000
FXUS66 KMFR 201650
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
850 AM PST TUE JAN 20 2009
.DISCUSSION...VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
DEPICT DENSE FOG THROUGH THE UMPQUA BASIN AND IN THE ILLINOIS
VALLEY. WILL KEEP THE DENSE FOG ADVISORY EXPIRATION TIME OF 10 AM
PST UNCHANGED THIS MORNING...ALTHOUGH THERE ARE LIKELY TO BE
LOCALLY DENSE FOG POCKETS THAT CLEAR LATER AROUND NOON OR SO.
OTHERWISE NO UPDATES EXPECTED IN THE SHORT TERM TO THE FORECAST.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED IN THE ROGUE VALLEY AND
ALONG THE COAST TODAY. LIFR CONDITIONS WILL CONTINUE AT KRBG AND
WILL GRADUALLY IMPROVE TO IFR BEGINNING AROUND NOON.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 10 AM PST THIS MORNING FOR ORZ023.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
KS/FB
000
FXUS66 KMFR 201115
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
315 AM PST TUE JAN 20 2009
.SHORT TERM...THE CURRENT WEATHER PATTERN THAT HAS BEEN WITH US
FOR THE PAST WEEK AND A HALF WILL CONTINUE FOR ONE MORE DAY.
TOMORROW...THE INVERSION BEGINS TO WEAKEN AS AN OFFSHORE TROF TO
THE SOUTHWEST BEGINS SENDING HIGH AND MID LEVEL MOISTURE NORTHWARD
WHICH WILL INVADE OUR SKY.
THE INVERSION REALLY BREAKS DOWN WEDNESDAY NIGHT INTO THURSDAY AS
PRECIPITATION BEGINS TO FALL INTO THE DRIER LOWER LEVELS OF THE
ATMOSPHERE. HAVE INTRODUCED A SLIGHT CHANCE OF PRECIPITATION ON
WEDNESDAY MAINLY IN NORTHERN CALIFORNIA. PCPN CHANCES INCREASE
WEDNESDAY NIGHT IN NORTHERN CALIFORNIA BUT IT SPREADS NORTHWARD
INTO SOUTHERN OREGON. MODEL QPF IS ON THE LIGHT SIDE. SNOW LEVELS
SHOULD REMAIN ABOVE PASSES BUT ELEVATIONS ABOVE THAT SHOULD SEE A
FRESHENING OF THE SNOWPACK CONSISTING OF JUST A FEW INCHES.
.LONG TERM...A MAJOR TROF BEGINS TO DROP SOUTHWARD THROUGH CANADA
ON THURSDAY AND REACHES THE NORTHERN ROCKIES ON FRIDAY. A GRADUAL
COOLING TREND MAINLY EAST OF THE CASCADES FRIDAY AND SATURDAY. A
SHORTWAVE IN THE TROF TRACKS SOUTHWARD THROUGH EASTERN WASHINGTON
SATURDAY NIGHT AND INTO OREGON ON SUNDAY BRINGING MUCH COLDER AIR
AND LOWERING SNOW LEVELS. EXPECT SNOW LEVELS TO REACH VALLEY
FLOORS EAST OF THE CASCADES SUNDAY AND REMAIN THERE THROUGH MID
WEEK NEXT WEEK. AT THIS TIME...MOISTURE LOOKS RATHER LIMITED SO
SNOW AMOUNTS LOOK TO BE LIGHT.
&&
.AVIATION...AREAS IFR IN THE VALLEYS WEST OF THE CASCADES DUE TO FOG AND
LOW CIGS. FOG WILL CLEAR BY MID MORNING EXCEPT NEAR KRBG WHERE CLEARING
WILL WAIT TILL THE AFTERNOON. OTHERWISE VFR.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 10 AM PST THIS MORNING FOR ORZ023.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
07/07/15
000
FXUS66 KMFR 200434
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
834 PM PST MON JAN 19 2009
.UPDATE...DENSE FOG HAS FORMED AGAIN ALONG THE I5 CORRIDOR NEAR
ROSEBURG. THEREFORE...HAVE ISSUED A DENSE FOG ADVISORY FOR DOUGLAS
COUNTY THROUGH TUESDAY MORNING. OTHERWISE...NO SIGNIFICANT CHANGES
TO THE PREVIOUS FORECAST.
&&
.AVIATION...IFR LOW CLOUDS AND STRATUS WILL BE WIDESPREAD AGAIN
TONIGHT OVER DOUGLAS COUNTY...IMPACTING KRBG. IN ADDITION...
LOCALIZED IFR LOW STRATUS AND FOG ARE EXPECTED OVERNIGHT IN THE
ILLINOIS VALLEY AND PORTIONS OF THE ROGUE VALLEY. KMFR MAY GO
DOWN BRIEFLY TO IFR CONDITIONS NEAR SUNRISE...BUT IF THAT HAPPENS
IT SHOULD BE BRIEF SINCE CONDITIONS HAVE BEEN UNIFORMLY TRENDING
DRIER.
