Small Craft Advisory 99, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKST WED JAN 28 2009

.MODEL DISCUSSION...
THE MODELS ARE IN FAIRLY GOOD AGREEMENT OVER MAINLAND ALASKA AND IN
THE GULF THROUGH FRIDAY NIGHT, BUT THE MODEL SOLUTIONS BEGIN TO
RADICALLY DIVERGE AROUND THE ALEUTIANS AROUND FRIDAY MORNING. CURRENT
HPC GUIDANCE TENDS TO LEAN TOWARD THE EUROPEAN SOLUTION IN THE MID
TERM THOUGH THERE IS SOME UNCERTAINLY BECAUSE THE MODELS HAVE NOT
BEEN CONSISTENT IN THE LAST FEW RUNS.

.ANALYSIS AND UPPER LEVELS...
THE MAIN UPPER LOW OVER NORTHWEST CANADA CONTINUES TO MOVE EAST. THE
UPPER TROUGH OVER NORTHERN ALASKA IS STARTING TO DEEPEN. THE BROAD
UPPER RIDGE OVER THE GULF AND SOUTHEAST ALASKA IS STILL DRIFTING
EAST.

AT THE SURFACE...A MODERATE SURFACE LOW LIES OVER THE ALASKA
PENINSULA WITH A WEATHER FRONT EXTENDING ACROSS KODIAK ISLAND AND THE
GULF OF ALASKA. SNOW ASSOCIATED WITH THIS SYSTEM HAD MOVED INTO MOST
OF SOUTHCENTRAL ALASKA AND THE BRISTOL BAY ZONE. GUSTY NORTH WINDS ON
THE WEST SIDE OF THE LOW COVERS MOST SOUTHWEST MAINLAND AND THE
BERING SEA. DRY COLD AIR ASSOCIATED WITH THIS NORTH WIND HAS KEPT
CLOUDS AND SNOW OUT OF THE KUSKOKWIM VALLEY AND KUSKOKWIM DELTA.

.SHORT TERM FORECAST...
UPPER AIR...THE UPPER RIDGE OVER THE GULF WILL MOVE INTO WESTERN
CANADA BY SATURDAY. THE UPPER TROUGH OVER NORTHERN ALASKA WILL
CONTINUE TO DEEPEN AS IT EXTENDS INTO THE EASTERN BERING AND
SOUTHWEST ALASKA THROUGH THURSDAY THEN SPREADS INTO SOUTHCENTRAL
ALASKA FRIDAY.

AT THE SURFACE...THE LOW NEAR CHIGNIK WILL MOVE WILL MOVE NORTHEAST
ACROSS KODIAK ISLAND THIS EVENING AND UP COOK INLET TO NEAR ANCHORAGE
THURSDAY AFTERNOON THEN WILL TURN EAST INTO PRINCE WILLIAM SOUND
FRIDAY. A SURFACE RIDGE OVER THE WESTERN BERING SEA WILL MOVE INTO
THE CENTRAL BERING FRIDAY. A COMPLEX LOW OVER OVER THE NORTHWEST
PACIFIC WILL MOVE SOUTH OF THE ALEUTIANS FRIDAY.

SOUTHCENTRAL ALASKA...SNOW WILL OVER MOST OF THE AREA THROUGH
THURSDAY THEN BECOME SNOW SHOWERS THURSDAY NIGHT AND FRIDAY. LARGEST
SNOW ACCUMULATION IS EXPECTED ALONG THE CENTRAL GULF COAST AND PRINCE
WILLIAM SOUND. COLD AIR ADVECTION ON THE WEST SIDE OF THE LOW WILL
MOVE INTO KODIAK ISLAND, COOK INLET AND SUSITNA VALLEY THURSDAY NIGHT
AND INTO THE KENAI PENINSULA AND MATANUSKA VALLEY FRIDAY. GUSTY NORTH
TO NORTHWEST WINDS WILL MOVE INTO THESE AREA WITH THE COLD AIR. WINDS
WILL BE ESPECIALLY STRONG OVER THE LOWER COOK INLET, THE BARREN
ISLANDS AND THROUGH CHANNELED TERRAIN ALONG THE ALEUTIAN RANGE.

SOUTHWEST MAINLAND...SNOW OVER THE BRISTOL BAY ZONE WILL CONTINUE
THROUGH TONIGHT THEN DIMINISH FROM THE WEST THURSDAY AFTERNOON AND
EVENING. GUSTY NORTH TO NORTHWEST WINDS OVER THE KUSKOKWIM DELTA ANS
PARTS OF THE KUSKOKWIM VALLEY WILL AS THE BULK OF THE COLD ADVECTION
SHIFTS EASTWARD WITH THE SURFACE LOW. THE GUSTY WINDS WILL CREATE
AREAS OF BLOWING SNOW ALONG DELTA COAST AND PASTS OF THE ALASKA
PENINSULA THROUGH THURSDAY.

BERING SEA...GUSTY NORTH WINDS OVER THE EASTERN BERING AND EASTERN
ALEUTIANS WILL CREATE AREAS OF BLOWING SNOW THROUGH THE PRIBILOFS AND
DUTCH HARBOR THROUGH TONIGHT. WINDS WILL DIMINISH THURSDAY AND
THURSDAY NIGHT. SNOW AND GUSTY EAST WINDS WILL MOVE INTO THE WESTERN
ALEUTIANS THURSDAY NIGHT AND SPREAD TO THE CENTRAL ALEUTIANS FRIDAY.

.LONG TERM FORECAST...
THE LOW OVER PRINCE WILLIAM SOUND FRIDAY NIGHT WILL DISSIPATE
SATURDAY. SNOW AND WIND OVER SOUTHCENTRAL ALASKA WILL DIMINISH
THROUGH FRIDAY NIGHT. A LOW SOUTH OF THE EASTERN ALEUTIANS FRIDAY
NIGHT WILL MOVE INTO THE SOUTHWEST GULF BY SUNDAY EVENING. THE
ASSOCIATED WEATHER FRONT EXTENDING EAST OF THE LOW SWING NORTH INTO
THE WESTERN GULF SATURDAY EVENING AND MOVE ONTO CENTRAL GULF COAST
SUNDAY. MORE SNOW AND GUSTY EAST WINDS WILL MOVE INTO KODIAK ISLAND
SATURDAY AND SPREAD TO THE CENTRAL GULF COAST SUNDAY. SOUTHWEST
ALASKA AND THE SOUTHCENTRAL INTERIOR WILL REMAIN DRY THROUGH THE
WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING EASTERN ALEUTIANS.
         BLIZZARD WATCH AKPEN.
MARINE...GALE 150, 155, 160, 170, 171,
FIRE WEATHER...NONE.

NM JAN 09