Heavy Snow in Alaska, November 1 to 2, 2015

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
403 PM AKDT SAT OCT 31 2015

.DISCUSSION...
12Z DETERMINISTIC MODELS INITIALIZED WELL AGAINST THE 12 ANALYSIS
AND VERIFIED REASONABLY AGAINST THE 18Z ANALYSIS DESPITE VERY
PROGRESSIVE FLOW AND RAPIDLY DEEPENING LOW OVER THE WESTERN
BERING SEA. MODEL SPREAD IS REASONABLE IN THE SHORT TERM...HOWEVER
SIGNIFICANT SPREAD EMERGES BETWEEN MODEL FAMILIES AND FROM RUN TO
RUN...BY 60 HOURS DECREASING CONFIDENCE IN MID TERM FORECAST AND
BEYOND.

ALOFT AT 500 HPA...UPPER LEVEL RIDGE OVER THE WEST COAST CONTINUES
TO MOVE TO THE EAST TO BE LOCATED OVER THE EASTERN INTERIOR
SUNDAY AS A DEEP UPPER LEVEL LOW MOVES EAST INTO THE CENTRAL
BERING SEA. NEGATIVE TILT OF THE LONG WAVE TROUGH COMBINED WITH
FAVORABLE LEFT FRONT QUADRANT OF THE JET COMBINING IDEAL
ENVIRONMENT FOR RAPID DEEPENING OF 971 MB LOW IN THE WESTERN
BERING SEA. A 997 MB LOW IN THE SOUTHERN CHUKCHI SEA WITH WARM
FRONT MOVING THROUGH THE WEST COAST IS THE FOCAL POINT FOR ONGOING
HEAVY SNOW EVENT. DEEP LAYER MOISTURE CONTINUES TO STREAM
NORTHEAST ALONG THE BACK OF UPPER LEVEL RIDGE MOVE EAST INTO THE
INTERIOR. FRONT CONTINUES TO MOVE EAST INTO THE WESTERN INTERIOR
TONIGHT AND CENTRAL INTERIOR SUNDAY.

ONGOING WINTER STORM WARNINGS FOR ZONES 207...208...209...210...216
AND 217 FOR HEAVY SNOW WERE EXTENDED INTO MONDAY MORNING AS MOIST
SOUTHWEST TO WEST UPSLOPE FLOW CONTINUES. ADVISORY LEVEL SNOW
MOVES INTO THE WESTERN PORTION OF ZONE 218...ZONE 219 AND ZONE 221
TONIGHT WHERE WINTER WEATHER ADVISORIES HAVE BEEN ISSUED. QPF
DIMINISHES AS THE FRONT STRETCHES AND WEAKENS AS IT CONTINUES TO
MOVE EAST INTO THE EASTERN INTERIOR SUNDAY...HOWEVER WILL NEED TO
MONITOR FOR ADDITIONAL HEADLINES FOR ADVISORY LEVEL SNOW AS THE
FRONT CONTINUES TO MOVE TO THE NORTHEAST.

MODEL GUIDANCE CONTINUES TO NUDGE UP STORM SURGE VALUES IN AND
AROUND NORTON SOUND MONDAY AND BEYOND AS LATEST MODEL RUNS
DEVELOP A DEEPER LOW WITH A MORE CONSISTENT SOUTHWEST FETCH
THROUGH THE BERING SEA NORTHEAST INTO NORTON SOUND. SURGE GUIDANCE
NOW PEAKING BETWEEN 6 TO 8 FT IN EASTERN NORTON SOUND AND 4 TO 6
FEET FURTHER WEST FROM GOLOVIN AND NOME AND AROUND 4 FEET IN THE
BERING STRAIT MONDAY. COASTAL FLOOD WATCHES ISSUED FOR ZONES
211...212...213 AND 214. MODEL WIND SPEEDS CONTINUE TO INCREASE
WITH SUSTAINED WINDS IN THE 25 TO 35 AND WIND GUSTS TO 50 MPH IN
AND NEAR NORTON SOUND. STILL CONSIDERABLE DIFFERENCES BETWEEN
MODELS ON STORM TRACK AND STRENGTH...CONTINUE TO MONITOR CLOSELY
FOR LATEST UPDATES AS SMALL DIFFERENCES IN STORM TRACK...STRENGTH
AND WIND DIRECTION WILL MAKE SIGNIFICANT DIFFERENCES THE TIMING
AND LOCATION OF POTENTIAL COASTAL FLOODING IN AND NEAR NORTON
SOUND AND ALONG THE LOWER YK DELTA COAST. HIGHEST WATER LEVEL ARE
EXPECTED MONDAY AND WILL LIKELY CONTINUE INTO TUESDAY. HIGH SURF
ADVISORY FOR ZONE 207 NORTH OF CAPE KRUSENSTERN ISSUED AS
SOUTHEAST WINDS CONTINUE TO BRING HIGH SURF TO KIVALINA. WINDS
EXPECTED TO SHIFT TO THE SOUTH AND THEN TO THE SOUTHWEST AS LOW
APPROACHES. SHISHMAREF LIKELY TO SEE HIGH SURF AFTER WINDS SHIFT
TO THE SOUTHWEST.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...HIGHEST WATER LEVELS ARE
EXPECTED ON MONDAY AND INTO TUESDAY AS DEEP BERING SEA STORM MOVES
JUST WEST OF ST LAWRENCE ISLAND MONDAY MORNING AND THROUGH THE
BERING STRAIT MONDAY EVENING.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FOR AKZ207.

COASTAL FLOOD WATCH FOR AKZ211-AKZ212-AKZ213-AKZ214.

WINTER STORM WARNING FOR AKZ207-AKZ208-AKZ209-AKZ210-AKZ216-
AKZ217.

WINTER WEATHER ADVISORY FOR AKZ218-AKZ219-AKZ221.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ215-PKZ220-PKZ225.

HEAVY FREEZING SPRAY WARNING FOR PKZ230.

BRISK WIND ADVISORY FOR PKZ235.
&&

CCC OCT 15