&&
.PREV DISCUSSION... /ISSUED 205 PM PST MON JAN 19 2009/
DISCUSSION...CURRENT VIS IMAGE SHOWS THE STRATUS IN THE ILLINOIS
VALLEY AND UMPQUA BASING SLOWLY ERODING AND IT SHOULD CLEAR OUT
BY EARLY THIS EVENING. HIGH CLOUDS ARE ALSO MOVING UP FROM THE
SOUTHEAST INTO MODOC LAKE AND KLAMATH COUNTIES. THE HIGH CLOUDS
MOVING IN ARE THE RESULT OF THE UPPER LEVEL RIDGE SHIFTING EAST OF
THE CWA.
NOT MUCH CHANGE IS EXPECTED FOR THE NEXT COUPLE OF DAYS. THE
SURFACE HIGH TO THE EAST WILL WEAKEN WHICH WILL WEAKEN THE
OFFSHORE FLOW TONIGHT THROUGH MONDAY. FOG AND LOW CLOUDS WILL ONCE
AGAIN DEVELOP IN THE UMPQUA BASIN AND ILLINOIS VALLEY. PATCHY
FREEZING FOG IS POSSIBLE IN THE ROGUE VALLEY.
AN UPPER LEVEL TROUGH WILL MOVE EAST AND SPLIT AS IT DOES TUESDAY
NIGHT INTO WEDNESDAY. THE GFS AND CANADIAN SHOW THE TROUGH
STRETCHING FURTHER SOUTH BEFORE SPLITTING AND TAKING MOST OF THE
ENERGY FORM THE WEAK CUTOFF LOW DOWN INTO SOUTHERN CALIFORNIA. THE
18Z NAM HAS TRENDED A LITTLE SOUTH COMPARED TO THE 12Z RUN...BUT
STILL TRACKS IT FURTHER NORTH. THE 12Z ECMWF IS SIMILAR TO THE 18Z
NAM. FOR NOW HAVE MADE LITTLE CHANGES TO THE FORECAST FROM
WEDNESDAY AND BEYOND DUE TO UNCERTAINTY. HOWEVER IT APPEARS THAT
THE SOLUTION SUGGESTED BY THE GFS AND CANADIAN IS MORE PLAUSIBLE.
HAVE KEPT SLIGHT CHANGES OF PRECIPITATION IN NORTHERN CALIFORNIA
AND SOUTHERN OREGON THURSDAY AND THURSDAY NIGHT.
THE PATTERN IS RATHER DISORGANIZED FRIDAY. THE GFS ECMWF AND
CANADIAN ALL SHOW A WEAK UPPER LEVEL LOW MOVING TOWARDS THE OREGON
COAST. HOWEVER...THE LOCATION OF THE LOW VARIES FROM MODEL TO
MODEL.
THE MODELS SHOW THE NORTHERN BRANCH SHOULD COME INTO PLAY BY NEXT
WEEKEND WHICH WILL BRING IN A COLDER AND MORE UNSETTLED WEATHER
PATTERN MAINLY ALONG AND WEST OF THE CASCADES. MUCH COLDER AIR
WILL ALSO MOVE IN WEST OF THE CASCADES.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 10 AM PST TUESDAY FOR ORZ023.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
MP/MWJ
000
FXUS66 KMFR 192205
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
205 PM PST MON JAN 19 2009
.DISCUSSION...CURRENT VIS IMAGE SHOWS THE STRATUS IN THE ILLINOIS
VALLEY AND UMPQUA BASING SLOWLY ERODING AND IT SHOULD CLEAR OUT
BY EARLY THIS EVENING. HIGH CLOUDS ARE ALSO MOVING UP FROM THE
SOUTHEAST INTO MODOC LAKE AND KLAMATH COUNTIES. THE HIGH CLOUDS
MOVING IN ARE THE RESULT OF THE UPPER LEVEL RIDGE SHIFTING EAST OF
THE CWA.
NOT MUCH CHANGE IS EXPECTED FOR THE NEXT COUPLE OF DAYS. THE
SURFACE HIGH TO THE EAST WILL WEAKEN WHICH WILL WEAKEN THE
OFFSHORE FLOW TONIGHT THROUGH MONDAY. FOG AND LOW CLOUDS WILL ONCE
AGAIN DEVELOP IN THE UMPQUA BASIN AND ILLINOIS VALLEY. PATCHY
FREEZING FOG IS POSSIBLE IN THE ROGUE VALLEY.
AN UPPER LEVEL TROUGH WILL MOVE EAST AND SPLIT AS IT DOES TUESDAY
NIGHT INTO WEDNESDAY. THE GFS AND CANADIAN SHOW THE TROUGH
STRETCHING FURTHER SOUTH BEFORE SPLITTING AND TAKING MOST OF THE
ENERGY FORM THE WEAK CUTOFF LOW DOWN INTO SOUTHERN CALIFORNIA. THE
18Z NAM HAS TRENDED A LITTLE SOUTH COMPARED TO THE 12Z RUN...BUT
STILL TRACKS IT FURTHER NORTH. THE 12Z ECMWF IS SIMILAR TO THE 18Z
NAM. FOR NOW HAVE MADE LITTLE CHANGES TO THE FORECAST FROM
WEDNESDAY AND BEYOND DUE TO UNCERTAINTY. HOWEVER IT APPEARS THAT
THE SOLUTION SUGGESTED BY THE GFS AND CANADIAN IS MORE PLAUSIBLE.
