Area Forecast Discussion
Issued by NWS Anchorage, AK

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213
FXAK68 PAFC 071338
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
438 AM AKST SUN FEB 7 2016

.ANALYSIS AND UPPER LEVELS...

ANOTHER STRONG BUT WEAKENING NORTH PACIFIC LOW IS NOW MOVING INTO
THE SOUTHERN GULF OF ALASKA THIS MORNING...WHICH IS INTERACTING
WITH A RATHER STOUT WESTERN NORTH AMERICAN RIDGE. A POWERFUL EAST
ASIAN JET STREAM CAN BE SEEN ON BOTH GOES WEST AND HIMAWARI
SATELLITE IMAGERY THIS MORNING...WITH A RAPIDLY INTENSIFYING LOW
FORMING ALONG IT. THIS LEAVES THE BERING SEA AND SOUTHERN ALASKA
UNDER A MUCH WEAKER FLOW REGIME AS THE PACIFIC JET STREAM REMAINS
TO OUR SOUTH AND THE EAST. WITH A WEAK HIGH PRESSURE RIDGE AXIS
NOSING THROUGH ALL OF SOUTHERN ALASKA...THIS IS LEAVING RATHER
QUIESCENT WEATHER INLAND WITH THE EXCEPTION OF THE NORTHERN GULF
COAST (AND PARTS OF THE WESTERN SUSITNA VALLEY) WHERE SHOWERS
REMAIN BEHIND A WEAKENING AND DEPARTING SHORTWAVE TROUGH. WITH
TIME...THE POWERFUL LOW FORMING SOUTHEAST OF KAMCHATKA AND
SOUTHWEST OF THE FAR WESTERN ALEUTIANS WILL EVENTUALLY BECOME THE
NEXT ANCHORING TROUGH FOR A CONTINUATION OF THE PERSISTENT
SOUTHEAST FLOW PATTERN OVER SOUTHERN ALASKA. IN OTHER WORDS...NO
CHANGE IN THE PATTERN WITH NO "WINTER" PATTERNS IN SIGHT.

&&

.MODEL DISCUSSION...

THE MODELS ARE IN EXCELLENT AGREEMENT WITH THE FRONT MOVING INTO
THE GULF OF ALASKA...AND THE TRACK OF THE LOW AS IT MOVES THROUGH
SOUTHWEST ALASKA. THEY ARE IN EXCELLENT AGREEMENT WITH THE DEEP
LOW MOVING INTO THE FAR SOUTHWESTERN ALEUTIANS TODAY AND
TONIGHT...AND REMAIN IN EXCELLENT LARGE SCALE AGREEMENT DEEP INTO
NEXT WEEK. THE ONLY DISCREPANCY OF NOTE IS WITH A BASAL LOW
DEVELOPING ACROSS THE EAST CENTRAL PACIFIC BEFORE IT MOVES INTO
THE GULF OF ALASKA WEDNESDAY. THE ECMWF IS UP TO 12 HOURS FASTER
WITH THIS SYSTEM...WHILE THE NAM AND GFS ARE SLOW OUTLIERS. THE
CANADIAN IS IN THE MIDDLE...WHILE THE GFS ENSEMBLE MEAN LOOKS LIKE
THE ECMWF. THE FORECAST FAVORS THE FASTER SOLUTIONS...WHICH BRINGS
THE FRONT INTO SOUTHCENTRAL BY WED MORNING AS OPPOSED TO
WEDNESDAY EVENING.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FRONT OVER THE NORTHERN GULF WILL REACH THE GULF COAST LATER
TODAY. THIS SYSTEM WILL THEN MOVE INLAND AND WEAKEN TONIGHT INTO
MONDAY AS THE ASSOCIATED SURFACE LOW CROSSES THE ALASKA PENINSULA
INTO BRISTOL BAY. MOST OF THE PRECIPITATION WITH THIS SYSTEM WILL
FALL ALONG THE COAST AND COASTAL MOUNTAINS...WITH ONLY ISOLATED TO
SCATTERED SHOWERS GETTING INLAND. POST-FRONTAL SHOWERS WILL
CONTINUE THROUGH MONDAY NIGHT...BUT SLOWLY TAPER OFF...IN THE
MOIST UPPER LEVEL SOUTHERLY FLOW.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

