966
FXAK69 PAFG 142322
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
222 PM AKST THU NOV 14 2024
SYNOPSIS
SNOW AND BLOWING SNOW HAVE DEVELOPED FOR THE Y-K DELTA AND LOWER
YUKON AREAS AS A STRONG LOW PRESSURE SYSTEM MOVES ASHORE AROUND
GOODNEWS BAY. THIS SYSTEM HAS ALSO BROUGHT STRONG GUSTY WINDS TO
UNALAKEET AND NORTON SOUND, WITH A TIGHT PRESSURE GRADIENT ON IT'S
NORTHERN SIDE. SNOW SPREADS EASTWARD THROUGH THE WEEKEND WITH
THIS SYSTEM, DROPPING 1 TO 3 INCHES OF ACROSS THE INTERIOR. HIGH
PRESSURE LINGERS OVER THE ARCTIC, BUT WITH INCREASING ICE COVERAGE
THE SEA EFFECTS WILL SLOWLY REDUCE THE CLOUD COVER AND SNOW
SHOWERS, ALLOWING SKY COVER TO DECREASE AND TEMPERATURES TO DROP
TONIGHT ALONG THE NORTH SLOPE.
DISCUSSION
CENTRAL AND EASTERN INTERIOR KEY MESSAGES...
- SOUTHERLY GAP WINDS WITH GUSTS TO 55 MPH DEVELOP IN THE EASTERN
ALASKA RANGE TONIGHT AND CONTINUE INTO FRIDAY MORNING.
- A WIDESPREAD ROUND OF LIGHT SNOW IS INCREASINGLY LIKELY FOR
FRIDAY INTO THE WEEKEND, WITH ACCUMULATIONS OF 1 TO 3 INCHES,
ACCOMPANIED BY HIGH TEMPERATURES ABOVE ZERO.
- EVEN COLDER TEMPERATURES ARE EXPECTED (LOCALLY COLDER THAN
-25F) EARLY NEXT WEEK.
NORTH SLOPE AND BROOKS RANGE...
- LIGHT WINDS AND INCREASING SEA ICE COVERAGE SHOULD COMBINE TO
LIMIT CLOUD COVER AND SEA EFFECT SNOW SHOWERS, ALLOWING FOR MUCH
COLDER TEMPERATURES ACROSS MUCH OF THE NORTH SLOPE THROUGH
TONIGHT.
- WINDS BECOME MORE NORTHEASTERLY AND INCREASE FOR FRIDAY-
SATURDAY ALLOWING FOR SEA EFFECT SNOW SHOWERS AND SOMEWHAT
WARMER TEMPS.
- A PATTERN SHIFT WILL CAUSE WINDS TO BECOME WEST TO NORTHWEST BY
EARLY NEXT WEEK. THIS WILL CAUSE AN INCREASE IN SEA EFFECT
SNOWFALL POTENTIAL NEXT WEE WITH OPEN WATERS STILL LINGERING ON
THE CHUKCHI SEA.
WEST COAST AND WESTERN INTERIOR...
- SNOW AND BLOWING SNOW HAS DEVELOPED TODAY ACROSS THE Y-K DELTA
AND LOWER YUKON DROPPING VISIBILITY TO A MILE OR LESS AT TIMES,
AS EAST TO NORTHEAST WINDS GUST UP TO 50 MPH.
- LIGHT TO MODERATE SNOWFALL FROM THE SEWARD PENINSULA SOUTHWARD
IS EXPECTED TODAY THROUGH FRIDAY, WITH TOTALS OF 3 TO 7 INCHES
OF SNOW ALONG AND SOUTH OF A LINE FROM GRAYLING TO SCAMMON BAY,
WITH THE HIGHEST AMOUNTS BETWEEN RUSSIAN MISSION AND HOLY CROSS.
- BELOW NORMAL TEMPERATURES PERSIST.
A STRONG LOW PRESSURE SYSTEM IS CURRENTLY APPROACHING THE
SOUTHWESTERN COAST, BRINGING STRONG WINDS AND SNOW ACCUMULATIONS
TO THE Y-K DELTA AND LOWER YUKON. RADAR RETURNS ARE STRONGER SOUTH
OF A LINE FROM NEWTOK THROUGH RUSSIAN MISSION, BUT EVEN THE
LIGHTER RADAR RETURNS ARE CORRELATING WELL WITH VISIBILITIES AS
LOW AS A MILE AS FAR NORTH AS MOUNTAIN VILLAGE AND HOLY CROSS.
WITH THE CURRENT CONDITIONS AND WINDS EXPECTED TO REMAIN STRONG
THROUGH TONIGHT, HAVE DECIDED TO EXPAND THE WINTER WEATHER
ADVISORY EAST, FARTHER INTO THE LOWER YUKON AND INNOKO VALLEYS.
