Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 181344
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
544 AM AKDT SAT APR 18 2015

.DISCUSSION...
MODELS IN GOOD AGREEMENT THROUGH 60 HOURS ON POSITION...TRACK AND
STRENGTH OF LOW PRESSURE SYSTEM MOVING INTO THE EASTERN BERING
SEA. THE 00Z RUNS OF THE NAM12...GFS...AND ECMWF ALL VERIFIED WELL
AGAINST THE 00Z AND 06Z ANALYSIS. MODEL SPREAD IS REASONABLE
THROUGH THE MID TERM AS WELL AS THE LONG TERM.

ALOFT AT 500 HPA...A LONG WAVE TROUGH CONTINUES ALONG THE EASTERN
BERING SEA WITH A 503 DAM LOW CURRENTLY 200 NM SOUTH OF DUTCH
HARBOR EXPECTED TO MOVE NORTH TO BE LOCATED OVER SAND POINT THIS
EVENING AND NEAR NUNIVAK ISLAND SUNDAY MORNING. A LONG WAVE RIDGE
REMAINS PARKED OVER BRITISH COLUMBIA AND EXTENDING NORTHWEST TO
NEAR POINT BARROW. A SHORT WAVE ROTATING AROUND THE UPPER LEVEL
LOW EXTENDS FROM NEAR AMBLER SOUTH TO NEAR BETHEL AND WILL
CONTINUE TO PUSH TO THE WEST TODAY. SEVERAL JET STREAKS MOVING
NORTH ALONG THE BACK SIDE OF THE RIDGE WILL PROVIDE AN ADDITIONAL
KICK TO MODERATE SOUTHERLY CHINOOK FLOW ACROSS THE ALASKA RANGE
TODAY AND SUNDAY. 700 MB WINDS PEAK AT NEAR 65 KTS THIS AFTERNOON
AND 850 MB WINDS PEAK AT NEAR 50 KTS THIS AFTERNOON...COMBINED
WITH WEAK TO MODERATE CRITICAL LEVEL WILL PUSH WINDS TO THE HIGH
END OF ADVISORY LEVEL THROUGH AND NEAR THE ALASKA RANGE PASSES
TODAY THROUGH LATE SUNDAY NIGHT AND INTO MONDAY MORNING.

ON THE SURFACE...A 974 MB LOW CENTERED 200 NM SOUTH OF DUTCH
HARBOR WILL CONTINUE TO MOVE TO THE NORTHEAST TO BE LOCATED NEAR
SAND POINT AS A 978 MB LOW SUNDAY MORNING WITH A SECONDARY 983 MB
LOW LOCATED OVER ST LAWRENCE ISLAND. AN INVERTED TROUGH OVER THE
WEST COAST TODAY WILL CONTINUE TO DEEPEN AND EVOLVE INTO THE 983
MB LOW THAT FORMS NEAR ST LAWRENCE ISLAND BY SUNDAY MORNING.
STRONG NORTH WINDS ON THE WEST SIDE OF THE LOW COMBINED WITH HEAVY
SNOW WILL PRODUCE BLIZZARD CONDITIONS BEGINNING THIS AFTERNOON
OVER ST LAWRENCE ISLAND AND THIS EVENING IN THE BERING STRAIT. A
BLIZZARD WARNING HAS BEEN ISSUED FOR THIS AREA. FURTHER EAST ALONG
THE SEWARD PENINSULA WEST COAST WARM AIR SURGING NORTH IN THE WARM
SECTOR WILL CREATE A MIXED BAG OF PRECIPITATION. SNOW THIS MORNING
WILL MIX WITH RAIN BY LATE MORNING OR EARLY AFTERNOON LIMITING
BOTH SNOW ACCUMULATIONS AND POTENTIAL FOR BLOWING SNOW TO REDUCE
VISIBILITY ENOUGH TO MEET ADVISORY CRITERIA ALONG THE WEST COAST
SOUTH OF THE SEWARD PENINSULA. WILL NEED TO MONITOR AS A DELAY IN
WARM AIR SURGE WITH RAIN MIXING IN WITH THE SNOW OR AN EARLIER
ONSET OF STRONGER WINDS IN AND AROUND THE NORTON SOUND ZONES COULD
BRING DOWN VISIBILITIES.

WINDS ON THE NORTH SLOPE WILL INCREASE TONIGHT AS THE GRADIENT
BETWEEN A HIGH PRESSURE RIDGE EXTENDING FROM WRANGEL ISLAND TO
BANKS ISLAND AND THE LOW DEVELOPING IN THE BERING SEA TIGHTENS.
EXPECT AREAS OF BLOWING SNOW TO DEVELOP OVER MUCH OF THE NORTH
SLOPE COAST TONIGHT. EAST WINDS IN THE 25 TO 35 MPH RANGE WILL
CONTINUE THROUGH SUNDAY.

&&

.FIRE WEATHER...

WARM AND DRY CONDITIONS ARE EXPECTED OVER THE CENTRAL AND EASTERN
INTERIOR...ESPECIALLY IN THE CHINOOK ZONES ALONG THE NORTH SLOPES
OF THE ALASKA RANGE. MIN RH VALUES THIS AFTERNOON LIKELY TO DIP
INTO THE 20S COMBINED WITH ADVISORY LEVEL WINDS IN AND NEAR THE
ALASKA RANG PASSES WILL COMBINE FOR METEOROLOGICAL RED FLAG
CONDITIONS HOWEVER NO HEADLINES AT THIS TIME AS FUELS IN SNOW FREE
AREAS NOT DRY ENOUGH.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR AKZ223-AKZ225-AKZ226-AKZ227.

BLIZZARD WARNING FOR AKZ213.

WINTER WEATHER ADVISORY FOR AKZ214.

GALE WARNING FOR PKZ210-PKZ220-PKZ225.

BRISK WIND ADVISORY FOR PKZ200-PKZ215-PKZ220-PKZ225-PKZ230-
PKZ235-PKZ240-PKZ245.
&&

$$

CCC APR 15



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