HAVE KEPT SLIGHT CHANGES OF PRECIPITATION IN NORTHERN CALIFORNIA
AND SOUTHERN OREGON THURSDAY AND THURSDAY NIGHT.
THE PATTERN IS RATHER DISORGANIZED FRIDAY. THE GFS ECMWF AND
CANADIAN ALL SHOW A WEAK UPPER LEVEL LOW MOVING TOWARDS THE OREGON
COAST. HOWEVER...THE LOCATION OF THE LOW VARIES FROM MODEL TO
MODEL.
THE MODELS SHOW THE NORTHERN BRANCH SHOULD COME INTO PLAY BY NEXT
WEEKEND WHICH WILL BRING IN A COLDER AND MORE UNSETTLED WEATHER
PATTERN MAINLY ALONG AND WEST OF THE CASCADES. MUCH COLDER AIR
WILL ALSO MOVE IN WEST OF THE CASCADES.
&&
.AVIATION...STRATUS IS SLOWLY BURNING OFF IN THE ILLINOIS VALLEY
AND UMPQUA BASIN. THE STRATUS SHOULD BREAK UP AND BURN OFF AT
KRBG BETWEEN 4 AND 5 PM PST WITH VFR CONDITIONS. HOWEVER IT IS
EXPECTED TO BE BRIEF WITH VFR RETURNING THIS EVENING AND LASTING
INTO MONDAY MORNING. THE ROGUE VALLEY SHOULD REMAIN VFR
TONIGHT WITH PATCHY FOG IN THE VICINITY OF THE AIRPORT LATE
TONIGHT INTO MONDAY MORNING. SKIES WILL REMAIN CLEAR AT THE COAST
AND KLAMATH BASIN TONIGHT INTO MONDAY WITH VFR CONDITIONS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
PETRUCELLI
000
FXUS66 KMFR 191705
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
905 AM PST MON JAN 19 2009
.DISCUSSION...NO CHANGES ARE NEEDED FOR THIS MORNING. THE UPPER
LEVEL RIDGE WILL SHIFT EAST OVER THE ROCKIES AND SLOWLY WEAKEN AS
AN UPPER LEVEL TROUGH SLOWLY MOVES EAST TOWARDS THE CWA. THE GFS
AND NAM AGREE THAT THE TROUGH WILL WEAKEN ANS SPLIT AS IT MOVES EAST
BY WEDNESDAY WITH PART OF THE ENERGY MOVING SOUTH OF THE CWA.
HOWEVER THEY DIFFER WITH RESPECT TO THE TRACK OF THE UPPER LOW
ONCE IT SPLITS. THE GFS AND CANADIAN TRACK IT FURTHER SOUTH AND
THE NAM TRACKS IT FURTHER NORTH. GIVEN THE STRENGTH OF THE
RIDGE...THE GFS/CANADIAN SOLUTION LOOKS MORE REASONABLE AND MAY
LEAN IN THAT DIRECTION FOR THE MIDDLE AND LATTER PART OF THE WEEK.
&&
.AVIATION...LOW CIGS AND VIS BELOW A MILE WILL CONTINUE IN THE
UMPQUA BASIN THROUGH THE MORNING HOURS. VIS WILL COME UP SOME IN
THE AFTERNOON TO AROUND 3 TO 4 MILES...BUT CIGS WILL REMAIN BELOW
1000 FEET. LOW CLOUDS AND FOG WILL ALSO CONTINUE IN THE ILLINOIS
VALLEY THIS MORNING THEN SLOWLY BURN OFF IN THE AFTERNOON.
ELSEWHERE VFR TODAY WITH CLEAR SKIES.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 9 AM PST THIS MORNING FOR ORZ023.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
99/99/99
000
FXUS66 KMFR 191000
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
200 AM PST MON JAN 19 2009
.SHORT TERM...THE STRONG RIDGE OVER THE REGION WILL SLOWLY SHIFT
EAST TO OVER THE GREAT BASIN BY WEDNESDAY. BOTH THE GFS AND ECMWF
SHOW A SYSTEM SPLITTING AND WEAKENING AS IT APPROACHES THE COAST
LATE WEDNESDAY. MOST OF THE MOISTURE WILL SPREAD INLAND OVER
CALIFORNIA...BUT A LITTLE COULD MAKE IT ACROSS THE BORDER INTO
SOUTHERN OREGON BY LATE WEDNESDAY NIGHT OR THURSDAY MORNING.
THE LATEST SATELLITE FOG PRODUCT SHOWS FOG IN MUCH OF THE UMPQUA
VALLEY...AND ALSO PORTIONS OF THE ILLINOIS VALLEY. SO FAR NO FOG HAS
DEVELOPED IN THE ROGUE VALLEY. THE SURFACE PATTERN HAS CHANGED
LITTLE SINCE LAST NIGHT WITH LOW LEVEL OFFSHORE FLOW CONTINUING
ACROSS THE REGION. SURFACE HIGH PRESSURE OVER NORTHEAST OREGON WILL
BEGIN TO WEAKEN TUESDAY...WHICH WILL ALLOW THE OFFSHORE PRESSURE
GRADIENT TO WEAKEN.
