Brisk Wind Advisory 28, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM AKST THU FEB 19 2009

.DISCUSSION...SERVICE BACKUP TODAY.
FORECASTS TODAY WERE HANDLED OUT OF THE FAIRBANKS AND JUNEAU WEATHER
OFFICES AS A SYSTEM UPGRADE IS BEING PERFORMED. THIS SHOULD BE
TRANSPARENT FOR USERS OF THE FORECASTS.

.MODEL DISCUSSION...
THE MODELS ARE IN DECENT AGREEMENT FOR THE FIRST FOUR DAYS OF THE
FORECAST. AFTER THIS THE 12Z GFS SEEMS TO VEER OFF THE MODEL
CONSENSUS...THOUGH LAST NIGHTS 00Z GFS LOOKS MUCH BETTER AND
GUIDANCE CAN BE TRUSTED OUT TO ALMOST DAY SIX. THE FORECAST WAS
NUDGED TOWARD THE NAM IN THE EARLY PERIODS FOR KODIAK ISLAND EAST...
AND TO THE GFS WEST OF KODIAK. THE FORECAST FOR DAY THREE THROUGH
EIGHT WAS LEFT PRETTY MUCH THE SAME AS IN THE PREVIOUS PACKAGE.

.ANALYSIS AND UPPER LEVELS...
SOUTHWESTERLY FLOW ALOFT THROUGH THE BERING SEA AND ALASKA THIS
AFTERNOON. A RIDGE OVER THE GULF OF ALASKA IS BEING SQUISHED
SOUTHWARD AS AN UPPER LEVEL DISTURBANCE (OPEN TROUGH AT 500 MB)
MOVES THROUGH SOUTHERN ALASKA. JET STREAM IS CONSOLIDATED FROM THE
WESTERN ALEUTIANS TO ABOUT THE ALASKA/YUKON BORDER.

.SHORT TERM FORECAST...
MOST OF THE MOISTURE FROM THE UPPER LEVEL TROUGH IS SITUATED EAST OF
VALDEZ WILL CONTINUE TO MOVE EAST TONIGHT. SOME RESIDUAL MOISTURE
AHEAD OF THE TROUGH AXIS WILL CONTINUE THE THREAT OF SHOWERS. THE
TROUGH AXIS WILL BE NEAR 148 DEGREES WEST LONGITUDE NOON FRIDAY AND
TO THE EASTERN BORDER OF ALASKA BY MIDNIGHT FRIDAY. STRONG NORTH TO
NORTHWEST FLOW AT ALL LEVELS BEHIND THE TROUGH WILL DRY THINGS OUT
QUICKLY. FAIRLY STRONG WINDS IN FAVORED AREAS ARE ALSO EXPECTED
WHICH WILL BE ENHANCED BY COLD ADVECTION.

.LONG TERM FORECAST...
AN UPPER LEVEL RIDGE WILL BUILD OVER THE AREA SATURDAY AND SUNDAY.
SYSTEMS WILL ATTEMPT TO CROSS THIS RIDGE FROM THE WEST BUT WILL
LIKELY NOT MAKE IT MUCH FURTHER EAST THAN THE ALASKA RANGE. THE MEAN
RIDGE POSITION SHOULD REMAIN OVER SOUTHERN ALASKA FOR MOST OF NEXT
WEEK FOR FAIRLY DRY CONDITIONS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HEAVY SNOW WARNING 145 SUSITNA VALLEY.
MARINE...STORM WARNING 130 170 172 175 176 179 185.
         GALE WARNING 120 121 129 132 150 165 171 180.
         HVY FRZ SPRY WRNG 121 125 129 130 141.
FIRE WEATHER...NONE.

LUDWIG FEB 09