000
FXUS66 KOTX 201230 AAA
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
430 AM PST TUE JAN 20 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH THE END OF THE
WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE REMAINING OVER THE
PACIFIC NORTHWEST. THE MOUNTAINS WILL CONTINUE TO EXPERIENCE CLEAR
SKIES...WHILE MOST VALLEY LOCATIONS WILL REMAIN TRAPPED UNDER LOW
CLOUDS AND FOG. LATE THIS WEEK THE RIDGE IS EXPECTED TO BREAK
DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER PATTERN.
&&
.DISCUSSION...
TODAY AND TONIGHT...HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS
THE INLAND NORTHWEST THROUGH THE REMAINDER OF THE WEEK. SATELLITE
SHOWS SOME UPPER LEVEL MOISTURE MOVING UP FROM THE SOUTH...BUT
THIS SHOULD HAVE LITTLE AFFECT ON THE SENSIBLE WEATHER ACROSS THE
FORECAST AREA. THE STRONG SURFACE INVERSION WILL REMAIN ACROSS THE
REGION. THIS WILL KEEP THE STRATUS AND FOG ACROSS THE AREA UNTIL
A WEATHER FEATURE STRONG ENOUGH TO MIX OUT THE BOUNDARY LAYER
COMES THROUGH. FORECAST CHALLENGES FOR TODAY AND TONIGHT WILL BE
THE EXTENT OF THE FOG/STRATUS AND HOW MUCH CLEARING WE WILL GET
TODAY. SEE LITTLE DIFFERENCES FOR THE NEXT 24 HOURS. WEAK EASTERLY
SURFACE FLOW WILL HELP TO MIX OUT THE FRINGES OF THE STRATUS/FOG
ALONG THE EASTERN EDGE AGAIN TODAY...OTHERWISE EXPECT ANY FOG THIS
MORNING TO LIFT INTO A STRATUS DECK. THE TEMPERATURE FORECAST WILL
BE TRICKY AT BEST. NEAR THE EDGES THAT MIX OUT EXPECT A QUICK SPIKE
IN TEMPERATURES...OTHERWISE LITTLE DIURNAL CHANGES. TEMPERATURES
SHOULD BE PRETTY SIMILAR TO YESTERDAY WITH PERHAPS A FEW DEGREES
WARMER NEAR THE PLACES THAT CLEAR OUT. IN THE MOUNTAINS EXPECT
ANOTHER SPECTACULAR DAY WITH SOME HIGH CIRRUS AROUND AND
TEMPERATURES WELL INTO THE 40S TO LOWER 50S AND LIGHT WINDS.
FOR TONIGHT AREAS AT THE LOWER ELEVATIONS THAT DO CLEAR OUT WILL
SEE GOOD RADIATIONAL COOLING AND FOG DEVELOPMENT A FEW HOURS AFTER
SUNSET...OTHERWISE LITTLE CHANGE IN THE STRATUS COVERAGE ACROSS
THE LOWLANDS. AGAIN TEMPERATURES SHOULD BE PRETTY SIMILAR TO WHAT
WE SEE THIS MORNING.
WITH LITTLE CHANGE IN MIXING HEIGHTS AND WINDS THE AREAS EAST OF THE
CASCADES ARE WELL WITHIN AIR STAGNATION PARAMETERS AND WILL KEEP
THAT GOING. A DENSE FOG ADVISORY WAS ISSUED EARLIER LAST EVENING AND
THAT HIGHLIGHT WILL BE ALLOWED TO CONTINUE THROUGH THE EARLY MORNING
HOURS AS WELL. /TOBIN
WEDNESDAY THROUGH MONDAY...THE UPPER PATTERN OVER THE NEAR SHORE
PACIFIC IS ALREADY SHOWING SIGNIFICANT SIGNS OF A TREMENDOUS
EVOLUTION THAT WILL TAKE PLACE BY MID-WEEK. THE UPPER LOW WE HAVE
BEEN WATCHING FOR DAYS HAS PUSHED ALL THE WAY EAST TO 140W AND
SHEARED GREATLY ALONG A NORTH-SOUTH AXIS ALONG 140W. AT THE SAME
TIME...AN UPPER TROPOSPHERIC PV ANOMALY AS DRIVEN SOUTHWARD AROUND
THE SOUTHERN SIDE OF THE SHEARED UPPER LOW...DRIVING HEIGHT FALLS
WELL SOUTH OF THE SHEARED LOW AND WORKING TO FORM ANOTHER UPPER
LOW NEAR 32N/150W. WHILE THIS SECOND UPPER LOW IS GRADUALLY
BEGINNING TO SHOW SIGNS OF A SOUTHERN STREAM CONNECTION...THE
NORTHERN STREAM HAS DRIVEN FAR TO THE NORTH ACROSS THE NORTH
PACIFIC AND INTO THE ALEUTIANS AND BERING SEA. AHEAD OF THE
NORTHERN STREAM...STRONG RIDGING HAS TAKEN HOLD OF THE STATE OF
ALASKA. WITH THE STRONG RIDGING PUSHING INTO ALASKA AND THE RIDGE
OVER THE INTERMOUNTAIN WEST LOOKS TO BE GETTING THE SQUEEZE FROM
BOTH THE NORTH VIA THE DISPLACEMENT OF COLD AIR OUT OF ALASKA AND
THE YUKON AS WELL AS FROM THE WEST VIA THE HEIGHT FALLS VIA THE
SOUTHERN STREAM. AS A RESULT OF THIS...BY WEDNESDAY AND ESPECIALLY
THURSDAY...VERY LITTLE OF THE RIDGE IS LEFT TO PROTECT THE
INLAND NORTHWEST FROM SYNOPTIC ACTIVITY.
WITH THE EVOLUTION OF THE LARGE SCALE PATTERN COMING INTO MUCH
CLEARER VIEW THAN HAS BEEN THE CASE OVER THE PAST SEVERAL
DAYS...THE SHORT WAVE DETAILS OF THE GLOBAL MODELS HAVE SWUNG INTO
MUCH BETTER AGREEMENT FOR THE LATTER HALF OF THE WEEK AND NEXT
WEEKEND AS WELL. FIRST TO THE EVOLUTION OF THE SOUTHERN
STREAM...FAIRLY GOOD MODEL AGREEMENT EXISTS ON BRINGING THE BULK
OF THE HEIGHT FALLS ON THE ECMWF/GFS/GEFS INTO THE GREAT BASIN BY
SATURDAY. AS THIS OCCURS...THE REMNANTS OF THE UPPER WAVE NEAR
140W GENERALLY SLIDE INTO THE BASE OF THE FORMING LONGWAVE
TROUGH...GRADUALLY SLIDING INLAND TO OUR SOUTH DURING THE END OF
THE WEEK. THE HEIGHT FALLS ACROSS THE SOUTHWEST BECOME VERY
IMPORTANT TO THE FORECAST OVER THE NORTHWEST AS THEY ARE THE
NECESSARY PRECURSOR TO OUR UPPER FLOW GOING MORE NORTHWESTERLY OR
NORTHERLY AND GIVE A FINAL SAYONARA TO THE RIDGE.
WITH THE SOUTHERN STREAM HELPING TO REALIGN THE UPPER FLOW TO A
MORE NORTHERLY DIRECTION...FAIRLY GOOD MODEL AGREEMENT EXISTS ON
BRINGING A MODERATELY STRONG SHORT WAVE DOWN THE ROCKIES WITH 850
MB TEMPERATURES OVER BRITISH COLUMBIA ON BOTH THE GFS AND ECMWF BY
FRIDAY PUSHING -20C. ADDITIONALLY...BOTH THE GFS AND ECMWF BRING A
FAIRLY STRONG FRONTAL BOUNDARY THROUGH THE AREA LATE
SATURDAY/SATURDAY NIGHT WITH 850 MB TEMPERATURES ACROSS THE CWA
DROPPING OFF PRECIPITOUSLY. THE GFS BRINGS THEM AS LOW AS -20C
ALONG THE CANADIAN BORDER...WHILE THE ECMWF AND ITS NORMAL WARM
BIAS ONLY TOUCHES -12C...BUT EITHER WAY A MUCH COLDER REGIME LOOKS
TO TAKE HOLD. ADDITIONALLY...THE FORMATION AND PERPETUATION OF THE
NORTHWESTERLY FLOW OF THE CWA WITH SEVERAL ILL-TIMED SHORT WAVES
ON THE GLOBAL SOLUTIONS WILL LIKELY LEAD TO A RATHER ACTIVE PERIOD
OF LIGHT SNOW ACCUMULATIONS BY THE WEEKEND AND NEXT WEEK AFTER
SOME ACCUMULATING SNOW ALONG THE ORIGINAL COLD FRONTAL PASSAGE
SATURDAY NIGHT.
WHILE AGREEMENT BETWEEN THE GFS AND ECMWF ADDS MUCH CONFIDENCE TO
THE EXTENDED PORTION OF THE FORECAST...THE TREND OF THE NAEFS ADDS
EVEN MORE DUE TO THE ADDITION OF THE CANADIAN ENSEMBLES TO THE
MIX...AND BECAUSE THE SHORT WAVE EVOLUTION OF THE CANADIAN GLOBAL
IS A BIT DIFFERENT THAN ANY OF THE GEFS MEMBERS. THE NAEFS EPS-
GRAMS SHOW ABOUT 5C OF COOLING OF MAX TEMPERATURES THROUGH NEXT
WEEKEND IN JUST THE MEAN WITH AT LEAST SOME ENSEMBLE MEMBERS
SUGGESTING LOWS INTO THE -20S CELSIUS BY EARLY NEXT WEEK. NEEDLESS
TO SAY...WINTER LOOKS TO RETURN. /FRIES
&&
.AVIATION...
THE STRATUS FIELD ACROSS THE COLUMBIA BASIN WILL CONTINUE TO
DOMINATE THROUGH 12Z WEDNESDAY. MVFR/IFR STRATUS NEAR KEAT/KMWH WILL
CONTINUE...WITH PATCHY IFR FOG. KLWS IS PROJECTED TO REMAIN UNDER
MVFR CIGS THROUGH 18-20Z TODAY. KGEG-KSFF-KPUW ARE EXPECTED TO
REMAIN UNDER IFR/LIFR CIGS AND VIS WITH FOG THROUGH 18-21Z TODAY
AS WELL. THEN SOME BRIEF IMPROVEMENT TO VFR/MVFR CONDITIONS IS
PROJECTED BEFORE THE STRATUS AND FOG BUILD BACK INTO THE REGION.
AN EASTERLY FLOW INTO KCOE IS EXPECTED TO BRING MAINLY VFR/MVFR
CONDITIONS WITH BRIEF IFR CIGS/VIS POSSIBLE. /TOBIN
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 27 23 34 22 33 22 / 0 0 0 0 10 10
COEUR D`ALENE 29 23 36 22 33 22 / 0 0 0 10 10 10
PULLMAN 30 27 38 27 37 26 / 0 0 0 10 10 10
LEWISTON 33 29 40 30 42 30 / 0 0 0 0 10 10
COLVILLE 28 20 33 19 32 19 / 0 0 0 0 10 10
SANDPOINT 30 18 34 22 32 21 / 0 0 0 10 10 10
KELLOGG 30 25 37 24 32 23 / 0 0 0 10 10 10
MOSES LAKE 27 24 31 23 33 22 / 0 0 0 0 0 10
WENATCHEE 27 25 32 24 35 23 / 0 0 0 0 10 0
OMAK 26 19 30 22 30 21 / 0 0 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST THURSDAY 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 THURSDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...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 NORTHEAST
MOUNTAINS...SPOKANE AREA...WASHINGTON PALOUSE.
&&
$$
000
FXUS66 KOTX 201032
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
232 AM PST TUE JAN 20 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH THE END OF THE
WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE REMAINING OVER THE
PACIFIC NORTHWEST. THE MOUNTAINS WILL CONTINUE TO EXPERIENCE CLEAR
SKIES...WHILE MOST VALLEY LOCATIONS WILL REMAIN TRAPPED UNDER LOW
CLOUDS AND FOG. LATE THIS WEEK THE RIDGE IS EXPECTED TO BREAK
DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER PATTERN.
&&
.DISCUSSION...
TODAY AND TONIGHT...HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS
THE INLAND NORTHWEST THROUGH THE REMAINDER OF THE WEEK. SATELLITE
SHOWS SOME UPPER LEVEL MOISTURE MOVING UP FROM THE SOUTH...BUT
THIS SHOULD HAVE LITTLE AFFECT ON THE SENSIBLE WEATHER ACROSS THE
FORECAST AREA. THE STRONG SURFACE INVERSION WILL REMAIN ACROSS THE
REGION. THIS WILL KEEP THE STRATUS AND FOG ACROSS THE AREA UNTIL
A WEATHER FEATURE STRONG ENOUGH TO MIX OUT THE BOUNDARY LAYER
COMES THROUGH. FORECAST CHALLENGES FOR TODAY AND TONIGHT WILL BE
THE EXTENT OF THE FOG/STRATUS AND HOW MUCH CLEARING WE WILL GET
TODAY. SEE LITTLE DIFFERENCES FOR THE NEXT 24 HOURS. WEAK EASTERLY
SURFACE FLOW WILL HELP TO MIX OUT THE FRINGES OF THE STRATUS/FOG
ALONG THE EASTERN EDGE AGAIN TODAY...OTHERWISE EXPECT ANY FOG THIS
MORNING TO LIFT INTO A STRATUS DECK. THE TEMPERATURE FORECAST WILL
BE TRICKY AT BEST. NEAR THE EDGES THAT MIX OUT EXPECT A QUICK SPIKE
IN TEMPERATURES...OTHERWISE LITTLE DIURNAL CHANGES. TEMPERATURES
SHOULD BE PRETTY SIMILAR TO YESTERDAY WITH PERHAPS A FEW DEGREES
WARMER NEAR THE PLACES THAT CLEAR OUT. IN THE MOUNTAINS EXPECT
ANOTHER SPECTACULAR DAY WITH SOME HIGH CIRRUS AROUND AND
TEMPERATURES WELL INTO THE 40S TO LOWER 50S AND LIGHT WINDS.
FOR TONIGHT AREAS AT THE LOWER ELEVATIONS THAT DO CLEAR OUT WILL
SEE GOOD RADIATIONAL COOLING AND FOG DEVELOPMENT A FEW HOURS AFTER
SUNSET...OTHERWISE LITTLE CHANGE IN THE STRATUS COVERAGE ACROSS
THE LOWLANDS. AGAIN TEMPERATURES SHOULD BE PRETTY SIMILAR TO WHAT
WE SEE THIS MORNING.
WITH LITTLE CHANGE IN MIXING HEIGHTS AND WINDS THE AREAS EAST OF THE
CASCADES ARE WELL WITHIN AIR STAGNATION PARAMETERS AND WILL KEEP
THAT GOING. A DENSE FOG ADVISORY WAS ISSUED EARLIER LAST EVENING AND
THAT HIGHLIGHT WILL BE ALLOWED TO CONTINUE THROUGH THE EARLY MORNING
HOURS AS WELL. /TOBIN
WEDNESDAY THROUGH MONDAY...THE UPPER PATTERN OVER THE NEAR SHORE
PACIFIC IS ALREADY SHOWING SIGNIFICANT SIGNS OF A TREMENDOUS
EVOLUTION THAT WILL TAKE PLACE BY MID-WEEK. THE UPPER LOW WE HAVE
BEEN WATCHING FOR DAYS HAS PUSHED ALL THE WAY EAST TO 140W AND
SHEARED GREATLY ALONG A NORTH-SOUTH AXIS ALONG 140W. AT THE SAME
TIME...AN UPPER TROPOSPHERIC PV ANOMALY AS DRIVEN SOUTHWARD AROUND
THE SOUTHERN SIDE OF THE SHEARED UPPER LOW...DRIVING HEIGHT FALLS
WELL SOUTH OF THE SHEARED LOW AND WORKING TO FORM ANOTHER UPPER
LOW NEAR 32N/150W. WHILE THIS SECOND UPPER LOW IS GRADUALLY
BEGINNING TO SHOW SIGNS OF A SOUTHERN STREAM CONNECTION...THE
NORTHERN STREAM HAS DRIVEN FAR TO THE NORTH ACROSS THE NORTH
PACIFIC AND INTO THE ALEUTIANS AND BERING SEA. AHEAD OF THE
NORTHERN STREAM...STRONG RIDGING HAS TAKEN HOLD OF THE STATE OF
ALASKA. WITH THE STRONG RIDGING PUSHING INTO ALASKA AND THE RIDGE
OVER THE INTERMOUNTAIN WEST LOOKS TO BE GETTING THE SQUEEZE FROM
BOTH THE NORTH VIA THE DISPLACEMENT OF COLD AIR OUT OF ALASKA AND
THE YUKON AS WELL AS FROM THE WEST VIA THE HEIGHT FALLS VIA THE
SOUTHERN STREAM. AS A RESULT OF THIS...BY WEDNESDAY AND ESPECIALLY
THURSDAY...VERY LITTLE OF THE RIDGE IS LEFT TO PROTECT THE
INLAND NORTHWEST FROM SYNOPTIC ACTIVITY.
