Snow Advisory 26, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
1230 PM AST SUN DEC 23 2007

.MODEL DISCUSSION...GFS MODEL IS OVERALL PREFERRED. SUCCESSIVE GFS
MODEL RUNS HAVE SLOWED DOWN CENTER MOVING ALONG AND SOUTH OF THE
ALEUTIANS TUE AND WED. THIS IS FAIR AGREEMENT WITH THE UMKET. FOR NOW
WILL BLEND HEAVILY TOWARD THE 12Z GFS ON THIS FORECAST PACKAGE.

.ANALYSIS AND UPPER LEVELS...
.EAST...
SHOULD BE ABLE TO ELIMINATE WINTER WEATHER ADVISORY FOR ZONE 121 ON
AFTER FORECAST PACKAGE.

STRONG PRESSURE RISES ON THE BACKSIDE AND COLD ADVECTION IS
CONTINUING UP COOK INLET AND ACROSS THE SOUTHERN KENAI PENINSULA THIS
AFTERNOON. EXPECT COLD ADVECTION SHOULD SPREAD TO THE ANCHORAGE
BOWL/NORTH KENAI PENINSULA THIS AFTERNOON. SNOW WILL TAPER OFF OVER
MUCH OF SOUTHCENTRAL TONIGHT AS UPPER TROUGH MOVES INTO THE INTERIOR.
EXPECT MAY SEE AREAS OF PATCHY FOG OVER SOUTHCENTRAL TONIGHT AS RIDGE
BUILDS OVER THE AREA. STRONG NW TO SW WINDS OVER THE WESTERN GULF AND
COOK INLET WILL DIMINISH THROUGH THIS EVENING. WINDS WILL INCREASE
AGAIN OVER THE WESTERN GULF EARLY MON MORNING AS NEXT NPAC CENTER
MOVES TO SOUTH OF KODIAK ISLAND.

970S MB CENTER NEAR KODIAK EARLY MON MORNING IS FORECAST TO MOVE INTO
WESTERN PRINCE WILLIAM SOUND MON NIGHT THEN GRADUALLY WEAKEN AND
GRADUALLY DRIFT TO THE EASTERN GULF ON TUE EVENING. CURRENT FORECAST
TRACK HAS CHANGED SOMEWHAT OVER THE LAST COUPLE OF RUNS. IF CURRENT
RUN HOLDS THEN EXPECT PRECIPITATION SHOULD START AS SNOW OVER KODIAK
LATE TONIGHT AND SHOULD CHANGE OR MIX WITH RAIN MON. WARM ADVECTION
IN ADVANCE OF LOW AND ASSOCIATED FRONT SHOULD PRODUCE A MIX OR
RAIN/SNOW OVER THE KENAI PEN AND NORTH GULF MON ALONG WITH STORM
FORCE WINDS OVER THE NORTH GULF WATERS. EXPECT SNOW/SNOW SHOWERS ON
THE BACKSIDE WITH COLD ADVECTION ALONG WITH STRONG NW WINDS OVER THE
WESTERN GULF. IF ALL HOLDS TRUE...THEN COULD SEE A FAIR SNOW EVENT
FOR THE ANCHORAGE BOWL MON NIGHT...THOUGH THERE IS STILL A DEGREE OF
UNCERTAINTY OF LOW POSITION.

.WEST...MAIN AREA OF CONCERN IS HANDLING OF NPAC LOW COMPLEX SOUTH OF
THE ALEUTIANS THIS AFTERNOON. SAT PICTURE SHOWS DUEL CENTERS WITH
NORTHERN MOST NEAR 51N 165W THIS AFTERNOON. THIS LOOKS LIKE IT IS
BECOMING THE DOMINATE CENTER. THE GFS40 PICKS THIS CENTER UP AND
CARRIES IT SOUTH OF MARINE AREA 150 EARLY MON MORNING. CURRENT
POSITION AND FORECAST TRACK LOOK FAVORABLE FOR BLIZZARD CONDITIONS
OVER THE AK PEN TONIGHT. HOWEVER...BLOWING SNOW ADVISORY OVER 181 AND
185 ARE SOMEWHAT IN DOUBT. FOR NOW WILL LET RUN AND SEE HOW THIS
DEVELOP FOR THE REMAINDER OF THE AFTERNOON AND EARLY EVENING. NEXT
STORM CENTER MOVES SOUTH OF THE CENTRAL ALEUTIANS TUE AND AND TO THE
EASTERN ALEUTIANS WED MORNING. TIMING OF STORMS AND GALES WILL BE
ADJUSTED SOME THIS FORECAST PACKAGE AS SYSTEM IS PROGGED TO MOVE
SLOWER THEN PREVIOUS RUNS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING ZONE 181. BLOWING SNOW ADVISORY ZONES 185
AND 161.
MARINE...SEE CURRENT MARINE PACKAGES FOR ADJUSTMENTS.
FIRE WEATHER...NONE.

RMC DEC 07