THIS LOW SHOULD MOVE ONSHORE SOMETIME THIS EVENING, WITH STRONG
WINDS CONTINUING OVERNIGHT INTO FRIDAY BEFORE THE LOW WEAKENS AND
SLIDES TOO FAR SOUTHEAST, REDUCING ITS INFLUENCE ON THAT PART OF
THE STATE. HOWEVER, AS THIS SYSTEM SLIDES TO THE EAST, THE
PRESSURE GRADIENT INCREASES ALONG THE EASTERN ALASKA RANGE TONIGHT
INTO FRIDAY, AND WE ARE EXPECTING SOME GAP WINDS ALONG ISABEL
PASS AND OTHER SIMILARLY ORIENTED PASSES, WHERE WE HAVE SENT OUT A
WIND ADVISORY FOR TONIGHT INTO FRIDAY. FRIDAY INTO SATURDAY, THIS
SYSTEM WILL SLIDE ACROSS THE KENAI PENINSULA AND FARTHER EAST
ALONG THE COASTLINE. AS THIS SYSTEM ADVECTS SOME WARMER
TEMPERATURES ALOFT INTO THE INTERIOR, SURFACE TEMPERATURES WILL
WARM UP FOR FRIDAY WITH MOST AREAS SOUTH OF THE BROOKS RANGE
SEEING TEMPERATURES ON THE POSITIVE SIDE OF ZERO. IT WILL ALSO
PUSH MOISTURE UP OVER THE ALASKA RANGE AND INTO THE INTERIOR,
WHERE WE CAN EXPECT SNOWFALL OF 1 TO 3 INCHES BEGINNING LATE
FRIDAY THROUGH SATURDAY NIGHT BEFORE IT DIMINISHES ON SUNDAY. WITH
THIS BEING MAINLY LIGHT OVERRUNNING SNOWFALL, WITH ONLY
RELATIVELY WEAK SURFACE WINDS, DO NOT EXPECT ANY SIGNIFICANT
IMPACTS IN THE INTERIOR.
EXTENDED FORECAST DAYS 4-7...
AN UPPER LOW WHICH DIVES ACROSS THE ARCTIC TO JUST NORTH OF THE
EASTERN ARCTIC COASTLINE WILL HELP FUNNEL A VERY COLD AIRMASS TO
MAINLY THE NORTH SLOPE AND INTERIOR ALASKA BEGINNING SUNDAY,
CONTINUING MONDAY BEFORE RETREATING NORTHEAST TUESDAY. IN FACT,
ENSEMBLE 850MB TEMPERATURE ANOMALIES FOR SUNDAY THROUGH TUESDAY
SHOW TEMPERATURES SIGNIFICANTLY BELOW NORMAL, THOUGH NOT EVEN
CLOSE TO RECORD LOWS FOR THE DATE. THE MIDDLE TO LATTER PART OF
NEXT WEEK WILL BRING POTENTIAL FOR SIGNIFICANT WEATHER, WITH A LOW
PRESSURE SYSTEM DEVELOPING OVER THE SEA OF OKHOTSK AS AN UPPER
LOW MOVES OUT OF ASIA. THIS SYSTEM GETS PRETTY TIGHTLY SPUN UP AND
TRACKS NORTH OVER EASTERN SIBERIA. WE STILL HAVE A LOT OF SPREAD
IN THE TRACK OF THIS LOW, BUT IN GENERAL THE ECMWF ENSEMBLE MEAN
IS FARTHER EAST THAN THE GEFS ENSEMBLE MEAN. THIS IS GOING TO
DEPEND ON THE STRENGTH AND POSITION OF THE RIDGE OVER THE N.
PACIFIC AND BERING SEA TUESDAY, WHICH IS WHAT PUSHES THE GEFS
FARTHER WEST THAN THE ECMWF RUNS. THERE WILL BE A GOOD MOISTURE
PLUME ORIGINATING IN THE SUB-TROPICS WHICH GETS WOUND INTO THIS
SYSTEM. AS CURRENTLY DEPICTED, THIS SYSTEM SHOULD BRING STRONG
WINDS TO NORTHWESTERN ALASKA TO WEDNESDAY AND THURSDAY, WITH HEAVY
SNOW POTENTIAL ON WEDNESDAY. COMBINED, WE ARE LOOKING AT ABOUT A
30-50 PERCENT POTENTIAL FOR A PERIOD OF BLIZZARD CONDITIONS.
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.
AFG WATCHES/WARNINGS/ADVISORIES
AK...WIND ADVISORY FOR AKZ849.
WINTER WEATHER ADVISORY FOR AKZ825-826-830.
PK...GALE WARNING FOR PKZ801-802-850.
HEAVY FREEZING SPRAY WARNING FOR PKZ801-802-804>807-852-854-
856>858.
GALE WARNING FOR PKZ803.
SMALL CRAFT ADVISORY FOR PKZ804.
SMALL CRAFT ADVISORY FOR PKZ805-807.
SMALL CRAFT ADVISORY FOR PKZ806.
HEAVY FREEZING SPRAY WARNING FOR PKZ810.
SMALL CRAFT ADVISORY FOR PKZ810.
GALE WARNING FOR PKZ811.
BRISK WIND ADVISORY FOR PKZ812.
SMALL CRAFT ADVISORY FOR PKZ816-817-851.
HEAVY FREEZING SPRAY WARNING FOR PKZ816.
HEAVY FREEZING SPRAY WARNING FOR PKZ817.
HEAVY FREEZING SPRAY WARNING FOR PKZ850.
HEAVY FREEZING SPRAY WARNING FOR PKZ851.
GALE WARNING FOR PKZ852.
GALE WARNING FOR PKZ853.
HEAVY FREEZING SPRAY WARNING FOR PKZ853.
SMALL CRAFT ADVISORY FOR PKZ854-856-858.
BRISK WIND ADVISORY FOR PKZ855.
GALE WARNING FOR PKZ857.
LE
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