WITH THE EVOLUTION OF THE LARGE SCALE PATTERN COMING INTO MUCH
CLEARER VIEW THAN HAS BEEN THE CASE OVER THE PAST SEVERAL
DAYS...THE SHORT WAVE DETAILS OF THE GLOBAL MODELS HAVE SWUNG INTO
MUCH BETTER AGREEMENT FOR THE LATTER HALF OF THE WEEK AND NEXT
WEEKEND AS WELL. FIRST TO THE EVOLUTION OF THE SOUTHERN
STREAM...FAIRLY GOOD MODEL AGREEMENT EXISTS ON BRINGING THE BULK
OF THE HEIGHT FALLS ON THE ECMWF/GFS/GEFS INTO THE GREAT BASIN BY
SATURDAY. AS THIS OCCURS...THE REMNANTS OF THE UPPER WAVE NEAR
140W GENERALLY SLIDE INTO THE BASE OF THE FORMING LONGWAVE
TROUGH...GRADUALLY SLIDING INLAND TO OUR SOUTH DURING THE END OF
THE WEEK. THE HEIGHT FALLS ACROSS THE SOUTHWEST BECOME VERY
IMPORTANT TO THE FORECAST OVER THE NORTHWEST AS THEY ARE THE
NECESSARY PRECURSOR TO OUR UPPER FLOW GOING MORE NORTHWESTERLY OR
NORTHERLY AND GIVE A FINAL SAYONARA TO THE RIDGE.
WITH THE SOUTHERN STREAM HELPING TO REALIGN THE UPPER FLOW TO A
MORE NORTHERLY DIRECTION...FAIRLY GOOD MODEL AGREEMENT EXISTS ON
BRINGING A MODERATELY STRONG SHORT WAVE DOWN THE ROCKIES WITH 850
MB TEMPERATURES OVER BRITISH COLUMBIA ON BOTH THE GFS AND ECMWF BY
FRIDAY PUSHING -20C. ADDITIONALLY...BOTH THE GFS AND ECMWF BRING A
FAIRLY STRONG FRONTAL BOUNDARY THROUGH THE AREA LATE
SATURDAY/SATURDAY NIGHT WITH 850 MB TEMPERATURES ACROSS THE CWA
DROPPING OFF PRECIPITOUSLY. THE GFS BRINGS THEM AS LOW AS -20C
ALONG THE CANADIAN BORDER...WHILE THE ECMWF AND ITS NORMAL WARM
BIAS ONLY TOUCHES -12C...BUT EITHER WAY A MUCH COLDER REGIME LOOKS
TO TAKE HOLD. ADDITIONALLY...THE FORMATION AND PERPETUATION OF THE
NORTHWESTERLY FLOW OF THE CWA WITH SEVERAL ILL-TIMED SHORT WAVES
ON THE GLOBAL SOLUTIONS WILL LIKELY LEAD TO A RATHER ACTIVE PERIOD
OF LIGHT SNOW ACCUMULATIONS BY THE WEEKEND AND NEXT WEEK AFTER
SOME ACCUMULATING SNOW ALONG THE ORIGINAL COLD FRONTAL PASSAGE
SATURDAY NIGHT.
WHILE AGREEMENT BETWEEN THE GFS AND ECMWF ADDS MUCH CONFIDENCE TO
THE EXTENDED PORTION OF THE FORECAST...THE TREND OF THE NAEFS ADDS
EVEN MORE DUE TO THE ADDITION OF THE CANADIAN ENSEMBLES TO THE
MIX...AND BECAUSE THE SHORT WAVE EVOLUTION OF THE CANADIAN GLOBAL
IS A BIT DIFFERENT THAN ANY OF THE GEFS MEMBERS. THE NAEFS EPS-
GRAMS SHOW ABOUT 5C OF COOLING OF MAX TEMPERATURES THROUGH NEXT
WEEKEND IN JUST THE MEAN WITH AT LEAST SOME ENSEMBLE MEMBERS
SUGGESTING LOWS INTO THE -20S CELSIUS BY EARLY NEXT WEEK. NEEDLESS
TO SAY...WINTER LOOKS TO RETURN. /FRIES
&&
.AVIATION...
STRATUS FIELD ACROSS THE COLUMBIA WILL CONTINUE TO DOMINATE
THROUGH 12Z WEDNESDAY. IFR/LIFR STRATUS ACROSS THE KEAT/KMWH WILL
CONTINUE...WITH PATCHY MVFR FOG. KLWS IS PROJECTED TO REMAIN UNDER
MVFR CIGS THROUGH 18-21Z TUESDAY. KGEG-KSFF-KPUW ARE EXPECTED TO
REMAIN UNDER IFR/LIFR CIGS AND VIS WITH FOG THROUGH 18-21Z TUESDAY
AS WELL. THEN SOME BRIEF IMPROVEMENT TO VFR/MVFR CONDITIONS IS
PROJECTED BEFORE THE STRATUS AND FOG COME BACK DOWN. AN EASTERLY
FLOW INTO KCOE IS EXPECTED TO BRING VFR/MVFR CONDITIONS WITH
BRIEF IFR CIGS/VIS. /TOBIN
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 27 23 34 22 33 22 / 0 0 0 0 10 10
COEUR D`ALENE 29 23 36 22 33 22 / 0 0 0 10 10 10
PULLMAN 30 27 38 27 37 26 / 0 0 0 10 10 10
LEWISTON 33 29 40 30 42 30 / 0 0 0 0 10 10
COLVILLE 28 20 33 19 32 19 / 0 0 0 0 10 10
SANDPOINT 30 18 34 22 32 21 / 0 0 0 10 10 10
KELLOGG 30 25 37 24 32 23 / 0 0 0 10 10 10
MOSES LAKE 27 24 31 23 33 22 / 0 0 0 0 0 10
WENATCHEE 27 25 32 24 35 23 / 0 0 0 0 10 0
OMAK 26 19 30 22 30 21 / 0 0 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST THURSDAY 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 THURSDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...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 NORTHEAST
MOUNTAINS...SPOKANE AREA...WASHINGTON PALOUSE.
&&
$$
000
FXUS66 KOTX 200637 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
1037 PM PST MON JAN 19 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH THE END OF THE
WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE REMAINING OVER THE
PACIFIC NORTHWEST. THE MOUNTAINS WILL CONTINUE TO EXPERIENCE CLEAR
SKIES...WHILE MOST VALLEY LOCATIONS WILL REMAIN TRAPPED UNDER LOW
CLOUDS AND FOG. LATE THIS WEEK THE RIDGE IS EXPECTED TO BREAK
DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER PATTERN.
&&
.DISCUSSION...
REST OF TONIGHT...STRONG HIGH PRESSURE WILL CONTINUE TO DOMINATE.
WV/IR IMAGERY SHOWS THE MID-LEVEL RIDGE AXIS NEAR THE ID/MT
BORDER. SURFACE HIGH PRESSURE IS CENTERED OVER NW MONTANA. THIS
BASICALLY TRANSLATES TO THE STRONG SUBSIDENCE INVERSION
REMAINING...LITTLE IF ANY MIXING AND LOW LEVEL MOISTURE TRAPPED IN
THE VALLEY/BASIN LOCATIONS. HENCE FOG AND STRATUS WILL REMAIN
ACROSS A GOOD PORTION OF THE CWA. THE STRATUS/FOG THAT THINNED OUT
LATE MONDAY AFTERNOON ACROSS NE WA AND THE PANHANDLE VALLEYS HAD
ALREADY BEGUN TO FILL BACK IN AROUND DUSK AND IS CONTINUING TO
EXPANDED BACK ACROSS THE NORTHEAST VALLEYS.
TWEAKS MADE FOR TIMING OF STRATUS/FOG REDEVELOPMENT ACROSS THE
NORTHEAST VALLEYS. OTHER TWEAKS MADE TO THE WINDS ACROSS THE NE
VALLEYS...WHICH ARE STILL LOCALLY BREEZY DOWN THE PURCELL TRENCH
BETWEEN BONNERS FERRY AND SANDPOINT. THESE WILL SLACKEN SOME INTO
THE OVERNIGHT AND ALLOW SOME STRATUS/FOG DEVELOPMENT HERE...BUT IT
WILL BE MUCH PATCHIER AS COMPARED TO THE VALLEYS AND UPPER BASIN
FURTHER SOUTHWEST. SENSORS AND WEB CAMS...AS WELL AS ASOS INDICATES
SOME AREAS OF DENSE FOG FROM NEAR DEER PARK SOUTHWARD IN THE
PALOUSE ALONG US-195. AS SUCH AS DENSE FOG ADVISORY HAS BEEN
ISSUED FOR TONIGHT AND EARLY TUESDAY.
TEMPERATURES WERE ALSO TWEAKED DOWN ACROSS THE NORTHEAST...AS
VALUES ARE FALLING A BIT QUICKER THAN THE FORECAST. TEMPERATURES
WERE LOWERED AN AVERAGE OF 2-4 DEGREES..PUTTING MUCH OF THE
NORTHEAST CWA OUTSIDE OF THE MOUNTAINS BETWEEN 10-20 DEGREES.
/JCOTE
&&
.AVIATION...
STRATUS FIELD TRAPPED UNDER THE INVERSION ACROSS THE
COLUMBIA WILL CONTINUE TO DOMINATE THROUGH 06Z WEDNESDAY. IFR/LIFR
STRATUS ACROSS THE KEAT/KMWH WILL CONTINUE...WITH PATCHY MVFR FOG.
KLWS IS PROJECTED TO REMAIN UNDER MVFR CIGS THROUGH 18-21Z
TUESDAY. KGEG-KSFF-KPUW ARE EXPECTED TO REMAIN UNDER IFR/LIFR CIGS
AND VIS WITH FOG THROUGH 18-21Z TUESDAY AS WELL. THEN SOME BRIEF
IMPROVEMENT TO VFR/MVFR CONDITIONS IS PROJECTED BEFORE THE STRATUS
AND FOG COME BACK DOWN. AN EASTERLY FLOW INTO KCOE IS EXPECTED TO
BRING MVFR/BRIEF IFR CIGS/VIS WITH PRIMARILY VFR CIGS DEVELOPING
AGAIN TUESDAY AFTERNOON. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 18 34 23 34 24 33 / 0 0 0 0 10 10
COEUR D`ALENE 18 37 23 37 25 33 / 0 0 0 0 10 10
PULLMAN 24 37 27 38 27 37 / 0 0 0 0 10 10
LEWISTON 27 39 29 41 30 42 / 0 0 0 0 10 10
COLVILLE 19 34 20 34 19 32 / 0 0 0 0 10 10
SANDPOINT 20 35 22 34 22 32 / 0 0 0 0 10 10
KELLOGG 22 35 25 37 24 32 / 0 0 0 0 10 10
MOSES LAKE 23 33 24 32 23 33 / 0 0 0 0 0 0
WENATCHEE 23 32 25 33 24 35 / 0 0 0 0 10 10
OMAK 23 31 23 30 22 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST THURSDAY 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 THURSDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
DENSE FOG ADVISORY UNTIL 12 PM PST TUESDAY FOR NORTHEAST
MOUNTAINS...SPOKANE AREA...WASHINGTON PALOUSE.
&&
$$
000
FXUS66 KOTX 192347
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
257 PM PST MON JAN 19 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH THE END OF THE
WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE REMAINING OVER THE
PACIFIC NORTHWEST. THE MOUNTAINS WILL CONTINUE TO EXPERIENCE CLEAR
SKIES...WHILE MOST VALLEY LOCATIONS WILL REMAIN TRAPPED UNDER LOW
CLOUDS AND FOG. LATE THIS WEEK THE RIDGE IS EXPECTED TO BREAK
DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER PATTERN.
&&
.DISCUSSION...UPDATED AVIATION...
TONIGHT...STRONG LOW-LEVEL INVERSIONS WILL LEAD TO MORE CLOUD AND
FOG CHOKED VALLEYS OVERNIGHT. AS OF 22Z...THE LATEST VISIBLE
SATELLITE AND FOG PRODUCTS DEPICTED WIDESPREAD LOW CLOUDS AND
PATCHY FOG OVER MOST OF EASTERN WASHINGTON...AND A SMALL PORTION
OF THE CENTRAL IDAHO PANHANDLE. THESE CLOUDS WILL GO NOWHERE
TONIGHT...AS THE STRONG INVERSIONS WILL PERSIST UP TO 900 MBS OR
ROUGHLY BETWEEN 3500-4000 FT MSL. SINCE MUCH OF THE CLOUD DECK
FIXED BENEATH THIS INVERSION HAS LIFTED OFF THE GROUND...SEE NO
REASON THAT WIDESPREAD FOG WILL DEVELOP OVERNIGHT. THE EXCEPTIONS
WILL OCCUR AT ELEVATIONS NEAR THE CLOUD BASES OR ROUGHLY BETWEEN
2500-3500 FT WHERE DENSE FOG IS POSSIBLE. WE COULD ALSO SEE DENSE FOG
REFORM OVERNIGHT IN LOCATIONS THAT CLEARED OUT TODAY AND WILL
RADIATE NICELY OVERNIGHT. THIS WOULD ENCOMPASS THE VALLEYS NEAR
THE CASCADES AND OVER NORTHEAST WASHINGTON...AS WELL AS OVER THE
CENTRAL IDAHO PANHANDLE.
FORECASTS IN THE PURCELL TRENCH FROM BONNERS FERRY TO COEUR
D`ALENE ARE A LITTLE TRICKIER...AS WE CONTINUE TO SEE GOOD
DRAINAGE WINDS. THE MODELS CONTINUE TO UNDERESTIMATE THE GRADIENTS
ACROSS THE CONTINENTAL DIVIDE RESULTING IN THE NORTHEAST WINDS OF
10-15 MPH. BOTH THE GFS AND NAM WEAKEN THE GRADIENTS OVERNIGHT AND
CONSEQUENTLY FORECAST NEARLY CALM WINDS. IF THIS WERE TO OCCUR
...FOG IS A SURE BET...BUT WOULD NOT BE SURPRISED IF THE WINDS
BLOW THROUGH MUCH OF THE NIGHT RESULTING IN MINIMAL FOG AND LOW
CLOUDS.
MIN TEMPERATURES WILL BE LARGELY DEPENDANT ON CLOUD COVER. AREAS
WITH WIDESPREAD LOW CLOUDS AND FOG SHOULD FALL NO MORE THAN
SEVERAL DEGREES FROM THIS AFTERNOONS READINGS. CLEAR AREAS WITH
LITTLE WIND...SUCH AS THE METHOW VALLEY...AND SOUTHERN STEVENS
COUNTIES COULD ONCE AGAIN DIP WELL INTO THE TEENS AND SINGLE
DIGITS. FX
TUESDAY THROUGH THURSDAY...HIGH PRESSURE AT THE SURFACE AND ALOFT
WILL BEGIN TO WEAKEN AND SHIFT EAST DURING THIS FORECAST PERIOD. A
PACIFIC TROUGH CURRENTLY LOCATED AROUND 145W WILL NUDGE THE RIDGE
AXIS EAST OF THE CONTINENTAL DIVIDE BUT LOW LEVEL INVERSIONS WILL
PERSIST THROUGH AT LEAST WEDNESDAY NIGHT. THIS WILL KEEP THE THREAT
OF LOW STRATUS AND FOG IN THE VALLEYS ACROSS THE FORECAST AREA.
MODELS ARE IN GOOD AGREEMENT IN HANDLING THE START OF THE BREAKDOWN
OF THE UPPER RIDGE. AS THE TROUGH APPROACHES THE REGION ON WEDNESDAY
THE UPPER LEVEL FLOW SPLITS WITH THE SHORTWAVE ENERGY BEING SHEARED
APART. MOST OF THIS ENERGY EITHER DROPS INTO A CLOSED LOW OFF THE
CALIFORNIA COAST OR REMAINS WELL TO OUR NORTH AS IT SWINGS THROUGH
NORTHERN BRITISH COLUMBIA. THIS SYSTEM WILL SERVE TO FLATTEN THE
RIDGE BUT LITTLE IN THE WAY OF PRECIPITATION IS EXPECTED BEFORE THE
WEEKEND. DAYTIME TEMPERATURES WILL CONTINUE THE BELOW NORMAL TREND
FOR VALLEY LOCATIONS AFFECTED BY FOG AND LOW STRATUS. THE HIGHER
ELEVATIONS WILL SEE A COOLING TREND AS THE RIDGE IS SUPPRESSED AND
COOLER AIR MOVES INTO THE MID LEVELS. /KELCH
FRIDAY AND SATURDAY...DURING THE PERIOD...THE LONGWAVE RIDGE
OVER THE WESTERN US WILL CONTINUE TO BREAKDOWN AS WE GO FROM A
MESSY DISORGANIZED OFFSHORE SPLIT FLOW BLOCKING PATTERN WITH
SEVERAL SHORTWAVE IMPULSES INTO A PHASED LONGWAVE RIDGE OF HIGH
PRESSURE AT 140-150W AND TROUGH ACROSS THE WEST DUE LARGELY TO
PHASING OF UPPER-LOW OFFSHORE OF CALIFORNIA WITH A STRONG NEGATIVE
HEIGHT ANOMALY DROPPING SOUTH FROM THE NORTHWEST TERRITORIES.
