Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 080127
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
427 PM 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 TODAY...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 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.

&&

.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 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 SLOWER. 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 VERTICALLY STACKED LOW SOUTH OF KODIAK ISLAND WILL CONTINUE TO
GRADUALLY FILL AS IT TRACKS NORTH TONIGHT THEN CROSSES THE ALASKA
PENINSULA AND MOVES INTO BRISTOL BAY MONDAY. THE ASSOCIATED
FRONTAL SYSTEM STRETCHING ACROSS THE WESTERN AND NORTH GULF WILL
MOVE OVER KODIAK ISLAND...THE EASTERN KENAI PENINSULA AND PRINCE
WILLIAM SOUND TONIGHT WHERE IT WILL BECOME STALLED THROUGH
MONDAY. THE POSITION OF THE FRONT AND TRACK OF THE LOW ARE BOTH
FAVORABLE FOR STRONG EAST TO SOUTHEAST GAP WINDS THROUGH TURNAGAIN
ARM AS WELL AS OTHER SIMILARLY ORIENTED TERRAIN GAPS. GUSTY
NORTHEAST WINDS WILL CONTINUE ACROSS KODIAK ISLAND THIS EVENING
THEN A SHIFT TO STRENGTHENING EASTERLY WINDS LATE TONIGHT THROUGH
MONDAY MORNING AS THE LOW PASSES BY THE SOUTH SIDE OF THE ISLAND.
ANOTHER WEAK AREA OF LOW PRESSURE WILL LIFT INTO THE CENTRAL AND
EASTERN GULF MONDAY AFTERNOON THEN TRACK NORTH TOWARDS YAKUTAT
MONDAY NIGHT THROUGH TUESDAY MORNING. THE NEXT STRONGER LOW
MOVING UP FROM THE SOUTH WILL CROSS 50N AROUND 145W TUESDAY
AFTERNOON WITH THE ASSOCIATED FRONTAL SYSTEM SPREADING INTO THE
SOUTHERN GULF.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A DECAYING FRONT WILL MOVE OVER THE MAINLAND TONIGHT. INITIALLY
TONIGHT THE ONLY IMPACT WILL BE AN INCREASE IN CLOUD COVER ALONG
WITH THE CHANCE FOR FLURRIES ALONG THE WOOD RIVER MOUNTAINS OR
SOME SPRINKLES TO THE EAST NEARER THE ALEUTIAN RANGE. AS THE FRONT
PASSES TOMORROW...A LITTLE MORE RAIN IS EXPECTED FROM DILLINGHAM
NORTH AND WEST...MIXED WITH SNOW AT HIGHER ELEVATIONS...AND RAIN
SHOWERS EAST OF DILLINGHAM. WINDS WILL TURN FROM THE EAST AND GET
A LITTLE GUSTY BUT SHOULD BE SUB-STRONG WIND RANGE. A FEW SHOWERS
WILL LINGER ON MONDAY NIGHT BUT A DRYING AND CLEARING TREND WILL
CONTINUE THROUGH TUESDAY WHEN WINDS WILL LIGHTEN AND TURN TO THE
NORTH. EXPECT TEMPERATURES SLIGHTLY ABOVE NORMAL FOR THIS TIME OF
YEAR WITH HIGHS IN THE 30S...WITH LOW 40S ALONG THE ALEUTIAN
RANGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
MOSTLY BENIGN CONDITIONS FOR MOST OF THE BERING SEA WITH LIGHT
WINDS AND ISOLATED TO SCATTERED RAIN/SNOW SHOWERS. HOWEVER...THERE
IS A FRONT APPROACHING THE WESTERN/CENTRAL ALEUTIANS ASSOCIATED
WITH A STRONG LOW PRESSURE SYSTEM IN THE NORTHERN PACIFIC. THE
GALE FORCE FRONT WILL JUST MAKE IT TO THE CHAIN AND SLOWLY SLIDE
WEST TO EAST THROUGH MID-WEEK. EXPECT CLOUDY CONDITIONS ALONG THE
CHAIN WITH AREAS OF RAIN AND SNOW.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE LONG TERM FORECAST REMAINS PREDOMINANTLY DRY ACROSS THE
SOUTHERN MAINLAND WITH STORMS SYSTEMS CONTINUING TO BRING ACTIVE
WEATHER ACROSS THE SOUTHERN BERING AND GULF OF ALASKA. TUESDAY
NIGHT INTO WEDNESDAY A LOW DEVELOPING ACROSS THE EASTERN PACIFIC
MOVES A FRONT INTO THE SOUTHERN GULF ON ITS TRACK TOWARD THE
ALASKA PENINSULA. GUSTY GALE FORCE WINDS AND RAIN WILL SPREAD
EAST TO WEST ACROSS THE GULF WITH STRONGER WINDS POSSIBLE IF A
DEEPER SURFACE LOW DEVELOPS. GUSTY WINDS ALONG CHANNELED COASTAL
TERRAIN IS EXPECTED TO INCREASE EARLY WEDNESDAY AS THIS NEXT
SYSTEM TIGHTENS THE PRESSURE GRADIENT ALONG THE NORTHERN GULF.
MODELS ARE STRUGGLING WITH HOW TO HANDLE THE LOW AS IT NEARS THE
ALASKA PENINSULA WEDNESDAY NIGHT AS A SECOND CLOSED LOW IN THE
NORTH PACIFIC PICKS UP A FASTER EASTERLY TRACK ON THE SOUTH SIDE
OF THE ALEUTIAN CHAIN. DUE TO THIS UNCERTAINTY IN THE MID RANGE
FORECAST CHANGES ARE LIKELY TO BE MADE FOR WINDS AND PRECIPITATION
ACROSS THE WESTERN GULF AND THE EASTERN BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 130 131 132 138 139 150 155 172 174 176 177.

&&
$$

SYNOPSIS AND MODEL DISCUSSION...JW
SOUTHCENTRAL ALASKA...JR
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MTL
LONG TERM...KH


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