TEMPERATURES AT
ALDER RIDGE/WINCHESTER TUESDAY AFTERNOON ARE ALREADY WARMING TO 50F
AND AS THE RIDGE AXIS MOVES INLAND LATE WEEK INTO THE
WEEKEND...850MB TEMPERATURES WILL BE WARMING FROM 4-6 CELSIUS UP TO
7-9 CELSIUS...EXPECT SURFACE TEMPS WILL CONTINUE FOLLOW THIS TREND
AND BECOME SLIGHTLY WARMER. CONFIDENCE IS STILL PRETTY LOW
REGARDING TEMPERATURE FORECAST FOR PALOUSE...L-C VALLEY WHERE
THERE REMAINS A SLIGHT POTENTIAL FOR WEAK EASTERLY GRADIENTS TO
MIX ERODE THE INVERSIONS OFF THE HIGHER TERRAIN. OTHERWISE...THE
FORECAST REMAINS ON TRACK WITH A LONGWAVE RIDGE DOMINATING THE
REGION KEEPING CONDITIONS DRY...SUNNY IN THE MOUNTAINS...CLOUDY
WITH FOG AND STRATUS IN THE VALLEYS WHERE STRONG LOW-LEVEL
INVERSIONS WILL RESULT IN POOR VENTILATION AND INCREASING LOW-
LEVEL POLLUTANTS. AIR STAGNATION ADVISORY WILL CONTINUE TO RUN
THROUGHOUT THE PERIOD.
MONDAY THROUGH WEDNESDAY...WE WILL SEE A SLOW MIGRATION OF
THE RIDGE AXIS TO THE EAST RESULTING IN A GRADUAL COOLING TREND
FOR THE MOUNTAINS BUT POSSIBLY WARMER TEMPERATURES FOR THE LOWER
ELEVATIONS AS BL MIXING INCREASES AND LOW-CLOUDS ERODE. HISTORY
TELLS US THAT MODELS TEND TO RUSH THE DEPARTURE OF THE RIDGE AND
OVER THE PREVIOUS 24 HOURS...HAVE BEGAN TO WITNESS A SLOWER
DEPARTURE OF THIS FEATURE PER GFS/EURO SOLUTIONS. HOWEVER...AS THE
RIDGE SHIFTS TO THE EAST...WE SHOULD SEE INCREASING SOUTHWESTERLY
FLOW AS A TROUGH AND ASSOCIATED CF PASSAGE APPROACH AND PASS THROUGH
ALSO BRINGING THE SLIGHT CHANCE FOR PRECIPITATION AND NEAR SEASONAL
TEMPERATURES. AS MENTIONED IN PREVIOUS AFD...MODELS ARE STRUGGLING
WITH THE STRENGTH OF THIS FEATURE AND CONFIDENCE REMAINS LOW ON
EXACT DETAILS. /BODNAR
&&
.AVIATION...
FOG AND VALLEY/COLUMBIA BASIN STRATUS WILL REMAIN A CONCERN THROUGH
12Z/15TH. HIGH PRESSURE WILL RESULT IN LIGHT WINDS AND CONTINUED
VERY MOIST AIR AT THE SURFACE ALLOWING FOG TO REMAIN WIDESPREAD WITH
IFR AND LIFR CONDITIONS THROUGH 18Z. FOG MAY ERODE OR LIFT SOME BTWN
18Z-00Z WITH SLIGHTLY INCREASED SURFACE HEATING. KGEG WILL SEE THE
WORST CONDITIONS WITH VISIBILITIES LIKELY REMAINING AOB 1/4SM
THROUGH 20Z...WITH MILD IMPROVEMENT DURING THE AFTERNOON...FOLLOWED
BY STRONG DETERIORATION BACK TO LIFR VISIBILITIES AFTER 00Z AGAIN.
TAF SITE KPUW WILL BE AN EXCEPTION TO THE FOG AND SHOULD KEEP MAINLY
VFR CONDITIONS THROUGH 12Z TOMORROW. STRATUS TOPS WILL REMAIN AROUND
4000 FEET MSL WITH MAINLY CLEAR CONDITIONS ABOVE THE STRATUS LAYER.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 35 30 35 32 35 29 / 0 0 0 0 0 0
COEUR D`ALENE 35 27 38 33 38 30 / 0 0 0 0 0 0
PULLMAN 46 33 41 30 39 33 / 0 0 0 0 0 0
LEWISTON 43 34 36 32 38 34 / 0 0 0 0 0 0
COLVILLE 35 29 35 26 35 25 / 0 0 0 0 0 0
SANDPOINT 35 27 34 27 34 27 / 0 0 0 0 0 0
KELLOGG 38 25 37 32 37 30 / 0 0 0 0 0 0
MOSES LAKE 35 29 36 31 36 31 / 0 0 0 0 0 0
WENATCHEE 36 30 36 29 36 30 / 0 0 0 0 0 0
OMAK 34 27 32 29 32 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR COEUR
D`ALENE AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR MOSES LAKE
AREA...SPOKANE AREA...UPPER COLUMBIA BASIN...WATERVILLE
PLATEAU...WENATCHEE AREA.
&&
$$
000
FXUS66 KSEW 141102
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST WED JAN 14 2009
.SYNOPSIS...A STRONG RIDGE OF HIGH PRESSURE WILL BUILD OVER THE
REGION INTO THE WEEKEND. THE AIR MASS WILL WARM AND DRY ALOFT WITH A
PRONOUNCED INVERSION DEVELOPING BY THURSDAY. AREAS OF DENSE FOG WILL
LIKELY DEVELOP TONIGHT...AND MAY PERSIST IN SOME AREAS INTO
THE WEEKEND. THE WEATHER IN THE MOUNTAINS WILL BE WARMER AND SUNNY.
&&
.SHORT TERM...IN THE BIG PICTURE...UPPER LEVEL RIDGING ALONG THE
WEST COAST WILL CONTINUE TO AMPLIFY THROUGH THE END OF THE WEEK.
THIS WILL CONTINUE TO KEEP THE AREA DRY AS SYSTEMS ARE STEERED WELL
NORTH OF THE REGION. THE SMALLER SCALE CHALLENGE REMAINS THE DAY TO
DAY VARIATION IN FOG AND LOW CLOUD COVERAGE. THERE IS WEAK OFFSHORE
FLOW THIS MORNING. HOWEVER...AS MIGHT BE EXPECTED UNDER A STRONG
RIDGE THIS TIME OF YEAR...STRONG LOW LEVEL INVERSIONS ARE IN PLACE
AND WILL NOT BE GOING ANYWHERE ANYTIME SOON. ACARS DATA AND THE KSEW
PROFILER VERIFY THAT THE INVERSION EXTENDS UP TO ABOUT 4000 TO 5000
FEET THIS MORNING. COASTAL AREAS AND THE CASCADES FOOTHILLS WILL
BENEFIT FROM THE OFFSHORE FLOW WITH LIMITED NIGHT AND MORNING FOG.
ELSEWHERE...IT WILL BE MORE OF A CHALLENGE BREAKING OUT OF THE GREY
BLANKET AND INTO THE SUN. MODEL SOUNDINGS SHOW WARMING ALOFT...WITH
TEMPERATURES WARMING INTO THE LOWER 60S DOWN TO ABOUT 925 MB BY
LATER THURSDAY AND AGAIN ON FRIDAY. THIS WILL EFFECTIVELY SQUEEZE
THE LOW CLOUD LAYER OVER THE INTERIOR...FOR MORE DENSE AREAS OF
MORNING FOG...BUT A BETTER CHANCE AT SOME AFTERNOON CLEARING FOR
SOME AREAS. A QUIET WEATHER PATTERN THIS TIME OF YEAR PRESENTS A
UNIQUE CHALLENGE...AREAS GETTING MAXIMUM BENEFIT FROM THE UPPER
LEVEL RIDGING..I.E. COAST...WILL PROBABLY SEE TEMPERATURES WELL
ABOVE NORMAL WHILE SPOTS STUCK IN DENSE FOG OVER THE SOUTHWEST
INTERIOR COULD SEE BELOW AVERAGE TEMPERATURES. A DISTANCE OF JUST A
FEW MILES IN THE HORIZONTAL OR A FEW HUNDRED FEET IN THE VERTICAL
COULD MEAN QUITE A DIFFERENCE IN CONDITIONS.