.LONG TERM...THE GFS AND ECMWF GENERALLY AGREE THAT A SPLIT FLOW
WILL STILL BE AROUND THURSDAY AND FRIDAY...SO ANY SYSTEMS THAT MAKE
IT TO THE COAST WILL BE WEAK. BEYOND FRIDAY...FORECAST CONFIDENCE IS
LOW. THE ENSEMBLE MEANS DO SHOW A RIDGE DEVELOPING NEAR 150W AND A
COOL AND MOIST NORTHWEST FLOW OVER THE PACIFIC NORTHWEST.
&&
.AVIATION...AREAS OF IFR CONDITIONS THIS MORNING MAINLY IN THE
ILLINOIS AND UMPQUA VALLEYS...IMPROVING THIS AFTERNOON. VFR
CONDITIONS WILL PREVAIL ELSEWHERE.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 9 AM PST THIS MORNING FOR ORZ023.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
RH/MS
000
FXUS66 KMFR 190454
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
854 PM PST SUN JAN 18 2009
.UPDATE...HAVE ISSUED A DENSE FOG ADVISORY FOR DOUGLAS
COUNTY FOR TONIGHT. OTHERWISE NO ADDITIONAL CHANGES.
&&
.AVIATION...VALLEY IFR FOR LOW CLOUDS AND FOG WILL PERSIST IN THE
UMPQUA BASIN AND SHOULD REFORM IN THE ILLINOIS AND PORTIONS OF THE
ROGUE VALLEY. HOWEVER...OVERALL IFR COVERAGE SHOULD BE REDUCED
RELATIVE TO PREVIOUS NIGHTS...PARTICULARLY OVER THE SOUTHERN END
OF THE ROGUE VALLEY.
&&
.PREV DISCUSSION... /ISSUED 539 PM PST SUN JAN 18 2009/
FIRST EVENING UPDATE...WINDS THIS AFTERNOON HAVE ENTRAINED DRY
AIR INTO PORTIONS OF THE TRAPPED INVERSION LAYER NEAR THE
SURFACE...PARTICULARLY OVER THE ROGUE VALLEY. WHILE THE INVERSION
IS STILL IN PLACE NEAR THE SURFACE AND SHOULD GAIN STRENGTH
OVERNIGHT...IT NOW LOOKS LIKELY THAT FOG AND STRATUS WILL NOT BE
AS EXTENSIVE IN THE ROGUE VALLEY...EXCEPT FOR ELEVATIONS BELOW
ABOUT 1500 FT NEAR THE AIRPORT AND NORTHWARD. IN ADDITION...FOG
AND STRATUS SHOULD CLEAR EARLIER IN THE DAY ON MONDAY DUE TO DRIER
CONDITIONS IN THE TRAPPED LAYER. THEREFORE...I HAVE ADJUSTED
MEDFORD TEMPERATURES UPWARD FOR MONDAY AND TUESDAY.
PREV DISCUSSION... /ISSUED 206 PM PST SUN JAN 18 2009/
DISCUSSION...THE UPPER LEVEL RIDGE WILL SHIFT EAST OF THE CWA
TONIGHT INTO MONDAY WITH A WEAK SOUTH TO SOUTHEAST FLOW ALOFT.
CURRENT VIS SHOWS THE CLOUDS SLOWLY ERODING IN THE UMPQUA
BASIN...ILLINOIS VALLEY AND CHRISTMAS VALLEY. THESE AREAS SHOULD
CLEAR OUT BY THIS EVENING. THE SUBSIDENCE INVERSION WILL REMAIN IN
PLACE TONIGHT INTO MONDAY...THEREFORE WOULD EXPECT THE LOW CLOUDS
AND FOG TO RE-DEVELOP ONCE AGAIN LATE THIS EVENING AND LASTING
INTO MONDAY MORNING. TEMPERATURES HAVE WARMED UP IN THE VALLEY
WITH MEDFORD REPORTING 50 DEGREES IN THE PAST HOUR AND IN THE MID
TO UPPER 60S OVER SOME OF THE RIDGETOPS. IT WILL CONTINUE TO
REMAIN WINDY OVER THE RIDGETOPS THIS AFTERNOON AND TONIGHT WHICH
WILL KEEP TEMPERATURES MILD.
