Gale Warning 121, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1257 PM AKST WED NOV 18 2015

.DISCUSSION...
AN ACTIVE AND PROGRESSIVE WEATHER PATTERN IS EXPECTED TO
CONTINUE OVER AND NEAR THE NORTHERN ALASKA FORECAST AREA
FOR THE NEXT WEEK TO 10 DAYS.

UPPER AIR...
A WEAK SHORT WAVE TROUGH NOW MOVING ACROSS THE SOUTHERN
WEST COAST AREA WILL DAMPEN OUT OVER THE INTERIOR TONIGHT
AS A MIGRATORY RIDGE BEGINS TO BUILD THE ALASKA MAINLAND.
THE RIDGE WILL BUILD THROUGH THURSDAY EVENING AS IT MOVES
EAST...RIDGE AXIS THURSDAY EVENING WILL EXTEND FROM THE
WESTERN BROOKS RANGE SOUTHEASTWARD INTO THE YUKON TERRITORY.
BY EARLY FRIDAY MORNING THE RIDGE DECREASE IN AMPLITUDE
AS IT MOVES ON EASTWARD INTO CANADA.

A STRONG UPPER LOW CENTERED NEAR 54N/170E...ABOUT 150 NM
NORTHWEST OF SHEMYA...WILL MOVE EASTWARD TO NEAR THE SEWARD
PENINSULA BY LATE THURSDAY NIGHT WHILE WEAKENING...THEN OPEN UP
INTO A TROUGH OVER NORTHWEST ALASKA BY LATE FRIDAY EVENING. THIS
WILL RESULT IN A LIGHTER MAINLY WESTERLY FLOW PATTERN WHICH SHOULD
PERSIST OVER NORTHERN ALASKA THROUGH SUNDAY. A RATHER WEAK RIPPLE
WILL MOVE ACROSS THE INTERIOR FRIDAY NIGHT INTO SATURDAY...FOLLOWED
BY ANOTHER WEAKENING SHORT WAVE TROUGH WHICH WILL ARRIVE ON THE
WEST COAST LATE SATURDAY NIGHT THEN WEAKEN FURTHER AS IT MOVES
ACROSS THE INTERIOR SUNDAY INTO SUNDAY EVENING.

SURFACE...
A BROAD AREA OF 1020-1024 MB HIGH PRESSURE OVER THE NORTHERN
ALASKA MAINLAND WILL MOVE SOUTHEASTWARD...BUILDING TO A
1030 MB HIGH CENTERED OVER THE SOUTHERN YUKON TERRITORY
BY LATE TONIGHT THEN WEAKENING SOME THURSDAY.

A 973 MB LOW CENTERED NEAR 54N/170E...ABOUT 150 NM NORTHWEST
OF SHEMYA...WILL DEEPEN TO A 970 MB CENTER NEAR 56N/178W BY
THIS EVENING. THE LOW WILL MOVE TO THE NORTON SOUND AREA
BY LATE THURSDAY NIGHT WHILE FILLING TO AROUND 980 MB.
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADIAN MODELS ARE
IN GOOD AGREEMENT ON FORECAST POSITIONS AND CENTRAL
PRESSURES THROUGH LATE THURSDAY NIGHT. THE LOW WILL THEN
RAPIDLY WEAKEN THROUGH LATE FRIDAY NIGHT WITH ONLY A
VERY WEAK CENTER REMAINING OVER THE WESTERN INTERIOR.

AS THE FIRST WEAKENING SHORT WAVE TROUGH MOVES EASTWARD...
FOLLOWED BY THE MUCH STRONGER UPPER LOW AND ITS ASSOCIATED
SURFACE SYSTEM...SNOW WILL SPREAD ACROSS THE WEST COAST
AND WESTERN INTERIOR WITH HEAVY SNOWFALL AMOUNTS EXPECTED
IN MANY AREAS.

THE FOLLOWING ARE EXPECTED STORM TOTAL SNOW AMOUNTS THROUGH
FRIDAY AFTERNOON...
ZONE 209.....UP TO 6 INCHES.
ZONE 210.....4 TO 8 INCHES.
ZONE 211.....5 TO 9 INCHES.
ZONE 212.....4 TO 10 INCHES...HEAVIEST IN THE NULATO HILLS.
ZONE 213.....6 TO 10 INCHES...HEAVIEST OVER ST LAWRENCE ISLAND.
ZONE 214.....5 TO 10 INCHES.
ZONE 215.....8 TO 12 INCHES.
ZONE 216.....6 TO 10 INCHES.
ZONE 217.....UP TO 8 INCHES.
ZONE 219.....UP TO 8 INCHES.
ZONE 227.....8 TO 15 INCHES FROM THE MCGRATH AREA WEST.