.LONG TERM...RIDGING REMAINS OVER THE REGION THROUGH THE WEEKEND
WITH AREAS OF FOG STICKING AROUND...ESPECIALLY INTERIOR AREAS. THE
EXTENDED MODELS CONTINUE TO SHOW A CHANGE IN THE PATTERN EARLY NEXT
WEEK AS UPPER LEVEL RIDGING SHIFTS EASTWARD INTO THE ROCKIES AND
FLATTENS. THERE IS PLENTY OF VARIATION IN THE MODEL SOLUTIONS...BUT
RECENT RUNS OF THE GFS AND EURO MODELS SHOW UPPER LEVEL RIDGING
RETROGRADING BACK TO 140W TO 150W...WITH CUT OFF SYSTEMS HEADING
INTO OUR SOUTH. THIS DOES NOT LOOK PARTICULARLY WET...BUT CERTAINLY
LOOKS MORE UNSETTLED BEYOND THE MIDDLE OF NEXT WEEK. 27
&&
.AVIATION...THE MAIN CONCERN TODAY IS FOG AND LOW CLOUDS ACROSS THE
LOWLANDS. WITH HIGH PRES IN THE REGION...STRONG SUBSIDENCE INVERSION
WILL STRENGTHEN WITH MOISTURE AND LOW CLOUDS TRAPPED WITHIN A LAYER
ONLY AROUND 700-1000FT ABOVE THE SURFACE. PRES GRADIENTS ARE WEAK
AND WITH VERY LITTLE VERTICAL MIXING WE COULD END UP WITH IFR TO
LIFR CONDITIONS THROUGH THE EARLY AFTERNOON. MODELS DO SHOW SOME
IMPROVEMENT TO THE CIGS AND VIS BY MIDDAY BUT IT WILL BE HARD TO
SCOUR OUT ANY MOISTURE. THUS THE INTERIOR MAY STAY CLOUDY THROUGHOUT
THE AFTERNOON...WITH CLEARING MAINLY ALONG THE COAST. TRAPPED AIR
POLLUTANTS MAY ALSO LEAD TO LOWER VIS IN HZ...PARTICULARLY ACROSS
THE CENTRAL SOUND. HIGH PRES WILL SHIFT OVER WA WED NIGHT INTO THU
WITH ANOTHER ROUND OF LOW CLOUDS AND FOG EXPECTED...ESPECIALLY
ACROSS THE INTERIOR.
KSEA...FOG IS STILL POSSIBLE EARLY THIS MORNING WITH WEAK NORTHERLY
WINDS AND STRATUS DECK LOWERING. DEWPOINTS REMAIN HIGH SO ITS ONLY A
MATTER OF TIME BEFORE IT DEVELOPS. ACARS SOUNDINGS AND NOAA SAND
POINT PROFILER SHOWS THE START OF THE INVERSION NEAR 2500 FT...AND
NAM BUFFER SOUNDING SHOWS WARMING NEAR 700FT AGL THIS AFTERNOON. SO
FOG WILL LIKELY PERSIST THROUGH THE MORNING WITH IFR BKN-OVC LAYER
EXPECTED THIS AFTERNOON. MAY ALSO SEE LOWER VIS IN HZ WITH A
STAGNANT AIRMASS IN PLACE. FOG EXPECTED TO REDEVELOP ONCE AGAIN LATE
TONIGHT INTO THU MORNING. 33
&&
.MARINE...HIGH PRES CENTER 1033MB OVER THE COASTAL/OFFSHORE WATERS
WILL SHIFT INLAND TODAY WITH LIGHT WINDS OVER THE WATERS. HIGH PRES
WILL MOVE EAST OF THE CASCADES OVERNIGHT WITH INCREASING OFFSHORE
FLOW EXPECTED. OFFSHORE FLOW PATTERN WILL PERSIST THROUGH THE
WEEKEND. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER IN
KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...NONE.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KPQR 141041
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
241 AM PST WED JAN 14 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE LOW-LEVEL FLOW SHOULD BEGIN TO
DEVELOP TODAY...AND THEN INTENSIFY TONIGHT AND THURSDAY. EXPECT THE
OFFSHORE FLOW TO LAST THROUGH SUNDAY. STRONG VALLEY INVERSIONS WILL
RESULT IN UNSEASONABLY WARM DAYTIME TEMPERATURES IN THE COAST RANGE
AND CASCADES FOR THE NEXT FEW DAYS.
&&
.SHORT TERM...STRONG UPPER LEVEL RIDGE WILL BE THE DOMINANT FEATURE
FOR THE NEXT FEW DAYS. MODELS MAINTAIN A NEARLY 590 DECAMETER HIGH
CENTERED OFF THE N CALIFORNIA COAST TODAY...AND THEN DRIFT IT A
LITTLE N FRI AND SAT. 00Z SALEM SOUNDING SHOWED THE TOP OF THE
INVERSION AT AROUND 1700 FT AGL...WHICH WILL SUBSIDE FURTHER AS THE
UPPER RIDGE AXIS EDGES INTO THE AREA. EXTREMELY DRY AIR ABOVE THE
INVERSION WILL CONTINUE INTO THE WEEKEND...WITH UNSEASONABLY WARM
TEMPS. THE 00Z SALEM SOUNDING SHOWED 55 DEG FROM 2000 FT TO 5500 FT.
SEVERAL SPOTS IN THE CASCADES...ESPECIALLY THE CENTRAL CASCADES...
REACHED INTO THE 60S TUE...AND WILL REPEAT OR EVEN WARM SOME MORE
THROUGH THE WEEK.
MODELS AND GRADIENT TRENDS SUGGEST LIGHT OFFSHORE FLOW WILL DEVELOP
TODAY...THEN STRENGTHEN SOME TONIGHT AND THU. EXPECT PERSISTENT FOG
AND LOW CLOUDS IN THE CENTRAL AND SOUTH WILLAMETTE VALLEY AND THE I-5
CORRIDOR UP THROUGH KELSO. A SOLID STRATUS DECK WILL ALSO BE
DEVELOPING IN THE GORGE E OF CASCADE LOCKS DURING THE NEXT SEVERAL
DAYS. THE DEVELOPING E WIND WILL LIMIT FOG AND LOW CLOUDS IN THE N
WILLAMETTE VALLEY AND CLARK COUNTY TO THE W SIDE OF THE METRO AREA.
RW
&&
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
STRONG WARM CORE HIGH PRESSURE OVER THE WESTERN USA WILL KEEP REGION
DRY SO KEPT POPS AT OR NEAR ZERO ON MANY DAYS IN EXTENDED.
TEMPERATURES SHOULD MODERATE NICELY DURING THE AFTERNOON IN THE
MOUNTAINS THOUGH INVERSION SHOULD KEEP STRATUS/FOG AROUND MOST OF DAY
WITH LITTLE MIXING THUS LOWERED VALLEY TEMPS. MAY GET SOME MIXING
AFTER SATURDAY AS OFFSHORE FLOW BEGINS ALSO MODELS NOT IN AGREEMENT
THEREAFTER SO FOR NOW KEEPING IT DRY. WOLFE
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE LEADING TO
VERY STABLE CONDITIONS ACROSS THE DISTRICT. MOISTURE TRAPPED UNDER
THE INVERSION HAS LED TO ANOTHER ROUND OF IFR CONDITIONS IN THE
INTERIOR THIS MORNING. ALONG THE COAST...OFFSHORE FLOW WILL ALLOW
VFR CONDITIONS TO CONTINUE. VFR CONDITIONS WILL RETURN ACROSS THE
INTERIOR THIS AFTERNOON AS LOW LEVEL OFFSHORE DEVELOPS.
