000
FXAK69 PAFG 201246
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
346 AM AKST TUE JAN 20 2009
.DISCUSSION...
HE WEATHER PATTERN WILL MUCH QUIETER THIS WEEK...BUT NOT WITHOUT
SOME CONCERNS. THE MODELS ARE IN GOOD AGREEMENT IN THE SHORT TERM
(48-60 HOURS)...WITH INCREASING SPREAD BY THURSDAY AS THE MODELS
STRUGGLE WITH THE DETAILS OF HIGH LATITUDE CUTOFF HIGHS AND LOWS.
TOWARD THE END OF THEIR RESPECTIVE RUNS THE MODELS COME BACK INTO
BETTER AGREEMENT BY DAYS 8-10.
AN UPPER TROUGH PUSHING ACROSS THE CENTRAL INTERIOR WILL SLIDE OFF
INTO THE EASTERN INTERIOR TODAY...AND OFF INTO CANADA BY LATE
TONIGHT. THE UPPER TROUGH WILL BE ACCOMPANIED BY AREAS OF LIGHT
SNOW WITH THE UPPER FLOW GRADUALLY VEERING INTO THE NORTH IN THE
WAKE OF THE UPPER TROUGH. AN UPPER RIDGE BUILDING ACROSS SOUTHWEST
AK WILL GRADUALLY EXPAND NORTH INTO THE CHUKCHI SEA BY WED NIGHT AND
THEN MOVE THE CLOSED CENTER TO THE EASTERN BEAUFORT SEA COAST BY THE
END OF THE WEEK. MODELS AND ENSEMBLES ARE IN REASONABLY GOOD
AGREEMENT ON THIS IDEA. A BUILDING SURFACE RIDGE ACROSS NORTHERN AK
MID-WEEK SLIDES OFF INTO NW CANADA ON THURSDAY. THIS WILL BRING
SOME STRONGER WIND AND POSSIBLE WIND CHILL AND BLOWING SNOW CONCERNS
TO THE SUMMITS OF THE INTERIOR WED-THUR.
MODELS AND ENSEMBLES REALLY START TO DIVERGE LATE IN THE WEEK AND
THUS FORECAST CONFIDENCE DIMINISHES. THE POINT OF CONTENTION IS
WHETHER OR NOT A LOW DEVELOPS ACROSS THE SOUTHERN INTERIOR LATE IN
THE WEEK UNDERNEATH THE UPPER RIDGE THAT PINCHES OFF ACROSS THE
ARCTIC. THE ECMWF AND CANADIAN ARE ON BOARD WITH THIS SOLUTION BUT
THE GFS AND MOST OF THE ENSEMBLES KEEP THE UPPER LOW WELL TO THE
EAST OF THE AREA.
HOWEVER...BY EARLY NEXT WEEK THE MODELS AND ENSEMBLES COME INTO
BETTER AGREEMENT AGAIN IN BUILDING A RIDGE IN THE BERING SEA AND
BRINGING A MUCH COLDER AIRMASS BACK INTO NORTHERN AK.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
GALE WARNING FOR PKZ210.
BRISK WIND ADVISORY FOR PKZ200-PKZ220-PKZ225.
&&
$$
CF JAN 09
000
FXAK69 PAFG 200023
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
323 PM AKST MON JAN 19 2009
.DISCUSSION...
EMBEDDED SHORT WAVE IN THE SOUTHERLY FLOW ALOFT WILL
WILL GRADUALLY MOVE EASTWARD...REACHING THE ALCAN
BORDER BY 12Z WED. HIGH AMPLITUDE UPPER RIDGE WILL
BUILD OVER WESTERN ALASKA AND NORTHWESTWARD THROUGH
12Z WED...SETTING UP A COLD NORTHERLY FLOW OVER THE
EASTERN INTERIOR. TEMPERATURES ALOFT WILL WARM SOME
OVER WESTERN ALASKA WHILE COOLING WILL OCCUR OVER THE
EASTERN INTERIOR. BY 12Z WED...850 MB TEMPERATURES
OVER THE NORTHEAST INTERIOR WILL FALL TO -20C OR A
LITTLE COLDER. A LITTLE MODERATION IN TEMPERATURE
MAY OCCUR LATER IN THE WEEK INTO THE WEEKEND.
