Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 222121
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
121 PM AKDT TUE APR 22 2014

ANALYSIS AND UPPER LEVELS...
HIGH PRESSURE WITH ACCOMPANYING SUBSIDENCE INVERSIONS SETTLED
OVER THE MAINLAND OVERNIGHT. GENERALLY FAIR SKIES WITH LOCALIZED
AREAS OF FOG WERE EVIDENT THIS MORNING ESPECIALLY OVER THE NORTH
GULF COAST. A WEAKENING OCCLUDED FRONT EXTENDED SOUTH ACROSS THE
EASTERN BERING SEA TO WELL SOUTH OF THE AK PEN. THERE WERE SOME
AREAS OF LIGHT RAIN AND GUSTY SOUTHEAST WINDS ASSOCIATED WITH THIS
FEATURE OVER THE AK PEN. DRY CONDITIONS WITH BRISK SOUTH TO EAST
WINDS WERE OBSERVED OVER THE DELTA AND BRISTOL BAY ZONES. A COUPLE
OF WEAK LOWS JUST NORTH OF THE ALEUTIANS WERE PRODUCING RAIN AND
SNOW SHOWERS AND GUSTY WINDS ACROSS THE CHAIN.

MODEL DISCUSSION...
THE GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT AND REASONABLE ON
SYNOPTIC SCALE FEATURES THROUGH THE SHORT TERM. THE GFS AND
ESPECIALLY THE NAM ARE INDICATING INCREASED POTENTIAL FOR
AFTERNOON AND EVENING CONVECTION OVER INTERIOR SW AND SOUTHCENTRAL
ALASKA MID TO LATE THIS WEEK.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
SUBSIDENCE ACROSS SOUTHCENTRAL WILL WEAKEN OVER THE NEXT COUPLE OF
DAYS AS THE UPPER RIDGE MOVES NORTH AND WEST. WESTERLY MOVING SHORT
WAVES COMING OUT OF CANADA AND COOLING TEMPS ALOFT WILL INCREASE
THE INSTABILITY ACROSS THE REGION AND KICK OFF SHOWERS THROUGH
FRI. THUNDERSTORM POTENTIAL EXISTS ALONG THE ALASKA RANGE IN THE
COPPER RIVER BASIN AND TALKEETNA MOUNTAINS. CONDITIONS BECOME
MORE FAVORABLE FOR AFTERNOON AND EVENING CONVECTION THU AND FRI.
COASTAL STRATUS AND FOG LOOKS LIKELY AGAIN TONIGHT AND WED
NIGHT...WITH SOME INTRUSION INTO COOK INLET WITH A WEAK SOUTH
PUSH FROM THE RIDGE IN THE GULF. KODIAK ISLAND WILL HAVE A BREAK
OVER THE NEXT DAY OR SO FROM STEADY RAINS UNTIL NEXT FRONTAL
SYSTEM APPROACHES FROM THE SOUTH ON FRI.

SOUTHWEST ALASKA...
RIDGING OVER SW ALASKA WILL SUPPRESS INTERIOR CONVECTION AND HOLD
THE WEAKENING FRONT OVER THE EASTERN BERING SEA AT BAY KEEPING
COASTAL REGIONS ON THE DRY SIDE THROUGH WED. AFTERNOON AND EVENING
CONVECTION BECOMES MORE PROMISING THU AND FRI AS THE UPPER RIDGE
TRACKS NORTH AND WEAK TRIGGERING WAVES MOVE IN FROM THE EAST.
SO THINKING THAT ISOLATED THUNDERSTORMS BECOME A REAL POSSIBILITY
OVER THE INTERIOR WITH SHOWERS ELSEWHERE.

WINDS ALONG THE COASTAL ZONES SHOULD REMAIN BRISK THROUGH EARLY
WED BEFORE DIMINISHING.

BERING SEA/ALEUTIANS... THE LOW IN THE BERING WILL SPIN
ESSENTIALLY IN PLACE THROUGH WED...WITH SHOWERS AND PATCHY FOG
ACROSS THE ENTIRE REGION...AND GALE FORCE WIND OVER THE WESTERN
ALEUTIANS. WED NIGHT THE NORTH PACIFIC LOW ARRIVES WITH RAIN
SPREADING ALONG THE ALEUTIANS THROUGH FRI. AS THE LOW HEADS INTO
THE GULF OF ALASKA...IMPULSES MOVING AROUND THE NORTHERN FLANK
WILL ALSO KEEP RAIN AND SNOW SHOWERS OVER THE BERING THROUGH THE
END OF THE WEEK.

LONG TERM FORECAST...
THE EC...GFS...AND WPC ARE IN DECENT AGREEMENT THROUGH
SATURDAY...CONTINUING THE EASTWARD MOVEMENT OF THE ALEUTIAN LOW
INTO THE SOUTHERN GULF OF ALASKA. AT THAT POINT AGREEMENT ENDS
WITH COMPLEX SOLUTIONS TO THE GULF LOW...AND EITHER A KAMCHATKA
LOW...OR A RIDGE DOMINATING THE WESTERN BERING. THE FORECAST
UTILIZES THE GFS THROUGH SAT...AND THEN DEFERS TO WPC AND ITS
WIDER ARRAY OF MODELS. THIS MAINTAINS A WEAKENING LOW IN THE
SOUTHERN GULF...AND A KAMCHATKA LOW ON SUN THAT DIVES TO THE
CENTRAL ALEUTIANS BY TUE. THE RESULT IS RAIN ON THE AKPEN AND
KODIAK ISLAND THROUGH THE WEEKEND...WITH WIND AND A MIX OF RAIN
AND SNOW FOR THE WESTERN BERING AND ALEUTIANS EARLY NEXT WEEK. THE
REST OF THE FORECAST AREA WILL BE DRY.
BERING SEA/ALEUTIANS...

AFC WATCHES/WARNINGS/ADVISORIES...

PUBLIC...NONE
MARINE...GALE WARNING 177 178
FIRE WEATHER...NONE

$$

RMC APR 14



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