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000
FXAK68 PAFC 141306
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
506 AM AKDT MON APR 14 2014

.ANALYSIS AND UPPER LEVELS...
MID-LEVEL CLOUDINESS IS ALL THAT REMAINS OF THE PREVIOUS SYSTEM
FOR MUCH OF THE SOUTHCENTRAL. THE REMNANTS OF THE FRONT AND UPPER
LEVEL TROUGH ARE SITTING OVER THE NORTH GULF COAST WHERE A COMPACT
LOW LEVEL CIRCULATION IS EVIDENT ON RADAR AND SATELLITE WITH AREAS
OF LIGHT RAIN. THE NEXT SYSTEM IS MOVING INTO THE SOUTHWESTERN
GULF AND LOOKS TO BE PAST PEAK INTENSITY AS THE OCCLUSION IS
WRAPPED AROUND THE CENTER AND THE SYSTEM IS ELONGATING AS THE JET
LIES TO THE SOUTH AND RIDGING IS BUILDING IN BEHIND IT OVER THE
EASTERN ALEUTIANS/BERING SEA. A LARGE COMPLEX LOW SITS OVER THE
WESTERN BERING SEA WITH HIGH AMPLITUDE FLOW ON EITHER SIDE OF THE
UPPER LOW PRESSURE.

&&

.MODEL DISCUSSION...
GUIDANCE REMAINS IN GOOD AGREEMENT WITH THE EVOLUTION OF UPPER
LEVEL FEATURES. MODELS ARE SHOWING THE BERING SEA SYSTEM MERGING
INTO ONE LARGE LOW CENTER WHILE A WEAKER CIRCULATION SITS IN THE
GULF. BOTH SYSTEMS LACK THE JET SUPPORT NEEDED FOR FURTHER
DEVELOPMENT SO THEY WILL STAGNATE OVER THE NEXT COUPLE DAYS. THE
ONE FACET GUIDANCE IS NOT HANDLING THE GREATEST IS THE MESO-
CIRCULATIONS IN THE GULF OF ALASKA. SEVERAL LOBES OF SHEAR
VORTICITY ARE EVIDENT ON WATER VAPOR WITH WEAK CIRCULATIONS OR
INVERTED TROUGHS AT THE SURFACE THAT ARE TOO SMALL FOR EVEN HIGH
RESOLUTION GUIDANCE TO ACCURATELY DEPICT. FORECAST CONFIDENCE IS
AVERAGE FOR THIS PACKAGE.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...SKIES SHOULD REMAIN CLEAR FOR THE COOK INLET
REGION THIS MORNING MAKING FOR A PLEASANT DAY. AS FLOW IN THE GULF
BEGINS TO SHIFT FROM THE EAST SOME MID LEVEL CLOUDS WILL BEGIN TO
FILTER IN FOLLOWED BY A CHANCE FOR LIGHT RAIN AND SNOW SHOWERS
TUESDAY MORNING WITH THE BEST CHANCES ALONG THE NORTH GULF COAST.
LIGHT RAIN WILL CONTINUE THROUGH THE LATE MORNING ALONG THE NORTH
GULF COAST BEFORE A BREAK IN THE AFTERNOON. NO MAJOR SYSTEMS OR
FRONTS WILL AFFECT THE SOUTHCENTRAL IN THE SHORT TERM BUT ONSHORE
FLOW ALONG WESTERN PRINCE WILLIAM SOUND WILL KEEP PRECIPITATION IN
THE FORECAST WITH MID-LEVEL CLOUDS ELSEWHERE WITH SEASONABLE
TEMPERATURES.

SOUTHWEST ALASKA...
AN UPPER LEVEL MINOR TROUGH LOCATED OVER SAINT MATTHEW ISLAND
EXTENDING TO THE NUNIVAK ISLAND WILL TRACK TO THE BERING STRAIT BY
THIS AFTERNOON. THIS WILL BRING A PERIOD OF RAIN/SNOW SHOWERS
FROM THE KUSKOKWIM BAY NORTHWARD THROUGH THE AFTERNOON. THE REST
OF SOUTHWEST ALASKA WILL BE UNDER THE INFLUENCE OF AN UPPER LEVEL
RIDGE THROUGH MON EVENING. BY TUESDAY MORNING A NORTH PACIFIC LOW
WILL BE LOCATED SOUTHWEST OF THE PRIBILOF ISLANDS BRINGING
SOUTHEASTERLY FLOW WITH A FRONTAL BOUNDARY ALONG THE SOUTHWEST
ALASKA COASTLINE. THIS WILL BRING WARMER TEMPERATURES WITH A LARGE
SWATH OF MOISTURE TO THE COASTLINE BEFORE TRACKING INLAND.


BERING SEA/ALEUTIANS...
THE WEAK SURFACE LOW WEST OF THE NUNIVAK ISLAND WEAKENS INTO A
TROUGH AS IT TRACKS TOWARDS THE BERING STRAIT BY MONDAY EVENING.
THIS WILL BRING SHOWERY PRECIPITATION FROM THE KUSKOKWIM BAY
THROUGH SAINT LAWRENCE ISLAND THIS AFTERNOON. A NORTH PACIFIC LOW
PRESSURE SYSTEM WILL BE POSITIONED BETWEEN ADAK AND ATKA BY MONDAY
AFTERNOON. THE PRESSURE GRADIENT WILL INCREASE CAUSING GALE FORCE
WINDS ALONG THE CENTRAL/EASTERN ALEUTIANS SPREADING INTO THE
EASTERN BERING SEA TOWARDS THE PRIBILOF ISLANDS. THERE WILL BE A
FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW PRESSURE SYSTEM BRINGING
WARMER TEMPERATURES GOING INTO TUESDAY MORNING. BY TUESDAY THE
CENTRAL/WESTERN ALEUTIANS AND WESTERN BERING SEA WILL BE ON THE
BACKSIDE OF THE LOW PRESSURE WITH COOLER TEMPERATURES ACCOMPANIED
BY SHOWERY PRECIPITATION. THIS NORTH PACIFIC LOW WILL BECOME
STATIONARY JUST WEST OF THE PRIBILOF ISLANDS THROUGH THURSDAY
BEFORE DISSIPATING. THIS LOW WILL CONTINUE TO PRODUCE SHOWERY
PRECIPITATION THROUGH THURSDAY.

&&

.LONG TERM FORECAST...
THE CONDITIONS LOOK TO BE STABLE STARTING BY FRIDAY GOING THROUGH
THE WEEKEND. THE SOUTHCENTRAL ALASKA WILL BE INFLUENCED BY AN
UPPER LEVEL RIDGE EXCEPT FOR A NORTH PACIFIC LOW OVER THE FAR
SOUTHEASTERN GULF. THIS WILL PRODUCE EASTERLY FLOW ALONG THE
NORTHERN GULF COASTLINES WITH THE CHANCE FOR SHOWERS AS THE NORTH
PACIFIC LOW FILLS AND EVENTUALLY DISSIPATES. THE SOUTHWEST
ALASKA WILL HAVE OFFSHORE FLOW WITH THE BERING AND ALEUTIAN CHAIN
HAVING NORTHEASTERLY FLOW. THE EASTERN BERING SEA WILL HAVE A
WEAK TROUGH GENERATING SHOWERY PRECIPITATION WITH STRATUS BY END
OF THIS WEEK THROUGH THE WEEKEND.

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 174 176.
FIRE WEATHER...NONE.
&&

$$

MTL/PD APR 14