BY 00Z FRIDAY...A BLOCKING HIGH ALOFT WILL SPLIT OFF FROM
THE RIDGE...WITH THE CENTER OVER THE CENTRAL ARCTIC COAST.
PROGS ARE IN REASONABLY CLOSE AGREEMENT THROUGH 00Z THU...
BY 00Z FRI THE ECMWF DEPARTS FROM THE GFS/NAM SOLUTIONS
BY MOVING AN UPPER LOW WESTWARD UNDER THE BLOCK INTO THE
INTERIOR...ALONG WITH SOMEWHAT COLDER TEMPERATURES ALOFT.
ECMWF MOVING THIS WORM-IN-THE-APPLE FEATURE TO THE NORTHWEST
COAST BY 00Z SAT...GFS AND GFS ENSEMBLES MAINTAINING A MUCH
SIMPLER PATTERN WITH RIDGING FROM THE MACKENZIE DELTA
AREA SOUTHWARD. CURRENT CANADIAN 500 MB PROGS APPEAR TO
BE SHOWING A TREND SIMILAR TO THE ECMWF.
BRISK EAST WINDS DEVELOPING OVER MARINE AREA 210 TONIGHT...
INCREASING TO MINIMUM GALE OVER WESTERN PARTS OF THE AREA TUE
AS AN INVERTED SURFACE TROUGH EXPANDS NORTHWESTWARD FROM
THE CENTRAL ALEUTIANS INTO THE BERING...WITH A LOW CENTER
SPLITTING OFF OVER THE FAR WESTERN BERING BY 00Z WED.
BRISK EAST WINDS DEVELOPING TUE OVER MARINE AREA 200.
1028 MB HIGH OVER THE CHUKCHI SEA BUILDING TO 1048 MB
OVER THE ARCTIC COAST BY 00Z WED.
AREAS OF SNOW LIKELY IN SECTIONS OF THE CENTRAL AND EASTERN
INTERIOR TONIGHT AND TUE WITH THE EASTWARD MOVING SHORT WAVE.
FREEZING PRECIPITATION IS POSSIBLE THE SOUTHEAST INTERIOR THIS
EVENING AS 1000-850 MB LAYER MEAN TEMPERATURES REMAIN NEAR
OR ABOVE 0C...BUT GRADUAL COOLING IS EXPECTED THROUGH 18Z
TUE. BY 18Z TUE...1000-850 MB LAYER MEAN TEMPERATURE WILL BE
BELOW FREEZING IN ALL PARTS OF THE EASTERN INTERIOR...AND ANY
PRECIPITATION THAT OCCURS WILL BE ALL SNOW.
STRONG PRESSURE GRADIENT DEVELOPING OVER THE INTERIOR WED
AS STRONG SURFACE HIGH CONTINUES TO BUILD AND MOVES INTO
NORTHWEST CANADA...PRODUCING GUSTY WINDS IN CHANNELED
AREAS AND OVER SUMMITS.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY AKZ222.
FREEZING RAIN ADVISORY AKZ222.
BRISK WIND ADVISORY PKZ200.
GALE WARNING PKZ210.
&&
$$
RF JAN 09
000
FXAK69 PAFG 190057
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
357 PM AKST SUN JAN 18 2009
.DISCUSSION...