KPDX AND APPROACHES...IFR CONDITIONS EXPECTED TO CONTINUE THIS
MORNING WITH CONDITIONS IMPROVING TO VFR BY 20Z. CONDITIONS WILL
LIKELY REMAIN VFR TONIGHT WITH STRONGER OFFSHORE FLOW.
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE
COASTAL WATERS...RESULTING IN RATHER LIGHT WINDS AND SEAS THROUGH
THE WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY WILLAMETTE VALLEY...CLARK COUNTY AND
LOWLANDS OF SOUTHWEST WASHINGTON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 141028
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
228 AM PST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEK AND DOMINATE
THE WEATHER PATTERN INTO THE WEEKEND. WARM AND DRY CONDITIONS IN
THE MOUNTAINS AND WIDESPREAD LOW CLOUDS AND FOG ACROSS THE LOW
LANDS FOR THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
TODAY AND TONIGHT...A STRONG UPPER LEVEL RIDGE WILL CONTINUE TO
BUILD OVER THE REGION TODAY. SPOKANE RAOBS OVER THE LAST 24 HOURS
INDICATE A STRENGTHENING INVERSION TREND. GFS AND NAM MODELS ARE
SIMILAR WITH THE UPPER LEVEL FIELD OF MOTION ADVERTISING A GENERAL
STATIC FLOW REGIME TODAY FOLLOWED BY A STRENGTHENING AND SHIFTING OF
THE RIDGE INTO THE REGION FROM IT`S CURRENT AXIS POSITION OFF THE
COAST. THIS BODES ILL FOR ANY RELIEF FROM THE MUSHY AND FOGGY
VALLEY/BASIN CONDITIONS CURRENTLY BEDEVILING THE REGION. AN
ALREADY WEAK SURFACE PRESSURE GRADIENT WILL REMAIN WEAK AS AN AXIS
OF SURFACE HIGH PRESSURE BECOMES ESTABLISHED OVER THE IDAHO
PANHANDLE. WITH LITTLE IN THE WAY OF WEATHER SYSTEMS TO SHAKE
LOOSE THE INVERSION AND STIR UP THE LOW LEVELS...A GENERAL
PERSISTENCE FORECAST OF MUCH OF THE SAME FOR THE NEXT 24 HOURS AS
OCCURRED IN THE LAST 24 HOURS IS PLAUSIBLE AND WELL WARRANTED.
THUS ALL CURRENT DENSE FOG ADVISORIES AND THE AIR STAGNATION
ADVISORY WILL REMAIN VALID. GENERALLY FOGGY AND COOL LOWER
ELEVATION CONDITIONS EXPECTED TODAY AND TONIGHT...WITH ONLY THE
PALOUSE REGION EXPERIENCING ANY MIXING AT ALL WITH THE SURFACE HIGH
OVER IDAHO ALLOWING A WEAK DRYING DOWNSLOPE BREEZE THROUGH
PULLMAN AND INTO THE BASIN. ON THE SKI SLOPES ABOVE 4000 FEET OR
SO GENERALLY SUNNY CONDITIONS. MUCH OF THE SAME TONIGHT AS IS
OCCURRING NOW...WITH WIDESPREAD FOG AND FREEZING FOG CONTINUING.
/FUGAZZI
THURSDAY THROUGH SUNDAY...ONLY CHANGE TO THE PREVIOUS
FORECAST PACKAGE WAS TO INCREASE TEMPERATURES ACROSS THE NORTHERN
BLUE MTS...CAMAS PRAIRIE AND PANHANDLE MOUNTAINS. TEMPERATURES AT
ALDER RIDGE/WINCHESTER TUESDAY AFTERNOON ARE ALREADY WARMING TO 50F
AND AS THE RIDGE AXIS MOVES INLAND LATE WEEK INTO THE
WEEKEND...850MB TEMPERATURES WILL BE WARMING FROM 4-6 CELSIUS UP TO
7-9 CELSIUS...EXPECT SURFACE TEMPS WILL CONTINUE FOLLOW THIS TREND
AND BECOME SLIGHTLY WARMER. CONFIDENCE IS STILL PRETTY LOW
REGARDING TEMPERATURE FORECAST FOR PALOUSE...L-C VALLEY WHERE
THERE REMAINS A SLIGHT POTENTIAL FOR WEAK EASTERLY GRADIENTS TO
MIX ERODE THE INVERSIONS OFF THE HIGHER TERRAIN. OTHERWISE...THE
FORECAST REMAINS ON TRACK WITH A LONGWAVE RIDGE DOMINATING THE
REGION KEEPING CONDITIONS DRY...SUNNY IN THE MOUNTAINS...CLOUDY
WITH FOG AND STRATUS IN THE VALLEYS WHERE STRONG LOW-LEVEL
INVERSIONS WILL RESULT IN POOR VENTILATION AND INCREASING LOW-
LEVEL POLLUTANTS. AIR STAGNATION ADVISORY WILL CONTINUE TO RUN
THROUGHOUT THE PERIOD.
MONDAY THROUGH WEDNESDAY...WE WILL SEE A SLOW MIGRATION OF
THE RIDGE AXIS TO THE EAST RESULTING IN A GRADUAL COOLING TREND
FOR THE MOUNTAINS BUT POSSIBLY WARMER TEMPERATURES FOR THE LOWER
ELEVATIONS AS BL MIXING INCREASES AND LOW-CLOUDS ERODE. HISTORY
TELLS US THAT MODELS TEND TO RUSH THE DEPARTURE OF THE RIDGE AND
OVER THE PREVIOUS 24 HOURS...HAVE BEGAN TO WITNESS A SLOWER
DEPARTURE OF THIS FEATURE PER GFS/EURO SOLUTIONS. HOWEVER...AS THE
RIDGE SHIFTS TO THE EAST...WE SHOULD SEE INCREASING SOUTHWESTERLY
FLOW AS A TROUGH AND ASSOCIATED CF PASSAGE APPROACH AND PASS THROUGH
ALSO BRINGING THE SLIGHT CHANCE FOR PRECIPITATION AND NEAR SEASONAL
TEMPERATURES. AS MENTIONED IN PREVIOUS AFD...MODELS ARE STRUGGLING
WITH THE STRENGTH OF THIS FEATURE AND CONFIDENCE REMAINS LOW ON
EXACT DETAILS. /BODNAR
&&
.AVIATION...
FOG WILL REMAIN A CONCERN THROUGH 06Z/15TH. HIGH PRESSURE WILL
RESULT IN LIGHT WINDS AND CONTINUED VERY MOIST AIR AT THE SURFACE
ALLOWING FOG TO INCREASE IN COVERAGE THROUGH 18Z. THEN THE FOG MAY
ERODE OR LIFT SOME BTWN 18Z-00Z WITH SLIGHTLY INCREASED SURFACE
HEATING. KGEG WILL SEE THE WORST CONDITIONS WITH VISIBILITIES
LIKELY REMAINING BELOW 1/4SM THROUGH 20Z. TAF SITE KPUW WILL BE AN
EXCEPTION TO THE FOG AND SHOULD KEEP MAINLY VFR CONDITIONS THROUGH
TOMORROW. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 35 30 35 32 35 29 / 0 0 0 0 0 0
COEUR D`ALENE 35 27 38 33 38 30 / 0 0 0 0 0 0
PULLMAN 46 33 41 30 39 33 / 0 0 0 0 0 0
LEWISTON 43 34 36 32 38 34 / 0 0 0 0 0 0
COLVILLE 35 29 35 26 35 25 / 0 0 0 0 0 0
SANDPOINT 35 27 34 27 34 27 / 0 0 0 0 0 0
KELLOGG 38 25 37 32 37 30 / 0 0 0 0 0 0
MOSES LAKE 35 29 36 31 36 31 / 0 0 0 0 0 0
WENATCHEE 36 30 36 29 36 30 / 0 0 0 0 0 0
OMAK 34 27 32 29 32 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR COEUR
D`ALENE AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR MOSES LAKE
AREA...SPOKANE AREA...UPPER COLUMBIA BASIN...WATERVILLE
PLATEAU...WENATCHEE AREA.