A LOW PRESSURE SYSTEM SOUTH OF THE ALASKA PENINSULA WILL SWING A
FRONT THROUGH THE SOUTHWEST MAINLAND. THE MAIN IMPACT OF THIS
FRONT WILL BE MIDDLE AND HIGH CLOUDINESS AND AN INCREASE IN WINDS
THROUGH THIS AFTERNOON. SOME SPOTTY LIGHT PRECIPITATION WILL BE
POSSIBLE LATE SUNDAY FOLLOWED BY GUSTY EASTERLY WINDS DEVELOPING
BEHIND THE FRONT AS IT MOVES EAST TO WEST ACROSS THE AREA
BEGINNING LATER MONDAY MORNING. SHOWERY PRECIPITATION AND
EASTERLY WINDS WILL CONTINUE THROUGH LATE MONDAY NIGHT...STRONGEST
THROUGH THE GAPS OF THE ALEUTIAN RANGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A COUPLE OF FRONTAL BOUNDARIES WILL AFFECT THE AREA...ONE SWINGING OVER
THE ALASKA PENINSULA LATER TODAY WITH A WEAKENING SURFACE LOW
MOVING INTO BRISTOL BAY...THE OTHER WILL JUST REACH THE WESTERN
AND CENTRAL ALEUTIANS SUNDAY AFTERNOON. THIS FRONT WILL BE AROUND
GALE FORCE WITH THE MAIN LOW PASSING SOUTH OF THE CHAIN. THE MAIN
IMPACTS FOR THE LAND AREAS WILL BE PERIODS OF LIGHT SNOW FOR THE
CENTRAL AND WESTERN ALEUTIANS...POSSIBLY MIXING WITH RAIN TOWARD
THE CENTRAL ALEUTIANS AT TIMES.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE GULF AND BERING
THROUGH THE BEGINNING OF NEXT WEEKEND...WITH DRIER CONDITIONS FOR
FAVORED DOWNSLOPING INLAND LOCATIONS. A WEAKENING LOW PRESSURE
SYSTEM PUSHING OVER THE ALASKA PENINSULA MONDAY EVENING WILL TRACK
INTO THE NORTHEASTERN BERING WHILE DISSIPATING TUESDAY MORNING...
KEEPING SCATTERED RAIN AND SNOW SHOWERS OVER PARTS OF THE SOUTHERN
MAINLAND THROUGH EARLY TUESDAY MORNING. AT THE SAME TIME...ANOTHER
LOW ORGANIZES SOUTH OF THE CENTRAL ALEUTIANS MONDAY EVENING...AND
TRACKS EASTWARD THROUGH TUESDAY. THE SURFACE LOW ASSOCIATED WITH
THIS SYSTEM IS EXPECTED TO BRING A GALE FORCE FRONT ACROSS THE
CENTRAL AND EASTERN ALEUTIANS OVERNIGHT MONDAY...WITH EQUALLY AS
GUSTY WINDS ALONG THE WESTERN FLANK OF THE SYSTEM AS COLDER AIR
OFF EASTERN RUSSIA ADVECTS OVER THE WESTERN ALEUTIANS AND BERING
THROUGH WEDNESDAY MORNING. THIS SYSTEM STARTS TO LOSE MOMENTUM BY
WEDNESDAY AS A RIDGE BUILDS OVER SOUTHERN ALASKA. THIS RIDGE
CURRENTLY LOOKS TO SHUNT PROGRESS OF THIS LOW AND ANOTHER LOW
TRACKING IN FROM THE EASTERN BEAUFORT SEA. THIS KEEPS TEMPERATURE
TRENDS ABOVE NORMAL FOR MUCH OF THE SOUTHERN MAINLAND THROUGH NEXT
WEEKEND. ANOTHER WEAKER SYSTEM TRACKING UP FROM THE NORTH PACIFIC
WILL BRING A FRONT THROUGH THE GULF WEDNESDAY MORNING AND SLOWLY
TRACK INTO THE NORTHERN GULF COAST BY THURSDAY MORNING... BRINGING
ANOTHER ROUND OF WET AND WINDY WEATHER TO THE AREAS SURROUNDING
THE NORTHERN GULF COAST.

OVERALL THE MODELS ARE IN FAIR AGREEMENT THROUGH MUCH OF THE
EXTENDED FORECAST...WITH THE EC AND CANADIAN MODELS HAVING THE
BEST HANDLE ON THE SYSTEMS ENTERING OUR AREA THROUGH NEXT WEEKEND.
AS ONE COULD IMAGINE...THERE ARE THE USUAL TIMING AND STRENGTH
DIFFERENCES BETWEEN THE MODELS GIVEN HOW FAR OUT THE FORECAST
GOES. HOWEVER...FORECAST CONFIDENCE IS SLIGHTLY HIGHER THAN NORMAL
GIVEN THE FAIR SYNOPTIC AGREEMENT AMONGST THE MODELS WITH REGARDS
TO THE ACTIVE WEATHER PATTERN THAT WILL CONTINUE TO DOMINATE THE
REGION THROUGH NEXT WEEKEND.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORM 131 132 138 150
         GALE  119 120 130 136 137 139 155 160 174 175 176
               177 178 351 352
         HEAVY FREEZING SPRAY 180

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JA
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...RF/TP



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