Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 040203
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
503 PM AKST WED FEB 3 2016

.ANALYSIS AND UPPER LEVELS...
THE MAIN FEATURE IMPACTING THE AREA IS A LOW THAT IS SOUTH OF THE
ALASKA PENINSULA AND TRACKING TOWARDS THE BERING. THIS LOW IS PART
OF A BROAD LONGWAVE TROUGH THAT ORIGINATES OVER RUSSIA AND EXTENDS
THROUGH THE BERING. THE MAIN JET IS WELL SOUTH OF THE AREA BUT A
WEAKER JET STREAK IS HELPING TO PUSH THE LOW NORTH. THE LOW HAS
ALSO BROUGHT UP WARMER AIR FROM THE SOUTH BRINGING RAIN TO AREAS
ALONG THE NORTH GULF COAST AND ALASKA PENINSULA. HOWEVER...THE
BULK OF THE PRECIPITATION IS NOT MAKING IT PAST THE COASTAL
RANGES. WITH THE LOW SOUTH OF THE AREA AND RIDGING THAT IS
EXTENDING JUST NORTH OF SOUTHCENTRAL ALASKA...STRONGER NORTHEAST
WINDS ARE BEING SEEN IN MANY PLACES AROUND SOUTHCENTRAL AND
SOUTHWEST ALASKA.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT WITH THE MAIN LOW TRACKING
TOWARDS THE BERING. THEY ARE ALL ALSO IN DECENT AGREEMENT WITH A
STRONG SHORTWAVE MOVING THROUGH THE GULF THURSDAY MORNING.
HOWEVER...THEY DO VARY ON ITS STRENGTH SOMEWHAT. THE GFS AND NAM
ARE STRONGER THAN THE GEM WHILE ALL THREE ARE STRONGER THAN THE
EC. THE STRONGER SOLUTION OF THE GFS WAS USED IN THE FORECAST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FRONT ASSOCIATED WITH THE LOW NEAR THE SHUMAGINS WILL SLOWLY
DISSIPATE IN PLACE OVER THE NORTHERN GULF COAST
OVERNIGHT...KEEPING PRECIPITATION MAINLY ON THE COAST..ALTHOUGH A
FEW SHOWERS ARE MAKING IT INTO THE ANCHORAGE BOWL THIS AFTERNOON. THE
970MB LOW IN THE NORTHEASTERN PACIFIC WILL CONTINUE TO DEEPEN AND
MOVE INTO KODIAK ISLAND BY THURSDAY AFTERNOON. THE FRONT WITH THIS
LOW IS EXPECTED TO ARC NORTHWARD AHEAD OF THE SYSTEM AND WILL
BEGIN TO IMPACT THE NORTHERN GULF COAST BY TOMORROW MORNING. THIS
WILL PROVIDE A RE-ENFORCING SHOT OF PRECIPITATION TO THE COAST
WITH MOSTLY RAIN AT SEA LEVEL WITH SNOW AT HIGHER ELEVATIONS. AS
STATED IN THE PREVIOUS DISCUSSION...THERE IS ENOUGH OF A PUSH WITH
THE SECOND FRONT THAT SOME MOISTURE WILL PUSH OVER THE TERRAIN TO
GENERATE ISOLATED TO SCATTERED SHOWERS INLAND THROUGH FRIDAY
AFTERNOON.

