Gale Warning 217, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST MON MAR 1 2010

.MODEL DISCUSSION...
MODELS IN GENERALLY GOOD AGREEMENT THROUGH 120 HOURS. GFS PREFERRED
OVERALL DUE TO BETTER RUN TO RUN CONSISTENCY AND BEST INITIALIZATION.
ECMWF A CLOSE SECOND.

.ANALYSIS AND UPPER LEVELS...
HIGH AMPLITUDE RIDGE OF HIGH PRESSURE OVER WESTERN CANADA GRADUALLY
MIGRATES EASTWARD. DEEP UPPER LEVEL TROUGH EXTENDING FROM HIGH ARCTIC
ACROSS WESTERN ALASKA HOLDS THROUGH 60 HOURS. UPPER LEVEL CUT OFF LOW
SOUTH OF KODIAK ISLAND WEAKENS AND MOVES OFF TO THE SOUTHEAST.

.SURFACE FEATURES...
A SMALL 972 MB LOW JUST SOUTHEAST OF KODIAK ISLAND WILL REMAIN NEARLY
STATIONARY AND DISSIPATE BY LATE MON NIGHT. ASSOCIATED OCCLUDED FRONT
LIES ALONG THE WESTERN SLOPES OF THE ALASKA RANGE AND WILL GRADUALLY
DETERIORATE.
A 971 MB LOW IN THE NORTHEAST PACIFIC WILL WEAKEN TO 983 MB JUST
SOUTH OF SEWARD MON NIGHT THEN MOVE INLAND NEAR KAMISHAK BAY TUE
MORNING.
A LARGE 974 MB LOW SOUTHWEST OF SHEMYA WILL INTENSIFY TO 959 MB NEAR
NORTH OF SEGUAM ISLAND THEN MOVE TO NEAR SITKINAK TUE NIGHT AS A 971
MB LOW. ASSOCIATED WARM FRONT MOVES INTO THE WESTERN AND CENTRAL
ALEUTIANS TODAY. THE FRONT QUICKLY OCCLUDES AS IT MOVES
NORTHEASTWARD...PASSING OVER DUTCH HARBOR LATE TONIGHT AND COLD BAY
BY TOMORROW AFTERNOON. NORTHERN EDGE OF FRONT GRAZES THE PRIBILOFS
LATE TONIGHT OR EARLY TUESDAY.

.SHORT TERM FORECAST...
BROAD AREA OF PRECIPITATION WILL LINGER OVER SOUTHCENTRAL ALASKA AND
THE NORTH GULF COAST THROUGH TUESDAY NIGHT. WEAK DYNAMICS ALOFT WILL
LIMIT SNOWFALL TOTALS TO A FEW INCHES. SOUTHEASTERLY FLOW SURFACE AND
ALOFT WILL KEEP ANCHORAGE BOWL AND MATSU VALLEY IN A DOWNSLOPE
PATTERN THROUGH THIS EVENING...EXPECT A FEW SUNNY BREAKS AND GUSTY
WINDS THROUGH CHANNELED AREAS. PRECIPITATION FALLING MAINLY AS RAIN
ALONG THE COAST. PATCHY AREAS OF LIGHT FREEZING RAIN POSSIBLE OVER
THE SOUTHERN KENAI PENINSULA THIS MORNING.
INCREASED CLOUD COVER HAS MODERATED TEMPERATURES OVER SOUTHWESTERN
ALASKA BUT COLD NORTHERLY FLOW WILL CONTINUE THROUGH TONIGHT. LOW
WIND CHILLS...ESPECIALLY FOR THE KUSKOKWIM DELTA...WILL REMAIN A
CONCERN THROUGH TOMORROW MORNING.
COLD AIR ADVECTION OVER THE EASTERN BERING...ALASKA PENINSULA...AND
EASTERN ALEUTIANS WILL USHER IN PERIODS OF SNOW SHOWERS TODAY. WINDS
SHIFTING FROM NORTHWEST TO EAST OR SOUTHEAST BY LATE AFTERNOON. BRIEF
PERIOD OF CLEARING IN THESE AREAS TONIGHT BEFORE ARRIVAL OF NEXT
SYSTEM TOMORROW.
ALEUTIAN SYSTEM EXPECTED TO HAVE STORM FORCE WINDS BOTH IN ADVANCE OF
THE FRONT AND ALONG THE SOUTHWESTERN FLANK OF THE LOW ITSELF.
POSSIBLE GUSTS TO AROUND 75 MPH THROUGH CHANNELED AREAS OF THE
CENTRAL ALEUTIANS TONIGHT AND TOMORROW MORNING. MIXED RAIN AND SNOW
WILL PREDOMINATE ALONG THE CHAIN AND ACROSS THE ALASKA
PENINSULA...BUT CHANGE OVER TO SNOW SHOWERS ONCE THE LOW PASSES TO
THE EAST. SNOW AND BLOWING SNOW WILL DEFINITELY BE THE CONCERN FOR
THE PRIBILOFS THROUGHOUT. POSSIBLE BLIZZARD AT SAINT PAUL AND SAINT
GEORGE TONIGHT AND TUESDAY. PRECIPITATION SHIELD SHOULD REACH THE
BRISTOL BAY COAST TUESDAY EVENING...SNOW AND BLOWING SNOW WILL BE A
CONCERN HERE AS WELL...ESPECIALLY ALONG THE WESTERN CAPES.

.LONG TERM FORECAST...
PATTERN SHIFT AFTER 72 HOURS. DEEP NORTH TO SOUTH TROF DEVELOPS AT
500 MB FROM WESTERN RUSSIA INTO NORTHERN PACIFIC. RIDGE OF HIGH
PRESSURE ALOFT BUILDS OVER GULF OF ALASKA AND MAINLAND ALASKA.
PATTERN CONDUCIVE TO STRONG LOW PRESSURE SYSTEMS TRACKING ALONG THE
ALEUTIAN CHAIN AND BEING STEERED TOWARDS NORTHWEST ALASKA. ALSO
CONDUCIVE TO WARMING OVER SOUTHCENTRAL AND SOUTHWESTERN ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...WIND 187...BLIZ 195
MARINE...GALE 120 150 155 171 176 179
        STORM 170 172 175
FIRE WEATHER...NONE.

ASB MAR 10