Gale Warning 338, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM AKDT MON MAR 30 2009

.ANALYSIS AND UPPER LEVELS...
QUIET CONDITIONS AT THE SURFACE THIS AFTERNOON COMPARED TO THE
PREVIOUS SEVERAL DAYS. THE LOW THAT AFFECTED THE AREA YESTERDAY
CONTINUES TO MOVE NORTH TOWARD THE SEWARD PENINSULA WHILE WEAKENING.
ELSEWHERE...A 997 MB LOW IS DEVELOPING SOUTH OF SHEMYA AND A 983 MB
NORTH PACIFIC LOW IS MOVING NORTHEAST TOWARD THE SOUTHERN GULF OF
ALASKA. IN THE UPPER LEVELS...THE BROAD TROUGH IS STILL IN PLACE OVER
THE EASTERN BERING SEA. VARIOUS IMPULSES ROTATING AROUND THE TROUGH
BASE ARE IMPACTING SOUTHWEST AND SOUTHCENTRAL ALASKA. A POLAR VORTEX
THAT DEVELOPED IN THE COLD AIR ADVECTION IN THE BERING SEA IS NOW
EAST OF THE PRIBILOF ISLANDS AND IS MOVING TOWARD THE BRISTOL BAY
REGION. IT WILL THEN PROCEED OVER COOK INLET BY LATE TONIGHT. THIS
FEATURE CAN BE EASILY SEEN ON THE IR SATELLITE.

.MODEL DISCUSSION...
MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH 60 HOURS...OR 00Z
THURSDAY. SOLUTIONS DIVERGE REGARDING INTENSITY AND POSITION OF THE
UPCOMING LOWS MOVING INTO THE BERING SEA AND SOUTHERN GULF. GENERAL
CONSENSUS IS THAT THE MODELS ARE SATISFACTORY ON HANDLING THE OVERALL
PATTERN. THE GFS/NAM SOLUTIONS WERE USED TO CONSTRUCT THE AFTERNOON
PACKAGE...DUE TO CONTINUED CONSISTENCY AND GOOD INITIALIZATION.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
SCATTERED SNOW SHOWERS WILL PERSIST ACROSS SOUTHCENTRAL TONIGHT AS A
SHORTWAVE TROUGH SWINGS NORTH THROUGH THE AREA. EXPECT PRECIPITATION
TO LINGER INTO TOMORROW ALONG THE SUSITNA VALLEY...EASTERN PRINCE
WILLIAM SOUND...AND THE COPPER RIVER BASIN. SNOW WILL OVERSPREAD
KODIAK ISLAND TOMORROW AFTERNOON AS THE AFOREMENTIONED NORTH PACIFIC
LOW MOVES INTO THE SOUTHERN GULF. ACROSS THE REMAINDER OF
SOUTHCENTRAL EXPECT THE WEATHER TO REMAIN FAIRLY QUIET ON TUESDAY.
PERIODIC SHORTWAVES WILL MOVE THROUGH THE AREA TUESDAY NIGHT AND
WEDNESDAY...KEEPING THE THREAT OF SCATTERED SNOW SHOWERS ACROSS
SOUTHCENTRAL.

.SOUTHWEST...
CONDITIONS ALONG THE KUSKOKWIM DELTA COAST WILL BE IMPROVING THIS
AFTERNOON AS THE GRADIENT GRADUALLY RELAXES. SNOW SHOWERS WILL
AFFECT SOUTHWEST THROUGH TOMORROW AS VARIOUS SHORTWAVES ROTATE AROUND
THE BASE OF THE TROUGH. THE NORTH PACIFIC LOW MOVING INTO THE GULF
WILL SPREAD MORE WIDESPREAD SNOW OVER SOUTHERN BRISTOL BAY AND THE
AKPEN TUESDAY. OTHERWISE...LIGHT WINDS AND CLOUDY SKIES WILL BE THE
RULE THROUGH WEDNESDAY.

.BERING SEA AND ALEUTIANS...
SNOW WILL CONTINUE ACROSS THE WESTERN ALEUTIANS TONIGHT BEFORE MOVING
INTO THE BERING SEA TOMORROW. PRECIPITATION WILL BE OVERSPREADING THE
EASTERN ALEUTIANS TONIGHT AS THE LOW IN THE NORTH PACIFIC MOVES
TOWARDS THE GULF OF ALASKA. TUESDAY NIGHT AND THE FIRST HALF OF
WEDNESDAY WILL BRING A BRIEF LULL AS THE NEXT NORTH PACIFIC LOW
APPROACHES FROM THE SOUTHWEST.

.LONG TERM FORECAST...
FLOW WILL BECOME MORE ZONAL ACROSS THE AREA THROUGH THE END OF THE
WEEK...RESULTING IN AN ACTIVE SURFACE PATTERN. MAIN FEATURES OF
INTEREST INCLUDE A LOW MOVING ACROSS THE BERING SEA TOWARDS SOUTHWEST
ALASKA MIDWEEK...AND A SERIES OF LOWS SKIRTING SOUTH OF THE ALEUTIAN
CHAIN AND MOVING INTO THE SOUTHERN GULF OF ALASKA. SIGNIFICANT
WEATHER IMPACTS WITH THESE SYSTEMS ARE EXPECTED TO BE LIMITED
PRIMARILY TO COASTAL AREAS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE...120 132 150 155 170 172 175 176
         HEAVY FREEZING SPRAY...138 140 141 165
FIRE WEATHER...NONE

NRH MAR 09