Gale Warning 524, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT SAT SEP 7 2013

.MODEL DISCUSSION...
MODELS ARE IN RELATIVELY GOOD SYNOPTIC AGREEMENT THROUGH THE SHORT
TERM. THE GFS THOUGH IS A LITTLE MORE AGGRESSIVE ON THE PRESSURE WITH
THE LOW CENTER HEADING TO THE E GULF TONIGHT. SATELLITE IMAGERY WOULD
SUPPORT THE MORE AGGRESSIVE GFS SOLUTION. MODELS ARE IN GENERAL
AGREEMENT IN THE QPF PRECIPITATION PATTERN...THOUGH THE ECMWF/GFS
"BROAD BRUSH" THE VALUES ACROSS SOUTHCENTRAL WITH THE LOW APPROACHING
THE EASTERN GULF COAST TONIGHT.

.ANALYSIS AND UPPER LEVELS...

UPPER LEVELS...THIS MORNINGS WATER VAPOR IMAGERY INDICATES THAT THE
DEEP SOUTHERLY FETCH OF MOISTURE HAS SHIFTED TO THE EASTERN GULF. THE
LOW OVER THE COOK INLET REGION OVERNIGHT IS MOVING NORTH AND
WEAKENING. A DEVELOPING LOW SOUTH OF THE GULF IS MOVING RAPIDLY
NORTH. THE A WEAK CENTER IS LOCATED OVER BRISTOL BAY WITH A MORE
PROMINENT LOW CENTER NEAR THE WESTERN  ALEUTIANS.

THE WAVE SOUTH OF THE GULF WILL MOVE RAPIDLY NORTH TONIGHT TO OVER
THE YUKON TERRITORY SUN AFTERNOON. THE BRUNT OF THE ENERGY IMPACTS SE
ALASKA AND THE EASTER GULF COAST...AND TO A LESSER EXTENT THE WESTERN
GULF AND COPPER RIVER BASIN. THE UPPER CENTER OVER BRISTOL BAY WILL
DRIFT NE THROUGH SUN AND UNDERGO LITTLE CHANGE IN INTENSITY. THE
CENTER NEAR THE WESTERN ALEUTIANS MOVES RAPIDLY EAST TO SOUTH OF THE
AK PEN LATE SUN SETTING UP BROAD SOUTHERLY TO SE FLOW OVER THE
GULF/SOUTHCENTRAL. A HIGH AMPLITUDE RIDGE BUILDS ACROSS THE BERING
SEA IN THE WAKE OF THIS CENTER.

.SURFACE
RAIN HAS TAPERED OFF ACROSS MUCH OF THE NORTH GULF COAST AND
SOUTHCENTRAL ALASKA THIS AFTERNOON. ANOTHER BATCH OF RAIN...THOUGH
NOT NEARLY AS HEAVY...IS EXPECTED TO SPREAD TO THE GULF COAST LATER
TODAY AND INTO THE COPPER RIVER BASIN OVERNIGHT. A WEAK LOW OVER THE
COPPER RIVER BASIN WEAKENS AND WILL DRIFT SLOWLY NW THROUGH SUNDAY. A
980S LOW SOUTH OF THE WESTERN ALEUTIANS MOVES EAST UNDER THE UPPER
CENTER TO SOUTH OF THE AK PEN SUN NIGHT AND MONDAY AND WEAKENS.

.SHORT TERM FORECAST...

.SOUTHCENTRAL ALASKA...
A DEVELOPING LOW SOUTH OF THE GULF MOVES TO THE EASTERN GULF TONIGHT
AND INTO THE YUKON TERRITORY SUN. THIS CENTER WILL BRING RENEWED
RAINS TO THE NORTH GULF AND A FRESH BATCH TO THE COPPER RIVER BASIN
TONIGHT AND SUN. RAIN SHOULD DIMINISH ACROSS THE NORTH GULF ON SUN
AFTERNOON AND OVER THE COPPER RIVER BASIN SUN EVENING AS THE LOW
CONTINUES TO TRACK NORTH. A LOW MOVING SOUTH OF THE AK PEN WILL BRING
GALES TO THE WESTERN GULF SUN NIGHT. GALES WILL LIKELY SPREAD ACROSS
THE GULF THROUGH MON. STRONG GAPS FLOWS ARE EXPECTED TO DEVELOP
ACROSS SOUTHCENTRAL...ESPECIALLY IN FAVORED AREAS OF 101 AND 125
THROUGH MON.

.SOUTHWEST ALASKA...FEW AREAS OF INSTABILITY REMAIN OVER SOUTHWEST
ALASKA WHICH CONTINUE TO BRING SHOWERS TO THE AREA THROUGHOUT THE DAY
TODAY AND INTO THE WEEKEND. A NEW LOW PUSHES INTO THE ALASKA
PENINSULA SUNDAY AFTERNOON AND WILL BRING STEADIER PRECIPITATION
AND GUSTY GAP WINDS THROUGH MONDAY AFTERNOON.

.BERING SEA AND ALEUTIANS...LOW PRESSURE TRACKING SOUTH OF THE
ALEUTIAN CHAIN CONTINUES TO DEEPEN TODAY AND PRODUCE STRONG WINDS AND
STEADY PRECIPITATION FOR THE CENTRAL AND EASTERN ALEUTIANS THROUGH
SUNDAY AFTERNOON. WINDS WILL BEGIN TO DIMINISH AS THE LOW WEAKENS AND
TRACKS INTO THE ALASKA PENINSULA MONDAY AFTERNOON. HIGH PRESSURE WILL
THEN BEGIN TO BUILD OVER THE WESTERN ALEUTIANS LATE SUNDAY NIGHT.

.LONG TERM FORECAST...
LATE IN THE WEEK THE PATTERN WILL BECOME MORE AMPLIFIED WITH RIDGING
BUILDING IN OVER THE BERING AND ALEUTIANS. OVER MAINLAND ALASKA A
BROAD UPPER LEVEL LOW WILL MOVE ACROSS THE STATE FROM NORTH TO SOUTH
BRINGING AREAS OF PRECIPITATION WITH IT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 130 AND 138 150 155 172 170 175.
FIRE WEATHER...NONE.

RMC/TP SEP 13