Heavy Freezing Spray Warning 19, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST SUN JAN 1 2012

.MODEL DISCUSSION...

MODELS IN REASONABLY GOOD AGREEMENT. GFS PRESENTS STRONGEST SOLUTION
BUT PREFERRED ECS BETTER DEFINITION OF RESIDUAL LOW THAT DEVELOPS
OVER PRINCE WILLIAM SOUND AT 24 HOURS. MOS GUIDANCE CONTINUES TO BE
UNUSEFUL...NOT PICKING UP ON LOW LEVEL STRATUS AND LIGHT SNOW OVER
EASTERN DOMAIN THIS MORNING NOR COLD AIR ADVECTION SHOWERS OUT WEST.

.ANALYSIS AND SHORT TERM FORECAST...

A 981 MB LOW MOVES OUT OF THE NORTH PACIFIC TODAY AND INTO THE
NORTHERN GULF STRENGTHENING TO 976 MB IN THE PROCESS. THE LOW WILL
THEN MOVE INLAND AND RAPIDLY DISSIPATE BY MON MORNING...BUT A SHALLOW
RESIDUAL SURFACE LOW WILL LINGER IN PRINCE WILLIAM SOUND THROUGH
TUESDAY MORNING. SNOW WILL INCREASE TODAY OVER PRINCE WILLIAM SOUND
AND THE EASTERN COPPER RIVER BASIN TODAY BUT TAPER OFF TO SCATTERED
SNOW SHOWERS BY LATE EVENING. THE REMAINDER OF SOUTHCENTRAL ALASKA
WILL EXPERIENCE ONLY A FEW HIGH CLOUDS.

OUT WEST...A 997 MB LOW IN THE EASTERN BERING SEA WILL MOVE INLAND
NEAR DILLINGHAM THIS EVENING AND DISSIPATE NEAR ILIAMNA BY LATE
SUNDAY NIGHT. ASSOCIATED SNOW SHOWERS WILL EFFECT MAINLY THE
KUSKOKWIM DELTA...COASTAL PORTIONS OF THE BRISTOL BAY REGION...AND
THE ALASKA PENINSULA.

AIRMASS OVER SOUTHERN ALASKA WILL REMAIN COLD WITH THE MAJORITY OF
THE AREA REMAINING UNDER WEAK COLD ADVECTION DESPITE APPROACHING LOW
PRESSURE SYSTEMS. VERY COLD HIGH PRESSURE OVER NORTHERN AND INTERIOR
ALASKA IS ACTING TO PREVENT WARM NORTH PACIFIC SYSTEMS FROM ADVANCING
VERY FAR INLAND.

.UPPER LEVELS AND LONG TERM FORECAST...
A BROAD LONG WAVE TROUGH WILL PERSIST OVER NORTHWESTERN ALASKA AND
THE BERING SEA THEN GRADUALLY. A WEAK WEAK UPPER LEVEL RIDGING
BUILDING OUT OF SOUTHEAST ALASKA AND INTO SOUTHCENTRAL ALASKA GAINS
MOMENTUM MIDWEEK. PATTERN SHIFT SHOULD ALLOW NORTH PACIFIC STORMS TO
BE STEERED TOWARDS SOUTHWEST ALASKA...BRINGING WARMER AND SLIGHTLY
SNOWIER CONDITIONS TOWARDS THE END OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 121 129 130 132 351 352
         HEAVY SPRAY 121 129 130 138 140 141 160 165 179 185
                     411 412 414
FIRE WEATHER...NONE.

ASB JAN 12