Small Craft Advisory 28, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST WED JAN 9 2013

.ANALYSIS AND UPPER LEVELS...THE UPPER LEVEL PATTERN TODAY HAS A
RIDGE OVER THE MAINLAND OF THE STATE WITH A LOW SITUATED IN THE FAR
WESTERN BERING SEA. THIS IS PRODUCING MODERATE TO STRONG SOUTHWEST
FLOW ALOFT OVER THE BERING SEA INTO SOUTHWEST ALASKA.
THE SURFACE PATTERN IS A BIT MORE COMPLEX WITH THE SURFACE LOW IN THE
WESTERN BERING SEA SLOWLY WEAKENING AND A FRONT EXTENDING OUT OF IT
THROUGH THE NORTHERN BERING SEA INTO SOUTHWEST ALASKA AND THEN TO
JUST WEST OF KODIAK. THIS FRONT IS MOVING TO THE NORTHEAST AND WILL
MOVE OVER SOUTH CENTRAL ALASKA TONIGHT INTO THURSDAY AFTERNOON.
THERE ARE MULTIPLE SMALLER LOWS IN THE BERING SEA REGION BEHIND THIS
FRONT WITH THE STRONGEST ONE BEING NEAR ATKA THIS AFTERNOON.

.MODEL DISCUSSION...THE CURRENT MODELS ARE IN MUCH BETTER AGREEMENT
ON MOST OF THE FEATURES THAN THEY WERE YESTERDAY. IN PARTICULAR THE
LOW THAT WILL BE MOVING INTO THE GULF OF ALASKA THURSDAY NIGHT AND
FRIDAY IS RESOLVED VERY WELL BY THE NAM AND ECMWF. THE GFS STARTS AND
ENDS WELL WITH THIS LOW BUT TAKES THE LOW AN AN UNLIKELY MEANDER
THROUGH BRISTOL BAY THURSDAY NIGHT SO IT WAS NOT USED DURING THAT
PERIOD. THE MODELS ALL HAVE A STRONG LOW ENTERING THE BERING SEA FRI
NIGHT OR SATURDAY WITH THE NAM AND GFS BEING A LITTLE FASTER THAN THE
ECMWF. THE LOW TRACK IS VERY CLOSE AND IS PROBABLY RELIABLE BUT SOME
TIMING ADJUSTMENTS FOR THE ALEUTIAN ISLANDS AND BERING SEA ARE LIKELY
AS THIS STORM DEVELOPS FURTHER AND BEGINS TO MOVE CLOSER TO THE AREA.

.SHORT TERM FORECAST...THE MOST HAZARDOUS WEATHER CURRENTLY IS ALONG
THE SOUTHWEST ALASKA COAST WHERE THERE IS A WINTER WEATHER ADVISORY
FOR BLOWING SNOW IN EFFECT. THESE CONDITIONS ARE EXPECTED TO IMPROVE
LATE THIS AFTERNOON THROUGH EARLY EVENING AS THE FRONT PUSHES PAST
THAT AREA. AS THIS FRONT MOVES NORTH AND EAST IT WILL BRING SNOW INTO
THE BRISTOL BAY AND KUSKOKWIM VALLEY REGION THIS EVENING AND MOVE
INTO SOUTH CENTRAL ALASKA TOWARD MORNING. THIS WILL BRING SOME SNOW
INTO SOUTH CENTRAL ALASKA FROM THE KENAI PENINSULA THROUGH THE
ANCHORAGE AND MAT-SU AREAS NORTH TO THE ALASKA RANGE. SNOW AMOUNTS
WILL BE MODEST AS THERE WILL BE LIMITED PRECIPITABLE WATER BY THIS
TIME WITH THE SYSTEM.
THIS FRONT SHOULD THEN MOVE TO THE ALCAN BORDER BY THURSDAY EVENING
BRINGING SNOW INTO THE COPPER RIVER BASIN THURSDAY.

.LONG TERM FORECAST...THE PATTERN IS STILL EXPECTED THIS WEEKEND TO
BRING A STRONG WARM UP TO SOUTHERN ALASKA. THIS SHOULD BEGIN IN
EARNEST IN SOUTHWEST ALASKA ON SATURDAY AND SPREAD INTO SOUTH CENTRAL
BY SATURDAY NIGHT INTO SUNDAY. THIS WILL LIKELY BRING RAIN AND WINDS
INTO MOST AREAS OF SOUTHWEST AND SOUTH CENTRAL ALASKA AT SOME POINT
THIS WEEKEND. FOR THE ANCHORAGE AND NEARBY AREAS THERE MAY BE A
CHANCE OF FREEZING RAIN SATURDAY INTO SATURDAY NIGHT AS THE WARMER
AIR ALOFT OVERRUNS THE COLD SURFACE AIR. HOWEVER BY SUNDAY NIGHT A
SECONDARY LOW WILL DEVELOP ALONG THE FRONT AND RACE NORTHWARD OVER
THE BRISTOL BAY REGION. THIS WILL LIKELY BRING HEAVIER RAIN AND
STRONG WINDS SUNDAY AND SUNDAY NIGHT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...WINTER WEATHER ADVISORY 155.
MARINE...GALE 150 155 170 176.
FIRE WEATHER...NONE.

JAN 13