IN THE SHORT TERM...OVERRUNNING PRECIPITATION IS OCCURRING
IN ZONES 220-221-222-223-224-225-226. PRECIPITATION TYPE
IN THESE ZONES IS EXPECTED TO BE SNOW...WITH AREAS OF FREEZING
RAIN IN ZONES 223-224-226. FREEZING RAIN HAS BEEN REPORTED
AT EAGLE AND NORTHWAY...AND SURFACE TEMPERATURES IN THE
EASTERN ALASKA RANGE ARE WARM ENOUGH FOR FREEZING RAIN TO
OCCUR. 1000-850 MB LAYER MEAN TEMPERATURES OVER MOST OF ZONES
222-224 AND ZONES 223-226 REMAINING NEAR OR ABOVE 0C THROUGH
TONIGHT...THEN GRADUALLY COOLING FROM THE NORTHWEST...FALLING
TO BELOW 0C OVER ALL THESE AREAS BY MON EVENING. EMBEDDED SHORT
WAVE IN THE SOUTHERLY FLOW ALOFT WILL WEAKEN AS IT EXITS EASTWARD
ACROSS THE EASTERN INTERIOR TONIGHT. AREAS OF SNOW PERSISTING
OVER MUCH OF THE SOUTHERN AND EASTERN INTERIOR THROUGH MON...
FREEZING PRECIPITATION POSSIBLE IN ZONES 223-224-226.
LITTLE OR NO PRECIPITATION EXPECTED OVER WEST COAST AREAS
THROUGH MON NIGHT.
SURFACE LOW NEAR BOUY 46035 EXPECTED TO MOVE NORTHWARD
FOR ANOTHER 6 HOURS OR SO...THEN BEGIN CURVING WESTWARD.
BRISK WINDS FROM THE FRINGE OF THIS SYSTEM WILL BRUSH
THE WESTERN PARTS OF MARINE AREA 210 TONIGHT AND MON.
EAST TO SOUTHEAST BRISK WINDS WILL EXPAND OVER AREAS
200 AND 210 MON NIGHT...DEVELOPING IN MARINE AREAS 215-220
TUE AS ANOTHER LOW MOVES NORTHWARD INTO THE SOUTHERN BERING.
BLOCKING HIGH ALOFT WILL DEVELOP BY TUE AFTERNOON WITH
THE CENTER NEAR COOK INLET. MEDIUM RANGE SOLUTIONS DIFFER...
ECMWF GRADUALY WEAKENING THE BLOCK AND MOVING IT NORTHWARD
THROUGH FRI AFTERNOON...OPERATIONAL GFS AND ENSEMBLES
MAINTAINING A BLOCK CENTERED OVER THE EXTREME SOUTHEAST INTERIOR.
BOTH ECMWF AND GFS HAVE DECENT CONTINUITY WITH THE PREVIOUS
RUN...ALTHOUGH FRI AFTERNOON 500 MB HEIGHTS FROM THE OPERATIONAL
GFS ARE ABOUT 6 DAM HIGHER THAN THE ENSEMBLE MEAN. THE ECMWF
SOLUTION...WITH THE BLOCK LOCATED FARTHER TO THE WEST...WOULD
BRING COLDER AIR INTO THE EASTERN INTERIOR THAN THE GFS DURING THE
MIDDLE PART OF THE WEEK. HPC SOLUTION LEANS HEAVILY TOWARDS
ENSEMBLE MEANS LATE IN THE MID RANGE PERIOD. IN DAYS 4-5...HPC
PREFERRING THE OPERATIONAL ECMWF OVER THE GFS...WITH ENSEMBLE
MEANS COMPRISING 40% OF THE MIX.
THE BOTTOM LINE IS ABOVE AVERAGE UNCERTAINTY IN THE MEDIUM
RANGE FORECAST.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY FOR AKZ223-AKZ224-AKZ226.
BRISK WIND ADVISORY FOR PKZ210-PKZ230-PKZ235.
&&
$$
RF JAN 09
000
FXAK69 PAFG 181306
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
406 AM AKST SUN JAN 18 2009
.DISCUSSION...