BOTH THE GFS AND ECMWF SUGGEST THE TROUGH OVER THE CENTRAL PACIFIC
SLOWLY MOVING EAST INTO THE RIDGE TUESDAY THEN SPLIT WITH BY WEDNESDAY
WITH PART OF THE ENERGY MOVING TOWARDS CENTRAL CALIFORNIA. THE GFS
CONTINUES TO BE TOO AGGRESSIVE WITH RESPECT TO QPF WHILE THE ECMWF
HAS BEEN CONSISTENT IN WEAKENING ANY ENERGY THAT MOVES INTO THE
RIDGE. HOWEVER...THE ECMWF AND THE GFS SHOW QPF MIGRATING NORTH
INTO SOUTHERN OREGON BY THE END OF NEXT WEEK AND HAVE ADJUSTED
POPS TO REFLECT THIS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 9 AM PST MONDAY FOR ORZ023.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
MP/MWJ
000
FXUS66 KMFR 190139
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
539 PM PST SUN JAN 18 2009
.UPDATE...WINDS THIS AFTERNOON HAVE ENTRAINED DRY AIR INTO
PORTIONS OF THE TRAPPED INVERSION LAYER NEAR THE
SURFACE...PARTICULARLY OVER THE ROGUE VALLEY. WHILE THE INVERSION
IS STILL IN PLACE NEAR THE SURFACE AND SHOULD GAIN STRENGTH
OVERNIGHT...IT NOW LOOKS LIKELY THAT FOG AND STRATUS WILL NOT BE
AS EXTENSIVE IN THE ROGUE VALLEY...EXCEPT FOR ELEVATIONS BELOW
ABOUT 1500 FT NEAR THE AIRPORT AND NORTHWARD. IN ADDITION...FOG
AND STRATUS SHOULD CLEAR EARLIER IN THE DAY ON MONDAY DUE TO OVER
DRIER CONDITIONS IN THE TRAPPED LAYER. THEREFORE...I HAVE ADJUSTED
MEDFORD TEMPERATURES UPWARD FOR MONDAY AND TUESDAY.
&&
.AVIATION...VALLEY IFR FOR LOW CLOUDS AND FOG WILL PERSIST IN THE
UMPQUA BASIN AND SHOULD REFORM IN THE ILLINOIS AND PORTIONS OF THE
ROGUE VALLEY. HOWEVER...OVERALL IFR COVERAGE SHOULD BE REDUCED
RELATIVE TO PREVIOUS NIGHTS...PARTICULARLY OVER THE SOUTHERN END
OF THE ROGUE VALLEY.
&&
.PREV DISCUSSION... /ISSUED 206 PM PST SUN JAN 18 2009/
DISCUSSION...THE UPPER LEVEL RIDGE WILL SHIFT EAST OF THE CWA
TONIGHT INTO MONDAY WITH A WEAK SOUTH TO SOUTHEAST FLOW ALOFT.
CURRENT VIS SHOWS THE CLOUDS SLOWLY ERODING IN THE UMPQUA
BASIN...ILLINOIS VALLEY AND CHRISTMAS VALLEY. THESE AREAS SHOULD
CLEAR OUT BY THIS EVENING. THE SUBSIDENCE INVERSION WILL REMAIN IN
PLACE TONIGHT INTO MONDAY...THEREFORE WOULD EXPECT THE LOW CLOUDS
AND FOG TO RE-DEVELOP ONCE AGAIN LATE THIS EVENING AND LASTING
INTO MONDAY MORNING. TEMPERATURES HAVE WARMED UP IN THE VALLEY
WITH MEDFORD REPORTING 50 DEGREES IN THE PAST HOUR AND IN THE MID
TO UPPER 60S OVER SOME OF THE RIDGETOPS. IT WILL CONTINUE TO
REMAIN WINDY OVER THE RIDGETOPS THIS AFTERNOON AND TONIGHT WHICH
WILL KEEP TEMPERATURES MILD.
BOTH THE GFS AND ECMWF SUGGEST THE TROUGH OVER THE CENTRAL PACIFIC
SLOWLY MOVING EAST INTO THE RIDGE TUESDAY THEN SPLIT WITH BY WEDNESDAY
WITH PART OF THE ENERGY MOVING TOWARDS CENTRAL CALIFORNIA. THE GFS
CONTINUES TO BE TOO AGGRESSIVE WITH RESPECT TO QPF WHILE THE ECMWF
HAS BEEN CONSISTENT IN WEAKENING ANY ENERGY THAT MOVES INTO THE
RIDGE. HOWEVER...THE ECMWF AND THE GFS SHOW QPF MIGRATING NORTH
INTO SOUTHERN OREGON BY THE END OF NEXT WEEK AND HAVE ADJUSTED
POPS TO REFLECT THIS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
MP/MWJ
000
FXUS66 KMFR 182206
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
206 PM PST SUN JAN 18 2009
.DISCUSSION...THE UPPER LEVEL RIDGE WILL SHIFT EAST OF THE CWA
TONIGHT INTO MONDAY WITH A WEAK SOUTH TO SOUTHEAST FLOW ALOFT.
CURRENT VIS SHOWS THE CLOUDS SLOWLY ERODING IN THE UMPQUA
BASIN...ILLINOIS VALLEY AND CHRISTMAS VALLEY. THESE AREAS SHOULD
CLEAR OUT BY THIS EVENING. THE SUBSIDENCE INVERSION WILL REMAIN IN
PLACE TONIGHT INTO MONDAY...THEREFORE WOULD EXPECT THE LOW CLOUDS
AND FOG TO RE-DEVELOP ONCE AGAIN LATE THIS EVENING AND LASTING
INTO MONDAY MORNING. TEMPERATURES HAVE WARMED UP IN THE VALLEY
WITH MEDFORD REPORTING 50 DEGREES IN THE PAST HOUR AND IN THE MID
TO UPPER 60S OVER SOME OF THE RIDGETOPS. IT WILL CONTINUE TO
REMAIN WINDY OVER THE RIDGETOPS THIS AFTERNOON AND TONIGHT WHICH
WILL KEEP TEMPERATURES MILD.
