Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 231329
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
529 AM AKDT THU APR 23 2015

.ANALYSIS AND UPPER LEVELS...
THE DOMINANT FEATURE ON WATER VAPOR SATELLITE THIS MORNING IS A
MATURE UPPER LEVEL LOW THAT ENCOMPASSES MOST OF THE BERING SEA.
THE OCCLUDED FRONT ASSOCIATED WITH THIS SYSTEM ARCS ACROSS THE
NORTHERN BERING SEA BEFORE TURNING SOUTHWARD FROM THE KUSKOKWIM
DELTA THROUGH BRISTOL BAY. THIS SYSTEM APPEARS TO BE QUICKLY
WEAKENING AS THE UPPER LEVEL JET IS ZONALLY ORIENTED AND SOUTH OF
THE CHAIN. THE FRONT IS BRINGING LIGHT SNOW TO THE KUSKOKWIM DELTA
ALONG WITH SOME AREAS OF BLOWING SNOW ALONG THE COAST. A MORE
SHOWERY REGIME EXISTS OVER THE BERING UNDER THE UPPER LOW. OVER
THE SOUTHCENTRAL MAINLAND...SLACK FLOW ALOFT MAKES FOR UNEXCITING
WEATHER AS THE AREA RESIDES BETWEEN THE DEPARTING GULF SYSTEM AND
THE INCOMING WEAK FRONT.

