Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 241247
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
447 AM AKDT SUN AUG 24 2014

.ANALYSIS AND UPPER LEVELS...
THE LARGE UPPER LOW CENTERED OVER THE CENTRAL BERING SEA CONTINUES
TO BE THE DOMINANT FEATURE ALOFT THIS MORNING. THE STACKED SYSTEM
IS WELL OCCLUDED AND INTO THE WEAKENING STAGE OF ITS LIFECYCLE.
THE OCCLUDED FRONT STRETCHES EASTWARD ACROSS THE ALASKA
RANGE/ALEUTIAN RANGE INTERFACE WHERE A WEAK TRIPLE POINT
CIRCULATION EXISTS IN THE VICINITY OF KODIAK ISLAND. THE WARM
FRONT IS BEGINNING TO REALLY SHOW UP ON THE MIDDLETON ISLAND
NEXRAD AS A SOLID AREA OF STRATIFORM PRECIPITATION IN THE CENTRAL
GULF. MASS BUILDUP AHEAD OF THE FRONT IS INCREASING GAP WINDS
ALONG TURNAGAIN ARM AND AREAS OF LIGHT RAIN ARE TRYING TO MAKE IT
OVER THE CHUGACH DESPITE WEAK DOWNSLOPE FLOW.

&&

.MODEL DISCUSSION...
GUIDANCE REMAINS LOCKED IN WITH THE CURRENT PATTERN WITH ALL
MODELS IN GREAT AGREEMENT WITH THE EVOLUTION OF THE LARGE SCALE
PATTERN. THE UPPER LOW IN THE BERING WILL DRIFT EAST AND ELONGATE
AS THE UPPER JET MAX SITS DOWNSTREAM. AS FAR AS THE FRONT IS
CONCERNED THE ONLY DIFFERENCE REMAIN IN THE STRENGTH OF
DOWNSLOPE FLOW AND AMOUNT OF PRECIPITATION COMING OVER THE
MOUNTAINS. THE GEM REGIONAL WAS FAVORED EARLY ON FOR BOTH DOMAINS
AND THE GFS/EC FOR THE LATTER PORTION OF THE SHORT TERM FORECAST.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...A WARM/OCCLUDED FRONT PUSHING TOWARD THE
NORTH GULF COAST WILL CONTINUE TO SPREAD RAIN INLAND TODAY.
EASTERLY WINDS IN THE LOW/MID LEVELS WILL TAKE SOME PUNCH OUT OF
THE PRECIPITATION IN THE COOK INLET REGION BUT SOUTHERLY FLOW
ALOFT SHOULD HELP THE MOISTURE OVERCOME DOWNSLOPE. IN THE
ANCHORAGE AREA PRECIPITATION WILL CHANGE FROM SHOWERY IN NATURE
TO WIDESPREAD RAIN BY THE AFTERNOON THEN RETURN TO SHOWERS ONCE
THE FRONT PASSES IN THE EVENING. OVERNIGHT...A DISTURBANCE
ROTATING AROUND THE UPPER TROUGH WILL BRING ANOTHER SHOT OF RAIN
TO THE COOK INLET REGION. MONDAY AND TUESDAY...COLD AIR ALOFT FROM
THE UPPER LOW CENTER WILL KEEP SHOWERS IN THE
FORECAST...ESPECIALLY ALONG HIGHER TERRAIN.

SOUTHWEST ALASKA...RAIN WILL CONTINUE TO INCREASE IN INTENSITY AND
COVERAGE THIS MORNING ACROSS INTERIOR BRISTOL BAY AND THE LOWER
KUSKOKWIM VALLEY. THE KUSKOKWIM DELTA WILL REMAIN MORE SHOWERY
WITH SOME HEAVIER PRECIPITATION COMING OFF THE KILBUCKS IN THE
AFTERNOON. AS THE UPPER LOW DRIFTS CLOSER RAIN WILL TURN TO
SHOWERS WITH THE CHANCE FOR THUNDERSTORMS IN THE AFTERNOON AND
EVENING ON MONDAY.

BERING SEA/ALEUTIANS...THE UPPER LOW WILL WEAKEN SUBSTANTIALLY
TODAY AND MOVE TO THE EAST. THE ALASKA PENINSULA WILL SEE THE
BRUNT OF THE SHOWERS ASSOCIATED WITH THE UPPER TROUGH AS IT MOVES
EASTWARD. BEHIND THE SYSTEM...GUSTY NORTHWESTERLY WINDS WILL TAKE
HOLD. A WEAK LOW PRESSURE SYSTEM WILL SKIRT THE CHAIN EARLY NEXT
WEEK.

&&

.LONG TERM FORECAST...
AN UPPER LEVEL WEAK RIDGE WILL BRIEFLY BRINGING DRIER CONDITIONS
FOR WEDNESDAY FOR SOUTHEAST MAINLAND. BY THURSDAY SEVERAL UPPER
LEVEL WEAK SHORTWAVES WILL TRACK THROUGH THE REGION KICKING OFF
SCATTERED SHOWERS. AN UPPER LEVEL TROUGH DROPS DOWN FROM THE
NORTH AND COMBINING WITH A LOW PRESSURE SYSTEM ENTERING THE
BRISTOL BAY AREA WILL BRING MORE CLOUDS AND SHOWERS TO THE REGION
GOING INTO NEXT WEEKEND. THE BERING SEA WILL HAVE A LOW PRESSURE
SYSTEM APPROACHING THE WESTERN ALEUTIANS BY WEDNESDAY. THE FRONTAL
BOUNDARY ASSOCIATED WITH THIS LOW WILL BE POSITIONED THROUGH THE
WESTERN ALEUTIANS. THIS LOW WILL TRACK THROUGH THE BERING SEA AND
REACH THE SOUTHWEST ALASKA COASTLINE BY FRIDAY NIGHT. THIS SYSTEM
WILL BRING WIDESPREAD RAIN WITH STRATUS AND FOG GOING INTO NEXT
WEEKEND.


&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 131.
FIRE WEATHER...NONE. &&

$$

MTL
AUG 14


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