DON`T EXPECT MUCH IN THE WAY OF SENSIBLE WEATHER FRIDAY THROUGH
MIDDAY SATURDAY OTHER THAN A FEW LIGHT MTN SNOW SHOWERS AS THE
REGION TRANSITIONS FROM A WEAK COL WITH LIGHT FLOW ALOFT TOWARDS
THE SLOW INTRUSION OF THE UPPER-LEVEL TROUGH DROPPING IN FROM THE
NORTH. THE COOLEST 850MB TEMPERATURES WILL EXIST ACROSS THE
NORTHEASTERN ZONES FRIDAY THEN THE MIDLEVEL COOLING WILL SLOWLY
SPILL SOUTHWARD THROUGH THE CWA SATURDAY MORNING.
THEREFORE...BASED ON FORECAST SOUNDINGS AND LACK OF COOLING
ALOFT...HAVE ADDED PATCHY FOG FOR THE WESTERN VALLEYS AND SOUTHERN
BASIN FOR ONE LAST MORNING...FRIDAY....BUT CONDITIONS WILL NOT BE
FAVORABLE IN SATURDAY.
THE STRONG COLD FRONT THAT HAS BEEN DISCUSSED IN PREVIOUS AFDS
IS NOW NOT EXPECTED TO ARRIVE UNTIL LATTER SATURDAY INTO SATURDAY
NT WHICH IS APPROX 6-12 HOURS LATTER THAN PREVIOUS MODEL RUNS PER
GFS. DPROG/DT OF THE GFS INDICATE THIS IS THE SLOWEST SOLUTIONS OF
THE PAST 4-5 RUNS BUT HAS COME INTO LINE WITH THE 00Z EURO. THE
ONE FLY IN THE OINTMENT IS THE STRENGTH IN THE LOW-LEVEL COLD
FRONT. THE GFS CONTINUES TO INDICATE A STRONG LOW-LEVEL INTRUSION
OF CANADIAN AIR THROUGH THE OKANOGAN VALLEY AND PURCELL TRENCH WHICH WAS
SIMILAR TO THE OOZ ECMWF HOWEVER...THE NEWER 12Z ECMWF KEEPS THE
COLDEST LOW-LEVEL AIR ALONG AND EAST OF THE DIVIDE. THIS WILL HAVE
TREMENDOUS WEIGHT ON HOW THE NORTHERN BRANCH OF THE SPLIT FLOW
BREAKS DOWN AS IT DROPS SOUTHEASTWARD FROM NORTHERN ALASKA AND
THUS HOW DEEP THE APPROACHING TROUGH BECOMES. THE EURO/GFS PROG
SIMILAR 500MB PATTERNS ALONG AND SOUTH OF THE CWA AND HAVE A
STRONG AGREEMENT THAT THE AIRMASS WILL AT LEAST COOL ENOUGH TO
SUPPORT SNOW FOR ALL LOCATIONS BY SATURDAY NT - SUNDAY WHEN THE
NEXT. THE STRENGTH AND DEPTH OF THE INCOMING WAVE WILL ALSO GUIDE
THE FORECAST FOR THE AMOUNT OF SNOW EXPECTED ON SATURDAY NT-
SUNDAY AS WELL AND THE OTHER BIG QUESTION...HOW COLD WILL IT GET?
MONDAY INTO MIDWEEK...OPERATIONAL GUIDANCE OF THE
GFS/ECMWF...5-WAVE CHART...AND CLIMATE PREDICTION GUIDANCE IN ONE
FORM OR ANOTHER IS ALL BEGINNING TO TREND TOWARD THE RIDGE
REMAINING OFFSHORE NEAR 150W RESULTING IN AN ACTIVE AND COOLER
NORTHWESTERLY FLOW FOR THE NORTHWESTERN US FOR THE END OF JANUARY
INTO FEBRUARY LEADING US BACK TOWARD ANOTHER BUSY WINTRY PATTERN.
THE EXACT DETAILS ARE WAY FAR OUT OF ANY CONFIDENCE...ESPECIALLY FOR
STORM TRACK AND CHANCE FOR PRECIPITATION BUT THE PATTERN WILL FAVOR
NEAR TO BELOW NORMAL TEMPERATURES. /BODNAR
&&
.AVIATION...
LIGHT NORTHEASTERLY GRADIENTS CONTINUE TO ERODE LIFR CIGS FROM
KCOE-KSFF-KGEG THROUGH 03Z THIS AFTERNOON. THIS WILL ALLOW FOR
ANOTHER NIGHT OF PRIME RADIATIONAL COOLING AND QUICK REDEVELOPMENT
OF LIFR FOG FOR KSFF-KGEG AND IN THE VCNTY OF KCOE. MUCH MORE
DIFFICULT FORECAST FOR KCOE WHERE VFR CONDITIONS WERE REPORTED VIA
AWOS LAST 24 HRS BUT CAMS/SPOTTERS IN THE VCNTY INDICATE THE CLEAR
CONDITIONS AT THE AIRPORT ARE LOCAL AND THIS WAS NOT THE CASE
FOR MUCH OF THE SURROUNDING AREA. OTHERWISE...THE REMAINDER OF THE
TERMINALS EXCEPT KLWS WILL CONTINUE UNDER A BLANKET OF IFR STRATUS
WITH LITTLE TO NO IMPROVEMENT THROUGH 00Z. /BODNAR
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 20 34 23 34 24 33 / 0 0 0 0 10 10
COEUR D`ALENE 23 37 23 37 25 33 / 0 0 0 0 10 10
PULLMAN 24 37 27 38 27 37 / 0 0 0 0 10 10
LEWISTON 27 39 29 41 30 42 / 0 0 0 0 10 10
COLVILLE 20 34 20 34 19 32 / 0 0 0 0 10 10
SANDPOINT 19 35 22 34 22 32 / 0 0 0 0 10 10
KELLOGG 23 35 25 37 24 32 / 0 0 0 0 10 10
MOSES LAKE 23 33 24 32 23 33 / 0 0 0 0 0 0
WENATCHEE 23 32 25 33 24 35 / 0 0 0 0 10 10
OMAK 24 31 23 30 22 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST THURSDAY 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 THURSDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 192257
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
257 PM PST MON JAN 19 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH THE END OF THE
WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE REMAINING OVER THE
PACIFIC NORTHWEST. THE MOUNTAINS WILL CONTINUE TO EXPERIENCE CLEAR
SKIES...WHILE MOST VALLEY LOCATIONS WILL REMAIN TRAPPED UNDER LOW
CLOUDS AND FOG. LATE THIS WEEK THE RIDGE IS EXPECTED TO BREAK
DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER PATTERN.
&&
.DISCUSSION...
TONIGHT...STRONG LOW-LEVEL INVERSIONS WILL LEAD TO MORE CLOUD AND
FOG CHOKED VALLEYS OVERNIGHT. AS OF 22Z...THE LATEST VISIBLE
SATELLITE AND FOG PRODUCTS DEPICTED WIDESPREAD LOW CLOUDS AND
PATCHY FOG OVER MOST OF EASTERN WASHINGTON...AND A SMALL PORTION
OF THE CENTRAL IDAHO PANHANDLE. THESE CLOUDS WILL GO NOWHERE
TONIGHT...AS THE STRONG INVERSIONS WILL PERSIST UP TO 900 MBS OR
ROUGHLY BETWEEN 3500-4000 FT MSL. SINCE MUCH OF THE CLOUD DECK
FIXED BENEATH THIS INVERSION HAS LIFTED OFF THE GROUND...SEE NO
REASON THAT WIDESPREAD FOG WILL DEVELOP OVERNIGHT. THE EXCEPTIONS
WILL OCCUR AT ELEVATIONS NEAR THE CLOUD BASES OR ROUGHLY BETWEEN
2500-3500 FT WHERE DENSE FOG IS POSSIBLE. WE COULD ALSO SEE DENSE FOG
REFORM OVERNIGHT IN LOCATIONS THAT CLEARED OUT TODAY AND WILL
RADIATE NICELY OVERNIGHT. THIS WOULD ENCOMPASS THE VALLEYS NEAR
THE CASCADES AND OVER NORTHEAST WASHINGTON...AS WELL AS OVER THE
CENTRAL IDAHO PANHANDLE.
FORECASTS IN THE PURCELL TRENCH FROM BONNERS FERRY TO COEUR
D`ALENE ARE A LITTLE TRICKIER...AS WE CONTINUE TO SEE GOOD
DRAINAGE WINDS. THE MODELS CONTINUE TO UNDERESTIMATE THE GRADIENTS
ACROSS THE CONTINENTAL DIVIDE RESULTING IN THE NORTHEAST WINDS OF
10-15 MPH. BOTH THE GFS AND NAM WEAKEN THE GRADIENTS OVERNIGHT AND
CONSEQUENTLY FORECAST NEARLY CALM WINDS. IF THIS WERE TO OCCUR
...FOG IS A SURE BET...BUT WOULD NOT BE SURPRISED IF THE WINDS
BLOW THROUGH MUCH OF THE NIGHT RESULTING IN MINIMAL FOG AND LOW
CLOUDS.
MIN TEMPERATURES WILL BE LARGELY DEPENDANT ON CLOUD COVER. AREAS
WITH WIDESPREAD LOW CLOUDS AND FOG SHOULD FALL NO MORE THAN
SEVERAL DEGREES FROM THIS AFTERNOONS READINGS. CLEAR AREAS WITH
LITTLE WIND...SUCH AS THE METHOW VALLEY...AND SOUTHERN STEVENS
COUNTIES COULD ONCE AGAIN DIP WELL INTO THE TEENS AND SINGLE
DIGITS. FX
TUESDAY THROUGH THURSDAY...HIGH PRESSURE AT THE SURFACE AND ALOFT
WILL BEGIN TO WEAKEN AND SHIFT EAST DURING THIS FORECAST PERIOD. A
PACIFIC TROUGH CURRENTLY LOCATED AROUND 145W WILL NUDGE THE RIDGE
AXIS EAST OF THE CONTINENTAL DIVIDE BUT LOW LEVEL INVERSIONS WILL
PERSIST THROUGH AT LEAST WEDNESDAY NIGHT. THIS WILL KEEP THE THREAT
OF LOW STRATUS AND FOG IN THE VALLEYS ACROSS THE FORECAST AREA.
MODELS ARE IN GOOD AGREEMENT IN HANDLING THE START OF THE BREAKDOWN
OF THE UPPER RIDGE. AS THE TROUGH APPROACHES THE REGION ON WEDNESDAY
THE UPPER LEVEL FLOW SPLITS WITH THE SHORTWAVE ENERGY BEING SHEARED
APART. MOST OF THIS ENERGY EITHER DROPS INTO A CLOSED LOW OFF THE
CALIFORNIA COAST OR REMAINS WELL TO OUR NORTH AS IT SWINGS THROUGH
NORTHERN BRITISH COLUMBIA. THIS SYSTEM WILL SERVE TO FLATTEN THE
RIDGE BUT LITTLE IN THE WAY OF PRECIPITATION IS EXPECTED BEFORE THE
WEEKEND. DAYTIME TEMPERATURES WILL CONTINUE THE BELOW NORMAL TREND
FOR VALLEY LOCATIONS AFFECTED BY FOG AND LOW STRATUS. THE HIGHER
ELEVATIONS WILL SEE A COOLING TREND AS THE RIDGE IS SUPPRESSED AND
COOLER AIR MOVES INTO THE MID LEVELS. /KELCH
FRIDAY AND SATURDAY...DURING THE PERIOD...THE LONGWAVE RIDGE
OVER THE WESTERN US WILL CONTINUE TO BREAKDOWN AS WE GO FROM A
MESSY DISORGANIZED OFFSHORE SPLIT FLOW BLOCKING PATTERN WITH
SEVERAL SHORTWAVE IMPULSES INTO A PHASED LONGWAVE RIDGE OF HIGH
PRESSURE AT 140-150W AND TROUGH ACROSS THE WEST DUE LARGELY TO
PHASING OF UPPER-LOW OFFSHORE OF CALIFORNIA WITH A STRONG NEGATIVE
HEIGHT ANOMALY DROPPING SOUTH FROM THE NORTHWEST TERRITORIES.
DON`T EXPECT MUCH IN THE WAY OF SENSIBLE WEATHER FRIDAY THROUGH
MIDDAY SATURDAY OTHER THAN A FEW LIGHT MTN SNOW SHOWERS AS THE
REGION TRANSITIONS FROM A WEAK COL WITH LIGHT FLOW ALOFT TOWARDS
THE SLOW INTRUSION OF THE UPPER-LEVEL TROUGH DROPPING IN FROM THE
NORTH. THE COOLEST 850MB TEMPERATURES WILL EXIST ACROSS THE
NORTHEASTERN ZONES FRIDAY THEN THE MIDLEVEL COOLING WILL SLOWLY
SPILL SOUTHWARD THROUGH THE CWA SATURDAY MORNING.
THEREFORE...BASED ON FORECAST SOUNDINGS AND LACK OF COOLING
ALOFT...HAVE ADDED PATCHY FOG FOR THE WESTERN VALLEYS AND SOUTHERN
BASIN FOR ONE LAST MORNING...FRIDAY....BUT CONDITIONS WILL NOT BE
FAVORABLE IN SATURDAY.
THE STRONG COLD FRONT THAT HAS BEEN DISCUSSED IN PREVIOUS AFDS
IS NOW NOT EXPECTED TO ARRIVE UNTIL LATTER SATURDAY INTO SATURDAY
NT WHICH IS APPROX 6-12 HOURS LATTER THAN PREVIOUS MODEL RUNS PER
GFS. DPROG/DT OF THE GFS INDICATE THIS IS THE SLOWEST SOLUTIONS OF
THE PAST 4-5 RUNS BUT HAS COME INTO LINE WITH THE 00Z EURO. THE
ONE FLY IN THE OINTMENT IS THE STRENGTH IN THE LOW-LEVEL COLD
FRONT. THE GFS CONTINUES TO INDICATE A STRONG LOW-LEVEL INTRUSION
OF CANADIAN AIR THROUGH THE OKANOGAN VALLEY AND PURCELL TRENCH WHICH WAS
SIMILAR TO THE OOZ ECMWF HOWEVER...THE NEWER 12Z ECMWF KEEPS THE
COLDEST LOW-LEVEL AIR ALONG AND EAST OF THE DIVIDE. THIS WILL HAVE
TREMENDOUS WEIGHT ON HOW THE NORTHERN BRANCH OF THE SPLIT FLOW
BREAKS DOWN AS IT DROPS SOUTHEASTWARD FROM NORTHERN ALASKA AND
THUS HOW DEEP THE APPROACHING TROUGH BECOMES. THE EURO/GFS PROG
SIMILAR 500MB PATTERNS ALONG AND SOUTH OF THE CWA AND HAVE A
STRONG AGREEMENT THAT THE AIRMASS WILL AT LEAST COOL ENOUGH TO
SUPPORT SNOW FOR ALL LOCATIONS BY SATURDAY NT - SUNDAY WHEN THE
NEXT. THE STRENGTH AND DEPTH OF THE INCOMING WAVE WILL ALSO GUIDE
THE FORECAST FOR THE AMOUNT OF SNOW EXPECTED ON SATURDAY NT-
SUNDAY AS WELL AND THE OTHER BIG QUESTION...HOW COLD WILL IT GET?
MONDAY INTO MIDWEEK...OPERATIONAL GUIDANCE OF THE
GFS/ECMWF...5-WAVE CHART...AND CLIMATE PREDICTION GUIDANCE IN ONE
FORM OR ANOTHER IS ALL BEGINNING TO TREND TOWARD THE RIDGE
REMAINING OFFSHORE NEAR 150W RESULTING IN AN ACTIVE AND COOLER
NORTHWESTERLY FLOW FOR THE NORTHWESTERN US LEADING US BACK TOWARD
ANOTHER BUSY WINTRY PATTERN. THE EXACTS ARE WAY FAR OUT OF ANY
CONFIDENCE...ESPECIALLY FOR STORM TRACK AND CHANCE FOR
PRECIPITATION BUT THE PATTERN WILL FAVOR NEAR TO BELOW NORMAL
TEMPERATURES. /BODNAR
&&
.AVIATION...
AVIATION CONCERNS FROM LOW STRATUS AND FOG WILL IMPACT ALL TAF
SITES THROUGH 18Z TUE. IFR/LIFR CONDITIONS WILL PERSIST AT ALL
SITES...HOWEVER CLEARING NEAR KCOE COULD PERSIST INTO THE EVENING.
THE POOREST VISIBILITIES AND CIGS WILL BE FOUND AT TAF SITES
ABOVE 2K FEET. THIS WOULD INCLUDE KGEG AND KPUW....HOWEVER
INCREASING EASTERLY FLOW AT KPUW MAY LEAD TO IMPROVED CONDITIONS
AND A BRIEF BREAKOUT DURING THE AFTERNOON AND EARLY EVENING. FX
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 20 34 23 34 24 33 / 0 0 0 0 10 10
COEUR D`ALENE 23 37 23 37 25 33 / 0 0 0 0 10 10
PULLMAN 24 37 27 38 27 37 / 0 0 0 0 10 10
LEWISTON 27 39 29 41 30 42 / 0 0 0 0 10 10
COLVILLE 20 34 20 34 19 32 / 0 0 0 0 10 10
SANDPOINT 19 35 22 34 22 32 / 0 0 0 0 10 10
KELLOGG 23 35 25 37 24 32 / 0 0 0 0 10 10
MOSES LAKE 23 33 24 32 23 33 / 0 0 0 0 0 0
WENATCHEE 23 32 25 33 24 35 / 0 0 0 0 10 10
OMAK 24 31 23 30 22 30 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...AIR STAGNATION ADVISORY UNTIL 4 PM PST THURSDAY 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 THURSDAY FOR EAST SLOPES
NORTHERN CASCADES...LOWER GARFIELD AND ASOTIN COUNTIES...