&&
$$
000
FXUS66 KOTX 140625
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1025 PM PST TUE JAN 13 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEK AND DOMINATE
THE WEATHER PATTERN INTO THE WEEKEND. WARM AND DRY CONDITIONS IN
THE MOUNTAINS AND WIDESPREAD LOW CLOUDS AND FOG ACROSS THE LOW
LANDS FOR THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
FOG PRODUCT SATELLITE AND SURFACE OBSERVATIONS INDICATE THAT DENSE
FOG HAS SPREAD INTO THE COEUR D`ALENE AREA SO THE DENSE FOG
ADVISORY HAS BEEN EXPANDED TO INCLUDE THIS AREA. LOW TEMPERATURES
WERE ALSO ADJUSTED SLIGHTLY DOWNWARD BASED ON CURRENT OBSERVATIONS
AND EXPECTED MINIMAL COOLING FOR THE REST OF TONIGHT WHERE LOW
CLOUDS AND STRATUS CURRENTLY RESIDE. LATEST 00Z GFS/CANADIAN
MODELS KEEP THE UPPER RIDGE PERSISTING OVER THE WEST THROUGH AT
LEAST MONDAY...SO CURRENT AIR STAGNATION ADVISORIES LOOKS GOOD. JW
&&
.AVIATION...
FOG WILL REMAIN A CONCERN THROUGH 06Z/15TH. HIGH PRESSURE WILL
RESULT IN LIGHT WINDS AND CONTINUED VERY MOIST AIR AT THE SURFACE
ALLOWING FOG TO INCREASE IN COVERAGE THROUGH 18Z. THEN THE FOG MAY
ERODE OR LIFT SOME BTWN 18Z-00Z WITH SLIGHTLY INCREASED SURFACE
HEATING. KGEG WILL SEE THE WORST CONDITIONS WITH VISIBILITIES
LIKELY REMAINING BELOW 1/4SM THROUGH 20Z. TAF SITE KPUW WILL BE AN
EXCEPTION TO THE FOG AND SHOULD KEEP MAINLY VFR CONDITIONS THROUGH
TOMORROW. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 31 35 33 35 32 35 / 0 0 0 0 0 0
COEUR D`ALENE 26 35 33 38 33 38 / 0 0 0 0 0 0
PULLMAN 30 44 30 41 30 39 / 0 0 0 0 0 0
LEWISTON 33 45 33 36 32 38 / 0 0 0 0 0 0
COLVILLE 31 34 29 35 26 35 / 0 0 0 0 0 0
SANDPOINT 26 34 29 34 27 34 / 0 0 0 0 0 0
KELLOGG 25 38 35 37 32 37 / 0 0 0 0 0 0
MOSES LAKE 29 35 32 36 31 36 / 0 0 0 0 0 0
WENATCHEE 28 35 33 36 29 36 / 0 0 0 0 0 0
OMAK 28 33 31 32 29 32 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
DENSE FOG ADVISORY UNTIL 4 PM PST WEDNESDAY FOR COEUR D`ALENE
AREA.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 4 PM PST WEDNESDAY FOR MOSES LAKE
AREA...SPOKANE AREA...UPPER COLUMBIA BASIN...WATERVILLE
PLATEAU...WENATCHEE AREA.
&&
$$
000
FXUS66 KOTX 140538
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
938 PM PST TUE JAN 13 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEK AND DOMINATE
THE WEATHER PATTERN INTO THE WEEKEND. WARM AND DRY CONDITIONS IN
THE MOUNTAINS AND WIDESPREAD LOW CLOUDS AND FOG ACROSS THE LOW
LANDS FOR THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
UPDATED AVIATION DISCUSSION
FOG PRODUCT SHOWS AS OF 615 PM MOST OF SPOKANE COUNTY COVERED BY
FOG AND STRATUS. SURFACE OBSERVATIONS AND CAMERAS INDICATE THAT
THE FOG IS DENSE ABOVE AROUND 2000 FEET SO DECIDED TO EXTEND THE
DENSE FOG ADVISORIES INTO THE SPOKANE AREA. WILL HAVE TO MONITOR
THE NORTH IDAHO PANHANDLE AND THE COEUR D`ALENE AREA AS WELL WHERE
CLEARING AT THE MOMENT WILL LEAD TO BETTER RADIATIONAL FOG
FORMATION POTENTIAL. THE LEWISTON AREA IS ALSO SEEING
DETERIORATING CONDITIONS SO WILL MONITOR THIS AREA FOR A POSSIBLE
DENSE FOG ADVISORY. FOR OTHER AREAS WITHIN THE ADVISORY...IE
WENATCHEE AND WATERVILLE PLATEAU...MOSES LAKE AREA...AND UPPER
COLUMBIA BASIN...THE FOG AND STRATUS IS MORE HIT OR MISS AT THE
MOMENT. HOWEVER WITH THE BREAKS IN THE CLOUD COVER I EXPECT THE
FOG COVERAGE TO INCREASE TONIGHT SO WILL LET ADVISORIES FOR THESE
AREAS REMAIN IN EFFECT.
OTHER CHANGE WAS TO LOWER MIN TEMPS SLIGHTLY FOR THE WENATCHEE...MOSES
LAKE AND OMAK AREA WHERE CURRENT READINGS WERE SLIGHTLY COOLER THEN
FORECAST LOWS. JW
&&
.AVIATION...
FOG WILL REMAIN A CONCERN THROUGH 06Z/15TH. HIGH PRESSURE WILL
RESULT IN LIGHT WINDS AND CONTINUED VERY MOIST AIR AT THE SURFACE
ALLOWING FOG TO INCREASE IN COVERAGE THROUGH 18Z. THEN THE FOG MAY
ERODE OR LIFT SOME BTWN 18Z-00Z WITH SLIGHTLY INCREASED SURFACE
HEATING. KGEG WILL SEE THE WORST CONDITIONS WITH VISIBILITIES
LIKELY REMAINING BELOW 1/4SM THROUGH 20Z. TAF SITE KPUW WILL BE AN
EXCEPTION TO THE FOG AND SHOULD KEEP MAINLY VFR CONDITIONS THROUGH
TOMORROW. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 33 35 33 35 32 35 / 0 0 0 0 0 0
COEUR D`ALENE 33 35 33 36 33 36 / 10 0 0 0 0 0
PULLMAN 30 44 30 41 30 40 / 0 0 0 0 0 0
LEWISTON 34 45 33 46 32 46 / 0 0 0 0 0 0
COLVILLE 32 34 29 32 25 32 / 0 0 0 0 0 0
SANDPOINT 33 34 29 34 27 34 / 10 0 0 0 0 0
KELLOGG 31 38 35 37 35 37 / 10 0 0 0 0 0
MOSES LAKE 31 35 32 36 31 36 / 0 0 0 0 0 0
WENATCHEE 29 35 33 36 33 36 / 0 0 0 0 0 0
OMAK 30 33 31 33 29 33 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 3 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
WA...AIR STAGNATION ADVISORY UNTIL 3 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 4 PM PST WEDNESDAY FOR MOSES LAKE
AREA...SPOKANE AREA...UPPER COLUMBIA BASIN...WATERVILLE
PLATEAU...WENATCHEE AREA.