BOTH THE GFS AND ECMWF SUGGEST THE TROUGH OVER THE CENTRAL PACIFIC
SLOWLY MOVING EAST INTO THE RIDGE TUESDAY THEN SPLIT WITH BY WEDNESDAY
WITH PART OF THE ENERGY MOVING TOWARDS CENTRAL CALIFORNIA. THE GFS
CONTINUES TO BE TOO AGGRESSIVE WITH RESPECT TO QPF WHILE THE ECMWF
HAS BEEN CONSISTENT IN WEAKENING ANY ENERGY THAT MOVES INTO THE
RIDGE. HOWEVER...THE ECMWF AND THE GFS SHOW QPF MIGRATING NORTH
INTO SOUTHERN OREGON BY THE END OF NEXT WEEK AND HAVE ADJUSTED
POPS TO REFLECT THIS.
&&
.AVIATION...LOW CLOUDS SHOULD BURN OFF IN THE UMPQUA BASING BY
THIS EVENING. LOW CLOUDS AND FOG WILL DEVELOP AGAIN IN THE UMPQUA
BASIN...ROGUE AND ILLINOIS VALLEYS LATE THIS EVENING AND LAST
INTO MOST OF MONDAY MORNING. CIGS WILL LOWER TO NEAR 100 FEET WITH
VISIBILITIES NEAR 1/4 MILE. OFFSHORE FLOW WILL CONTINUE AT THE
COAST WITH VFR CONDITIONS EXPECTED TO CONTINUE INTO MONDAY. VFR
NEAR LKMT TONIGHT AND MONDAY.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
PETRUCELLI
000
FXUS66 KMFR 181650
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
850 AM PST SUN JAN 18 2009
.DISCUSSION...A WEAK SHORTWAVE MOVED SOUND THE BASE OF THE RIDGE
EARLY THIS MORNING. THE NET RESULT FROM THIS HAS BEEN AN INCREASE
OFFSHORE FLOW. THIS HAS IN EFFECT LIMITED THE EXTENT OF THE FOG
AND LOW CLOUDS IN THE VALLEY AND ALSO THE DENSE FOG HAS NOT BEEN
AN ISSUE. THEREFORE THE DENSE FOG ADVISORY HAS BEEN CANCELED. THE
STRATUS HAS MOVED UP ALONG THE MARINE WATERS...BUT THERE IS ENOUGH
OF AN OFFSHORE COMPONENT TO KEEP THE STRATUS FROM MIGRATING TO THE
COAST. WE`LL UPDATE THE ZONES TO REMOVE THE DENSE FOG AND UPDATE
SKY COVER IN THE ROGUE VALLEY AS SKIES ARE CLEAR THIS MORNING.
&&
.AVIATION...LOW CIGS AND VIS WILL CONTINUE IN THE UMPQUA BASIN
THIS MORNING...BUT IT SHOULD BRUN OFF SOONER WITH VFR CONDITIONS
EXPECTED AROUND NOON. VFR TODAY AND THIS EVENING IN THE ROGUE
VALLEY AND KLAMATH BASIN. STRATUS SHOULD REMAIN OFF THE COAST
TODAY WITH SUFFICIENT OFFSHORE FLOW.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
PETRUCELLI
000
FXUS66 KMFR 181003
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
200 AM PST SUN JAN 18 2009
.SHORT TERM...NO CHANGE WITH OUR DRY WEATHER PATTERN AT LEAST
THROUGH THE SHORT TERM FORECAST PERIOD. A STRONG UPPER RIDGE LOCATED
ALONG THE PACIFIC NORTHWEST COAST WILL MOVE SLOWLY EAST TO THE GREAT
BASIN BY TUESDAY AFTERNOON.
NEAR THE SURFACE...A STRONG LOW LEVEL OFFSHORE FLOW PREVAILS EARLY
THIS MORNING DUE TO A STRONG SURFACE HIGH OVER NORTHEAST OREGON AND
A THERMAL THROUGH ALONG THE COAST. THE OFFSHORE PRESSURE GRADIENT
BETWEEN NORTH BEND AND REDMOND IS OVER 16 MILLIBARS. A SUBSIDENCE
INVERSION THAT HAS BEEN IN PLACE FOR THE PAST SEVERAL DAYS IS
HOLDING STRONG IN THE ROGUE VALLEY. THE 1AM TEMPERATURE AT THE
AIRPORT IN MEDFORD WAS 24...WHILE THE TEMPERATURE AT THE ASHLAND
AIRPORT...ELEVATION NEAR 1900 FEET WAS 57 DEGREES. EXPECT MORNING
VALLEY FOG TO BURN OFF MOST AREAS BY EARLY AFTERNOON...HOWEVER...
THERE COULD BE SOME LOCAL AREAS LIKE AROUND GRANTS PASS THAT MAY
HAVE TROUBLE COMPLETELY BREAKING OUT THIS AFTERNOON.