MOSES LAKE AREA...NORTHEAST MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 191911
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1111 AM PST MON JAN 19 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE THIS WEEK THE RIDGE IS EXPECTED TO
BREAK DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER
PATTERN.
&&
.DISCUSSION...
REST OF TODAY...VERY STRONG UPPER LEVEL RIDGE WILL REMAIN OVER
THE INLAND NW THROUGH THE DAY. THIS WILL KEEP A LID ON THE
LOW-LEVEL TEMPERATURE INVERSIONS AND WILL LIKELY KEEP THE
WIDESPREAD STRATUS DECK IN PLACE OVER MOST VALLEY LOCATIONS.
AN OVERLAY OF THE VISIBLE SATELLITE PIX AND TOPOGRAPHY SUGGESTS
STRATUS BASES ARE GENERALLY AROUND 1800-2400 FT MSL WITH TOPS
EXTENDING UP TO 3500-4000 MSL FT PER THE MORNING SOUNDING FROM
SPOKANE AND A BATCH OF RECENT PIREPS OVER SC WA. GIVEN THE
ELEVATED BASES OF THE STRATUS...THE OCCURRENCE OF DENSE FOG WILL
BE GENERALLY LIMITED TO HIGHER ELEVATIONS ABOVE 2000
FT...INCLUDING THE WEST PLAINS...SPOKANE`S SOUTH HILL...PORTIONS
OF THE WATERVILLE PLATEAU. THIS IS NOT WIDESPREAD ENOUGH TO
WARRANT THE ISSUANCE OF A DENSE FOG ADVISORY...SO WE WILL COVER
VIA SHORT TERM FORECASTS.
THE ONLY VALLEYS FREE OF LOW CLOUDS TODAY WILL BE NORTHERN
PORTIONS OF THE PURCELL TRENCH. THESE AREAS ARE SEEING MODERATE
NORTHEAST DRAINAGE WINDS AS A RESULT OF STRONG SURFACE HIGH
PRESSURE BANKED ON THE EAST SIDE OF THE CONTINENTAL DIVIDE. THE
MODELS ARE UNDERPLAYING THE STRENGTH OF THIS PRESSURE
GRADIENT...WITH THE CENTER OF THE HIGH ABOUT 6 MBS TOO WEAK OVER
WESTERN MONTANA. THE LATEST MESOSCALE ANALYSIS PLACES SLP READINGS
AROUND 1048 MBS. THE CLOSEST MODEL...NAM12... CLOCKS IN AT 1043 MBS.
ALTHOUGH THE CENTRAL PRESSURE WILL FALL A BIT OVER THE NEXT 24
HRS...IT HAS A LONG WAY TO GO TO REACH THE FORECASTS FROM THE
MODELS. CONSEQUENTLY...CLEAR LOCATIONS IN THE PURCELL TRENCH
EXTENDING FROM BONNERS FERRY TO THE OUTSKIRTS OF COEUR D`ALENE
WILL REMAIN THAT WAY THROUGH THE DAY. THE CLEARING COULD WORK ITS
WAY DOWN THE I90 CORRIDOR TO THE ID/WA BORDER...BUT THAT MAY BE
THE WESTWARD EXTENT OF IT.
AS FOR TEMPERATURES...ASIDE FROM THE PURCELL TRENCH...MIXING
POTENTIAL TODAY LOOKS VERY LIMITED IN THE VALLEYS AND THUS FURTHER
WARMING TODAY WILL BE SMALL. MOS NUMBERS SEEM TOO AGGRESSIVE IN
WARMING MAX TEMPS THIS AFTERNOON...AND IN MOST INSTANCES THEY
WERE CUT TO MORE REASONABLE LEVELS. FX
.AVIATION...
AVIATION CONCERNS FROM LOW STRATUS AND FOG WILL IMPACT ALL TAF
SITES THROUGH 18Z TUE. IFR/LIFR CONDITIONS WILL PERSIST AT ALL
SITES...HOWEVER CLEARING NEAR KCOE COULD PERSIST INTO THE EVENING.
THE POOREST VISIBILITIES AND CIGS WILL BE FOUND AT TAF SITES
ABOVE 2K FEET. THIS WOULD INCLUDE KGEG AND KPUW....HOWEVER
INCREASING EASTERLY FLOW AT KPUW MAY LEAD TO IMPROVED CONDITIONS
AND A BRIEF BREAKOUT DURING THE AFTERNOON AND EARLY EVENING. FX
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 28 25 34 25 33 25 / 0 0 0 0 0 10
COEUR D`ALENE 35 23 37 25 36 26 / 0 0 0 0 0 10
PULLMAN 30 27 37 29 36 28 / 0 0 0 0 0 10
LEWISTON 34 27 39 30 40 30 / 0 0 0 0 0 10
COLVILLE 31 25 34 22 32 20 / 0 0 0 0 0 10
SANDPOINT 34 21 35 24 32 24 / 0 0 0 0 0 10
KELLOGG 33 24 35 26 34 25 / 0 0 0 0 0 10
MOSES LAKE 30 26 33 23 31 23 / 0 0 0 0 0 0
WENATCHEE 31 26 32 25 32 24 / 0 0 0 0 0 10
OMAK 32 25 31 23 29 22 / 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 191136
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
330 AM PST MON JAN 19 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE THIS WEEK THE RIDGE IS EXPECTED TO
BREAK DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER
PATTERN.
&&
.DISCUSSION...
TODAY AND TONIGHT...LITTLE CHANGE TO THE OVERALL PATTERN FOR THE
LAST FEW DAYS...AND LITTLE CHANGE EXPECTED FOR THE NEXT FEW DAYS.
AT LEAST FOR THE NEXT 24 HOURS OR SO THE FORECAST AREA IS LOCKED
DOWN UNDER A STRONG RIDGE ALOFT WITH THE ASSOCIATED SUBSIDENCE
INVERSION KEEPING THE ATMOSPHERE STRONGLY DECOUPLED. A STRATUS
DECK WITH BASES NOW AROUND 1500 TO 2000 FEET MSL IS TRAPPED IN THE
COLUMBIA BASIN. THE STRONG SURFACE HIGH PRESSURE IS ORIENTED WITH
IT`S AXIS ALONG THE IDAHO PANHANDLE. THE RESULTANT GRADIENT HAS
ALLOWED THE DEEPEST MOIST SURFACE AIR TO POOL IN THE DEEP
BASIN...WHILE THE BOUNDARY LAYER HAS THINNED OVER THE NORTHEAST
ZONES ENOUGH TO ALLOW THE ANEMIC DEEP JANUARY DIURNAL MIXING TO
ALLOW A BREAK OUT OF THE FOG AND STRATUS YESTERDAY. OVERNIGHT THE
STRATUS FIELD HAS ADVANCED BACK INTO THE NORTHEAST VALLEYS AND
BASIN...BUT IT IS LIKELY SHALLOW AND THERE IS OPTIMISM THAT
SUN BREAKS WILL ONCE AGAIN GRACE THE VALLEYS AND BASIN NORTH AND
EAST OF A LINE FROM OMAK TO PULLMAN THIS AFTERNOON. OTHERWISE
LITTLE CHANGE TO THE OVERALL REGIME WITH STRATUS AND FOG EXPECTED
TO REFILL ALL OF THIS AFTERNOON`S MIXED OUT VALLEYS AGAIN TONIGHT.
/FUGAZZI
TUESDAY THROUGH SUNDAY...FEW SPECIFICS ARE CERTAIN DURING THIS
PORTION OF THE FORECAST...BUT ONE OVERARCHING THEME OF THE SECOND
HALF OF THIS WEEK WILL BE THE DEMISE OF THE RIDGE. THAT WILL ALSO
MEAN AN END TO THE LOW CLOUDS...FOG...AND STRATUS. HOWEVER...IT
WILL LIKELY MEAN A RETURN TO COLD TEMPERATURES AND SNOW FOR A GOOD
CHUNK OF THE FORECAST AREA.
BETWEEN TUESDAY AND THURSDAY THE VARIOUS GLOBAL MODELS REALLY DO A
HUGE NUMBER ON THE RIDGE THAT HAS BEEN OVER THE CWA. NOT ONLY DOES
THE RIDGE DEAMPLIFY GREATLY...BUT IT IS SHIFTED INTO THE FRONT
RANGE OF THE ROCKIES. AS THIS OCCURS...THE SPLIT UPPER FLOW OVER
THE CENTRAL PACIFIC AT THE MOMENT PUSHES CLOSER TO THE COAST.
STRONG DRYING EVIDENT ON THE WATER VAPOR IMAGERY IN ASSOCIATION
WITH THE SOUTHERN SECTION OF THE SPLIT LOOKS TO BE THE RESULT OF
A STRETCHING UPPER TROPOSPHERIC PV ANOMALY THAT SHOULD HELP TO
REINVIGORATE AN UPPER LOW AS IT APPROACHES CALIFORNIA BY THURSDAY.
MEANWHILE...UPPER RIDGING IN THE NORTHERN STREAM PUSHES INTO THE
HEART OF ALASKA. THIS FORCES A GENERAL RETROGRESSION OF THE ARCTIC
VORTEX OVER HUDSON BAY AND THE EASTERN HALF OF CANADA. AS A
RESULT...FLOW FROM THE NORTHERN STREAM STRONGLY SHIFTS NORTH TO
NORTHWEST ON THE GFS BY FRIDAY OVER THE CWA...AND BY SATURDAY
NIGHT ON THE ECMWF. IN SO DOING...A STRONG LOWER TROPOSPHERIC
RESPONSE IS FOUND IN BOTH MODELS RESULTING IN A RATHER IMPRESSIVE
COLD FRONTAL PASSAGE ACROSS THE AREA DURING THE LATTER HALF OF THE
WEEK. AGAIN...THE GFS IS QUITE A BIT QUICKER IN DOING SO THAN THE
ECMWF...BUT THE TREND TOWARD MUCH COLDER CONDITIONS EXISTS ON
BOTH. LIKEWISE...WITH THE FRONTAL PASSAGE...HIGH SNOW-TO-LIQUID
RATIO SNOWS WITH FRONTOGENETICAL LIFT LOOK TO CROSS THE AREA AS
NORTHWESTERLY FLOW ENERGY RUNS DOWN THE ARCTIC FRONT BY THE END OF
THE WEEK.
WITH THE MODELS EVOLVING STRONGLY TOWARD A MORE WINTRY SCENARIO BY
NEXT WEEKEND...TEMPERATURES HAVE BEEN SLASHED WHOLESALE.
LIKEWISE...POPS HAVE BEEN ADJUSTED UP TO OR ABOVE CLIMATOLOGY BY
NEXT WEEKEND WITH A NORTHWESTERLY FLOW AND SEVERAL SHORT WAVE
IMPULSES SET TO TRAVERSE THROUGH THE INLAND NORTHWEST. /FRIES
&&
.AVIATION...
WIDESPREAD STRATUS FIELD WITH BASES 1500 TO 2000 FEET MSL AND TOPS
AREOUND 3500 FEET MSL WILL PERSIST OVER THE COLUMBIA BASIN THROUGH
12Z TUESDAY. THIS WILL PROMOTE CONTINUED MORNING AND OVERNIGHT IFR
CEILINGS AND AFTERNOON LOW MVFR CEILINGS AT KLWS...KMWH AND KEAT
THROUGH THE TAF PERIOD. NORTH AND EAST OF A LINE FROM KOMK TO KPUW
SOME LATE MORNING EROSION OF STRATUS IS EXPECTED WITH VFR CONDITIONS
DURING THE AFTERNOON AT THE KGEG VCNTY TAF SITES AND POSSIBLY KPUW.
IFR CONDITIONS WILL RETURN TO THESE SITES AFETR 02Z TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 32 25 34 25 33 25 / 0 0 0 0 0 10
COEUR D`ALENE 35 23 37 25 36 26 / 0 0 0 0 0 10
PULLMAN 32 27 37 29 36 28 / 0 0 0 0 0 10
LEWISTON 33 27 39 30 40 30 / 0 0 0 0 0 10
COLVILLE 36 25 34 22 32 20 / 0 0 0 0 0 10
SANDPOINT 37 21 35 24 32 24 / 0 0 0 0 0 10
KELLOGG 35 24 35 26 34 25 / 0 0 0 0 0 10
MOSES LAKE 32 26 33 23 31 23 / 0 0 0 0 0 10
WENATCHEE 30 26 32 25 32 24 / 0 0 0 0 0 10
OMAK 32 25 31 23 29 22 / 0 0 0 0 0 10
&&
.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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 191018
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
218 AM PST MON JAN 19 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE THIS WEEK THE RIDGE IS EXPECTED TO
BREAK DOWN....WITH A RETURN TO A MORE ACTIVE WINTER WEATHER
PATTERN.
&&
.DISCUSSION...
TODAY AND TONIGHT...LITTLE CHANGE TO THE OVERALL PATTERN FOR THE
LAST FEW DAYS...AND LITTLE CHANGE EXPECTED FOR THE NEXT FEW DAYS.
AT LEAST FOR THE NEXT 24 HOURS OR SO THE FORECAST AREA IS LOCKED
DOWN UNDER A STRONG RIDGE ALOFT WITH THE ASSOCIATED SUBSIDENCE
INVERSION KEEPING THE ATMOSPHERE STRONGLY DECOUPLED. A STRATUS
DECK WITH BASES NOW AROUND 1500 TO 2000 FEET MSL IS TRAPPED IN THE
COLUMBIA BASIN. THE STRONG SURFACE HIGH PRESSURE IS ORIENTED WITH
IT`S AXIS ALONG THE IDAHO PANHANDLE. THE RESULTANT GRADIENT HAS
ALLOWED THE DEEPEST MOIST SURFACE AIR TO POOL IN THE DEEP
BASIN...WHILE THE BOUNDARY LAYER HAS THINNED OVER THE NORTHEAST
ZONES ENOUGH TO ALLOW THE ANEMIC DEEP JANUARY DIURNAL MIXING TO
ALLOW A BREAK OUT OF THE FOG AND STRATUS YESTERDAY. OVERNIGHT THE
STRATUS FIELD HAS ADVANCED BACK INTO THE NORTHEAST VALLEYS AND
BASIN...BUT IT IS LIKELY SHALLOW AND THERE IS OPTIMISM THAT
SUN BREAKS WILL ONCE AGAIN GRACE THE VALLEYS AND BASIN NORTH AND
EAST OF A LINE FROM OMAK TO PULLMAN THIS AFTERNOON. OTHERWISE
LITTLE CHANGE TO THE OVERALL REGIME WITH STRATUS AND FOG EXPECTED
TO REFILL ALL OF THIS AFTERNOON`S MIXED OUT VALLEYS AGAIN TONIGHT.
/FUGAZZI
TUESDAY THROUGH SUNDAY...FEW SPECIFICS ARE CERTAIN DURING THIS
PORTION OF THE FORECAST...BUT ONE OVERARCHING THEME OF THE SECOND
HALF OF THIS WEEK WILL BE THE DEMISE OF THE RIDGE. THAT WILL ALSO
MEAN AN END TO THE LOW CLOUDS...FOG...AND STRATUS. HOWEVER...IT
WILL LIKELY MEAN A RETURN TO COLD TEMPERATURES AND SNOW FOR A GOOD
CHUNK OF THE FORECAST AREA.
BETWEEN TUESDAY AND THURSDAY THE VARIOUS GLOBAL MODELS REALLY DO A
HUGE NUMBER ON THE RIDGE THAT HAS BEEN OVER THE CWA. NOT ONLY DOES
THE RIDGE DEAMPLIFY GREATLY...BUT IT IS SHIFTED INTO THE FRONT
RANGE OF THE ROCKIES. AS THIS OCCURS...THE SPLIT UPPER FLOW OVER
THE CENTRAL PACIFIC AT THE MOMENT PUSHES CLOSER TO THE COAST.
STRONG DRYING EVIDENT ON THE WATER VAPOR IMAGERY IN ASSOCIATION
WITH THE SOUTHERN SECTION OF THE SPLIT LOOKS TO BE THE RESULT OF
A STRETCHING UPPER TROPOSPHERIC PV ANOMALY THAT SHOULD HELP TO
REINVIGORATE AN UPPER LOW AS IT APPROACHES CALIFORNIA BY THURSDAY.
MEANWHILE...UPPER RIDGING IN THE NORTHERN STREAM PUSHES INTO THE
HEART OF ALASKA. THIS FORCES A GENERAL RETROGRESSION OF THE ARCTIC
VORTEX OVER HUDSON BAY AND THE EASTERN HALF OF CANADA. AS A
RESULT...FLOW FROM THE NORTHERN STREAM STRONGLY SHIFTS NORTH TO
NORTHWEST ON THE GFS BY FRIDAY OVER THE CWA...AND BY SATURDAY
NIGHT ON THE ECMWF. IN SO DOING...A STRONG LOWER TROPOSPHERIC
RESPONSE IS FOUND IN BOTH MODELS RESULTING IN A RATHER IMPRESSIVE
COLD FRONTAL PASSAGE ACROSS THE AREA DURING THE LATTER HALF OF THE
WEEK. AGAIN...THE GFS IS QUITE A BIT QUICKER IN DOING SO THAN THE
ECMWF...BUT THE TREND TOWARD MUCH COLDER CONDITIONS EXISTS ON
BOTH. LIKEWISE...WITH THE FRONTAL PASSAGE...HIGH SNOW-TO-LIQUID
RATIO SNOWS WITH FRONTOGENETICAL LIFT LOOK TO CROSS THE AREA AS
NORTHWESTERLY FLOW ENERGY RUNS DOWN THE ARCTIC FRONT BY THE END OF
THE WEEK.
