Gale Warning 333, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM AKDT FRI MAR 27 2009

.MODEL DISCUSSION...MODELS ARE IN GOOD AGREEMENT WITH THE OVERALL
PATTERN THROUGH THE WEEKEND. THE CONCERN IS WITH THE TRACK OF THE LOW
THAT WILL CROSS THE EASTERN ALEUTIAN CHAIN SATURDAY AND MOVE INTO
SOUTHWEST ALASKA SUNDAY. THE MODEL RUNS HAVE BEEN MOVING THIS LOW
TRACK NORTHWARD WITH PROGRESSIVE RUNS THOUGH THE LAST TWO RUNS ON
BOTH THE GFS AND ECMWF HAVE SLOWED THE NORTHWARD MOVEMENT BUT THE
ECMWF IS STILL NORTH OF THE GFS TRACK. CURRENTLY THE MODELS MATCH UP
WELL THROUGH SAT NIGHT AND THEN THE ECMWF BRINGS TO LOW CENTER TO
NUNIVAK ISLAND WHILE THE GFS IN MOVING IT INLAND A LITTLE NORTH OF
TOGIAK SUNDAY. THE GFS SOLUTION SEEMS TO BE A LITTLE BETTER WHEN
LOOKING AT ALL AVAILABLE FACTORS THEREFORE THAT IS THE ONE BEING USED
FOR GUIDANCE WITH THIS AFTERNOONS PACKAGE.

.ANALYSIS AND UPPER LEVELS...THE UPPER LEVEL HEMISPHERIC PATTERN WILL
BE UNDERGOING A LITTLE SHIFT AS THE LARGE HIGH OVER SIBERIA
RETROGRADES TO THE SOUTHWEST WHICH WILL IN TURN ALLOW THE UPPER LEVEL
TROUGH OVER THE CENTRAL BERING SEA TO DEEPEN THROUGH SATURDAY NIGHT
AS THE LOW SOUTH OF THE ALEUTIANS MOVES INTO THE BRISTOL BAY REGION.
THE APPROACHING LOW IS WELL POSITIONED ALONG THE JET STREAM TO BE
STRENGTHENED AS FORECAST AS IT MOVES NORTHEASTWARD.

.SHORT TERM FORECAST...BIGGEST ISSUE IN SOUTH CENTRAL TONIGHT WILL BE
THE LWO MOVING INTO PRINCE WILLIAM SOUND OVERNIGHT AND THEN INTO THE
COPPER RIVER BASIN SATURDAY. THIS WILL KEEP PERSISTENT LIGHT SNOW IN
THE ANCHORAGE AREA TONIGHT AND KEEP SNOW IN THE PRINCE WILLIAM SOUND
AREA AS WELL.
THE SYSTEM MOVING INTO BRISTOL BAY WILL BRING LOTS OF PRECIPITATION
AND WIND TO THE STATE FOR THE WEEKEND AND INTO THE FIRST HALF OF THE
NEXT WEEK. THE WARM FRONT MOVING NORTH WITH THIS SYSTEM INDUCES A
STRONG BARRIER JET ON SOME MODELS IN THE NORTHERN GULF...SO THE
POSSIBILITY OF STRONG WINDS TO STORM FORCE BEGINNING LATE SATURDAY
NIGHT INTO SUNDAY CERTAINLY IS WITHIN THE REALM OF POSSIBILITY.

.LONG TERM FORECAST...THE NEXT IN THE SERIES OF STRONG LOWS ON THE
DOWNSTREAM SIDE OF THE TROUGH LOOKS TO AFFECT THE REGION RIGHT ON THE
HEELS OF THIS WEEKENDS STORM SYSTEM.  MODELS WILL LIKELY FLUCTUATE
BETWEEN A TRACK NORTH OR SOUTH OF THE AKPEN.  EITHER WAY...CONTINUED
UNSETTLED WEATHER IS LIKELY THROUGH THE MIDDLE OF NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 130 132 138 140 150 155 160 165 170 171 172 175 179
              180.
         HEAVY FREEZING SPRAY 155 165 179.
FIRE WEATHER...NONE.

MAR 09