Small Craft Advisory 293, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM AKDT FRI APR 3 2009

.ANALYSIS AND UPPER LEVELS...
A 985 MB LOW EVIDENT ON SATELLITE IMAGERY IS MOVING INTO THE SOUTHERN
GULF OF ALASKA. SURFACE HIGH PRESSURE IS OVER THE CENTRAL ALEUTIANS
AND WESTERN BERING SEA. A LARGE AND ROBUST LOW PRESSURE SYSTEM CAN BE
SEEN ON WATER VAPOR IMAGERY SOUTH OF THE KAMCHATKA PENINSULA. IN THE
UPPER LEVELS A RIDGE IS LOCATED OVER THE ALEUTIANS AND BERING SEA.
ELSEWHERE...A PROGRESSIVE TROUGH AND ASSOCIATED CUT OFF LOW ARE OVER
THE MAINLAND AND GULF OF ALASKA.

.MODEL DISCUSSION...
MODEL PERFORMANCE IS GOOD THROUGH MONDAY...WITH ONLY MINOR
DIFFERENCES REGARDING POSITIONING AND INTENSITY OF SYSTEMS. MODELS
CONTINUE TO HOLD ONTO THE DUAL LOW SOLUTION FOR THE LOW APPROACHING
THE GULF OF ALASKA. STILL ANTICIPATING THE STRONGEST LOW TO BE TO THE
SOUTH.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
MAIN FOCUS REMAINS ON THE LOW FORMING IN THE NORTHERN GULF AND ITS
EFFECTS ON THE WEATHER FOR KODIAK ISLAND TODAY AND TONIGHT. MOISTURE
WILL BE PREVALENT AND COLD AIR ADVECTION WILL BE DEVELOPING THROUGH
THE DAY TODAY. EXPECT RAIN AND SNOW MIX TO TRANSITION TO ALL SNOW BY
THIS AFTERNOON...WITH MODERATE TO HEAVY SNOW REDUCING VISIBILITIES AS
WE HEAD INTO THIS EVENING. ACCORDINGLY...A BLIZZARD WARNING WILL BE
ISSUED FOR KODIAK ISLAND. ELSEWHERE...AN INVERTED TROUGH MOVING EAST
ACROSS THE AREA WILL RESULT IN WIDESPREAD LIGHT SNOW. AS THE TROUGH
MOVES OUT...GENERALLY FAIR WEATHER WILL RETURN TO SOUTHCENTRAL AS WE
HEAD INTO THE WEEKEND.

.SOUTHWEST...
HIGH PRESSURE MOVING INTO SOUTHWEST ALASKA WILL TRANSLATE INTO QUIET
WEATHER THROUGH SATURDAY. SCATTERED SNOW SHOWERS IN THE KUSKOKWIM
VALLEY WILL BE DISSIPATING TODAY AS THE TROUGH MOVES EAST. SCATTERED
SNOW SHOWERS WILL ALSO PERSIST ACROSS THE AKPEN ON THE BACKSIDE OF
THE GULF LOW.

.BERING SEA AND ALEUTIANS...
A ROBUST LOW OVER THE NORTH PACIFIC WILL MOVE INTO THE WESTERN
ISLANDS BY SATURDAY. A FRONT ASSOCIATED WITH THIS LOW WILL MOVE INTO
THE WESTERN ALEUTIANS FRIDAY AFTERNOON...AND PASS THROUGH THE EASTERN
ALEUTIANS BY SATURDAY NIGHT. STRONG MOISTURE TRANSPORT AND MILD
TEMPERATURES WILL ACCOMPANY THIS FRONT...RESULTING IN A RAIN SNOW MIX
POTENTIALLY AS FAR NORTH AS THE PRIBILOFS.

.LONG TERM FORECAST...
STILL EXPECTING THE PROGRESSIVE PATTERN TO SLOW IN RESPONSE TO
AMPLIFYING JET STREAM. FOR THE BEGINNING OF THE WEEK...THE RIDGE
CURRENTLY OVER THE BERING SEA WILL SHIFT OVER THE MAINLAND. AT THE
SAME TIME...AN UPPER TROUGH WILL BECOME ESTABLISHED OVER THE BERING.
THE MAIN FEATURE OF INTEREST IN THE LONG TERM LOOKS TO BE THE LARGE
LOW MOVING INTO THE BERING SEA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 171
MARINE...GALE...120 130 138 150 155 170 171 172 175 176 185
         STORM...132
         HEAVY FREEZING SPRAY...130 140 165
FIRE WEATHER...NONE

NRH APR 09