Small Craft Advisory 9, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKST SAT JAN 2 2010

.MODEL DISCUSSION...
NUMERICAL GUIDANCE IN VERY GOOD AGREEMENT EARLY ON...WITH SOME
TIMING DIFFERENCES ON A LOW JUST SOUTH OF THE ALEUTIANS CREEPING IN
BY ABOUT DAY 3. GFS DOING AN ACCEPTABLE JOB...AND WAS PREFERRED FOR
THE MORNING FORECASTS. TIMING OF EVENTS FOR DAYS 4 THROUGH 8 IS A
LITTLE UNCERTAIN BUT THE OVERALL PATTERN DEPICTED BY THE GFS IS
REASONABLE.

.ANALYSIS AND UPPER LEVELS...
UPPER LOW FORMING OVER SOUTHERN ALASKA THIS MORNING. HIGH PRESSURE
HAS RETREATED TO THE WESTERN BERING SEA. DEEP POLAR VORTEX TO THE
NORTHEAST OF ALASKA IS MOVING SLOWLY EASTWARD AND WILL NOT LONGER BE
A FACTOR IN THE LOCAL FORECAST.

.SHORT TERM FORECAST...
MOISTURE RETURNING TO SOUTHERN ALASKA TODAY AS THE DEVELOPING LOW
SLIDES WESTWARD...OPENING UP SOUTHERLY FLOW ALOFT. WARM AIR WILL
MOVE IN AT ALL LEVELS SUNDAY AND MONDAY AS 500 MB HEIGHTS BUILD AT
THE TOP END OF A WESTERN CANADIAN/LOWER 48 STATES RIDGE.

.LONG TERM FORECAST...
DEEP SOUTHERLY FLOW WILL BECOME WELL ENTRENCHED NEXT WEEK AS THE
WEST COAST RIDGE BECOMES A SIGNIFICANT BLOCKING HIGH. BY THE END
OF THE WEEK THE RIDGE LOOKS LIKE IT WILL RETREAT A BIT INTO THE
INTERIOR BUT REMAIN A STRONG BLOCKING FORCE...ALLOWING WARM
SOUTHERLY FLOW TO CONTINUE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 130 138 140 155 160 165 170 171 175 176 179
                         180 185.
         HEAVY FREEZING SPRAY 121 160 180 185.
FIRE WEATHER...NONE.

LUDWIG JAN 10