WITH THE MODELS EVOLVING STRONGLY TOWARD A MORE WINTRY SCENARIO BY
NEXT WEEKEND...TEMPERATURES HAVE BEEN SLASHED WHOLESALE.
LIKEWISE...POPS HAVE BEEN ADJUSTED UP TO OR ABOVE CLIMATOLOGY BY
NEXT WEEKEND WITH A NORTHWESTERLY FLOW AND SEVERAL SHORT WAVE
IMPULSES SET TO TRAVERSE THROUGH THE INLAND NORTHWEST. /FRIES
&&
.AVIATION...
LARGE AREA OF STRATUS WILL PERSIST AT KEAT/KMWH WHERE CONFIDENCE
IS HIGH OF CONTINUED IFR...MARGINAL MVFR CIGS AND VFR VSBYS. FOR
KGEG/KCOE/KSFF...A COMPLICATED FCST AS CLEARING THIS EVENING HAS
ALLOWED GROUND FOG TO FORM IN THE AREA...WITH AN AREA OF STRATUS POSSIBLY
A LITTLE HIGHER ABOVE THE SFC MOVING UP FROM THE SOUTHWEST NEARING
THESE AREAS AS OF 06Z THIS EVENING. THIS OPTED TO SHOW SOME LOWER
CIGS AND VSBYS TO BEGIN THE TAFS...BUT THEN SHOW IMPROVEMENT AS
THE SLIGHTLY HIGHER CIGS MOVE INTO THE AREA AND RADIATIONAL
COOLING DIMINISHES FOR LESS FOG POTENTIAL. FOR KPUW/KLWS...STRATUS
SHOULD PERSIST NEAR AND OVER THESE TAF SITES. OCCASIONAL E-SE
WINDS MAY BRIEFLY PUSH THE STRATUS OUT OF THESE AREAS BUT
PREVAILING CONDITIONS SHOULD REMAIN IFR AT KPUW AND MVFR AT KLWS.
TOPS OF THE STRATUS LAYER WILL VARY...BUT MOSTLY BE NEAR 3K FEET MSL.
JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 32 25 34 25 33 25 / 0 0 0 0 0 10
COEUR D`ALENE 35 23 37 25 36 26 / 0 0 0 0 0 10
PULLMAN 32 27 37 29 36 28 / 0 0 0 0 0 10
LEWISTON 33 27 39 30 40 30 / 0 0 0 0 0 10
COLVILLE 36 25 34 22 32 20 / 0 0 0 0 0 10
SANDPOINT 37 21 35 24 32 24 / 0 0 0 0 0 10
KELLOGG 35 24 35 26 34 25 / 0 0 0 0 0 10
MOSES LAKE 32 26 33 23 31 23 / 0 0 0 0 0 10
WENATCHEE 30 26 32 25 32 24 / 0 0 0 0 0 10
OMAK 32 25 31 23 29 22 / 0 0 0 0 0 10
&&
.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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 190602
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1002 PM PST SUN JAN 18 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE IN THE UPCOMING WEEK THE RIDGE IS
EXPECTED TO BREAK DOWN....WITH A POSSIBLE RETURN TO A MORE
ACTIVE WEATHER PATTERN.
&&
.DISCUSSION...
MINOR FORECAST ADJUSTMENTS HAVE BEEN MADE MAINLY FOR TONIGHT AND
MONDAY MORNING TO TWEAK SKY COVER AND LOW TEMPERATURES TONIGHT.
FOG PRODUCT CONTINUES TO SHOW ABUNDANT STRATUS CLOUDS BELOW AROUND
3000 FEET OVER CENTRAL AND SOUTHEAST WASHINGTON. FROM THE
SPOKANE/COEUR D`ALENE AREA NORTHWARD AS WELL AS SHOSHONE COUNTY
SKIES CLEARED EARLIER TODAY IN RESPONSE TO DRIER AIR MIXING DOWN.
NORTHEAST WINDS HELPED DRY OUT THE BOUNDARY LAYER. THIS OCCURRED
DUE TO DECENT PRESSURE GRADIENT BETWEEN AN IMPRESSIVELY STRONG
1046-1048MB SFC HIGH NEAR CRESTON BC...JUST NORTH OF THE ID/BC
BORDER...AND A MESO SFC LOW OF NEAR 1032 MB OVER SHOSHONE COUNTY.
THIS GRADIENT HAS CHANGED VERY LITTLE THIS EVENING SO THE WINDS
SHOULD KEEP THE SAND POINT AREA CLEAR OF FOG THROUGH MONDAY SO FOG
WAS REMOVED FROM HERE. FOR THE SPOKANE/COEUR D`ALENE AREA...THE
LARGE AREA OF STRATUS OVER THE BASIN IS MOVING NORTHEAST AND WILL MOVE
THESE AREAS BEFORE MIDNIGHT. FOR THE NE WA VALLEYS...EARLIER
CLEARING IS RESULTING IN INCREASING AREAS OF FOG THIS EVENING WITH
THIS TREND EXPECTED TO CONTINUE OVERNIGHT. THESE CLEAR SKIES
ALLOWED TEMPS TO FALL QUICKLY THIS EVENING...WITH LOW TEMPS
LOWERED FOR SPOKANE...DEER PARK...AND COLVILLE. WINCHESTER DOWN ON
THE CAMAS PRAIRIE WAS ALSO COOLED SIGNIFICANTLY BASED ON CLEAR
SKIES AND SNOW COVER ON THE GROUND...SIMILAR TO WHAT HAS BEEN
OBSERVED THE PAST COUPLE NIGHTS WITH TEENS EXPECTED. JW
&&
.AVIATION...
LARGE AREA OF STRATUS WILL PERSIST AT KEAT/KMWH WHERE CONFIDENCE
IS HIGH OF CONTINUED IFR...MARGINAL MVFR CIGS AND VFR VSBYS. FOR
KGEG/KCOE/KSFF...A COMPLICATED FCST AS CLEARING THIS EVENING HAS
ALLOWED GROUND FOG TO FORM IN THE AREA...WITH AN AREA OF STRATUS POSSIBLY
A LITTLE HIGHER ABOVE THE SFC MOVING UP FROM THE SOUTHWEST NEARING
THESE AREAS AS OF 06Z THIS EVENING. THIS OPTED TO SHOW SOME LOWER
CIGS AND VSBYS TO BEGIN THE TAFS...BUT THEN SHOW IMPROVEMENT AS
THE SLIGHTLY HIGHER CIGS MOVE INTO THE AREA AND RADIATIONAL
COOLING DIMINISHES FOR LESS FOG POTENTIAL. FOR KPUW/KLWS...STRATUS
SHOULD PERSIST NEAR AND OVER THESE TAF SITES. OCCASIONAL E-SE
WINDS MAY BRIEFLY PUSH THE STRATUS OUT OF THESE AREAS BUT
PREVAILING CONDITIONS SHOULD REMAIN IFR AT KPUW AND MVFR AT KLWS.
TOPS OF THE STRATUS LAYER WILL VARY...BUT MOSTLY BE NEAR 3K FEET MSL.
JW
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 19 34 25 34 25 34 / 0 0 0 0 0 0
COEUR D`ALENE 21 37 23 37 25 36 / 0 0 0 0 0 0
PULLMAN 25 33 27 35 29 36 / 0 0 0 0 0 0
LEWISTON 29 35 27 38 31 40 / 0 0 0 0 0 0
COLVILLE 19 35 25 35 22 33 / 0 0 0 0 0 0
SANDPOINT 20 37 21 37 24 33 / 0 0 0 0 0 0
KELLOGG 23 35 24 36 26 34 / 0 0 0 0 0 0
MOSES LAKE 27 32 26 32 23 33 / 0 0 0 0 0 0
WENATCHEE 25 31 26 32 25 33 / 0 0 0 0 0 0
OMAK 25 32 25 32 23 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 182356 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
356 PM PST SUN JAN 18 2009
...UPDATED AVIATION...
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE IN THE UPCOMING WEEK THE RIDGE IS
EXPECTED TO BREAK DOWN....WITH A POSSIBLE RETURN TO A MORE
ACTIVE WEATHER PATTERN.
&&
.DISCUSSION...
TONIGHT THROUGH TUESDAY...A RIDGE OF HIGH PRESSURE WILL REMAIN
THE DOMINATE FEATURE. THIS WILL KEEP THE INVERSION OVER THE
VALLEY/BASIN ZONES AND HOLD IN THE LOW LEVEL MOISTURE...AND
STAGNANT CONDITIONS. AFTERNOON MIXING HEIGHTS DO NOT MOVE MUCH
ABOVE 900 FEET THROUGH THE ENTIRE PERIOD...DOING LITTLE TO
COMPLETELY DRY OUT THE BOUNDARY LAYER. GUIDANCE IS HAVING A VERY
DIFFICULT TIME RESOLVING THE LOW LEVEL MOISTURE IN PLACE.
RELATIVELY SPEAKING THE NAM12 IS CLOSEST BUT STILL INITIALIZED
500-1000 FEET TOO SHALLOW. QUALITATIVELY THE NAM AND GFS SFC/BL RH
FIELDS STILL SUPPORT THE STRATUS HOLDING OVER BASIN AND VALLEY
ZONES TONIGHT AND REDEVELOPING IN THE LOCATIONS FURTHER
EAST...WITH AT LEAST PATCHY FOG (THAT INCLUDES NE WA AND N ID
VALLEYS THROUGH SPOKANE AREA AND PALOUSE). THIS IS EXPECTED TO BE
FOLLOWED BY SOME CLEARING INTO THE EASTERN FRINGES BY LATE
MORNING/EARLY AFTERNOON MONDAY. THIS DIURNAL TREND IS EXPECTED TO
CONTINUE INTO TUESDAY. BY TUESDAY THE RIDGE AXIS IS EXPECTED TO
SHIFT FURTHER EAST AND THE SSW MID-LEVEL FLOW THAT DEVELOPS BRINGS
A COUPLE SHORT-WAVE DISTURBANCES IN. THE MOST FAVORABLE
DISTURBANCE COMES TUESDAY. YET THE FORCING IS WEAK AND WHAT COMES
MAINLY SKIMS BY THE WEST AND IT IS STILL QUITE STARVED FOR
MOISTURE. LOOK FOR SOME INCREASE IN HIGHER CLOUDS...BUT STILL NO
RISK FOR PRECIPITATION. PRECISE TEMPERATURES WILL BE GREATLY
DEPENDANT AGAIN ON THE STRATUS/FOG COVERAGE...BUT LOOK FOR NEAR TO
SLIGHTLY ABOVE NORMAL TEMPERATURES. /JCOTE
TUESDAY NT THROUGH SUNDAY...THE TIMING OF THE BREAKDOWN OF THE
LONG-WAVE RIDGE CURRENTLY OVER THE REGION WILL BE THE FCST
CHALLENGE. PREVIOUS RUNS OF MAINLY THE GFS APPEARED TOO QUICK IN
TRYING TO EJECT THE ERN PAC TROF NOW AROUND 145W INTO THE
WEAKENING WRN CONUS 6000M RIDGE. THE LATEST MEDIUM RANGE GUIDANCE
HAS CERTAINLY TRENDED TOWARD A SLOWER...WEAKER...AND MORE
SOUTHERLY PATH OF THIS SHEARING SLOW-MOVING SHORTWAVE TROF. TAKING
ON A MODIFIED REX-TYPE BLOCKING PATTERN...THIS TROF WON`T LIKELY
REACH COASTAL OREGON UNTIL WED...KEEPING THE STAGNANT WX PATTERN
LOCKED IN PLACE A BIT LONGER FOR ERN WA AND N ID. THIS MORE SRN
TRACK OF THE FILLING TROF WILL MEAN A DRIER FCST THAN WHAT THE
PREVIOUS GFS WAS SHOWING AS IT TRIED TO LIFT A WARMFNT N THROUGH
OREGON AND SRN WA THURS AT THE SAME TIME IT FAVORED A 1050MB
ARCTIC AIRMASS SWEEPING SOUTH THRU ALBERT AND BC. THOUGH THIS COLD
FROPA FROM THE N IS STILL EXPECTED FRI...WE`VE TRENDED TOWARD A
DRIER FCST THURS NT. IN ADDITION...CONSENSUS WAS TO NOT FAVOR THE
GFS`S VERY STRONG AND COLD NORTHERLY STEERING FLOW THAT PUMPS IN
QUITE A BIT OF VERY COLD AIR BEHIND THE COLD FRONTAL PASSAGE FRI.
THIS MAINLY DUE TO PLENTY OF RUN- TO-RUN INCONSISTENCIES AS WELL A
SIZABLE DISAGREEMENTS BETWEEN THE EXTENDED RANGE MODELS. BZ
&&
.AVIATION...
STRATUS WILL REMAIN THE FCST CHALLENGE THROUGH AT LEAST 00Z
TUES...WITH A CANOPY OF 1-2K FT THICK STRATUS ANCHORED OVER THE
COLUMBIA BASIN. THE STRATUS WILL BE DEEPEST TOWARD KMWH-KEAT...WITH
PRIMARILY IFR/LCL MVFR CIGS IN THE FCST. THE EXCEPTION WILL BE
LATE THIS AFTERNOON UNTIL 03Z (FROM KCOE WEST TO KSFF AND KGEG)
WHERE THE ERN EDGE OF THE LOW CLOUDS HAVE BEEN ERODED A SIGNIFICANT
DISTANCE WEST INTO LINCOLN COUNTY. AFTER 03Z...WITH TEMPERATURES
DROPPING BACK TOWARD THE DEWPOINT...WE`RE STILL EXPECTING
PRIMARILY IFR CIGS TO REDEVELOP. BZ
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 24 34 25 34 25 34 / 0 0 0 0 0 0
COEUR D`ALENE 21 37 23 37 25 36 / 0 0 0 0 0 0
PULLMAN 27 33 27 35 29 36 / 0 0 0 0 0 0
LEWISTON 29 35 27 38 31 40 / 0 0 0 0 0 0
COLVILLE 25 35 25 35 22 33 / 0 0 0 0 0 0
SANDPOINT 20 37 21 37 24 33 / 0 0 0 0 0 0
KELLOGG 23 35 24 36 26 34 / 0 0 0 0 0 0
MOSES LAKE 27 32 26 32 23 33 / 0 0 0 0 0 0
WENATCHEE 26 31 26 32 25 33 / 0 0 0 0 0 0
OMAK 25 32 25 32 23 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 182258
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
258 PM PST SUN JAN 18 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE IN THE UPCOMING WEEK THE RIDGE IS
EXPECTED TO BREAK DOWN....WITH A POSSIBLE RETURN TO A MORE
ACTIVE WEATHER PATTERN.
&&
.DISCUSSION...
TONIGHT THROUGH TUESDAY...A RIDGE OF HIGH PRESSURE
WILL REMAIN THE DOMINATE FEATURE. THIS WILL KEEP THE INVERSION
OVER THE VALLEY/BASIN ZONES AND HOLD IN THE LOW LEVEL
MOISTURE...AND STAGNANT CONDITIONS. AFTERNOON MIXING HEIGHTS DO
NOT MOVE MUCH ABOVE 900 FEET THROUGH THE ENTIRE PERIOD...DOING
LITTLE TO COMPLETELY DRY OUT THE BOUNDARY LAYER. GUIDANCE IS
HAVING A VERY DIFFICULT TIME RESOLVING THE LOW LEVEL MOISTURE IN
PLACE. RELATIVELY SPEAKING THE NAM12 IS CLOSEST BUT STILL
INITIALIZED 500-1000 FEET TOO SHALLOW. QUALITATIVELY THE NAM AND
GFS SFC/BL RH FIELDS STILL SUPPORT THE STRATUS HOLDING OVER BASIN
AND VALLEY ZONES TONIGHT AND REDEVELOPING IN THE LOCATIONS FURTHER
EAST...WITH AT LEAST PATCHY FOG (THAT INCLUDES NE WA AND N ID
VALLEYS THROUGH SPOKANE AREA AND PALOUSE). THIS IS EXPECTED TO BE
FOLLOWED BY SOME CLEARING INTO THE EASTERN FRINGES BY LATE
MORNING/EARLY AFTERNOON MONDAY. THIS DIURNAL TREND IS EXPECTED TO
CONTINUE INTO TUESDAY. BY TUESDAY THE RIDGE AXIS IS EXPECTED TO
SHIFT FURTHER EAST AND THE SSW MID-LEVEL FLOW THAT DEVELOPS BRINGS
A COUPLE SHORT-WAVE DISTURBANCES IN. THE MOST FAVORABLE
DISTURBANCE COMES TUESDAY. YET THE FORCING IS WEAK AND WHAT COMES
MAINLY SKIMS BY THE WEST AND IT IS STILL QUITE STARVED FOR
MOISTURE. LOOK FOR SOME INCREASE IN HIGHER CLOUDS...BUT STILL NO
RISK FOR PRECIPITATION. PRECISE TEMPERATURES WILL BE GREATLY
DEPENDANT AGAIN ON THE STRATUS/FOG COVERAGE...BUT LOOK FOR NEAR TO
SLIGHTLY ABOVE NORMAL TEMPERATURES. /JCOTE
TUESDAY NT THROUGH SUNDAY...THE TIMING OF THE BREAKDOWN OF THE
LONG-WAVE RIDGE CURRENTLY OVER THE REGION WILL BE THE FCST
CHALLENGE. PREVIOUS RUNS OF MAINLY THE GFS APPEARED TOO QUICK IN
TRYING TO EJECT THE ERN PAC TROF NOW AROUND 145W INTO THE
WEAKENING WRN CONUS 6000M RIDGE. THE LATEST MEDIUM RANGE GUIDANCE
HAS CERTAINLY TRENDED TOWARD A SLOWER...WEAKER...AND MORE
SOUTHERLY PATH OF THIS SHEARING SLOW-MOVING SHORTWAVE TROF. TAKING
ON A MODIFIED REX-TYPE BLOCKING PATTERN...THIS TROF WON`T LIKELY
REACH COASTAL OREGON UNTIL WED...KEEPING THE STAGNANT WX PATTERN
LOCKED IN PLACE A BIT LONGER FOR ERN WA AND N ID. THIS MORE SRN
TRACK OF THE FILLING TROF WILL MEAN A DRIER FCST THAN WHAT THE
PREVIOUS GFS WAS SHOWING AS IT TRIED TO LIFT A WARMFNT N THROUGH
OREGON AND SRN WA THURS AT THE SAME TIME IT FAVORED A 1050MB
ARCTIC AIRMASS SWEEPING SOUTH THRU ALBERT AND BC. THOUGH THIS COLD
FROPA FROM THE N IS STILL EXPECTED FRI...WE`VE TRENDED TOWARD A
DRIER FCST THURS NT. IN ADDITION...CONSENSUS WAS TO NOT FAVOR THE
GFS`S VERY STRONG AND COLD NORTHERLY STEERING FLOW THAT PUMPS IN
QUITE A BIT OF VERY COLD AIR BEHIND THE COLD FRONTAL PASSAGE FRI.
