Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 120139
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
439 PM AKST THU FEB 11 2016

.ANALYSIS AND UPPER LEVELS...
AN EXPANSIVE LOW PRESSURE SYSTEM SPANNING ACROSS THE GULF TO THE
EASTERN BERING HAS A STRONG DEVELOPING WAVE LIFTING NORTH TOWARD
THE EASTERN GULF. THIS NEXT SYSTEM WILL BE THE FOCUS FOR RAIN AND
SNOW DEVELOPMENT TONIGHT THROUGH EARLY SATURDAY ACROSS THE GULF
AND SOUTHERN MAINLAND. ANOTHER CLOSED LOW OVER THE NORTH PACIFIC
PUSHED A FRONT INTO THE WESTERN ALEUTIANS AND IS SLOWLY ORGANIZING
AS IT MOVES TOWARD THE CHAIN. A THIRD LOW...IS NEARLY STATIONARY
OVER THE NORTHWEST TERRITORY AND IS MOVING WEAK WAVES TOWARD THE
SOUTHWEST COAST.

 &&

.MODEL DISCUSSION...

MODELS ARE IN RELATIVELY GOOD AGREEMENT WITH THE SYNOPTIC PATTERN
THROUGH SATURDAY. THE NAM AND GFS WERE BEST ALIGNED THROUGH FRIDAY
NIGHT AND WERE USED FOR INITIAL FORECAST EDITS. A SHIFT TOWARD THE
ECMWF PATTERN WAS MADE FOR THE UPCOMING WEEKEND...AS IT HAS PERFORMED
WITH THE BEST CONSISTENCY IN HANDLING THE FRONT MOVING TOWARD THE
ALASKA PENINSULA AND GULF THROUGH THE WEEKEND.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE NEXT IN A SERIES OF FRONTS MOVING THROUGH THE GULF WILL
SPREAD ANOTHER ROUND OF PRECIPITATION ALONG THE GULF COAST
TONIGHT...WITH TEMPERATURES REMAINING WARM ENOUGH TO SUPPORT
MAINLY RAIN IN MOST LOCATIONS. A WEAK UPPER LEVEL WAVE WILL THEN
MOVE INLAND ON FRIDAY MORNING AND BRING A CHANCE FOR A FEW SNOW
SHOWERS ON THE LEE SIDE OF THE COASTAL RANGE. A FEW POCKETS OF
FREEZING RAIN WILL ALSO BE POSSIBLE FROM ANCHORAGE INTO THE
MATANUSKA VALLEY AS A LAYER OF WARMER AIR REMAINS IN PLACE ALOFT
AND SURFACE TEMPERATURES HOVER JUST BELOW FREEZING. HOWEVER...ANY
PRECIPITATION THAT DOES MAKE IT OVER THE MOUNTAINS WILL REMAIN
LIGHT WITH NO ACCUMULATION EXPECTED. PRECIPITATION WILL THEN
REMAIN FOCUSED ALONG THE GULF COAST INTO THE WEEKEND IN PERSISTENT
ONSHORE FLOW AS AN EMBEDDED SURFACE LOW MOVES TOWARDS THE GULF
COAST. AN ASSOCIATED UPPER LOW WILL OPEN INTO A TROUGH AND LIFT
NORTHWARD FRIDAY NIGHT INTO SATURDAY...BRINGING A BETTER CHANCE
FOR PRECIPITATION TO INLAND AREAS OF SOUTHCENTRAL AK.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A WEAK DEFORMATION BAND SETTING UP OVER THE SOUTHWEST MAINLAND
THIS EVENING WILL BRING SNOWFALL TO WESTERN PORTIONS OF BRISTOL
BAY AND THE KUSKOKWIM VALLEY. THIS WILL BE A RELATIVELY WEAK
FEATURE...SO ACCUMULATIONS SHOULD REMAIN UNDER AND INCH OR TWO IN
MOST PLACES. FURTHER TO THE EAST MOST AREAS OF BRISTOL BAY SHOULD
REMAIN DRY WITH DOWNSLOPING OFF OF THE ALASKA/ALEUTIAN RANGES.
THE KUSKOKWIM DELTA SHOULD ALSO SEE ONLY PASSING SNOW SHOWERS AS
THE DEFORMATION BAND WILL MOSTLY DISSIPATE OFF TO THE EAST.
OTHERWISE THE WEATHER WILL BE RELATIVELY QUIET INTO SATURDAY WITH
DIMINISHING WINDS.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
BROAD EASTERLY FLOW OVER THE BERING WILL KEEP WEATHER THROUGHOUT MUCH
OF THE AREA QUIET THROUGH FRIDAY. A WEAK FRONTAL SYSTEM WILL CLIP THE
WESTERN ALEUTIANS...BRINGING RAIN/SNOW TO THE AREA THROUGH TONIGHT.
THE ASSOCIATED LOW WILL HOWEVER REMAIN WELL SOUTH OF THE AREA SO IMPACTS
SHOULD BE MINIMAL. THIS FRONT WILL THEN SLIDE INTO THE EASTERN
ALEUTIANS/AKPEN FOR SATURDAY...HOWEVER WINDS THROUGHOUT THE AREA
WILL REMAIN BELOW GALE FORCE.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...

A DRAMATIC WEATHER CHANGE IS CURRENTLY IN STORE FOR THE LONG
TERM...AS THE JET PUSHES NORTHWARD AND USHERS IN A MUCH MORE
ACTIVE WEATHER PATTERN. CURRENTLY THE JET IS LOCATED IN THE NORTH
PACIFIC WELL TO THE SOUTH OF ALASKA. HOWEVER...BY DAY THREE THE
JET UNDULATES AND PUSHES INTO THE WESTERN BERING. MODELS INDICATE
THE SUBSEQUENT RAPID DEVELOPMENT OF A LOW PRESSURE SYSTEM THAT
WILL STRENGTHEN AND RUSH TOWARDS THE WESTERN COAST OF ALASKA BY
THE MIDDLE OF NEXT WEEK. THIS WILL USHER IN A MUCH WETTER PATTERN
FOR THE WESTERN MAINLAND...ALONG WITH GUSTY WINDS THROUGH GAPS AND
ALONG THE COAST. A FRONT ASSOCIATED WITH THIS LOW WILL THEN
LIKELY PUSH ACROSS THE SOUTHCENTRAL MAINLAND. WHILE THERE
CURRENTLY IS COPIOUS UNCERTAINTY IN THE INTENSITY AND TIMING OF
THE FRONT...IT IS LIKELY THAT AT LEAST A FEW SNOW SHOWERS WILL
IMPACT SOUTHCENTRAL BY NEXT THURSDAY EVENING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.

&&

$$

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


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