MODELS IN DECENT AGREEMENT THROUGH JUST ABOUT 60 HOURS. ALTHOUGH
DO NOT BELIEVE THE MODELS ARE COMPLETELY ACCURATE. MODELS ARE
SUGGESTING THAT STRONG SOUTHERLY FLOW WILL CONTINUE TO DEVELOP
OVER CENTRAL ALASKA AGAIN BUT THIS TIME THE MODELS ARE INDICATING
THAT SNOWFALL IS LIKELY OVER THE CENTRAL INTERIOR. THIS SEEMS
UNLIKELY EVEN THOUGH THERE IS AN EMBEDDED SHORT WAVE MOVING
NORTHWARD. DO BELIEVE THERE IS GOING TO BE SOME SCATTERED SNOW
SHOWERS IN THE AREA THOUGH.
THE UPPER LEVEL LOW THAT STRUCK WESTERN ALASKA YESTERDAY HAS MOVED
ON NORTH OF THE ARCTIC COAST AND CONTINUED TO PUSH TONS OF WARM
AIR NORTHWARD OF THE ARCTIC COAST. COLDER AIR BEHIND THE LOW HAS
PUSHED ON TO THE WEST COAST AND SOME HAS PUSHED EASTWARD TO FROM
ABOUT BETTLES WESTWARD.
UPPER LEVEL SHORTWAVE WILL MOVE FROM WEST COAST TO ABOUT CORDOVA
BY EARLY TUESDAY MORNING. BLOCKING RIDGE SETS UP OVER NORTHERN
ALASKA BY EARLY TUESDAY AND REMAINS IN PLACE FOR THE FORESEEABLE
FUTURE.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
BRISK WIND ADVISORY FOR PKZ210-PKZ230-PKZ235.
&&
$$
CF JAN 09
000
FXAK69 PAFG 172159
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1259 PM AKST SAT JAN 17 2009
.DISCUSSION...
976 MB LOW OVER OUTER KOTZEBUE SOUND AT 21Z IS EXPECTED
TO WEAKEN DURING THE NEXT 6-9 HOURS AS A SECONDARY LOW
DEVELOPS NEAR BARROW LATER THIS AFTERNOON. BOTH LOW CENTERS
WILL EXIT RAPIDLY NORTHEASTWARD TONIGHT...WITH THE SECONDARY
LOW BECOMING THE MAIN LOW CENTER. A TROUGH IS EXPECTED
TO HANG BACK FROM THE LOW CENTERS...PERSISTING OFF THE
NORTHWEST COAST OF ALASKA THROUGH TONIGHT.
WINDS OVER THE SOUTHERN PORTIONS OF THE WEST COAST AND
INTERIOR WILL BEGIN TO DIMINISH THIS EVENING. OVER THE
NORTHERN PARTS OF THESE AREAS WINDS WILL BEGIN TO
DIMINISH LATE THIS EVENING. AKDOT UNOFFICIAL REPORT
INDICATES 100+ MPH WINDS IN ATIGUN PASS...WITH DALTON
HIGHWAY BLOCKED BY DRIFTS AND AVALANCHE SLIDES.
COLDER AIR WILL MOVE INTO THE WESTERN HALF OF THE FORECAST
AREA TONIGHT AS THE SURFACE LOWS EXIT TO THE NORTHEAST.
MILD TEMPERATURRES WILL CONTINUE OVER PARTS OF THE EASTERN
INTERIOR THROUGH MON...THEN COOL DOWN BY TUE AS THE SOUTHERLY
FLOW ALOFT IS REPALCED BY A BUILDING HIGH. THIS HIGH
WILL BRING SOME MILDER TEMPERATURES TO THE WEST COAST...
AND A PERIOD OF PLEASANT AND STORM-FREE CONDITIONS TO
THE FORECAST AREA.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR AKZ215-AKZ219-AKZ220-AKZ222
WINTER WEATHER ADVISORY FOR AKZ207-AKZ214.
WINTER STORM WARNING FOR AKZ205-AKZ206-AKZ208-AKZ209-AKZ210-
AKZ211-AKZ212-AKZ213-AKZ217.
HIGH WIND WARNING FOR AKZ216.
GALE WARNING FOR PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-PKZ240.
BRISK WIND ADVISORY FOR PKZ235-PKZ240-PKZ245.
&&
$$
RF JAN 09
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