&&
$$
000
FXUS66 KSEW 140535
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
935 PM PST TUE JAN 13 2009
.SYNOPSIS...A STRONG RIDGE OF HIGH PRESSURE WILL BUILD OVER THE
REGION INTO THE WEEKEND. THE AIR MASS WILL WARM AND DRY ALOFT WITH A
PRONOUNCED INVERSION DEVELOPING BY THURSDAY. AREAS OF DENSE FOG WILL
LIKELY DEVELOP WEDNESDAY NIGHT...AND MAY PERSIST IN SOME AREAS INTO
THE WEEKEND. THE WEATHER IN THE MOUNTAINS WILL BE WARMER AND SUNNY.
&&
.SHORT TERM...SATELLITE IMAGERY SHOWS HIGH AMPLITUDE RIDGE OFFSHORE.
STRATUS/FOG IMAGERY SHOWS CLOUDS OVER MOST OF WESTERN WASHINGTON
WITH ONLY THE COAST OUT OF THE CLOUDS. LOW LEVEL OFFSHORE GRADIENTS
HAVE NOT INCREASED MUCH TODAY. CLOUD TOP REPORTS THIS MORNING OVER
SEATTLE WERE IN THE 3500 TO 4000 FOOT RANGE. NO TOP REPORTS THIS
EVENING BUT WITH KBFI STILL AT 3100 OVERCAST AT 05Z EXPECT THERE HAS
BEEN LITTLE CHANGE IN THE TOPS TODAY. NOT MUCH CHANGE IN STORE FOR
TONIGHT AND TOMORROW. THE STRONG LOW LEVEL INVERSION THAT IS OVER
WESTERN WASHINGTON WILL CONTINUE TO STRENGTHEN AS THE TEMPERATURES
ALOFT WARM...ACARS SOUNDINGS ALREADY REPORTING 9C (48F) AT 5000 FEET
OVER SEATTLE. THIS WILL SLOWLY COMPRESS THE LOW LEVEL MOISTURE OVER
THE AREA. MODEL CROSS SECTIONS CONTINUE TO CLEAR THINGS OUT TOMORROW
AFTERNOON BUT WITH THE LACK OF MUCH WIND BELOW 850 MB AND THE
OFFSHORE GRADIENTS JUST SLOWLY INCREASING WILL STAY WITH THE CURRENT
FORECAST THAT DOES NOT CALL FOR MUCH CLEARING OVER THE INTERIOR.
UPPER LEVEL RIDGE AXIS BEGINS TO DRIFT EAST OVER THE AREA ON
THURSDAY WITH SOME INCREASE IN THE LOW LEVEL OFFSHORE FLOW. ONCE
AGAIN MOST OF THE OFFSHORE GRADIENTS IS CONFINED TO NEAR THE
CASCADES. INVERSION OVER THE AREA WILL CONTINUE TO STRENGTHEN AND
LOWER ON THURSDAY...NAM BUFR SOUNDINGS HAVE THE TEMPERATURE AT 2000
FEET OVER SEATTLE NEAR 60F. THIS WILL CONTINUE TO COMPRESS THE LOW
LEVEL MOISTURE OVER THE AREA. BECAUSE OF THIS EXPECT MORE FOG
THURSDAY MORNING VERSUS WEDNESDAY MORNING BUT A BETTER CHANCE FOR
SOME SUNSHINE IN THE AFTERNOON. SAME STORY ON FRIDAY WITH THE UPPER
LEVEL RIDGE RIGHT OVERHEAD AND LIGHT OFFSHORE GRADIENTS. LOW LEVEL
WINDS...BELOW 850 MB CONTINUE TO BE LIGHT...LESS THAN 10 KNOTS.
WITHOUT MORE MIXING WILL KEEP MENTION OF FOG/LOW CLOUDS IN THE
FORECAST ON FRIDAY. CURRENT FORECAST HAS THE TRENDS COVERED. NO
UPDATE THIS EVENING. FELTON
.LONG TERM...PREVIOUS DISCUSSION FOLLOWS. FCST TRENDS TOWARD
CLIMO...BUT MAYBE TOO FAST WITH MORE CLOUDS AND A LOWERING FREEZING
LEVEL. STILL A LITTLE EARLY TO CALL FOR RETROGRESSION OF THE RIDGE
OR SAY MUCH ABOUT A POSSIBLE COLD FRONT ARND TUE. 12Z GFS HAS BACKED
OFF OR DELAYED THE RETROGRESSION. ECMWF STILL HAS A COLD FRONT...NOW
TIMED FOR TUESDAY EVENING...BUT THEN THE ECMWF REBUILDS THE RIDGE A
BIT AND BY THE END OF NEXT WEEK IT IS STILL AWFULLY RIDGY W/ TWO CUT
OFF LOWS...SRN CALIF AND OFFSHORE...CUTTING UNDER A BROAD FLAT
WEAKER RIDGE. THE GFS COLD FRONT LATE MON OR TUE IS NONEXISTENT
NOW...BUT BY THE END OF NEXT WEEK ALSO HAS A CUT OFF LOW UNDER A
RIDGE ALONG 130W. BASED ON THE 12Z RUN THERE IS A GOOD CHANCE IT
WILL STAY DRY WITH LOW CLOUDS AND FOG IN THE LOWLANDS BUT I SEE NO
REASON TO PULL THE INFLUENCE OF CLIMO OUT OF THE GRIDS YET. 5 WAVE
CHART FROM THE 06Z RUN SHOWS A STRONG RIDGE ALONG 150W BY THE END OF
NEXT WEEK...12Z RUN HAS A MUCH WEAKER RIDGE WITH THE AXIS AROUND
135W. HAVE NOT EVEN LOOKED AT THE 18Z RUN TDY. 19
&&
.AVIATION...HIGH AMPLITUDE RIDGE CONTINUES TO BUILD OFFSHORE WITH
NWLY FLOW ALOFT AND LIGHT OFFSHORE FLOW AT THE SURFACE. THE MAIN
CONCERN OVERNIGHT IS FOG ACROSS THE LOWLANDS. THE LOW LEVEL
INVERSION WILL STRENGTHEN OVERNIGHT CREATING A TRAPPED SHALLOW MOIST
LAYER AT THE SURFACE TO AROUND 1000FT AGL. IT WILL BE EXTREMELY
DIFFICULT TO SCOUR OUT ANY LOW LEVEL MOISTURE ON WED AS THE LOW
LEVEL INVERSION REMAINS QUITE STRONG WITH LARGE SCALE SUBSIDENCE.
THUS WILL LIKELY SEE CIGS NEAR IFR WITH FOG REDEVELOPING WED NIGHT.
KSEA...MAIN CONCERN IS FOG OVERNIGHT WHICH STILL LOOKS LIKELY. IT IS
JUST A MATTER OF TIMING AT THIS POINT. WITH THE STRONG LOW LEVEL
INVERSION IN PLACE...MAY ONLY SEE A BRIEF WINDOW OF IMPROVING
CONDITIONS WED AFTERNOON BEFORE FOG REDEVELOPS WED NIGHT. LOW CLOUDS
WILL BE QUITE SHALLOW WITH CLOUD TOPS NEAR 1000FT. WINDS WILL STAY
LIGHT NORTHERLY. 33
&&
.MARINE...HIGH PRES OVER THE COASTAL/OFFSHORE WATERS WILL SHIFT
INLAND OVERNIGHT WITH LIGHT WINDS OVER THE WATERS. HIGH PRES WILL
MOVE EAST OF THE CASCADES ON WED WITH INCREASING OFFSHORE FLOW.
OFFSHORE FLOW PATTERN WILL PERSIST THROUGH THE WEEKEND. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WARNING REMAINS IN EFFECT FOR THE CEDAR RIVER IN
KING COUNTY.