AS THE NEXT BERING SEA LOW MOVES EAST...IT WILL GENERATE
STORM FORCE NORTH TO NORTHEAST WINDS ARE EXPECTED THE NORTHERN
BERING SEA INCLUDING ST LAWRENCE ISLAND AND THE BERING STRAIT
TONIGHT THROUGH THROUGH MID DAY THURSDAY...WITH NORTHERLY GALES
LIKELY PERSISTING THURSDAY AFTERNOON INTO FRIDAY. BLIZZARD
CONDITIONS ARE EXPECTED OVER THESE AREAS THROUGH MID DAY FRIDAY.

CONDITIONS REMAIN VERY FAVORABLE FOR THE DEVELOPMENT OF VERY
STRONG SOUTHERLY CHINOOK WINDS IN AND NEAR ALASKA RANGE PASSES
THURSDAY AFTERNOON. VERY STRONG WINDS ARE EXPECTED TO CONTINUE
THROUGH FRIDAY MORNING. AFTER THE UPPER RIDGE AXIS PASSES BY TO
THE EAST...STRONG SOUTHERLY WIND FLOW WILL DEVELOP ALOFT...
WITH WINDS AS HIGH AS 75-80 KT ACROSS THE ALASKA RANGE AT 700
MB AND 800 MB. NAM MODEL BOUNDARY LAYER WINDS MAX OUT AT AS HIGH
AS 80 KT ACROSS PARTS OF THE EASTERN ALASKA RANGE. GUSTS TO 70
MPH ARE EXPECTED IN THE WIND PRONE AREAS OF ZONES 223-225...GUSTS
TO 80 MPH IN THE PASSES SOUTH OF ZONE 226 SOUTH OF DELTA JUNCTION.
STRONG SOUTH OR SOUTHWEST WINDS MAY OCCUR ALONG SECTIONS OF THE
ALASKA HIGHWAY NORTHWEST OF TOK IN ZONE 224. GUSTS TO 70 MPH ARE
ALSO EXPECTED IN WIND PRONE AREAS NEAR THE ALASKA RANGE IN ZONE
227.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

MEDIUM RANGE OUTLOOK...AN ACTIVE AND PROGRESSIVE WEATHER
PATTERN WILL LIKELY CONTINUE WITH POTENTIAL FOR SEVERAL
SIGNIFICANT WEATHER EVENTS IN THE 5-10 DAY TIME FRAME. ANOTHER
UPPER LEVEL RIDGE IS PROGGED BEGIN TO BUILD OVER THE BERING SEA
SUNDAY...INCREASING SHARPLY IN AMPLITUDE AS IT MOVES TO THE
EASTERN ARCTIC COAST AND EASTERN INTERIOR BY TUESDAY AFTERNOON.
THESE RESULTS AGREE FAIRLY WELL WITH THE GEFS ENSEMBLE MEAN
POSITION. CURRENT GFS/ECMWF RUNS ARE IN GENERALLY GOOD AGREEMENT
THROUGH TUESDAY ON THE DEVELOPMENT AND MOVEMENT OF THIS RIDGE.
THERE WILL BE POTENTIAL FOR STRONG SOUTH WINDS ACROSS THE WEST
COAST AND NORTHERN BERING SEA MONDAY INTO TUESDAY...ALONG WITH
ANOTHER INTRUSION OF WARM AIR WITH TEMPERATURES CLIMBING TO NEAR
OR MAYBE ABOVE FREEZING. AS THE RIDGE PROGRESSES FARTHER TO THE
EAST...THERE WILL BE POTENTIAL FOR ANOTHER EPISODE OF STRONG
SOUTHERLY CHINOOK WINDS IN ALASKA RANGE PASSES TUESDAY NIGHT INTO
WEDNESDAY. MODEL RUNS MAY VARY FROM DAY TO DAY...CURRENT GFS/ECMWF
RUNS BECOME INCREASINGLY DIVERGENT AFTER TUESDAY...SO SUBSEQUENT
MODEL RUNS WILL HAVE TO BE MONITORED CLOSELY.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FOR AKZ223-AKZ224-AKZ225-AKZ226.

WINTER STORM WARNING FOR AKZ211-AKZ212-AKZ214-AKZ215-AKZ216-
AKZ227.

BLIZZARD WARNING FOR AKZ213.

WINTER STORM WATCH FOR AKZ209-AKZ210-AKZ217-AKZ219.

HEAVY FREEZING SPRAY WARNING FOR PKZ200-PKZ210-PKZ220-PKZ225.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ220-PKZ225.

STORM WARNING FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ215.

GALE WARNING FOR PKZ200-PKZ220.
&&

RF NOV 15