.LONG TERM...DUE TO THE STRONG RIDGE OVER THE GREAT BASIN REGION...I
PREFER THE ECMWF OVERALL...WHICH TENDS TO BE SLOWER AND WEAKER THAN
THE GFS WITH ENERGY APPROACHING THE PACIFIC NORTHWEST COAST
BEGINNING WEDNESDAY. LATE IN THE PERIOD THE ECMWF FORECASTS A RIDGE
NEAR 150W AND A COOLER NW FLOW OVER THE REGION.
&&
.AVIATION...AREAS OF IFR CONDITIONS SOUTHWEST OREGON VALLEYS THIS
MORNING...IMPROVING BY THIS AFTERNOON. VFR CONDITIONS WILL PREVAIL
ELSEWHERE.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 9 AM PST THIS MORNING FOR
ORZ023-ORZ024-ORZ026.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
RH/MS
000
FXUS66 KMFR 180542
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
942 PM PST SAT JAN 17 2009
.UPDATE...NO CHANGES PLANNED TO PREVIOUS FORECAST. THE PROBLEM OF
THE DAY REMAINS WHERE AND WHEN FOG WILL FORM. VERY DRY AIR ALOFT
HAS BEEN STEADILY ERODING THE TOP OF THE VALLEY TRAPPED MOISTURE
LAYER SO THAT FOG IS INCREASINGLY BEING CONFINED TO THE LOWEST
LEVELS OF BROAD VALLEYS...LIKE CENTRAL POINT OR WHITE CITY...OR IN
NARROW STEEP VALLEYS...LIKE THE ILLINOIS VALLEY OR THE GRANTS PASS
AREA. NEVERTHELESS...CURRENT OBSERVATION TRENDS SUPPORT DENSE FOG
FORMING AGAIN NEAR THE AIRPORT IN MEDFORD...THOUGH ASHLAND MAY BE
HIGH ENOUGH IN ELEVATION TO NOT SEE FOG TONIGHT.
&&
.AVIATION...IFR LOW CLOUDS AND FOG WILL AGAIN FORM OVER KMFR AND
KRBG TONIGHT AND PERSIST THROUGH SUNDAY AFTERNOON. IN
ADDITION...EXPECT IFR CONDITIONS GENERALLY WIDESPREAD IN SOUTHWESTERN
OREGON VALLEYS AS WELL AS LOCALLY IN THE SHASTA VALLEY IN SISKIYOU
COUNTY.
&&
.PREV DISCUSSION... /ISSUED 205 PM PST SAT JAN 17 2009/
DISCUSSION...CURRENT VIS IMAGE SHOWS THE LOW CLOUDS BEGINNING TO
DISSIPATE IN THE ROGUE AND ILLINOIS AND UMPQUA BASIN AND IT SHOULD
CLEAR OUT IN ALL AREAS BY LATE THIS AFTERNOON.
THE UPPER LEVEL RIDGE WILL SHIFT NORTH OF THE REGION TONIGHT AS A
WEAK SHORTWAVE ROTATES AROUND THE BASE OF THE RIDGE. THIS
SHORTWAVE WILL INCREASE THE ONSHORE FLOW SOME LEADING TO INCREASED
WINDS ON THE RIDGETOPS. TEMPERATURES THERE WILL ALSO CONTINUE TO
BE MILDER. EXPECT THE LOW CLOUDS AND FOG TO RE-DEVELOP AGAIN THE
ROGUE...ILLINOIS AND SHASTA VALLEY AND UMPQUA BASIN TONIGHT AND
LASTING INTO SUNDAY MORNING. THE FOG AND LOW CLOUDS SHOULD START
TO BURN OFF LATE SUNDAY MORNING FOLLOWED BY MOSTLY CLEAR SKIES IN
THE AFTERNOON.
THE RIDGE WILL SHIFT EAST OF THE CWA SUNDAY NIGHT INTO MONDAY
WHICH WILL LEAD TO A WEAKER SUBSIDENCE INVERSION WHICH COULD ALLOW
SOME OF THE DRIER AIR LOFT TO MIX DOWN NEAR THE SURFACE. THIS WILL
HELP TO DECREASE THE EXTENT AND DURATION OF THE VALLEY FOG. THE
FLOW WILL BECOME SOUTHERLY TUESDAY AND TUESDAY NIGHT AS AN UPPER
LEVEL LOW SLOWLY MOVES EAST.
DIFFERENCE EXIST BETWEEN THE GFS AND ECMWF WITH RESPECT TO THE
STRENGTH AND TRACK OF THE TROUGH. THE GFS SUGGEST THE THROUGH WILL
NOT WEAKEN MUCH AND MOVE INTO THE CWA TUESDAY NIGHT INTO
WEDNESDAY. HOWEVER...THE ECMWF SHOWS THE TROUGH WEAKENING AND
SPLITTING AS IT MOVES EAST WITH A WEAK UPPER LEVEL LOW MOVING INTO
CENTRAL CALIFORNIA BY THE MIDDLE OF NEXT WEEK. SUSPECT THE GFS MAY
BE OUT TO LUNCH WITH RESPECT TO THE STRENGTH OF THE TROUGH WHILE
THE ECMWF SOLUTION LOOKS MORE REASONABLE. THEREFORE THE EXTENDED
WILL LEAN TOWARDS THE ECMWF SOLUTION AND WILL KEEP POPS UNDER
CLIMO VALUES. HPC HAS ALSO INDICATED THAT THEY WERE GOING TO LEAN
MORE ON THE ECMWF AND OVER TIME ECMWF ENSEMBLES.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY UNTIL 9 AM PST SUNDAY FOR ORZ023-ORZ024-
ORZ026.