FLOOD ADVISORY REMAINS IN EFFECT FOR THE GREEN RIVER IN KING
COUNTY.
PZ...NONE.
$$
WWW.WEATHER.GOV/SEATTLE
000
FXUS66 KPQR 140435
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 PM PST TUE JAN 13 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE LOW-LEVEL FLOW SHOULD BEGIN
TO DEVELOP LATE TONIGHT OR WED MORNING...AND THEN INTENSIFY WED
AFTERNOON THROUGH THU. EXPECT THE OFFSHORE FLOW TO LAST THROUGH
SUNDAY. STRONG VALLEY INVERSIONS WILL RESULT IN UNSEASONABLY
WARM DAYTIME TEMPERATURES IN THE COAST RANGE AND CASCADES FOR THE
NEXT FEW DAYS.
&&
.SHORT TERM...STRONG UPPER LEVEL RIDGE WILL BE THE DOMINANT FEATURE
FOR THE NEXT FEW DAYS. MODELS MAINTAIN A NEARLY 590 DECAMETER HIGH
CENTERED OFF THE N CALIFORNIA COAST THROUGH WED...AND THEN DRIFT IT A
LITTLE NORTH FRI AND SAT. 00Z SALEM SOUNDING SHOWED THE TOP OF THE
INVERSION AT AROUND 1700 FT AGL. PILOT REPORT AT 0235Z OVER EUGENE
PLACED THE TOP AT 1900 FEET MSL. EXTREMELY DRY AIR ABOVE THE
INVERSION. SEVERAL RAWS SITES IN THE COAST RANGE AND CASCADES HAD
DAYTIME HUMIDITY VALUES LESS THAN 20 PERCENT...WITH SOME ISOLATED
AREAS BELOW 10 PERCENT. IN ADDITION...THE SALEM SOUNDING SHOWED 55
DEG AT 5500 FEET. SEVERAL SPOTS IN THE CASCADES...ESPECIALLY THE
CENTRAL CASCADES...REACHED INTO THE 60S TODAY.
THE OVERALL PATTERN WILL NOT CHANGE MUCH THROUGH THE SHORT TERM. THE
ONLY DIFFERENCE WILL BE THE DEGREE OF OFFSHORE FLOW. MODELS SUGGEST
LIGHT OFFSHORE FLOW SHOULD DEVELOP LATE TONIGHT OR WED MORNING. NAM-
12 INDICATES AROUND A -3.0 MB GRADIENT KPDX-KDLS 15Z WED. IT WILL
STRENGTHEN LATE WED AFTERNOON THROUGH THU. NAM BUFR SOUNDINGS SHOW
SEVERAL DEGREES OF WARMING BETWEEN 925 MB AND 850 MB. NAM AND GFS
INDICATE 850 MB TEMPS OF 16C 00Z THU FOR THE COAST AND COAST RANGE
AND TO 14C IN THE CASCADES. VERY LIKELY THAT SOME SOUTH ASPECTS IN
THE COAST RANGE...CASCADE FOOTHILLS AND CASCADES WILL HIT 70 DEGREES
...ESPECIALLY THU AND FRI. EXPECT PERSISTENT FOG AND LOW CLOUDS
IN THE CENTRAL AND SOUTH WILLAMETTE VALLEY AND THE I-5 CORRIDOR
BETWEEN KPDX AND KKLS. A SOLID STRATUS DECK CAN BE EXPECTED IN THE
GORGE EAST OF CASCADE LOCKS. THE DEVELOPING EAST WIND WILL LIMIT FOG
AND LOW CLOUDS IN THE NORTH WILLAMETTE VALLEY AND CLARK COUNTY TO THE
WEST SIDE.
MAV AND MET GUIDANCE CONTINUE TO BE TOO COLD FOR MINS. HAD TO RAISE
TONIGHTS MINS 2-4 DEGREES IN MOST AREAS BASED ON CURRENT DEW POINTS.
WEISHAAR.
&&
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
STRONG WARM CORE HIGH PRESSURE OVER THE WESTERN USA WILL KEEP REGION
DRY SO KEPT POPS AT OR NEAR ZERO ON MANY DAYS IN EXTENDED.
TEMPERATURES SHOULD MODERATE NICELY DURING THE AFTERNOON IN THE
MOUNTAINS THOUGH INVERSION SHOULD KEEP STRATUS/FOG AROUND MOST OF DAY
WITH LITTLE MIXING THUS LOWERED VALLEY TEMPS. MAY GET SOME MIXING
AFTER SATURDAY AS OFFSHORE FLOW BEGINS ALSO MODELS NOT IN AGREEMENT
THEREAFTER SO FOR NOW KEEPING IT DRY. WOLFE
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE LEADING TO
VERY STABLE CONDITIONS ACROSS THE DISTRICT. MOISTURE TRAPPED UNDER
INVERSION LEADING TO ANOTHER ROUND OF IFR FOG DEVELOPING THIS
EVENING FOR THE INLAND VALLEYS. EXPECT VSBYS 1/4SM TO 1/2SM AT TIMES
IN FOG THROUGH MID MORNING WED. ALONG THE COAST...OFFSHORE FLOW IS
CLEARING THINGS OUT...MAINLY VFR EXPECTED EXCEPT FOR SOME MVFR
STRATUS KAST NORTHWARD.
KPDX AND APPROACHES...IFR CONDITIONS EXPECTED TO REDEVELOP BY 08Z...
WITH PERIODS OF 1/4SM TO 1/2SM VSBY FOG LIKELY BETWEEN 10Z-16Z. FOG
GRADUALLY LIFTS WED MORNING WITH CONDITIONS IMPROVING TO VFR BY
20Z. WEAGLE
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE
COASTAL WATERS...RESULTING IN RATHER LIGHT WINDS AND SEAS TONIGHT.
CENTRAL OREGON COASTAL WATERS WILL SEE A LITTLE STRONGER NORTH WIND
THIS EVENING WITH A THERMAL TROUGH ALONG THE COAST. FLOW TURNS
LIGHT-MODERATE OFFSHORE MIDWEEK AS HIGH PRESSURE BUILDS INLAND.
WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY WILLAMETTE VALLEY...CLARK COUNTY AND
LOWLANDS OF SOUTHWEST WASHINGTON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
Http://weather.gov/portland
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KPQR 140435
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 PM PST TUE JAN 13 2009
.SYNOPSIS...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE LOW-LEVEL FLOW SHOULD BEGIN
TO DEVELOP LATE TONIGHT OR WED MORNING...AND THEN INTENSIFY WED
AFTERNOON THROUGH THU. EXPECT THE OFFSHORE FLOW TO LAST THROUGH
SUNDAY. STRONG VALLEY INVERSIONS WILL RESULT IN UNSEASONABLY
WARM DAYTIME TEMPERATURES IN THE COAST RANGE AND CASCADES FOR THE
NEXT FEW DAYS.
&&
.SHORT TERM...STRONG UPPER LEVEL RIDGE WILL BE THE DOMINANT FEATURE
FOR THE NEXT FEW DAYS. MODELS MAINTAIN A NEARLY 590 DECAMETER HIGH
CENTERED OFF THE N CALIFORNIA COAST THROUGH WED...AND THEN DRIFT IT A
LITTLE NORTH FRI AND SAT. 00Z SALEM SOUNDING SHOWED THE TOP OF THE
INVERSION AT AROUND 1700 FT AGL. PILOT REPORT AT 0235Z OVER EUGENE
PLACED THE TOP AT 1900 FEET MSL. EXTREMELY DRY AIR ABOVE THE
INVERSION. SEVERAL RAWS SITES IN THE COAST RANGE AND CASCADES HAD
DAYTIME HUMIDITY VALUES LESS THAN 20 PERCENT...WITH SOME ISOLATED
AREAS BELOW 10 PERCENT. IN ADDITION...THE SALEM SOUNDING SHOWED 55
DEG AT 5500 FEET. SEVERAL SPOTS IN THE CASCADES...ESPECIALLY THE
CENTRAL CASCADES...REACHED INTO THE 60S TODAY.
