Area Forecast Discussion
Issued by NWS Anchorage, AK

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000
FXAK68 PAFC 251249
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
449 AM AKDT SAT OCT 25 2014

.ANALYSIS AND UPPER LEVELS...
THE PATTERN ALOFT CONTINUES TO BE ANCHORED BY A DEEP LOW PRESSURE
CENTERED OVER EASTERN RUSSIA. THE POLAR JET STREAM IS ZONALLY
ORIENTED FROM THE KAMCHATKA PENINSULA STRETCHING INTO THE BERING
SEA JUST OVER 100 KT. THE FLOW BECOMES MUCH MORE DIFLUENT TO THE
EAST OVER MAINLAND ALASKA WITH A COUPLE OF WEAK EMBEDDED
DISTURBANCES EVIDENT ON WATER VAPOR THIS MORNING. THE FIRST OF
WHICH BROUGHT FLURRIES AND LIGHT SNOW TO ANCHORAGE AND THE
MATANUSKA VALLEY...IS PROGRESSING INTO THE COPPER RIVER BASIN. A
STRONGER WAVE CURRENTLY RESIDES OVER THE CENTRAL BERING
SEA...PROGRESSING TOWARD THE SOUTHWEST MAINLAND.

A WEAK CIRCULATION IN THE LOW LEVELS SITS OVER THE NORTHERN GULF
KEEPING NUMEROUS SHOWERS IN THE AREA AS WELL AS PUMPING SOME
MOISTURE ALOFT OVER THE COPPER RIVER BASIN. THE COOK INLET REGION
IS SEEING DECREASING CLOUDINESS BEHIND THE DEPARTING TROUGH WITH
LIGHT WINDS AND SEASONABLE TEMPERATURES. LOW PRESSURE IN THE GULF
KEEPS AN ENHANCED SURFACE PRESSURE GRADIENT ALONG THE COASTAL
MOUNTAINS...FORCING SOME MODERATE STRENGTH "OUTFLOW" WINDS FROM
WESTERN PRINCE WILLIAM SOUND THROUGH THE NORTHEAST GULF COAST.

&&

.MODEL DISCUSSION...
GUIDANCE IS IN PRETTY GOOD AGREEMENT WITH THE UPCOMING SYNOPTIC
PATTERN. THE NEXT MAJOR FEATURE IN THE FLOW IS A SHORTWAVE TROUGH
UNDER THE JET IN THE BERING SEA. MODELS HAVE THIS FEATURE CROSSING
THE SOUTHWEST MAINLAND TODAY AND THE SOUTHERN MAINLAND EARLY
SUNDAY. MUCH LIKE THE LAST WAVE...GUIDANCE IS NOT VERY HOT ON THIS
ONE EITHER. THERE DOES APPEAR TO BE A STRONGER AREA OF LIFT
ASSOCIATED WITH THIS WAVE PASSING OVER THE SOUTHERN EDGE OF THE
KENAI PENINSULA BUT MOISTURE APPEARS LACKING AND THERE IS NOT A
WHOLE LOT GOING ON IN THE LOW LEVELS TO ACCOMPANY THIS FEATURE SO
THE LACK OF SIMULATED PRECIPITATION IS NOT SURPRISING. BOTH
DOMAINS PREFERRED A TRANSITION FROM THE 00Z NORTH AMERICAN MODEL
TO THE 00Z EUROPEAN MODEL.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...LOWER CLOUDS WILL BE DECREASING TODAY AS THE
UPPER TROUGH MOVES OFF AND DRIER AIR FILTERS INTO THE
COOK INLET REGION. HIGHER CLOUDS WILL STREAM INTO THE
SOUTHCENTRAL TODAY BUT MOST OF THE REGION WILL SEE SOME GOOD
SUNSHINE TO GO ALONG WITH SEASONABLE TEMPERATURES AND LIGHT WINDS.
LIGHT SNOW WILL LINGER OVER THE COPPER RIVER BASIN TODAY AND INTO
SUNDAY AS THE NEXT TROUGH KEEPS THE AREA UNDER FAVORABLE DYNAMICS.
RAIN SHOWERS WILL CONTINUE ALONG THE NORTHERN GULF AS THE LOW
LEVEL CIRCULATION THAT IS IN PLACE WILL LINGER THROUGH SUNDAY
BEFORE MOVING AWAY. GUSTY WINDS WILL REMAIN ALONG THE NORTH GULF
COAST THROUGH THE WEEKEND.

SOUTHWEST ALASKA...A QUICK MOVING DISTURBANCE ALOFT WILL TRAVERSE
THE MAINLAND TODAY BRINGING A QUICK SHOT OF RAIN AND SNOW ALONG
THE KUSKOKWIM DELTA COAST WITH SNOW INLAND. AN ABOVE FREEZING
LAYER JUST OFF THE SURFACE COULD PROMOTE SOME SLEET OR FREEZING
RAIN PROVIDED SURFACE TEMPERATURES STAY COLD ENOUGH. THIS
DISTURBANCE WILL WEAKEN AS IT MOVES EASTWARD OVERNIGHT BRINGING
LIGHT SNOW TO THE LOWER KUSKOKWIM VALLEY AND INTERIOR BRISTOL
BAY. THE ACTIVE PATTERN CONTINUES ON SUNDAY WHEN ANOTHER FRONT
COMES ASHORE THE DELTA BRINGING MORE RAIN AND SNOW.

BERING SEA/ALEUTIANS...A SMALL LINGERING LOW PRESSURE KEEPS SOME
SHOWERS IN THE FORECAST FOR THE EASTERN ALEUTIANS AND ALASKA
PENINSULA THIS MORNING. WINDS WILL LIGHTEN UP OVERNIGHT WITH THE
CHANCE FOR PATCHY FOG. A DEVELOPING SYSTEM IN THE WESTERN BERING
WILL STRENGTHEN WINDS FROM WEST TO EAST THROUGH THE WEEKEND WHILE
A FRONTAL BOUNDARY TRAVERSES THE BERING SEA BRINGING A PERIOD OF
RAIN AND SNOW.


&&

.LONG TERM FORECAST...
WHILE MODEL AGREEMENT BEYOND EARLY NEXT WEEK REMAINS QUITE POOR...THERE
HAVE BEEN SOME SMALL IMPROVEMENT IN THE MODELS SINCE YESTERDAY.
THERE IS NOW GOOD AGREEMENT THAT REMAIN THE REMNANTS OF TROPICAL
STORM ANA MOVE ONSHORE SOUTH OF THE PANHANDLE...WELL SOUTH AND
EAST OF OUR AOR. THE WEAK LOW THAT WILL FORM BEHIND THIS SYSTEM
WILL ALSO QUICKLY DIVE SOUTHWARD INTO THE NORTH PACIFIC TUESDAY-
WEDNESDAY...KEEPING PRECIPITATION CONFIDED TO THE GULF COAST AND
WESTERN BERING THROUGH WEDNESDAY.

BECAUSE OF THE POOR MODEL AGREEMENT WITH LOW LOCATION...THE LONG
TERM FORECAST ONCE AGAIN HEAVILY USED WPC GUIDANCE TODAY (WHICH
USED MOSTLY ENSEMBLES AND THE 00Z EC THROUGH TUESDAY).


&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 177 178 181 185.
FIRE WEATHER...NONE. &&

$$

MTL OCT 14



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