Storm Warning 242, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST SUN NOV 28 2010

.MODEL DISCUSSION...
MODELS ARE IN GENERAL AGREEMENT...BUT WITH SOME MINOR DETAIL
DIFFERENCES. PREFERRED THE NAM FOR THE EARLY PORTION OF THE FORECAST
FOR ITS BETTER HANDLING OF FINE DETAILS. ITS CLOSE AGREEMENT TO THE
ECMWF BOOSTS CONFIDENCE AS WELL. LONGER TERM GUIDANCE NOT IN SUCH
GOOD AGREEMENT...AND FORECASTS LEAN A LITTLE MORE TOWARD HPC
GUIDANCE FOR THE EXTENDED PERIODS.

.ANALYSIS AND UPPER LEVELS...
EAST MOVING OPEN-WAVE LOW OVER SOUTH CENTRAL ALASKA THIS MORNING.
RIDGE OVER THE CENTRAL ALEUTIANS MOVING INTO SOUTHWEST ALASKA. THERE
IS A LOW WEST OF THE WESTERN ALEUTIANS MOVING NORTH INTO THE BERING
SEA THIS MORNING.

.SHORT TERM FORECAST...
THE UPPER LOW OVER SOUTH CENTRAL ALASKA WILL MOVE SLOWLY SOUTHEAST
TODAY. PRECIPITATION WILL CUT OFF BEHIND THIS LOW LATER THIS MORNING
FROM ANCHORAGE WESTWARD BUT CONTINUE EAST OF ANCHORAGE AS EASTWARD
PROGRESSION OF THIS LOW WILL HALT LATER TODAY. AN UPPER LOW WILL
THEN FORM ON THIS OPEN WAVE...CLOSE OFF...AND DROP SOUTH INTO THE
NORTHERN GULF OF ALASKA TONIGHT AND MONDAY. STRONG HIGH PRESSURE
WILL BUILD INTO SOUTH CENTRAL ALASKA BEHIND THIS LOW BRINGING QUITE
WINDY CONDITIONS TO AREAS SUCH AS THOMPSON PASS...THROUGH THE BARREN
ISLANDS...AS WELL AS NEAR WHITTIER AND VALDEZ. THE GULF LOW WILL
SLOWLY DRIFT SOUTHEAST LATER MONDAY INTO TUESDAY.

THE WESTERN BERING SEA LOW WILL MOVE NORTHEAST TODAY AND MONDAY. A
WEATHER FRONT ASSOCIATED WITH THIS LOW WILL MOVE EASTWARD ACROSS THE
BERING SEA AND ALEUTIANS...BREAKING UP MONDAY NIGHT AS IT NEARS THE
ALASKA PENINSULA. ON TUESDAY ANOTHER SYSTEM WILL MOVE INTO THE
WESTERN ALEUTIANS AND BERING SEA.

.LONG TERM FORECAST...
HIGH PRESSURE WILL HOLD ON OVER SOUTH CENTRAL ALASKA UNTIL LATE IN
THE WEEK AS A STRONGER SYSTEM MOVES INTO THE BERING SEA AND BEGINS
TO PUSH MOISTURE INTO SOUTHERN ALASKA BY THE WEEKEND. THE GLOBAL
MODELS ARE A LITTLE DIVERGENT ON TIMING AND STRENGTH OF THIS
POSSIBLE PATTERN CHANGE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING 127 128 130 132 176.
         GALE WARNING 120 121 125 126 129 138 140 150 155 175 185.
         HEAVY FREEZING SPRAY 140.
FIRE WEATHER...NONE.

LUDWIG NOV 10