THE OVERALL PATTERN WILL NOT CHANGE MUCH THROUGH THE SHORT TERM. THE
ONLY DIFFERENCE WILL BE THE DEGREE OF OFFSHORE FLOW. MODELS SUGGEST
LIGHT OFFSHORE FLOW SHOULD DEVELOP LATE TONIGHT OR WED MORNING. NAM-
12 INDICATES AROUND A -3.0 MB GRADIENT KPDX-KDLS 15Z WED. IT WILL
STRENGTHEN LATE WED AFTERNOON THROUGH THU. NAM BUFR SOUNDINGS SHOW
SEVERAL DEGREES OF WARMING BETWEEN 925 MB AND 850 MB. NAM AND GFS
INDICATE 850 MB TEMPS OF 16C 00Z THU FOR THE COAST AND COAST RANGE
AND TO 14C IN THE CASCADES. VERY LIKELY THAT SOME SOUTH ASPECTS IN
THE COAST RANGE...CASCADE FOOTHILLS AND CASCADES WILL HIT 70 DEGREES
...ESPECIALLY THU AND FRI. EXPECT PERSISTENT FOG AND LOW CLOUDS
IN THE CENTRAL AND SOUTH WILLAMETTE VALLEY AND THE I-5 CORRIDOR
BETWEEN KPDX AND KKLS. A SOLID STRATUS DECK CAN BE EXPECTED IN THE
GORGE EAST OF CASCADE LOCKS. THE DEVELOPING EAST WIND WILL LIMIT FOG
AND LOW CLOUDS IN THE NORTH WILLAMETTE VALLEY AND CLARK COUNTY TO THE
WEST SIDE.
MAV AND MET GUIDANCE CONTINUE TO BE TOO COLD FOR MINS. HAD TO RAISE
TONIGHTS MINS 2-4 DEGREES IN MOST AREAS BASED ON CURRENT DEW POINTS.
WEISHAAR.
&&
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
STRONG WARM CORE HIGH PRESSURE OVER THE WESTERN USA WILL KEEP REGION
DRY SO KEPT POPS AT OR NEAR ZERO ON MANY DAYS IN EXTENDED.
TEMPERATURES SHOULD MODERATE NICELY DURING THE AFTERNOON IN THE
MOUNTAINS THOUGH INVERSION SHOULD KEEP STRATUS/FOG AROUND MOST OF DAY
WITH LITTLE MIXING THUS LOWERED VALLEY TEMPS. MAY GET SOME MIXING
AFTER SATURDAY AS OFFSHORE FLOW BEGINS ALSO MODELS NOT IN AGREEMENT
THEREAFTER SO FOR NOW KEEPING IT DRY. WOLFE
&&
.AVIATION...STRONG HIGH PRESSURE ALOFT AND AT THE SURFACE LEADING TO
VERY STABLE CONDITIONS ACROSS THE DISTRICT. MOISTURE TRAPPED UNDER
INVERSION LEADING TO ANOTHER ROUND OF IFR FOG DEVELOPING THIS
EVENING FOR THE INLAND VALLEYS. EXPECT VSBYS 1/4SM TO 1/2SM AT TIMES
IN FOG THROUGH MID MORNING WED. ALONG THE COAST...OFFSHORE FLOW IS
CLEARING THINGS OUT...MAINLY VFR EXPECTED EXCEPT FOR SOME MVFR
STRATUS KAST NORTHWARD.
KPDX AND APPROACHES...IFR CONDITIONS EXPECTED TO REDEVELOP BY 08Z...
WITH PERIODS OF 1/4SM TO 1/2SM VSBY FOG LIKELY BETWEEN 10Z-16Z. FOG
GRADUALLY LIFTS WED MORNING WITH CONDITIONS IMPROVING TO VFR BY
20Z. WEAGLE
&&
.MARINE...STRONG HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE
COASTAL WATERS...RESULTING IN RATHER LIGHT WINDS AND SEAS TONIGHT.
CENTRAL OREGON COASTAL WATERS WILL SEE A LITTLE STRONGER NORTH WIND
THIS EVENING WITH A THERMAL TROUGH ALONG THE COAST. FLOW TURNS
LIGHT-MODERATE OFFSHORE MIDWEEK AS HIGH PRESSURE BUILDS INLAND.
WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...AIR STAGNATION ADVISORY WILLAMETTE VALLEY...CLARK COUNTY AND
LOWLANDS OF SOUTHWEST WASHINGTON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
Http://weather.gov/portland
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 140240
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
640 PM PST TUE JAN 13 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEK AND DOMINATE
THE WEATHER PATTERN INTO THE WEEKEND. WARM AND DRY CONDITIONS IN
THE MOUNTAINS AND WIDESPREAD LOW CLOUDS AND FOG ACROSS THE LOW
LANDS FOR THE REMAINDER OF THE WEEK.
&&
.DISCUSSION...
FOG PRODUCT SHOWS AS OF 615 PM MOST OF SPOKANE COUNTY COVERED BY
FOG AND STRATUS. SURFACE OBSERVATIONS AND CAMERAS INDICATE THAT
THE FOG IS DENSE ABOVE AROUND 2000 FEET SO DECIDED TO EXTEND THE
DENSE FOG ADVISORIES INTO THE SPOKANE AREA. WILL HAVE TO MONITOR
THE NORTH IDAHO PANHANDLE AND THE COEUR D`ALENE AREA AS WELL WHERE
CLEARING AT THE MOMENT WILL LEAD TO BETTER RADIATIONAL FOG
FORMATION POTENTIAL. THE LEWISTON AREA IS ALSO SEEING
DETERIORATING CONDITIONS SO WILL MONITOR THIS AREA FOR A POSSIBLE
DENSE FOG ADVISORY. FOR OTHER AREAS WITHIN THE ADVISORY...IE
WENATCHEE AND WATERVILLE PLATEAU...MOSES LAKE AREA...AND UPPER
COLUMBIA BASIN...THE FOG AND STRATUS IS MORE HIT OR MISS AT THE
MOMENT. HOWEVER WITH THE BREAKS IN THE CLOUD COVER I EXPECT THE
FOG COVERAGE TO INCREASE TONIGHT SO WILL LET ADVISORIES FOR THESE
AREAS REMAIN IN EFFECT.
OTHER CHANGE WAS TO LOWER MIN TEMPS SLIGHTLY FOR THE WENATCHEE...MOSES
LAKE AND OMAK AREA WHERE CURRENT READINGS WERE SLIGHTLY COOLER
THEN FORECAST LOWS.
&&
.AVIATION...
FROM PREVIOUS DISCUSSION...BUILDING HIGH PRESSURE ACROSS THE NORTHWEST WILL
RESULT IN A STRONG INVERSION OVER THE COLUMBIA BASIN. THIS WILL
PROMOTE WIDESPREAD FOG AND STRATUS DEVELOPMENT AGAIN TONIGHT.