AS THE SECOND FRONT TRAVERSES NORTHWARD...STORM FORCE WINDS ARE
EXPECTED TO DEVELOP ALONG THE NORTHERN GULF COAST ON THURSDAY.
WITH THE COLD AIR MASS REMAINING IN PLACE OVER THE COPPER RIVER
BASIN...WINDS THROUGH THOMPSON PASS ARE EXPECTED TO REMAIN
ELEVATED THOUGH EARLY THURSDAY AFTERNOON. WITH THE SNOW ALREADY
ON THE GROUND AND SEVERAL MORE INCHES OF NEW SNOW EXPECTED WITH
THE SECOND FRONT...THE BLOWING SNOW ADVISORY HAS BEEN EXTENDED
THROUGH NOON THURSDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A SURFACE LOW CONTINUES TO ADVANCE THIS EVENING TOWARD THE ALASKA
PENINSULA BRINGING GUSTY NORTH TO EAST WINDS ACROSS THE EASTERN
AREAS OF THE PENINSULA...BRISTOL BAY...AND KUSKOKWIM DELTA.
SCATTERED SHOWERS ACROSS THE SOUTHWEST WILL BE A MIX OF RAIN AND
SNOW ACROSS BRISTOL BAY WITH COLDER TEMPERATURES TO THE NORTH
KEEPING PRECIPITATION ALL SNOW FOR THE KUSKOKWIM DELTA AND VALLEY.
AS THE SURFACE LOW CROSSES OVER TO THE EASTERN BERING...WARM AIR
ADVECTS IN FROM THE NORTH PACIFIC THROUGH THE END OF THE WEEK
BRINGING ABOVE NORMAL TEMPERATURES INTO FRIDAY. A STRONGER UPPER
LEVEL WAVE MOVES FROM THE WESTERN GULF THURSDAY NIGHT AND TRACKS
TOWARD THE SOUTHWEST COAST. THIS BRINGS ANOTHER SURGE OF WARMER
AIR FURTHER NORTH WHICH IS EXPECTED TO BRING MIXED PRECIPITATION
INTO THE KUSKOKWIM VALLEY...HOWEVER NORTHEASTERLY FLOW WILL KEEP
AREAS WEST OF SLEETMUTE ALL SNOW.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A NORTH PACIFIC SURFACE LOW CROSSES OVER TO THE EASTERN BERING
TONIGHT BRINGING GUSTY WINDS AND PRECIPITATION THROUGH THURSDAY.
THIS SYSTEM REINFORCES A WARM AIRMASS ACROSS THE ALASKA PENINSULA
KEEPING PRECIPITATION MAINLY RAIN THROUGH THURSDAY NIGHT DURING
THE FOLLOWING SHORTWAVES THAT ROTATE THROUGH THE UPPER FLOW.
MIXED PRECIPITATION IS EXPECTED ACROSS THE EASTERN ALEUTIANS AND
TOWARD THE PRIBILOF ISLANDS...HOWEVER THE PRIBILOF ISLANDS AND
NORTH AND WEST SHOULD STAY ALL SNOW UNDER THE INFLUENCE OF COLD
NORTHERLY FLOW.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE MODELS REMAIN IN VERY GOOD AGREEMENT THAT THE PERSISTENT
PATTERN OF A BROAD UPPER LEVEL TROUGH OVER THE BERING/NORTH
PACIFIC WITH RIDGING OVER THE PANHANDLE/YUKON TERRITORY WILL
CONTINUE INTO EARLY NEXT WEEK. AS A RESULT THERE IS GOOD
CONFIDENCE THAT MOST OF THE SOUTH MAINLAND WILL EXPERIENCE
TEMPERATURES AT OR ABOVE NORMAL STARTING SATURDAY AS THE REGION
EXPERIENCES MOIST SOUTHERLY FLOW AND WIDESPREAD CLOUDINESS.
STARTING LATE SATURDAY AND INTO SUNDAY THERE IS INCREASING
CONFIDENCE THAT A GALE FORCE LOW WILL MOVE FROM THE NORTH PACIFIC
INTO THE NORTH GULF COAST...BRINGING GUSTY WINDS AND RAIN TO THAT
AREA THROUGH SUNDAY. THE ASSOCIATED LOW HOWEVER WILL BE LOCATED
WELL SOUTH OF KODIAK ISLAND...KEEPING MOST OF SOUTHCENTRAL DRY
WITH DRY DOWN INLET FLOW AND CROSS BARRIER FLOW. BY MONDAY AND
TUESDAY PRECIPITATION CHANCES OVER SOUTHCENTRAL BEGIN TO INCREASE
AS THE LOW MOVES NORTHWARD TOWARDS COOK INLET...HOWEVER WITH WARM
SOUTHERLY FLOW THERE IS GOOD CONFIDENCE THAT MOST (IF NOT ALL) OF
THIS SHOULD FALL IN THE FORM OF RAIN IN THE LOWER ELEVATIONS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...BLOWING SNOW ADVISORY...131.
MARINE...GALE...120 127 130 131 138 139
                150 155 160 165 172 174 176 177 178 180
         STORM...119
         HEAVY FREEZING SPRAY...180 181 185.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...DK
SOUTHCENTRAL ALASKA...RF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DEK



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