Blizzard in Alaska, January 27, 2016

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
109 PM AKST WED JAN 27 2016

.DISCUSSION...

UPPER AIR...
A LIGHT SOUTH TO SOUTHEAST FLOW ALOFT WILL PERSIST OVER NORTHERN
ALASKA THROUGH FRIDAY. A WEAK SHORT WAVE TROUGH IS NOW MOVING
NORTHWARD ACROSS THE ARCTIC SLOPE AND WILL MOVE OFFSHORE NORTH OF
THE ARCTIC COAST EARLY THIS EVENING. A SECOND WEAK SHORT WAVE
TROUGH WILL MOVE NORTHWARD ACROSS THE INTERIOR TONIGHT...AND
ACROSS THE ARCTIC SLOPE THURSDAY INTO THURSDAY EVENING. AN UPPER
LOW NEAR 54N/172W WILL MOVE EAST THEN RECURVE NORTHWARD TO BE
ABOUT 50 MILES SOUTH OF ST LAWRENCE ISLAND BY FRIDAY AFTERNOON. A
SHORT WAVE TROUGH ROTATING AROUND THIS NORTHWARD MOVING LOW CENTER
WILL MOVE ACROSS THE SOUTHWEST ALASKA MAINLAND COAST FRIDAY
MORNING AND SWING NORTHWARD TO NORTON SOUND AND EASTWARD INTO THE
WESTERN INTERIOR BY FRIDAY EVENING. CURRENT MODEL RUNS AGREE
FAIRLY WELL THROUGH FRIDAY EVENING.

SURFACE...
MODERATELY STRONG EAST WINDS ARE CONTINUING ALONG THE ARCTIC COAST
FROM THE DEADHORSE AREA EAST AS A RESULT OF THE PERSISTING TIGHT
PRESSURE GRADIENT FROM EAST OF POINT THOMPSON INTO THE YUKON
TERRITORY...POSSIBLY BOOSTED SOME BY THE NORTHWARD MOVING SHORT
WAVE TROUGH ALOFT. THIS GRADIENT IS EXPECTED TO GRADUALLY WEAKEN
LATER TONIGHT INTO THURSDAY...RESULTING IN DECREASING WINDS AND AN
END TO THE REDUCED VISIBILITIES IN BLOWING SNOW. AREAS OF FOG WILL
LIKELY PERSIST THROUGH TONIGHT ALONG THE ARCTIC COAST.

STRONG NORTH TO NORTHEAST WINDS WITH BLOWING SNOW ARE CONTINUING
OVER THE BERING STRAIT AND THE NORTHERN BERING SEA FROM ST
LAWRENCE ISLAND NORTH AND WEST DUE TO THE TIGHT PRESSURE GRADIENT
BETWEEN A RIDGE OVER EASTERN SIBERIA AND LOWER PRESSURE SOUTH AND
EAST OF ST LAWRENCE ISLAND. STRONG NORTH TO NORTHEAST WINDS ARE
EXPECTED CONTINUE OVER THESE AREAS THROUGH FRIDAY...THEN DECREASE
SLOWLY FRIDAY NIGHT INTO SATURDAY. BLIZZARD CONDITIONS ARE
EXPECTED TO REDEVELOP THURSDAY AFTERNOON AND CONTINUE THROUGH
FRIDAY EVENING AS A WEAKENING LOW CENTER MOVES NORTHWARD TO NEAR
DALL POINT BY FRIDAY MORNING...BRINGING ANOTHER PERIOD OF SNOW TO
THE BERING STRAIT...ST LAWRENCE ISLAND...AND THE NORTHERN BERING
SEA. SNOW AMOUNTS OF 2 TO 4 INCHES ARE EXPECTED THURSDAY AFTERNOON
THROUGH FRIDAY AFTERNOON,,,WITH SEVERAL ADDITIONAL INCHES POSSIBLE
FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON. NAM12 MOS WIND
GUIDANCE FOR GAMBELL AND TIN CITY CONTINUES TO KEEP WIND SPEEDS
TOO HIGH...YESTERDAYS NAM12 GUIDANCE DID NOT VERIFY WELL.
A BLIZZARD WATCH FOR THIS EVENT WILL BE ISSUED THIS AFTERNOON.