AREAS OF VFR/MVFR THIS AFTERNOON ARE VERY LIKELY TO DETERIORATE
IFR/LIFR BY 03Z...AREAS THAT ARE ALREADY AT IFR OR LESS WILL NOT
SEE ANY IMPROVEMENT OVER NIGHT. SOME MIXING IS POSSIBLE AFT 18Z
WED WITH CONDITIONS IMPROVING TO MVFR/IFR OR BETTER AT MOST TAF
SITES. /TOBIN
&&
.PREV DISCUSSION... /ISSUED 337 PM PST TUE JAN 13 2009/
TONIGHT THROUGH FRIDAY...A FEW SUBTLE CHANGES TO THE MODEL
SOLUTIONS THROUGH THE WEEKEND. HIGH PRESSURE JUST INSIDE 130W IS
BEGINNING THE SLOW TREK EASTWARD...MUCH AS THE MODELS HAD
PREDICTED. THE RIDGE AXIS IS EXPECTED TO BE JUST OFF THE
WASHINGTON COAST BY WEDNESDAY AFTERNOON...BUT THEN NOT MOVING
INLAND UNTIL SATURDAY WHICH IS 24 HOURS LATER THAN PREVIOUS MODEL
GUIDANCE. WITH THE FLOW REMAINING NORTHWESTERLY A FEW WEAK WAVES
WILL OVER TOP THE THE RIDGE THROUGH THE SHORT TERM. BUT
PRECIPITATION WISE THIS WILL HAVE MORE OF AN AFFECT ON AREAS EAST
OF MY ZONES THEN AROUND HERE.
THE COMBINATION OF BUILDING HIGH PRESSURE...LIGHT WINDS AND AMPLE
BOUNDARY LAYER MOISTURE IS THE PERFECT PATTERN FOR FOG AND STRATUS
DEVELOPMENT. AS THE RIDGE SLOWLY MOVES INTO THE REGION THE SURFACE
INVERSION WILL DEEPEN AND AREAS ACROSS THE LOWEST ELEVATIONS
SHOULD SEE FOG LIFT INTO A STRATUS DECK. OTHERWISE AREAS BELOW
ABOUT 3000-3500 FEET WILL SEE A MIX OF FOG AND STRATUS THROUGH
SATURDAY. IN ADDITION WITH THE RIDGE AXIS JUST TO THE WEST A
SERIES OF VERY WEAK DISTURBANCES WILL MOVE ALONG OR JUST EAST OF
THE MONTANA BORDER. AS MENTIONED ABOVE THIS SHOULD HAVE LITTLE
AFFECT ON PRECIPITATION CHANCES FOR THE IDAHO PANHANDLE...BUT WILL
HAVE SOME INFLUENCE ON THE MIXING POTENTIAL...MUCH LIKE THIS AFTERNOON.
THE MODELS ARE SIMILAR IN THE SURFACE PRESSURE GRADIENT SLOWLY
MIGRATING OVER TO THE NORTHEAST-EAST. LIGHT EASTERLY WINDS AND
THE WAVES SHOULD PROVIDE SOME MIXING TO THE NORTHEAST MOUNTAIN VALLEYS
AND THE NORTH IDAHO VALLEYS...BUT THE TIMING AND STRENGTH OF THIS
MIXING WILL BE DIFFICULT AT BEST TO FORECAST. AT THE SAME TIME THE
EASTERLY FLOW WILL CAP THE BASIN AND THE EAST SLOPE VALLEYS. IN
AREAS THAT HAVE A DIFFICULT TIME MIXING UP THE INVERSION
TEMPERATURES WILL SEE VERY SMALL DIURNAL CHANGES AND TEMPERATURES
WILL MAINLY BE IN THE LOWER 30S. THE PLACES THAT DO MIX OUT AND
ALL AREAS ABOVE ABOUT 3500 FEET WILL SEE PLENTY OF SUNSHINE AND
WARM AIR ADVECTION. THIS WILL RESULT IN VERY WARM AFTERNOON
TEMPERATURES WITH HIGH WELL INTO THE 40S. THE RUB IS JUST EXACTLY
WHERE AND EXACTLY WHEN SOME OF THE FRINGE AREAS ALONG THE EDGE OF
THE STRATUS WILL MIX OUT. AT BEST THIS IS A GOOD SCENARIO TO BE
OFF IN TEMPERATURES BY A LARGE MARGIN.
THE STRENGTHENING INVERSION AND LACK OF MIXING WILL BEGIN TO
INCREASE PARTICULATES ACROSS EASTERN WASHINGTON. CONDITIONS WILL
DETERIORATE THE NEXT FEW DAYS AND AFTER COORDINATING WITH THE AIR
QUALITY AGENCIES A STAGNATION ADVISORY WAS ISSUED AND WILL REMAIN
IN EFFECT THROUGH SUNDAY.
THE VISIBILITIES AROUND SPOKANE INCREASED THIS AFTERNOON...BUT
ACROSS THE DEEP BASIN AND WEST INTO THE WENATCHEE AREA VISIBILITIES
REMAIN AT OR BELOW 1/4 MILE. WE WILL KEEP THE DENSE FOG ADVISORY
GOING IN THOSE AREAS THROUGH THE NIGHT AND WILL ENLARGE THE AREA
AS NEEDED. /TOBIN
FRIDAY NIGHT THROUGH WEDNESDAY...UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN US. BIG FORECAST CONCERN IS WHEN THE BREAKDOWN OF THE
RIDGE WILL OCCUR. MODELS DO NOT HAVE A REAL GOOD HANDLE ON THE
TIMING. THE RIDGE SHIFTS EAST OVER THE INTER MOUNTAIN WEST MONDAY
AND THE 850MB FLOW BECOMES SOUTHERLY. THIS WILL OPEN UP THE INLAND
NORTHWEST TO WAVES MOVING UP OVER THE RIDGE. MODELS ARE HINTING AT
THE IDEA OF A COLD FRONT MOVING ACROSS TUES NIGHT/WED AND BREAKING
DOWN THE RIDGE. HOWEVER GIVEN THE STRENGTH OF THE RIDGE...WOULDN`T
BE SURPRISED IF THE RIDGE PERSISTS LONGER. ADDED A SLIGHT CHANCE
OF SNOW IN THE MOUNTAINS TUE NIGHT...BUT DID NOT WANT TO GO ANY
HIGHER GIVEN THE UNCERTAINTY. MAIN FORECAST CHANGE WAS TO WARM THE
MOUNTAINS SEVERAL DEGREES GIVEN THE INVERSIONS AND WARM 850MB
TEMPS. IN THE VALLEYS SKIES WILL REMAIN MOSTLY CLOUDY WITH LOW
CLOUDS AND FOG. /NISBET
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 33 35 33 35 32 35 / 0 0 0 0 0 0
COEUR D`ALENE 33 35 33 36 33 36 / 10 0 0 0 0 0
PULLMAN 30 44 30 41 30 40 / 0 0 0 0 0 0
LEWISTON 34 45 33 46 32 46 / 0 0 0 0 0 0
COLVILLE 32 34 29 32 25 32 / 0 0 0 0 0 0
SANDPOINT 33 34 29 34 27 34 / 10 0 0 0 0 0
KELLOGG 31 38 35 37 35 37 / 10 0 0 0 0 0
MOSES LAKE 31 35 32 36 31 36 / 0 0 0 0 0 0
WENATCHEE 29 35 33 36 33 36 / 0 0 0 0 0 0
OMAK 30 33 31 33 29 33 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 3 PM PST SUNDAY FOR CENTRAL
PANHANDLE MOUNTAINS...COEUR D`ALENE AREA...IDAHO PALOUSE...
LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA...
NORTHERN PANHANDLE.
WA...AIR STAGNATION ADVISORY UNTIL 3 PM PST SUNDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST BLUE MOUNTAINS...NORTHEAST
MOUNTAINS...OKANOGAN HIGHLANDS...OKANOGAN VALLEY...SPOKANE
AREA...UPPER COLUMBIA BASIN...WASHINGTON PALOUSE...
WATERVILLE PLATEAU...WENATCHEE AREA.
DENSE FOG ADVISORY UNTIL 4 PM PST WEDNESDAY FOR MOSES LAKE
AREA...SPOKANE AREA...UPPER COLUMBIA BASIN...WATERVILLE
PLATEAU...WENATCHEE AREA.
&&
$$
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