THIS MAINLY DUE TO PLENTY OF RUN- TO-RUN INCONSISTENCIES AS WELL A
SIZABLE DISAGREEMENTS BETWEEN THE EXTENDED RANGE MODELS. BZ
&&
.AVIATION...
STRATUS WILL REMAIN THROUGH AT LEAST 18Z MONDAY...WITH A DEPTH OF
ABOUT 1-2KFT. THE STRATUS WILL BE DEEPEST TOWARD KMWH-KEAT. EXPECT
PRIMARILY IFR/LCL MVFR CIGS. AN EXCEPTION LAYS BETWEEN 18-03Z
SUNDAY ACROSS KCOE/KSFF/KGEG/KPUW/KLWS. AN EASTERLY EROSION OF THE
STRATUS DURING THE DAYTIME WILL BRING PERIODS OF VFR CIGS. AFTER
03-06Z WITH TEMPERATURES DROPPING BACK TOWARD THE DEWPOINT
PRIMARILY IFR CIGS EXPECTED TO REDEVELOP. PATCHY FOG WILL BRING
LCL MVFR AND BRIEF LIFR VIS. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 24 34 25 34 25 34 / 0 0 0 0 0 0
COEUR D`ALENE 21 37 23 37 25 36 / 0 0 0 0 0 0
PULLMAN 27 33 27 35 29 36 / 0 0 0 0 0 0
LEWISTON 29 35 27 38 31 40 / 0 0 0 0 0 0
COLVILLE 25 35 25 35 22 33 / 0 0 0 0 0 0
SANDPOINT 20 37 21 37 24 33 / 0 0 0 0 0 0
KELLOGG 23 35 24 36 26 34 / 0 0 0 0 0 0
MOSES LAKE 27 32 26 32 23 33 / 0 0 0 0 0 0
WENATCHEE 26 31 26 32 25 33 / 0 0 0 0 0 0
OMAK 25 32 25 32 23 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 182032 AAB
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
1232 PM PST SUN JAN 18 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE IN THE UPCOMING WEEK THE RIDGE IS
EXPECTED TO BREAK DOWN....WITH A POSSIBLE RETURN TO A MORE
ACTIVE WEATHER PATTERN.
&&
.DISCUSSION...
UPDATE...FORECAST UPDATE SENT WITH SOME TWEAKS TO CLOUD COVER
AND WIND OVER THE EAST FOR THIS AFTERNOON...AND TO REMOVE SOME OF
THE PATCHY FOG. HIGH TEMPERATURES WERE ALSO ADJUSTED UP A COUPLE
DEGREES OVER A FEW EASTERN LOCATIONS OWING TO MORE SUNSHINE. THE
DEEPER BASIN AND MORE SHELTERED NORTHERN AND WESTERN VALLEYS
CONTINUE TO LOOK ON TRACK...WITH TEMPERATURES NOT QUICK TO RISE
UNDER THE DEEPER STRATUS DECK. /JCOTE
&&
.AVIATION...
STRATUS WILL REMAIN THROUGH AT LEAST 18Z MONDAY...WITH A DEPTH OF
ABOUT 1-2KFT. THE STRATUS WILL BE DEEPEST TOWARD KMWH-KEAT. EXPECT
PRIMARILY IFR/LCL MVFR CIGS. AN EXCEPTION LAYS BETWEEN 18-03Z
SUNDAY ACROSS KCOE/KSFF/KGEG/KPUW/KLWS. AN EASTERLY EROSION OF THE
STRATUS DURING THE DAYTIME WILL BRING PERIODS OF VFR CIGS. AFTER
03-06Z WITH TEMPERATURES DROPPING BACK TOWARD THE DEWPOINT
PRIMARILY IFR CIGS EXPECTED TO REDEVELOP. PATCHY FOG WILL BRING
LCL MVFR AND BRIEF LIFR VIS. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 33 26 32 25 33 25 / 0 0 0 0 0 0
COEUR D`ALENE 36 26 36 26 35 25 / 0 0 0 0 0 0
PULLMAN 33 27 34 28 35 29 / 10 0 0 0 0 0
LEWISTON 33 29 35 29 40 31 / 10 0 0 0 0 0
COLVILLE 36 26 32 23 32 22 / 0 0 0 0 0 0
SANDPOINT 36 20 36 25 35 24 / 0 0 0 0 0 0
KELLOGG 37 26 42 27 37 26 / 0 0 0 0 0 0
MOSES LAKE 32 26 32 23 31 23 / 10 0 0 0 0 0
WENATCHEE 31 26 29 24 32 25 / 0 0 0 0 0 0
OMAK 32 23 29 24 30 23 / 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 181812 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
1012 AM PST SUN JAN 18 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF THE WEEK...WITH THE STRONG RIDGE OF HIGH PRESSURE
REMAINING OVER THE PACIFIC NORTHWEST. THE MOUNTAINS WILL LIKELY
EXPERIENCE CLEAR SKIES...WHILE THE LOW ELEVATIONS LARGELY TRAPPED
IN LOW CLOUDS. AIR STAGNATION WILL BE A PROBLEM FOR VALLEY
LOCATIONS WITH THE PRESENCE OF LIGHT WINDS AND A PROLONGED STRONG
LOW LEVEL INVERSION. LATE IN THE UPCOMING WEEK THE RIDGE IS
EXPECTED TO BREAK DOWN....WITH A POSSIBLE RETURN TO A MORE
ACTIVE WEATHER PATTERN.
&&
.DISCUSSION...
REST OF TODAY...STRONG HIGH PRESSURE WILL CONTINUE TO DOMINATE
THE WEATHER...WITH NEARLY ALL THE DEEPER MOISTURE AND ENERGY BEING
DEFLECTED AROUND THE REGION. THE 12Z SOUNDING INDICATED THIS HIGH
WITH A STRONG INVERSION AND LARGELY DRY MID AND UPPER LEVELS. YET
MOISTURE REMAINS TRAPPED IN THE LOWEST 1000-2000 FEET...DEEPEST
FURTHER SW INTO COLUMBIA BASIN. AS SUCH THE STRATUS AND PATCHY FOG
REMAINS OVER A GOOD PORTION OF THE BASIN AND VALLEYS. THERE HAVE
BEEN BREAKS IN THIS DECK AROUND ITS EASTERN FRINGES...FROM THE
C`DA/SPOKANE AREA SOUTHWARD INTO THE PALOUSE. THIS TREND IS
EXPECTED TO CONTINUE THROUGH THE AFTERNOON. YET THE MORE SHELTERED
VALLEYS ACROSS NORTHERN WASHINGTON (FROM THE OKANOGAN VALLEY TO THE
WA/ID BORDER) WILL SEE LITTLE IMPETUS TO BREAK OUT OF THE STRATUS.
SIMILAR CAN BE SAID FOR THE DEEPER BASIN COLUMBIA THROUGH THE
RIVER VALLEYS ALONG THE EAST SLOPES OF THE CASCADES WHERE THE BL
MOISTURE IS DEEPER. WE WILL CONTINUE TO MONITOR HIGH TEMPERATURES
FOR THIS AFTERNOON...ESPECIALLY EASTERLY LOCATIONS WHICH WILL BE
GREATLY DEPENDANT ON HOW MUCH CLEARING DEVELOPS OR DOES NOT
DEVELOP. /JCOTE
&&
.AVIATION...
STRATUS WILL REMAIN THROUGH AT LEAST 18Z MONDAY...WITH A DEPTH OF
ABOUT 1-2KFT. THE STRATUS WILL BE DEEPEST TOWARD KMWH-KEAT. EXPECT
PRIMARILY IFR/LCL MVFR CIGS. AN EXCEPTION LAYS BETWEEN 18-03Z
SUNDAY ACROSS KCOE/KSFF/KGEG/KPUW/KLWS. AN EASTERLY EROSION OF THE
STRATUS DURING THE DAYTIME WILL BRING PERIODS OF VFR CIGS. AFTER
03-06Z WITH TEMPERATURES DROPPING BACK TOWARD THE DEWPOINT
PRIMARILY IFR CIGS EXPECTED TO REDEVELOP. PATCHY FOG WILL BRING
LCL MVFR AND BRIEF LIFR VIS. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 32 26 32 25 33 25 / 0 0 0 0 0 0
COEUR D`ALENE 34 26 36 26 35 25 / 0 0 0 0 0 0
PULLMAN 35 27 34 28 35 29 / 10 0 0 0 0 0
LEWISTON 33 29 35 29 40 31 / 10 0 0 0 0 0
COLVILLE 36 26 32 23 32 22 / 0 0 0 0 0 0
SANDPOINT 34 20 36 25 35 24 / 0 0 0 0 0 0
KELLOGG 37 26 42 27 37 26 / 0 0 0 0 0 0
MOSES LAKE 32 26 32 23 31 23 / 10 0 0 0 0 0
WENATCHEE 31 26 29 24 32 25 / 0 0 0 0 0 0
OMAK 30 23 29 24 30 23 / 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 181127
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
328 AM PST SUN JAN 18 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF NEXT WEEK. THE STRONG RIDGE OF HIGH PRESSURE WILL REMAIN
OVER THE PACIFIC NORTHWEST UNTIL WEDNESDAY. THE MOUNTAINS WILL
LIKELY EXPERIENCE 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. LATE IN THE UPCOMING WEEK
THE RIDGE IS EXPECTED TO BREAK DOWN WITH AN INCREASING POSSIBILITY
OF A RETURN TO A MORE ACTIVE WEATHER PATTERN.
&&
.DISCUSSION...
TODAY AND TONIGHT...GOOD MODEL AGREEMENT FOR THE NEXT 24 HOURS
FEATURING A STRONG UPPER LEVEL RIDGE AXIS SHIFTING FROM THE COAST
THIS MORNING TO THE IDAHO PANHANDLE BY THIS EVENING. THE AIR MASS
AND FLOW ABOVE THE INVERSION LAYER IS DRY WITH NO DISTURBANCES TO
SHAKE UP THE SOUNDING PROFILE WHICH WILL CONTINUE TO FEATURE A
STRONG SUBSIDENCE INVERSION OVER THE ENTIRE REGION. THIS SOLIDLY
DECOUPLED AIR MASS WILL ALLOW PLENTY OF SUN AND RELATIVELY MILD
TEMPERATURES ON THE MOUNTAIN SLOPES ABOVE THE STRATUS DECK AROUND
4000 FEET MSL AND ABOVE...WITH CONTINUING CLOUDY AND COOL WEATHER
IN THE LOWER ELEVATIONS. THE ORIENTATION OF THE SURFACE PRESSURE
GRADIENT WILL PROMOTE THE DEEPEST MOIST AND STABLE AIR TO SLOSH
INTO THE DEEP BASIN TODAY WITH THE POSSIBILITY OF A FEW AFTERNOON
SUN BREAKS IN THE STRATUS OVER THE NORTHEASTERN BASIN AND NORTHERN
VALLEYS THIS AFTERNOON...BUT THE DEEP WINTER MURK WILL RETURN
SHORTLY AFTER SUNSET AT ALL VALLEY LOCATIONS. HIGH AND LOW TEMPS
ONCE AGAIN DISPLAYING VERY LITTLE DIURNAL DIFFERENCE UNDER THE
INVERSION. AIR STAGNATION ADVISORY CONTINUES. /FUGAZZI
MONDAY THROUGH WEDNESDAY...A SLOW BREAKDOWN IN THE PATTERN LOOKS
TO BE IN STORE FOR THE INLAND NORTHWEST DURING THE FIRST HALF OF
THE UPCOMING WEEK. WHILE THE GLOBAL MODEL SOLUTIONS VARY IN THE
WAY THEY MANAGE TO BREAK DOWN THE AMPLIFIED RIDGE OVER THE
NORTHWEST...THEY ALL SEEM TO DO IT IN ONE FASHION OR ANOTHER.
THE MID-LEVEL RIDGE AXIS SHOULD HAVE PUSHED EASTWARD TOWARD
WESTERN MONTANA BY MONDAY AFTERNOON. THE MODELS GRADUALLY WORK TO
SQUASH THE RIDGE DOWN A BIT THROUGH THE DAY TUESDAY...TRACKING A
HARDLY NOTICEABLE SHORT WAVE OVER THE TOP OF THE RIDGE. THIS HAS
THE IMPACT OF INCREASING THE CLOUDS OVER THE CASCADES BY MID-
WEEK...AND ALSO STARTS TO INDUCE SURFACE PRESSURE FALLS OVER THE
CANADIAN FRONT RANGE. THE PRESSURE FALLS OVER ALBERTA GRADUALLY
WORK TO REVERSE THE PRESSURE GRADIENT OVER THE CWA...SO SURFACE
FLOW GOES FROM A DRY NORTHEASTERLY FLOW IN THE BOUNDARY LAYER WITH
DECREASING FOG OVER THE CWA...TO A WEAKER OR EVEN SOUTHERLY FLOW
THAT WOULD REDEVELOP LIGHT FOG OVER THE UPPER BASIN AND WEST
PLAINS AREAS BY WEDNESDAY. HOWEVER...THIS WOULD LIKELY BE RATHER
SHORT LIVED DUE TO THE PATTERN BREAKDOWN.
BY THE END OF THE DAY WEDNESDAY...ALL MODELS HAVE TREMENDOUSLY
WEAKENED THE RIDGE AND PUSHED IT WELL EAST OF THE CWA. WITH SOME
SORT OF A SPLIT FLOW PATTERN SUGGESTED BY BOTH THE ECMWF AND GFS
THROUGH LATER IN THE WEEK...THE RIDGE LOOKS TO QUICKLY BECOME AN
ITEM OF THE PAST. ON A SIDE NOTE...THE CANADIAN GLOBAL SOLUTION
LOOKS VERY SIMILAR TO THE ECMWF...AND AS A RESULT...THE ECMWF
SOLUTION IS STILL FAVORED OVER THE GFS. HOWEVER...NEITHER THE GFS
NOR THE ECMWF RESULTS IN TREMENDOUS QPF OVER THE CWA THROUGH THE
NEXT WEEK. BUT...WITH A MUCH HEAVIER INFLUENCE OF PACIFIC AIR
OVER THE CWA BY LATER IN THE WEEK...POPS HAVE BEEN RAISED CLOSE TO
CLIMO WITH TEMPERATURES NEAR NORMAL. /FRIES
&&
.AVIATION...
