Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 282146
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1246 PM AKST SUN DEC 28 2014

.DISCUSSION...
CURRENT MODELS ARE GENERALLY SIMILAR ON HANDLING OF THE
MAJOR FEATURES OUT THROUGH TUE NIGHT...SOME SMALL DIFFERENCES
BETWEEN THE GFS/ECMWF SHOWING UP BY WED NIGHT.

UPPER AIR...
A HIGH AMPLITUDE UPPER LEVEL RIDGE CURRENTLY EXTENDS FROM THE
EASTERN ARCTIC OCEAN TO THE EASTERN NORTH GULF COAST AND SOUTH
SOUTHEASTWARD ACROSS THE EASTERN GULF OF ALASKA. A STRONG SHORT
WAVE MOVING UP THE WEST SIDE OF THE RIDGE IS NOW OVER THE CHUKCHI
SEA AND WILL BE MOVING NORTHEASTWARD THEN EASTWARD ACROSS THE TOP
OF THE RIDGE. THE SHORT WAVE WILL BE WEAKENING LATER TONIGHT AND
MONDAY AS IT APPROACHES LONGITUDE 140W OVER THE EASTERN ARCTIC
OCEAN. THE SHORT WAVE WILL SUBSTANTIALLY FLATTEN THE TOP OF THE
UPPER RIDGE AS IT TRACKS ACROSS THE ARCTIC OCEAN. BY MON
MORNING...THE RIDGE AXIS IS EXPECTED TO EXTEND FROM 73N/105W TO
THE SOUTHERN YUKON TERRITORY AND SOUTHWARD ACROSS THE EASTERN GULF
OF ALASKA.

THE NEXT SHORT WAVE...WHICH IS OF LOW AMPLITUDE...IS NOW
CROSSING THE ALASKA PENINSULA. IT WILL STRENGTHEN A LITTLE AS IT
MOVES TO OUTER NORTON SOUND AND ST LAWRENCE ISLAND BY LATE
TONIGHT...THEN DAMPEN OUT OVER NORTHWEST ALASKA MON MORNING AS
ANOTHER RIDGE BEGINS TO REBUILD. AXIS OF THIS NEXT RIDGE WILL
EXTEND FROM THE CHUKOTSK PENINSULA TO THE PANHANDLE BY MON
AFTERNOON AND FROM THE EASTERN SIBERIAN COASTAL WATERS
SOUTHEASTWARD ACROSS THE PANHANDLE BY TUE AFTERNOON.

A MUCH STRONGER SHORT WAVE WILL MOVE NORTHWARD TO OUTER BRISTOL
BAY BY LATE MON NIGHT AND MOVE NORTHWARD TO THE CHUKOTSK PENINSULA
AND NORTHWEST ALASKA BY LATE TUE NIGHT...PUTTING A SUBSTANTIAL
DENT IN THE REBUILT UPPER RIDGE. THIS SHORT WAVE WILL WEAKEN WED
NIGHT AND THU AS IT MOVES NORTHWARD INTO THE BEAUFORT SEA...TO BE
FOLLOWED BY ANOTHER RIDGE BUILDING OVER THE CHUKCHI SEA AND
ALASKA WEST COAST BY THU MORNING.

THIS WILL BE FOLLOWED BY A WEAKER SHORT WAVE MOVING ACROSS THE
BERING SEA TUE NIGHT...DAMPENING OUT OVER WESTERN ALASKA WED
NIGHT. ECMWF IS KEEPING THIS SHORT WAVE WAVE STRONGER THAN THE GFS
WED NIGHT.

SURFACE... 996 MB LOW CENTERED JUST NORTH OF THE CHUKOTSK
PENINSULA WILL MOVE TO 300 MILES NORTH OF BARROW BY LATE SUN
NIGHT...AND TO ABOUT 400 MILES NORTH OF THE MACKENZIE DELTA BY MON
AFTERNOON...MAINTAINING A CENTRAL PRESSURE AROUND 1000 MB.

THE NEXT LOW PRESSURE SYSTEM ON DECK WILL BE A 984 MB
CENTER MOVING NORTHWARD TO THE WESTERN ALASKA PENINSULA BY MON
EVENING...THEN WEAKENING TO A 985-990 MB CENTER NEAR OR JUST
NORTHWEST OF ST LAWRENCE ISLAND BY TUE EVENING.

WINTER STORM CONDITIONS HAVE ENDED IN ZONES 210-211. BLIZZARD
CONDITIONS ARE NOW ENDING IN ZONE 209. WINTER STORM CONDITIONS
HAVE ENDED IN ZONES 207-208...WILL RUN A STRONG WIND HEADLINE
THROUGH 6 PM. WE WILL ALLOW THE WINTER STORM WARNINGS FOR HEAVY
SNOW IN ZONES 215-216-NULATO HILLS IN ZONE 212 TO RUN THROUGH
TONIGHT. ADDITIONAL SNOW AMOUNTS OF 3 TO 6 INCHES EXPECTED IN
ZONES 215-216...AND IN THE NULATO HILLS IN ZONE 212. LIGHTER SNOW
AMOUNTS EXPECTED TONIGHT OVER THE REMAINDER OF ZONE 212-
214-210-211-SOUTHERN ZONE 208-WESTERN AREAS OF ZONES 219-221. SNOW
COULD BE MIXED WITH RAIN...WITH FREEZING RAIN POSSIBLE...IN ZONES
214-215-227-SOUTHERN ZONE 212 WHERE MODELS ARE INDICATING AN
ABOVE FREEZING LAYER ALOFT.

FOR MON...SNOW EXPECTED OVER THE WESTERN AND CENTRAL INTERIOR
AND MOST OF THE WEST COAST FROM NORTON SOUND NORTHWARD. SNOW
COULD BE MIXED WITH RAIN...WITH FREEZING RAIN POSSIBLE...IN ZONE
215-SOUTHERN ZONE 216-ZONE 227-WESTERN ZONE 221.

STRONG SOUTHERLY CHINOOK WINDS ARE EXPECTED TO CONTINUE IN
AND NEAR ALASKA RANGE PASSES...HIGH WIND WARNINGS FOR ZONES 225-226-227
AND WIND ADVISORY FOR AREAS OF ZONE 223 NEAR DELTA JUNCTION HAVE
BEEN EXTENDED THROUGH TUE. NAM12 FORECAST WINDS ACROSS THE ALASKA
RANGE AT 800 MB ARE AS HIGH AS 60 KT IN SOME AREAS. WINDS ARE
ALREADY GUSTING TO OVER 50 MPH AT SOME SITES IN ZONES 223 AND 225.

MORE PRECIPITATION IS EXPECTED OVER THE WEST COAST AND INTERIOR
MON NIGHT AND TUE WITH THE NEXT SURFACE SYSTEM AND ITS ACCOMPANYING
STRONG SHORT WAVE ALOFT. OVER THE SOUTHERN WEST COAST AREAS AND
SOUTHERN PARTS OF THE WESTERN INTERIOR...MOST LIKELY PRECIPITATION
TYPE WILL BE RAIN OR RAIN/SNOW MIX FREEZING RAIN POSSIBLE.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR AKZ223.

HIGH WIND WARNING FOR AKZ225-AKZ226-AKZ227.

WINTER STORM WARNING FOR AKZ212-AKZ215-AKZ216.

WINTER WEATHER ADVISORY FOR AKZ202.

SMALL CRAFT ADVISORY FOR PKZ210.

GALE WARNING FOR PKZ225-PKZ230-PKZ235.

BRISK WIND ADVISORY FOR PKZ200-PKZ215-PKZ220.
&&

$$

RF DEC 14



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