Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 011343
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
443 AM AKST SUN FEB 1 2015

.ANALYSIS AND UPPER LEVELS...
HIGH PRESSURE SITS OVER MAINLAND ALASKA KEEPING THE MAJORITY OF
THE ACTIVITY TO THE SOUTH. ONE OF THOSE FEATURES IS A FRONT THAT
IS STALLING AND BREAKING APART AS IT MOVES OVER THE ALASKA
PENINSULA. OUT WEST ANOTHER HIGH IS BUILDING IN OVER THE WESTERN
ALEUTIANS.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT FOR THE SHORT AND MID TERMS.
SOME DISCREPANCIES DO ARISE WITH THE LOW SOUTH OF THE ALASKA
PENINSULA. THE EC AND NAM ARE PUSHING IT WEST FASTER THAN THE GEM
OR GFS. THE NAM ALSO BRINGS IT FURTHER SOUTH THAN THE OTHER
MODELS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (TODAY AND MONDAY)...
THE UPPER LEVEL RIDGE OVER SOUTHERN ALASKA WILL SLOWLY DRIFT SOUTH
OVER THE NEXT COUPLE OF DAYS. THE OFFSHORE SURFACE GRADIENT WILL
INCREASE TODAY THEN SLACKEN OFF TONIGHT AND MONDAY AS THE UPPER
RIDGE PUSHES INTO THE GULF OF ALASKA. DRY CONDITIONS ARE
EXPECTED...WITH JUST SOME PATCHY FOG IN PLACES UNDER A STEEP
INVERSION.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY AND MONDAY)... A
DISSIPATING FRONT WILL SPREAD SOME HIGHER CLOUDS OVER THE MAINLAND
TODAY. WINDS IN MOST AREAS WILL GRADUALLY RELAX AND LOSE THE GUSTS
IN MOST LOCATIONS. DRY CONDITIONS WILL PERSIST ACROSS THE MAINLAND
WITH SLIGHTLY WARMER TEMPERATURES THAN THE LAST COUPLE DAYS. LACK
OF CLOUDS AND WINDS TONIGHT WILL STILL ALLOW FOR TEMPERATURES TO
DROP SHARPLY AT NIGHT. A DRY FRONT FROM THE BERING SEA WILL SPREAD
CLOUDS OVER THE KUSKOKWIM DELTA ON MONDAY WHICH WILL AID IN
WARMING TEMPERATURES.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)... A
WEAKENING FRONT OVER THE EASTERN ALEUTIANS AND ALASKA PENINSULA
WILL KEEP THE CHANCE FOR RAIN SHOWERS IN THE FORECAST TODAY BUT
MAINLY DRY CONDITIONS SHOULD PERSIST. HIGH PRESSURE WILL REMAIN
OVER THE BERING KEEPING DRY CONDITIONS IN PLACE WITH MODERATE
NORTHEASTERLY WINDS.

&&

.LONG TERM FORECAST (TUESDAY THROUGH SUNDAY)...
A DRY SHORTWAVE WILL MOVE SOUTHEASTWARD THROUGH THE MAINLAND ON
TUESDAY. THIS SHORTWAVE WILL NOT BRING ANY PRECIPITATION TO THE
AREA...BUT IT WILL SUPPLY ENOUGH ENERGY AND COLD AIR TO BEGIN
WEAKENING THE RIDGE OVER THE SOUTHERN MAINLAND. THIS RIDGE WILL
THEN RETREAT COMPLETELY INTO THE BERING SEA AS A SECOND SHORTWAVE
ASSOCIATED WITH A DEEP UPPER LEVEL ARCTIC TROUGH CENTERED OFF THE
NORTHWEST CANADIAN COAST DIVES INTO THE SOUTH MAINLAND EARLY ON
WEDNESDAY. THE NAM...GFS...AND IN SOME RESPECTS THE GEM HAVE ALL
TRENDED SLIGHTLY MORE AGGRESSIVE WITH THIS SECOND SHORTWAVE...SO
A SLIGHT CHANCE OF SNOW SHOWERS WAS INTRODUCED THROUGHOUT THE GULF
COAST AS COLD AIR ASSOCIATED WITH THE SHORTWAVE ENTERS THE
MARITIME ENVIRONMENT.

BY THE MIDDLE OF NEXT WEEK...THERE IS STILL A BIT OF QUESTION AS
TO JUST HOW COLD IT WILL GET OVER SOUTHWEST AND SOUTHCENTRAL
ALASKA AS MODELS LACK CONTINUITY WITH THE PATH THE ARCTIC TROUGH
TAKES AS IT DIGS ACROSS ALASKA AND TOWARD THE YUKON. IT CAN BE
SAID IN HIGH CONFIDENCE THAT WELL BELOW AVERAGE TEMPERATURES WILL
BE COMMON ACROSS MOST LOCATIONS. IN ADDITION...A SECOND ARCTIC
TROUGH WILL DROP SOUTH QUICKLY STARTING LATE THURSDAY NIGHT AND
BRING A BLAST OF EVEN COLDER TEMPERATURES. CONFIDENCE WITH THE
TRACK OF THE UPPER TROUGH IS MUCH LESS THAN ITS PREDECESSOR...BUT
IT IS MORE THAN POSSIBLE THAT THIS SECOND BLAST OF COLD AIR COULD
BRING THE COLDEST TEMPERATURES OF THE SEASON TO MUCH OF SOUTHWEST
AND SOUTHCENTRAL ALASKA. IT IS IMPORTANT TO NOTE THAT THE TRACK OF
THE UPPER LEVEL LOW AND POSITION OF THE UPPER LEVEL HIGH PRESSURE
WILL PLAY A FACTOR INTO WHERE EXACTLY THE COLDEST TEMPERATURES
OCCUR. NONETHELESS...WELL BELOW TEMPERATURES WILL ONCE AGAIN BE
SEEN AND PERSIST INTO THE UPCOMING WEEKEND.

A RELATIVELY DRY PERIOD WILL CONTINUE THROUGH THE LONG TERM AS
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN THROUGH MUCH OF
THE WEEK. THE RIDGE BEGINS TO BREAK DOWN ON FRIDAY AS A STRONG LOW
MOVING NORTH FROM THE NORTH PACIFIC BEGINS TO FLATTEN OUT THE
RIDGE AND BRINGS RAIN CHANCES BACK TO THE NORTHERN GULF COAST AND
THE EASTERN ALEUTIANS. OTHER THAN THAT...A SPELL OF MOSTLY CLEAR
TO CLEAR SKIES SHOULD BE OBSERVED FOR THE MAINLAND.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 127.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...DK
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...ML
LONG TERM...DEK/MC



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