WIDESPREAD STRATUS FIELD UNDER STRONG INVERSION WITH BASES AROUND
2000-2500 FT MSL AND TOPS AROUND 4000 FT MSL WILL PERSIST THROUGH
12Z MONDAY ACROSS MOST OF THE REGION. THUS...MOST TAF SITES WILL
REMAIN LOCKED UNDER LOW MVFR OR IFR CEILINGS. BREIF IMPROVEMENT TO
VFR CONDITIONS IS LIKELY AT KCOE...KSFF AND PERHAPS KGEG AND KPUW
FOR A FEW HOURS THIS AFTERNOON...WITH A RETURN TO IFR OR LOW MVFR
CONDITIONS AFTER SUNSET TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 32 26 32 25 33 25 / 0 0 0 0 0 0
COEUR D`ALENE 34 26 36 26 35 25 / 0 0 0 0 0 0
PULLMAN 35 27 34 28 35 29 / 10 0 0 0 0 0
LEWISTON 33 29 35 29 40 31 / 10 0 0 0 0 0
COLVILLE 36 26 32 23 32 22 / 0 0 0 0 0 0
SANDPOINT 34 20 36 25 35 24 / 0 0 0 0 0 0
KELLOGG 37 26 42 27 37 26 / 0 0 0 0 0 0
MOSES LAKE 32 26 32 23 31 23 / 10 0 0 0 0 0
WENATCHEE 31 26 29 24 32 25 / 0 0 0 0 0 0
OMAK 30 23 29 24 30 23 / 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 181023
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
223 AM PST SUN JAN 18 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF NEXT WEEK. THE STRONG RIDGE OF HIGH PRESSURE WILL REMAIN
OVER THE PACIFIC NORTHWEST UNTIL WEDNESDAY. THE MOUNTAINS WILL
LIKELY EXPERIENCE 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. LATE IN THE UPCOMING WEEK
THE RIDGE IS EXPECTED TO BREAK DOWN WITH AN INCREASING POSSIBILITY
OF A RETURN TO A MORE ACTIVE WEATHER PATTERN.
&&
.DISCUSSION...
TODAY AND TONIGHT...GOOD MODEL AGREEMENT FOR THE NEXT 24 HOURS
FEATURING A STRONG UPPER LEVEL RIDGE AXIS SHIFTING FROM THE COAST
THIS MORNING TO THE IDAHO PANHANDLE BY THIS EVENING. THE AIR MASS
AND FLOW ABOVE THE INVERSION LAYER IS DRY WITH NO DISTURBANCES TO
SHAKE UP THE SOUNDING PROFILE WHICH WILL CONTINUE TO FEATURE A
STRONG SUBSIDENCE INVERSION OVER THE ENTIRE REGION. THIS SOLIDLY
DECOUPLED AIR MASS WILL ALLOW PLENTY OF SUN AND RELATIVELY MILD
TEMPERATURES ON THE MOUNTAIN SLOPES ABOVE THE STRATUS DECK AROUND
4000 FEET MSL AND ABOVE...WITH CONTINUING CLOUDY AND COOL WEATHER
IN THE LOWER ELEVATIONS. THE ORIENTATION OF THE SURFACE PRESSURE
GRADIENT WILL PROMOTE THE DEEPEST MOIST AND STABLE AIR TO SLOSH
INTO THE DEEP BASIN TODAY WITH THE POSSIBILITY OF A FEW AFTERNOON
SUN BREAKS IN THE STRATUS OVER THE NORTHEASTERN BASIN AND NORTHERN
VALLEYS THIS AFTERNOON...BUT THE DEEP WINTER MURK WILL RETURN
SHORTLY AFTER SUNSET AT ALL VALLEY LOCATIONS. HIGH AND LOW TEMPS
ONCE AGAIN DISPLAYING VERY LITTLE DIURNAL DIFFERENCE UNDER THE
INVERSION. AIR STAGNATION ADVISORY CONTINUES. /FUGAZZI
MONDAY THROUGH WEDNESDAY...A SLOW BREAKDOWN IN THE PATTERN LOOKS
TO BE IN STORE FOR THE INLAND NORTHWEST DURING THE FIRST HALF OF
THE UPCOMING WEEK. WHILE THE GLOBAL MODEL SOLUTIONS VARY IN THE
WAY THEY MANAGE TO BREAK DOWN THE AMPLIFIED RIDGE OVER THE
NORTHWEST...THEY ALL SEEM TO DO IT IN ONE FASHION OR ANOTHER.
THE MID-LEVEL RIDGE AXIS SHOULD HAVE PUSHED EASTWARD TOWARD
WESTERN MONTANA BY MONDAY AFTERNOON. THE MODELS GRADUALLY WORK TO
SQUASH THE RIDGE DOWN A BIT THROUGH THE DAY TUESDAY...TRACKING A
HARDLY NOTICEABLE SHORT WAVE OVER THE TOP OF THE RIDGE. THIS HAS
THE IMPACT OF INCREASING THE CLOUDS OVER THE CASCADES BY MID-
WEEK...AND ALSO STARTS TO INDUCE SURFACE PRESSURE FALLS OVER THE
CANADIAN FRONT RANGE. THE PRESSURE FALLS OVER ALBERTA GRADUALLY
WORK TO REVERSE THE PRESSURE GRADIENT OVER THE CWA...SO SURFACE
FLOW GOES FROM A DRY NORTHEASTERLY FLOW IN THE BOUNDARY LAYER WITH
DECREASING FOG OVER THE CWA...TO A WEAKER OR EVEN SOUTHERLY FLOW
THAT WOULD REDEVELOP LIGHT FOG OVER THE UPPER BASIN AND WEST
PLAINS AREAS BY WEDNESDAY. HOWEVER...THIS WOULD LIKELY BE RATHER
SHORT LIVED DUE TO THE PATTERN BREAKDOWN.
BY THE END OF THE DAY WEDNESDAY...ALL MODELS HAVE TREMENDOUSLY
WEAKENED THE RIDGE AND PUSHED IT WELL EAST OF THE CWA. WITH SOME
SORT OF A SPLIT FLOW PATTERN SUGGESTED BY BOTH THE ECMWF AND GFS
THROUGH LATER IN THE WEEK...THE RIDGE LOOKS TO QUICKLY BECOME AN
ITEM OF THE PAST. ON A SIDE NOTE...THE CANADIAN GLOBAL SOLUTION
LOOKS VERY SIMILAR TO THE ECMWF...AND AS A RESULT...THE ECMWF
SOLUTION IS STILL FAVORED OVER THE GFS. HOWEVER...NEITHER THE GFS
NOR THE ECMWF RESULTS IN TREMENDOUS QPF OVER THE CWA THROUGH THE
NEXT WEEK. BUT...WITH A MUCH HEAVIER INFLUENCE OF PACIFIC AIR
OVER THE CWA BY LATER IN THE WEEK...POPS HAVE BEEN RAISED CLOSE TO
CLIMO WITH TEMPERATURES NEAR NORMAL. /FRIES
&&
.AVIATION...
STRATUS LAYER BASES MOSTLY BETWEEN 1000-2000 FEET MSL...WITH TOPS
NEAR 3000-4000 FEET. THE PERSISTENT RIDGE WILL KEEP STRATUS IN
PLACE WITH LITTLE CHANGE THROUGH 18Z SUNDAY. HIGHER ELEVATION TAF
SITES SUCH AS KGEG AND KPUW WILL EXPERIENCE IFR CEILINGS WITH
OCCASIONAL IFR VIS. OTHER TAF SITES SHOULD REMAIN BELOW THE
STRATUS LAYER WITH MAINLY VFR VSBYS...AND HIGH IFR/LOW MVFR CIGS.
IMPROVEMENT TO VFR CEILINGS POSSIBLE AFTER 18Z FOR
KCOE...KPUW...KLWS AS STRATUS IS PUSHED WEST INTO THE BASIN. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 32 26 32 25 33 25 / 0 0 0 0 0 0
COEUR D`ALENE 34 26 36 26 35 25 / 0 0 0 0 0 0
PULLMAN 35 27 34 28 35 29 / 10 0 0 0 0 0
LEWISTON 33 29 35 29 40 31 / 10 0 0 0 0 0
COLVILLE 36 26 32 23 32 22 / 0 0 0 0 0 0
SANDPOINT 34 20 36 25 35 24 / 0 0 0 0 0 0
KELLOGG 37 26 42 27 37 26 / 0 0 0 0 0 0
MOSES LAKE 32 26 32 23 31 23 / 10 0 0 0 0 0
WENATCHEE 31 26 29 24 32 25 / 0 0 0 0 0 0
OMAK 30 23 29 24 30 23 / 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 180323
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
723 PM PST SAT JAN 17 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF NEXT WEEK. THE STRONG RIDGE OF HIGH PRESSURE WILL REMAIN
OVER THE PACIFIC NORTHWEST UNTIL WEDNESDAY. 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 UPDATE HAS BEEN MADE FOR THE REST OF TONIGHT INTO
SATURDAY. SURFACE OBSERVATIONS INDICATE THE STRATUS LAYER TO HAVE
BASES BETWEEN 2300-2900 FEET OVER MOST OF THE COLUMBIA BASIN. WITH
THE STRATUS BASES NOT EXPECTED TO DROP SUBSTANTIALLY
TONIGHT...VISIBILITIES WILL LIKELY STAY AT OR ABOVE 10 MILES SO
PATCHY FOG WAS REMOVED FOR TONIGHT AND TOMORROW FOR AREAS BELOW
1500 FEET SUCH AS WENATCHEE...OMAK...MOSES LAKE...AND LEWISTON.
HOWEVER STILL MAY SEE SOME PATCHY FREEZING DRIZZLE OR FLURRIES IN
THESE AREAS SO THIS WAS MAINTAINED IN THE FORECAST. OTHER CHANGE
WAS RELATED TO THE NORTHEAST WINDS COMING DOWN THE PURCELL TRENCH.
THESE WINDS HAVE DRIED OUT THE BOUNDARY LAYER ENOUGH TO ERODE THE
STRATUS FROM BONNERS FERRY TO COEUR D`ALENE. NORTHEAST WINDS OF 5
TO 10 MPH ARE EXPECTED TO CONTINUE OVERNIGHT SO SKY COVER WAS
REDUCED IN THESE AREAS WITH ONLY PATCHY FOG COVERAGE EXPECTED
OVERNIGHT. GIVEN MORE CLEARING TEMPS QUICKLY DROPPED IN COEUR
D`ALENE TO 25 DEGREES SO FORECAST LOW WAS LOWERED HERE. JW
&&
.AVIATION...
STRATUS LAYER BASES MOSTLY BETWEEN 1000-2000 FEET MSL...WITH TOPS
NEAR 3000-4000 FEET. THE PERSISTENT RIDGE WILL KEEP STRATUS IN
PLACE WITH LITTLE CHANGE THROUGH 18Z SUNDAY. HIGHER ELEVATION TAF
SITES SUCH AS KGEG AND KPUW WILL EXPERIENCE IFR CEILINGS WITH
OCCASIONAL IFR VIS. OTHER TAF SITES SHOULD REMAIN BELOW THE
STRATUS LAYER WITH MAINLY VFR VSBYS...AND HIGH IFR/LOW MVFR CIGS.
IMPROVEMENT TO VFR CEILINGS POSSIBLE AFTER 18Z FOR
KCOE...KPUW...KLWS AS STRATUS IS PUSHED WEST INTO THE BASIN. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 26 32 26 32 24 34 / 0 0 0 0 0 0
COEUR D`ALENE 22 35 26 34 24 36 / 0 0 0 0 0 0
PULLMAN 27 36 27 34 29 38 / 10 10 0 0 0 0
LEWISTON 27 35 29 33 29 38 / 10 10 0 0 0 0
COLVILLE 26 33 26 30 22 32 / 10 10 0 0 0 0
SANDPOINT 21 31 20 35 24 37 / 10 10 0 0 0 0
KELLOGG 30 37 26 42 26 43 / 10 10 0 0 0 0
MOSES LAKE 24 30 26 32 21 32 / 10 10 0 0 0 0
WENATCHEE 26 30 26 29 22 33 / 10 10 0 0 0 0
OMAK 24 30 23 29 24 32 / 10 10 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 172327 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
327 PM PST SAT JAN 17 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF NEXT WEEK. THE STRONG RIDGE OF HIGH PRESSURE WILL REMAIN
OVER THE PACIFIC NORTHWEST UNTIL WEDNESDAY. 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 AND SUNDAY...A LONG-WAVE RIDGE WILL CONTINUE TO DOMINATE
THE WEST COAST. THIS BODES FOR KEEPING THE STRONG LOW LEVEL
INVERSIONS IN PLACE. THE BULK OF THE ATMOSPHERIC PROFILE REMAINS
DRY...WITH THE CONTINUED EXCEPTION OF LOWEST LAYERS. AS A RESULT
VISIBLE SATELLITE SHOWED THE STRATUS ENTRENCHED OVER THE BASIN AND
VALLEY LOCATIONS SATURDAY. THERE WAS ONLY A LITTLE SLOSHING AND
MINOR EROSION ON THE EASTERN FRINGES. THE 12Z SOUNDING SHOWED THE
STRATUS DECK TO BE ABOUT 2000 FEET DEEP OVER THE SPOKANE AREA. GFS
AND NAM12 GUIDANCE SUGGEST SOME INCREASED DRYING FROM ABOVE
OVERNIGHT INTO SUNDAY AS THE MID-LEVEL ANTICYCLONE CENTER (NOW
NEAR THE WA COAST) REVOLVES INLAND. THIS WOULD TRANSLATE TO A
SHALLOWER STRATUS DECK...ESPECIALLY ACROSS THE NORTH AND EASTERN
CWA. THIS SHOULD ERODE THE RISK FOR FLURRIES/PATCHY FREEZING
DRIZZLE. WITH THE DEPICTED EROSION OF THE MOIST LAYER I WOULD
EXPECT A BETTER CHANCE FOR SUN BREAKS SUNDAY AFTERNOON. EXCEPTIONS
WOULD BE ACROSS THE UPPER COLUMBIA BASIN THROUGH THE OKANOGAN
VALLEY AND SOME OF THE DEEPER NORTHERN VALLEYS...WHERE EROSION
OF THE MOIST LAYER WOULD BE MORE DIFFICULT. ANOTHER QUESTION
REVOLVES AROUND FOG COVERAGE TONIGHT AND EARLY SUNDAY. WILL IT BE
PATCHY OR MORE WIDESPREAD AGAIN? EXPECT PATCHY FOG IN THE
EVENING...THEN TOWARD THE OVERNIGHT HOURS INTO SUNDAY MORNING MORE
AREAS OF FOG ARE EXPECTED TO DEVELOP ACROSS THE WEST PLAINS OF
SPOKANE THROUGH THE WATERVILLE PLATEAU AGAIN. HOWEVER IT IS NOT
EXPECTED TO BE AS WIDESPREAD AS RECENT DAYS SO WILL HOLD OFF ON
ADDING ANY FOG ADVISORIES...AT LEAST FOR NOW. /JCOTE
SUNDAY NT THROUGH TUES...THE DILEMMAS WE ARE DEALING WITH CENTER
AROUND THE INCREASING DEPTH OF THE DRY LYR ALOFT ACCOMPANYING THE
NEARLY 6000M 500MB RIDGE THAT SLOWLY TRANSLATES E TO N ID BY MON.
PATTERN RECOGNITION SUPPORTS THIS DEEPENING DRY LYR...AND
SUBSEQUENT SHRINKING OF THE SFC MOIST LYR. VSBL SATELLITE
OVERLAYED WITH TOPO SHOWS CLOUD TOPS RANGING FROM 2500 FT IN N ID
TO AROUND 4500 FEET CLOSER TO THE CASCADES. FCST SOUNDINGS ALL
SHOW A LOWERING OF THE SUBSIDENCE INVERSION BY AT LEAST 1000 FEET
OVERALL BY MON...SHRINKING THE MOIST LYR DEPTH TO THE POINT WHERE
IT LOOKS LIKES MANY TOWNS WOULD EASILY MIX OUT THE COLD MOIST SFC
AIR...ESPECIALLY IF NEAR MTN SLOPES. BASED ON WHAT WE SEE ON SATELLITE
(THE CLEARING SKIES OVER N ID VALLEYS IN BONNER COUNTY)...WE`VE
CUT BACK QUITE A BIT ON THE EXTENT OF STRATUS COVERAGE FOR N ID IN
THE AFTERNOON HRS...AND TRIED TO EXPOSE ALL MTNS TO MORE SUN BY
CUTTING BACK ON THE DEPTH OF THE STRATUS TOPS. WE`VE REMOVED ANY
SIGNIFICANT THREAT OF STRATUS/FOG-GENERATED PCPN IN THIS SHALLOW
MOIST BOUNDARY LYR. BZ
TUESDAY NIGHT THROUGH SATURDAY...MODEL CONSENSUS AND CONSISTENCY IS
LACKING FOR THE EXTENDED PERIOD. THE ADVANCING PACIFIC TROUGH THAT
WILL NUDGE THE RIDGE AXIS TO OUR EAST ON TUESDAY IS BEING HANDLED
QUITE DIFFERENTLY BY THE LATEST MEDIUM RANGE GUIDANCE. THE 12Z GFS TRACKS
THE SHORTWAVE TROUGH RIGHT OVER THE INLAND NORTHWEST WHILE THE
ECMWF DROPS A CLOSED LOW WELL TO OUR SOUTH WITH THE RIDGE
REBOUNDING QUICKLY OVER THE REGION. AM LEANING TOWARD THE EC
SOLUTION GIVEN THE STRENGTH OF THE RIDGE. THE FORECAST WILL REMAIN
DRY THROUGH FRIDAY OTHER THAN SLIGHT CHANCE POPS IN THE MOUNTAINS.