&&

.MODEL DISCUSSION...
MODELS REMAIN IN EXCELLENT AGREEMENT WITH THE SYNOPTIC FEATURES
THROUGH THE SHORT TERM. THERE IS GOOD MODEL CONSENSUS ON THE MAIN
FRONT INTERACTING WITH A BOUNDARY ALREADY IN PLACE OVER THE
BRISTOL BAY AREA WHICH WILL SERVE TO ENHANCE SHOWER ACTIVITY
TODAY. NO REAL DISCREPANCY SHOWS UP UNTIL THIS WEEKEND WHEN THE
CURRENT BERING SYSTEM TAPS SOME ENERGY SOUTH OF THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
BENIGN AND PLEASANT CONDITIONS WILL PREVAIL ACROSS SOUTHCENTRAL
AK INTO THE WEEKEND AS THE DEPARTING LOW OVER THE SOUTHERN GULF
USHERS IN A CLEARING AND DRYING TREND WITH TEMPERATURES NEAR TO
ABOVE NORMAL AND GENERALLY LIGHT WINDS. A WEAK FRONT ASSOCIATED
WITH A BERING SEA LOW WILL BEGIN TO MOVE OVER KODIAK ISLAND TODAY
AND KEEP RAIN OVER THE WESTERN GULF THROUGH FRIDAY NIGHT. ANY
IMPACTS FROM THIS FRONT OVER THE MAINLAND WILL GENERALLY BE
LIMITED TO INCREASING MID/HIGH LEVEL CLOUDS THROUGH FRIDAY...WITH
OCCASIONAL RAIN CLIPPING THE SOUTHERN KENAI PENINSULA TONIGHT
THROUGH FRIDAY NIGHT.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2...THU AND
FRI)...THE FRONT IS FALLING APART ACROSS THE WEST COAST THIS
MORNING. IT BROUGHT BOUTS OF HEAVIER SNOW AND GUSTY SOUTHERLY
WINDS TO MOST COASTAL LOCATIONS. BUT THOSE WINDS ALSO HELPED TO
KEEP TEMPERATURES WARM ENOUGH TO LIMIT MUCH SNOW FROM BLOWING.
THUS...THE ADVISORY FOR THE DELTA COAST IS CANCELLED. AS THE FRONT
SLOWLY WORKS ITS WAY INLAND...SOUTHWEST WINDS ARE MEETING SOME
SOUTHEAST WINDS FARTHER TO THE EAST TO CREATE A FAIRLY BROAD AREA
OF LOW LEVEL CONVERGENCE. RADAR HAS BLOSSOMED OVER THE PAST FEW
HOUR JUST WEST OF KING SALMON EXTENDING ALL THE WAY NORTH TO ST
MARY. THE WARM AIR ASSOCIATED WITH THIS SYSTEM HAS TURNED JUST
ABOUT ALL OF THE PRECIPITATION OVER TO A MIX OF RAIN AND SNOW...IF
NOT ALL RAIN. THE BAND SHOULD DRIFT SLOWLY TO THE EAST THROUGH THE
DAY AS MORE SHOWERS PUSH INLAND OVER THE COAST. INTO FRIDAY...THE
FRONT WILL CONTINUE TO DISSIPATE OVER THE ENTIRE AREA. THIS WILL
MAKE FOR WIDESPREAD RAIN SHOWERS...POSSIBLY MIXING WITH SOME SNOW
ALONG THE COAST AND DURING THE COLDER OVERNIGHT HOURS.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2...THU AND
FRI)...THE FRONT HAS PUSHED ALL THE WAY THROUGH THE AREA. NOW WE
WILL HAVE TO CONTEND WITH THE VERTICALLY STACKED LOW ITSELF
TRACKING SLOWLY TO THE EAST-SOUTHEAST. MINIMUM GALE FORCE WINDS ON
THE SOUTH SIDE OF THE LOW WILL MOVE FROM THE WESTERN ALEUTIANS TO
THE CENTRAL ALEUTIANS THROUGH THE DAY. RAIN AND SNOW SHOWERS WILL
ALSO ACCOMPANY THE LOW. AS SOME COLDER AIR STARTS TO WORK INTO THE
WESTERN ALEUTIANS LATE TONIGHT AND INTO FRIDAY...THIS SHOULD LEAD
TO ANOTHER ROUND OF SNOW SHOWERS..ESPECIALLY ON THE BERING SIDE OF
THE CHAIN. THIS COLDER AIR WILL ALSO TIGHTEN THE GRADIENT AND
BRING JUST ENOUGH MIXING THAT ANOTHER ROUND OF GALE FORCE WINDS
WILL WORK THROUGH THE CENTRAL ISLANDS BY FRIDAY NIGHT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE UPPER LEVEL CLOSED LOW WILL BE POSITIONED SOUTH OF THE
EASTERN ALEUTIANS BY SATURDAY. AS THIS SYNOPTIC FEATURE MOVES
EASTWARD IT CONSOLIDATES WITH ANOTHER UPPER LEVEL LOW INTO THE
LOWER GULF BY SUNDAY AND BECOMES ELONGATED BY TUESDAY AS IT
STRETCHES INTO THE NORTHERN GULF THROUGH WEDNESDAY. THIS GALE
FORCE LOW WILL BRING STRONG EAST TO SOUTHEASTERLY WINDS TO THE
NORTHERN GULF AS THE SURFACE LOW MOVES INTO THE LOWER CENTRAL GULF
BY SUNDAY. THIS SYSTEM WILL REMAIN IN THE GULF AS IT GRADUALLY
FILLS AND DISSIPATES GOING INTO THE MIDDLE OF NEXT WEEK. LOOK FOR
WARMER TEMPERATURES WITH THE WARM AIR ADVECTION AND ACCOMPANIED BY
A LARGE SWATH OF MOISTURE WITH WETTING RAINS FOR THE COASTAL
AREAS. THE SOUTHCENTRAL INLAND AREAS WILL HAVE DRIER CONDITIONS
WITH A FEW ISOLATED SHOWERS SPILLING OVER THE CHUGACH AND KENAI
MOUNTAINS OVER THE WEEKEND HEADING INTO THE EARLY PART OF NEXT
WEEK.

THE CENTRAL BERING SEA WILL HAVE A RIDGE OF HIGH PRESSURE MOVING IN
BY SATURDAY WITH GUSTY NORTHWESTERLY WINDS DOWNSTREAM OVER THE
EASTERN ALEUTIANS. THIS RIDGE WILL BE REPLACED BY A KAMCHATKA LOW
DROPPING DOWN INTO THE WESTERN ALEUTIANS BY SUNDAY. THE MODELS
ARE STRUGGLING WITH THIS FEATURES AS IT MOVES ACROSS THE BERING
SEA...BY MONDAY THIS SYSTEM DIMINISHES TO BECOME A TROUGH
RESULTING IN SOUTHWESTERLY WINDS THROUGH THE MIDWEEK IN THE BERING
SEA. THE FORECAST CONFIDENCE IS AVERAGE HEADING INTO THE WEEKEND
BUT BEGINS TO WEAKEN AS WE HEAD INTO NEXT WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING...174 175 176 177 178.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MO
LONG TERM...PLD



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