THE INTERIOR...TANANA VALLEY JET WINDS ARE EXPECTED TO CONTINUE
THURSDAY EVENING...THEN DIMINISH AS THE BIG DELTA-NORTHWAY PRESSURE
DIFFERENCE DECREASES. EAST WINDS ARE CURRENTLY GUSTING TO AROUND
45 MPH IN THE DELTA JUNCTION/FORT GREELY AREA.

GUSTY SOUTH WINDS ARE EXPECTED IN ALASKA RANGE PASSES THIS
EVENING...AND AGAIN IN EASTERN ALASKA RANGES WEST OF THE TOK
CUTOFF THURSDAY EVENING. WINDS SHOULD BE BELOW ADVISORY
LEVEL...MAXIMUM WINDS ALOFT AT 800 MB ACROSS THE ALASKA
RANGE RUN AROUND 40 KT.

NORTHWARD MOVING SHORT WAVE TROUGH IS EXPECTED TO PRODUCE ABOUT
AN INCH OF SNOW IN THE EASTERN BROOKS RANGE AND IMMEDIATELY NEARBY
AREAS TONIGHT THROUGH EARLY THURSDAY MORNING...WITH A CHANCE OF
SNOW OR SCATTERED SNOW SHOWERS OVER THE REMAINDER OF THE NORTHERN
INTERIOR AND THE CENTRAL BROOKS RANGE.

TEMPERATURES OVER ALL OF NORTHERN ALASKA WILL CONTINUE TO
BE MUCH ABOVE NORMAL IN THE SHORT TERM PERIOD.

MEDIUM RANGE OUTLOOK...
CURRENT GFS/ECMWF/CANADIAN RUNS CONTINUE YESTERDAYS TREND OF
BUILDING A STRONG UPPER LEVEL RIDGE ACROSS THE ALASKA MAINLAND
BY SUNDAY...WITH MODERATELY STRONG SOUTH TO SOUTHEAST FLOW
ACROSS THE WEST COAST AND NORTHERN BERING SEA OVER THE WEEKEND
INTO EARLY NEXT WEEK. A STRONG SURFACE LOW PROJECTED TO MOVE INTO
THE SOUTHWESTERN BERING SEA SATURDAY NIGHT INTO SUNDAY COULD BRING
STRONG SOUTHEAST WINDS TO ST LAWRENCE ISLAND AND POSSIBLY THE
COASTAL AREAS OF THE YUKON DELTA. RIDGING IS EXPECTED TO WEAKEN
LATER IN THE WEEK BUT WITH A SOUTH TO SOUTHEAST FLOW PATTERN ALOFT
LIKELY CONTINUING. THE CURRENT CLIMATE PREDICTION CENTER 6-10 DAY
FORECAST CALLS FOR A 30 TO 60 PERCENT PROBABILITY OF ABOVE NORMAL
TEMPERATURES OVER MOST OF NORTHERN ALASKA...AND A 30 TO 50 PERCENT
PROBABILITY OF BELOW NORMAL PRECIPITATION. THE NCEP ENSEMBLE MEAN
TEMPERATURE ANOMALY FORECAST INDICATES POSITIVE ANOMALIES OF 9 TO
12 DEGREES CELSIUS OVER ALMOST ALL OF NORTHERN ALASKA FOR WEEK 1.
FOR WEEK 2...POSITIVE TEMPERATURE ANOMALIES RANGE FROM 1-3 DEGREES
CELSIUS OVER THE EASTERN INTERIOR TO AROUND 6 DEGREES CELSIUS OVER
THE WEST COAST. PRECIPITATION IS EXPECTED TO BE NEAR NORMAL OVER
MOST OF NORTHERN ALASKA FOR WEEKS 1 AND 2.

 &&

.AFG WATCHES/WARNINGS/ADVISORIES...
BLIZZARD WATCH FOR AKZ213.

WINTER WEATHER ADVISORY FOR AKZ214.

GALE WARNING FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ200-PKZ220-PKZ225-PKZ240-PKZ245.
&&

RF JAN 16