THE MAIN EFFECT OF ANY DISTURBANCE THAT MAY MAKE IT THROUGH THE
RIDGE WILL BE TO COOL THE MID LEVELS AND THUS WEAKEN THE
PERSISTENT INVERSION. MODELS ARE IN BETTER AGREEMENT ON A STRONGER
SHORTWAVE AFFECTING THE REGION OVER THE WEEKEND. POPS INCREASE
ACROSS THE FORECAST AREA BUT REMAIN BELOW CLIMATOLOGY AT THIS
TIME. STRONG LOW LEVEL INVERSIONS WILL CONTINUE TO DICTATE DIURNAL
TEMPERATURE SWINGS WITH LITTLE CHANGE IN TEMPERATURES FOR THOSE
LOCATIONS AFFECTED BY FOG AND LOW STRATUS. TEMPERATURES WILL FALL
ACROSS THE HIGHER ELEVATIONS AS COLDER MID LEVEL AIR INFILTRATES
THE NORTHERN ZONES. TEMPERATURES WILL TREND A BIT BELOW SEASONAL
NORMALS BY FRIDAY BUT THE REALLY COLD AIRMASS SHOULD REMAIN ON THE
EAST SIDE OF THE CONTINENTAL DIVIDE. /KELCH
&&
.AVIATION...
STRATUS LAYER BASES MOSTLY BETWEEN 1000-2000 FEET MSL...WITH TOPS
NEAR 3000-4000 FEET. THE PERSISTENT RIDGE WILL KEEP STRATUS IN
PLACE WITH LITTLE CHANGE THROUGH 18Z SUNDAY. HIGHER ELEVATION TAF
SITES SUCH AS KGEG AND KPUW WILL EXPERIENCE IFR CEILINGS WITH
OCCASIONAL IFR VIS. OTHER TAF SITES SHOULD REMAIN BELOW THE
STRATUS LAYER WITH MAINLY VFR VSBYS...AND HIGH IFR/LOW MVFR CIGS.
IMPROVEMENT TO VFR CEILINGS POSSIBLE AFTER 18Z FOR
KCOE...KPUW...KLWS AS STRATUS IS PUSHED WEST INTO THE BASIN. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 26 32 26 32 24 34 / 0 0 0 0 0 0
COEUR D`ALENE 25 35 26 34 24 36 / 0 0 0 0 0 0
PULLMAN 27 36 27 34 29 38 / 10 10 0 0 0 0
LEWISTON 27 35 29 33 29 38 / 10 10 0 0 0 0
COLVILLE 26 33 26 30 22 32 / 10 10 0 0 0 0
SANDPOINT 24 31 20 35 24 37 / 10 10 0 0 0 0
KELLOGG 30 37 26 42 26 43 / 10 10 0 0 0 0
MOSES LAKE 24 30 26 32 21 32 / 10 10 0 0 0 0
WENATCHEE 26 30 26 29 22 33 / 10 10 0 0 0 0
OMAK 24 30 23 29 24 32 / 10 10 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 172240
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
240 PM PST SAT JAN 17 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF NEXT WEEK. THE STRONG RIDGE OF HIGH PRESSURE WILL REMAIN
OVER THE PACIFIC NORTHWEST UNTIL WEDNESDAY. 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 AND SUNDAY...A LONG-WAVE RIDGE WILL CONTINUE TO DOMINATE
THE WEST COAST. THIS BODES FOR KEEPING THE STRONG LOW LEVEL
INVERSIONS IN PLACE. THE BULK OF THE ATMOSPHERIC PROFILE REMAINS
DRY...WITH THE CONTINUED EXCEPTION OF LOWEST LAYERS. AS A RESULT
VISIBLE SATELLITE SHOWED THE STRATUS ENTRENCHED OVER THE BASIN AND
VALLEY LOCATIONS SATURDAY. THERE WAS ONLY A LITTLE SLOSHING AND
MINOR EROSION ON THE EASTERN FRINGES. THE 12Z SOUNDING SHOWED THE
STRATUS DECK TO BE ABOUT 2000 FEET DEEP OVER THE SPOKANE AREA. GFS
AND NAM12 GUIDANCE SUGGEST SOME INCREASED DRYING FROM ABOVE
OVERNIGHT INTO SUNDAY AS THE MID-LEVEL ANTICYCLONE CENTER (NOW
NEAR THE WA COAST) REVOLVES INLAND. THIS WOULD TRANSLATE TO A
SHALLOWER STRATUS DECK...ESPECIALLY ACROSS THE NORTH AND EASTERN
CWA. THIS SHOULD ERODE THE RISK FOR FLURRIES/PATCHY FREEZING
DRIZZLE. WITH THE DEPICTED EROSION OF THE MOIST LAYER I WOULD
EXPECT A BETTER CHANCE FOR SUN BREAKS SUNDAY AFTERNOON. EXCEPTIONS
WOULD BE ACROSS THE UPPER COLUMBIA BASIN THROUGH THE OKANOGAN
VALLEY AND SOME OF THE DEEPER NORTHERN VALLEYS...WHERE EROSION
OF THE MOIST LAYER WOULD BE MORE DIFFICULT. ANOTHER QUESTION
REVOLVES AROUND FOG COVERAGE TONIGHT AND EARLY SUNDAY. WILL IT BE
PATCHY OR MORE WIDESPREAD AGAIN? EXPECT PATCHY FOG IN THE
EVENING...THEN TOWARD THE OVERNIGHT HOURS INTO SUNDAY MORNING MORE
AREAS OF FOG ARE EXPECTED TO DEVELOP ACROSS THE WEST PLAINS OF
SPOKANE THROUGH THE WATERVILLE PLATEAU AGAIN. HOWEVER IT IS NOT
EXPECTED TO BE AS WIDESPREAD AS RECENT DAYS SO WILL HOLD OFF ON
ADDING ANY FOG ADVISORIES...AT LEAST FOR NOW. /JCOTE
SUNDAY NT THROUGH TUES...THE DILEMMAS WE ARE DEALING WITH CENTER
AROUND THE INCREASING DEPTH OF THE DRY LYR ALOFT ACCOMPANYING THE
NEARLY 6000M 500MB RIDGE THAT SLOWLY TRANSLATES E TO N ID BY MON.
PATTERN RECOGNITION SUPPORTS THIS DEEPENING DRY LYR...AND
SUBSEQUENT SHRINKING OF THE SFC MOIST LYR. VSBL SATELLITE
OVERLAYED WITH TOPO SHOWS CLOUD TOPS RANGING FROM 2500 FT IN N ID
TO AROUND 4500 FEET CLOSER TO THE CASCADES. FCST SOUNDINGS ALL
SHOW A LOWERING OF THE SUBSIDENCE INVERSION BY AT LEAST 1000 FEET
OVERALL BY MON...SHRINKING THE MOIST LYR DEPTH TO THE POINT WHERE
IT LOOKS LIKES MANY TOWNS WOULD EASILY MIX OUT THE COLD MOIST SFC
AIR...ESPECIALLY IF NEAR MTN SLOPES. BASED ON WHAT WE SEE ON SATELLITE
(THE CLEARING SKIES OVER N ID VALLEYS IN BONNER COUNTY)...WE`VE
CUT BACK QUITE A BIT ON THE EXTENT OF STRATUS COVERAGE FOR N ID IN
THE AFTERNOON HRS...AND TRIED TO EXPOSE ALL MTNS TO MORE SUN BY
CUTTING BACK ON THE DEPTH OF THE STRATUS TOPS. WE`VE REMOVED ANY
SIGNIFICANT THREAT OF STRATUS/FOG-GENERATED PCPN IN THIS SHALLOW
MOIST BOUNDARY LYR. BZ
TUESDAY NIGHT THROUGH SATURDAY...MODEL CONSENSUS AND CONSISTENCY IS
LACKING FOR THE EXTENDED PERIOD. THE ADVANCING PACIFIC TROUGH THAT
WILL NUDGE THE RIDGE AXIS TO OUR EAST ON TUESDAY IS BEING HANDLED
QUITE DIFFERENTLY BY THE LATEST MEDIUM RANGE GUIDANCE. THE 12Z GFS TRACKS
THE SHORTWAVE TROUGH RIGHT OVER THE INLAND NORTHWEST WHILE THE
ECMWF DROPS A CLOSED LOW WELL TO OUR SOUTH WITH THE RIDGE
REBOUNDING QUICKLY OVER THE REGION. AM LEANING TOWARD THE EC
SOLUTION GIVEN THE STRENGTH OF THE RIDGE. THE FORECAST WILL REMAIN
DRY THROUGH FRIDAY OTHER THAN SLIGHT CHANCE POPS IN THE MOUNTAINS.
THE MAIN EFFECT OF ANY DISTURBANCE THAT MAY MAKE IT THROUGH THE
RIDGE WILL BE TO COOL THE MID LEVELS AND THUS WEAKEN THE
PERSISTENT INVERSION. MODELS ARE IN BETTER AGREEMENT ON A STRONGER
SHORTWAVE AFFECTING THE REGION OVER THE WEEKEND. POPS INCREASE
ACROSS THE FORECAST AREA BUT REMAIN BELOW CLIMATOLOGY AT THIS
TIME. STRONG LOW LEVEL INVERSIONS WILL CONTINUE TO DICTATE DIURNAL
TEMPERATURE SWINGS WITH LITTLE CHANGE IN TEMPERATURES FOR THOSE
LOCATIONS AFFECTED BY FOG AND LOW STRATUS. TEMPERATURES WILL FALL
ACROSS THE HIGHER ELEVATIONS AS COLDER MID LEVEL AIR INFILTRATES
THE NORTHERN ZONES. TEMPERATURES WILL TREND A BIT BELOW SEASONAL
NORMALS BY FRIDAY BUT THE REALLY COLD AIRMASS SHOULD REMAIN ON THE
EAST SIDE OF THE CONTINENTAL DIVIDE. /KELCH
&&
.AVIATION...
STRATUS LAYER BASES MOSTLY BETWEEN 1000-2000 FEET MSL...WITH TOPS
NEAR 3500-4000 FEET. THE PERSISTENT RIDGE WILL KEEP STRATUS IN
PLACE WITH LITTLE CHANGE THROUGH 18Z SUNDAY. HIGHER ELEVATION TAF
SITES SUCH AS KGEG AND KPUW WILL EXPERIENCE IFR CEILINGS WITH
OCCASIONAL IFR VIS. OTHER TAF SITES SHOULD REMAIN BELOW THE
STRATUS LAYER WITH MAINLY VFR VSBYS...AND HIGH IFR/LOW MVFR CIGS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 26 32 26 32 24 34 / 0 0 0 0 0 0
COEUR D`ALENE 25 35 26 34 24 36 / 0 0 0 0 0 0
PULLMAN 27 36 27 34 29 38 / 10 10 0 0 0 0
LEWISTON 27 35 29 33 29 38 / 10 10 0 0 0 0
COLVILLE 26 33 26 30 22 32 / 10 10 0 0 0 0
SANDPOINT 24 31 20 35 24 37 / 10 10 0 0 0 0
KELLOGG 30 37 26 42 26 43 / 10 10 0 0 0 0
MOSES LAKE 24 30 26 32 21 32 / 10 10 0 0 0 0
WENATCHEE 26 30 26 29 22 33 / 10 10 0 0 0 0
OMAK 24 30 23 29 24 32 / 10 10 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 172049 AAB
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
1249 PM PST SAT JAN 17 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF NEXT WEEK. THE STRONG RIDGE OF HIGH PRESSURE WILL REMAIN
OVER THE PACIFIC NORTHWEST UNTIL WEDNESDAY. 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...
FORECAST UPDATE SENT TO ADJUST SOME AFTERNOON TEMPERATURES...WINDS
AND CLOUD COVER. SOME WINDS COMING DOWN THE PURCELL TRENCH (BETWEEN
ABOUT BONNERS FERRY TO SANDPOINT AND COMING OUT THROUGH THE C`DA
AREA) HAVE ALLOWED FOR SOME DRYING AND EROSION CLOUDS. SOME OF IT
EVEN SNEAKING INTO EASTERN SPOKANE COUNTY...NEAR AND EAST OFF KSFF.
THIS HAS ALLOWS FOR MORE SUNSHINE AND A BIT MILDER TEMPERATURES.
OTHERWISE FORECAST IS ON TRACK. /JCOTE
&&
.AVIATION...
STRATUS LAYER BASES MOSTLY BETWEEN 1000-2000 FEET MSL...WITH TOPS
NEAR 3500-4000 FEET. THE PERSISTENT RIDGE WILL KEEP STRATUS IN
PLACE WITH LITTLE CHANGE THROUGH 18Z SUNDAY. HIGHER ELEVATION TAF
SITES SUCH AS KGEG AND KPUW WILL EXPERIENCE IFR CEILINGS WITH
OCCASIONAL IFR VIS. OTHER TAF SITES SHOULD REMAIN BELOW THE
STRATUS LAYER WITH MAINLY VFR VSBYS...AND HIGH IFR/LOW MVFR CIGS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 31 26 32 26 31 25 / 0 0 0 0 0 0
COEUR D`ALENE 36 25 35 26 32 25 / 0 0 0 0 0 0
PULLMAN 32 27 36 27 33 30 / 0 10 10 0 0 0
LEWISTON 33 27 35 29 34 31 / 0 10 10 0 0 0
COLVILLE 37 26 33 26 32 23 / 0 10 10 0 0 0
SANDPOINT 37 24 31 26 30 25 / 0 10 10 0 0 0
KELLOGG 43 30 37 30 36 27 / 0 10 10 0 0 0
MOSES LAKE 32 24 30 24 30 23 / 0 10 10 0 0 0
WENATCHEE 29 26 30 26 29 24 / 0 10 10 0 0 0
OMAK 29 24 30 23 29 26 / 0 10 10 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
000
FXUS66 KOTX 171802 AAA
AFDOTX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
1002 AM PST SAT JAN 17 2009
.SYNOPSIS...
THE STAGNANT WEATHER PATTERN WILL CONTINUE THOUGH AT LEAST THE
MIDDLE OF NEXT WEEK. THE STRONG RIDGE OF HIGH PRESSURE WILL REMAIN
OVER THE PACIFIC NORTHWEST UNTIL WEDNESDAY. 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...
REST OF TODAY...WV/IR IMAGERY CONTINUES TO SHOW A LONG-WAVE RIDGE
OVER THE WEST COAST. THE BRUNT OF ANY PACIFIC ENERGY WILL CONTINUE
TO BE DIRECTED AWAY FROM THE INLAND NW. A WEAK MID-LEVEL
DISTURBANCE WILL PIVOT AROUND THE NORTH AND EAST SIDE OF THE
RIDGE...BUT THIS WILL HAVE LITTLE INFLUENCE ON SENSIBLE WEATHER
OTHER THAN SOME PASSING HIGHER CLOUDS. THOUGH MOST INDIVIDUALS IN
THE VALLEY/BASIN AREA WILL NOT SEE THESE HIGHER CLOUDS...FOR THE
STRATUS DECK. NEAR THE SURFACE...THE 12Z SOUNDING SHOWS A HIGHER
INVERSION HEIGHT AND A DEEPENING MOIST LAYER. THE STRATUS LAYER IS
RIPENING AND LIFTING...SLACKENING THE WIDESPREAD DENSE FOG FROM
THE WATERVILLE PLATEAU THROUGH THE WEST PLAINS AND WA PALOUSE.
THUS THE DENSE FOG ADVISORY HAS BEEN CANCELLED...THOUGH THERE WILL
REMAIN PATCHY FOG THROUGH AFTERNOON AS THE RISK FOR A FEW FLURRIES
OR PATCHY DRIZZLE. WE WILL HAVE TO WATCH FOR A RETURN TO LOWER
VISIBILITY LATER THIS EVENING INTO SUNDAY MORNING...BUT INITIAL
ANALYSIS SUGGEST LESS WIDESPREAD. THE AIR STAGNATION ADVISORY REMAINS
IN PLACE...WITH LITTLE ON THE IMMEDIATE HORIZON TO BREAK THE LOW
LEVEL INVERSION. /JCOTE
&&
.AVIATION...
STRATUS LAYER BASES MOSTLY BETWEEN 1000-2000 FEET MSL...WITH TOPS
NEAR 3500-4000 FEET. THE PERSISTENT RIDGE WILL KEEP STRATUS IN
PLACE WITH LITTLE CHANGE THROUGH 18Z SUNDAY. HIGHER ELEVATION TAF
SITES SUCH AS KGEG AND KPUW WILL EXPERIENCE IFR CEILINGS WITH
OCCASIONAL IFR VIS. OTHER TAF SITES SHOULD REMAIN BELOW THE
STRATUS LAYER WITH MAINLY VFR VSBYS...AND HIGH IFR/LOW MVFR CIGS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 31 26 31 26 31 25 / 0 0 0 0 0 0
COEUR D`ALENE 31 26 32 26 32 25 / 0 0 0 0 0 0
PULLMAN 32 27 33 27 33 30 / 0 0 0 0 0 0
LEWISTON 33 29 34 29 34 31 / 0 0 0 0 0 0
COLVILLE 34 26 33 26 32 23 / 0 0 0 0 0 0
SANDPOINT 31 26 31 26 30 25 / 0 0 0 0 0 0
KELLOGG 35 30 36 30 36 27 / 0 0 0 0 0 0
MOSES LAKE 30 24 30 24 30 23 / 0 0 0 0 0 0
WENATCHEE 28 26 29 26 29 24 / 0 0 0 0 0 0
OMAK 29 23 29 23 29 26 / 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 MOUNTAINS...OKANOGAN
HIGHLANDS...OKANOGAN VALLEY...SPOKANE AREA...UPPER COLUMBIA
BASIN...WASHINGTON PALOUSE...WATERVILLE PLATEAU...WENATCHEE
AREA.
&&
$$
| 