CA...DENSE FOG ADVISORY UNTIL 9 AM PST SUNDAY FOR CAZ081.
PACIFIC COASTAL WATERS...NONE.
$$
MP/MWJ
000
FXUS66 KMFR 172205
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
205 PM PST SAT JAN 17 2009
.DISCUSSION...CURRENT VIS IMAGE SHOWS THE LOW CLOUDS BEGINNING TO
DISSIPATE IN THE ROGUE AND ILLINOIS AND UMPQUA BASIN AND IT SHOULD
CLEAR OUT IN ALL AREAS BY LATE THIS AFTERNOON.
THE UPPER LEVEL RIDGE WILL SHIFT NORTH OF THE REGION TONIGHT AS A
WEAK SHORTWAVE ROTATES AROUND THE BASE OF THE RIDGE. THIS
SHORTWAVE WILL INCREASE THE ONSHORE FLOW SOME LEADING TO INCREASED
WINDS ON THE RIDGETOPS. TEMPERATURES THERE WILL ALSO CONTINUE TO
BE MILDER. EXPECT THE LOW CLOUDS AND FOG TO RE-DEVELOP AGAIN THE
ROGUE...ILLINOIS AND SHASTA VALLEY AND UMPQUA BASIN TONIGHT AND
LASTING INTO SUNDAY MORNING. THE FOG AND LOW CLOUDS SHOULD START
TO BURN OFF LATE SUNDAY MORNING FOLLOWED BY MOSTLY CLEAR SKIES IN
THE AFTERNOON.
THE RIDGE WILL SHIFT EAST OF THE CWA SUNDAY NIGHT INTO MONDAY
WHICH WILL LEAD TO A WEAKER SUBSIDENCE INVERSION WHICH COULD ALLOW
SOME OF THE DRIER AIR LOFT TO MIX DOWN NEAR THE SURFACE. THIS WILL
HELP TO DECREASE THE EXTENT AND DURATION OF THE VALLEY FOG. THE
FLOW WILL BECOME SOUTHERLY TUESDAY AND TUESDAY NIGHT AS AN UPPER
LEVEL LOW SLOWLY MOVES EAST.
DIFFERENCE EXIST BETWEEN THE GFS AND ECMWF WITH RESPECT TO THE
STRENGTH AND TRACK OF THE TROUGH. THE GFS SUGGEST THE THROUGH WILL
NOT WEAKEN MUCH AND MOVE INTO THE CWA TUESDAY NIGHT INTO
WEDNESDAY. HOWEVER...THE ECMWF SHOWS THE TROUGH WEAKENING AND
SPLITTING AS IT MOVES EAST WITH A WEAK UPPER LEVEL LOW MOVING INTO
CENTRAL CALIFORNIA BY THE MIDDLE OF NEXT WEEK. SUSPECT THE GFS MAY
BE OUT TO LUNCH WITH RESPECT TO THE STRENGTH OF THE TROUGH WHILE
THE ECMWF SOLUTION LOOKS MORE REASONABLE. THEREFORE THE EXTENDED
WILL LEAN TOWARDS THE ECMWF SOLUTION AND WILL KEEP POPS UNDER
CLIMO VALUES. HPC HAS ALSO INDICATED THAT THEY WERE GOING TO LEAN
MORE ON THE ECMWF AND OVER TIME ECMWF ENSEMBLES.
&&
.AVIATION...CIG AND VISIBILITIES WILL INCREASE LATE THIS AFTERNOON
IN THE UMPQUA BASIN AND ROGUE AND ILLINOIS VALLEY WITH CLOUDS AND
FOG BURNING OFF. VFR CONDITIONS WILL CONTINUE THIS EVENING...THEN
CLOUDS AND FOG WILL RE DEVELOP OVERNIGHT TONIGHT AND LASTING INTO
MOST OF SUNDAY MORNING. CIGS WILL LOWER TO 100 FEET WITH VIS
LOWERING TO 1/4 MILE OR LESS.
OFFSHORE FLOW WILL CONTINUE AT THE COAST WHICH WILL KEEP SKIES
CLEAR. VFR WITH CLEAR SKIES WILL CONTINUE NEAR KLMT TONIGHT INTO
SUNDAY.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST WEDNESDAY FOR ORZ023-
ORZ024-ORZ026-ORZ029-ORZ030-ORZ031.
DENSE FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM PST SUNDAY
FOR ORZ023-ORZ024-ORZ026.
CA...DENSE FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM PST SUNDAY
FOR CAZ081.
PACIFIC COASTAL WATERS...NONE.
$$
PETRUCELLI
| 
