Gale Warning 1055, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
1205 PM AKST WED DEC 15 2010

.ANALYSIS AND UPPER LEVELS...A STABLE HIGH AMPLITUDE PATTERN IS
IN PLACE WITH BLOCKING RIDGE OVER THE BERING SEA AND DEEP LOW
OVER THE GULF. WINDS PEAKED ACROSS SOUTHCENTRAL THIS MORNING
AND WILL VERY SLOWLY DIMINISH TODAY AND TONIGHT AS THE GULF LOW
SINKS SOUTHWARD AND THE PRESSURE GRADIENT SLACKENS. THE GRADIENT
IS TIGHTENING ALONG THE ALASKA PENINSULA AND EASTERN ALEUTIANS AS
RIDGE SLIDES EASTWARD A BIT...SO WINDS THERE HAVE INCREASED THIS
MORNING. KODIAK ISLAND IS THE ONLY LAND AREA OBSERVING PRECIP THIS
MORNING AS SNOW SHOWERS ALONG THE PERIPHERY OF THE GULF LOW PASS
THROUGH.

.MODEL DISCUSSION...MODELS GENERALLY IN VERY GOOD AGREEMENT
THROUGH THE NEXT FEW DAYS. THERE ARE SOME DIFFERENCES WITH TRACK
OF LOW APPROACHING THE WESTERN ALEUTIANS SATURDAY. SINCE NONE OF
THE MODELS ARE VERY CONSISTENT WITH THIS WILL TAKE A BLEND OF THE
SOLUTIONS FOR NOW.

.SHORT TERM FORECAST...

SOUTHCENTRAL/SOUTHWEST...COLD ADVECTION HAS ENDED AND SURFACE
PRESSURE GRADIENT WILL BEGIN TO SLACKEN THIS AFTERNOON AS GULF
LOW TRACKS SOUTHWARD INTO THE NORTHEAST PACIFIC. THIS WILL ALLOW
WINDS TO DIMINISH ENOUGH TO TAKE DOWN THE HIGH WIND WARNINGS
CURRENTLY IN EFFECT FOR THE MATANUSKA VALLEY AND EASTERN PRINCE
WILLIAM SOUND. AFTER INITIALLY SLACKENING THE PRESSURE GRADIENT
WILL REMAIN RELATIVELY TIGHT AND WILL HOLD STEADY THROUGH THE END
OF THE WEEK AS A STRONG SURFACE HIGH PERSISTS OVER INTERIOR ALASKA
AND LOW PRESSURE REMAINS DOWN OVER THE NORTHEAST PACIFIC. SURFACE
WINDS WILL DECOUPLE FROM STRONGER WINDS ALOFT FOR MUCH OF THE REGION
TONIGHT...WHICH WILL ALLOW TEMPERATURES TO FALL. MEANWHILE...GAP
WINDS WILL CONTINUE ESPECIALLY ALONG THE GULF COAST. A SERIES OF
NORTHERLY JETS MOVING DOWN THE EAST SIDE OF THE UPPER RIDGE WILL
PROVIDE SUPPORT FOR OCCASIONALLY STRONGER WINDS THROUGH THESE GAPS.

BERING/ALEUTIANS...A SERIES OF STORMS WILL RIDE UP AND OVER THE
BERING SEA RIDGE THE NEXT FEW DAYS GRADUALLY SQUASHING THE RIDGE
TO THE SOUTH. THIS WILL ALLOW A SYSTEM TO MAKE EASTWARD PROGRESS
ACROSS THE BERING THIS WEEKEND.

.LONG TERM FORECAST...AFTER A BRIEF CHANGE IN THE UPPER PATTERN
THIS WEEKEND WITH ZONAL FLOW FROM THE BERING TO MAINLAND ALASKA
MODELS INDICATE THE RIDGE WILL REBUILD OVER THE BERING SEA AS WE
HEAD THROUGH NEXT WEEK. THEREFORE...MAINLAND ALASKA WILL HAVE A
CHANCE OF A QUICK SHOT OF SNOW THIS WEEKEND AND THEN COLD AND DRY
WILL RETURN. CHANCES ARE THERE WILL BE ANOTHER WINDS EVENT MID
TO LATE NEXT WEEK AS THE RIDGE AMPLIFIES AND ARCTIC AIR ONCE AGAIN
PLUNGES SOUTHWARD ACROSS MAINLAND ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 111 131 135.
MARINE...STORM WARNING...127 132.
         GALE WARNING...120 121 126 128 129 130 138 140 150 155 160
                        165 170 176.
         HEAVY FREEZING SPRAY WARNING...121 125 126 127 128 129 130
                                        138 140 141 150 160 180.
FIRE WEATHER...NONE.

SEB DEC 10