Heavy Freezing Spray Warning 3, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
250 PM AKST TUE JAN 11 2011

.ANALYSIS AND UPPER LEVELS...
THE LARGE UPPER LEVEL HIGH IS NOW CENTERED NEAR THE BERING STRAIT.
NORTHEASTERLY FLOW AROUND THE EASTERN PERIPHERY OF THE HIGH IS
BRINGING UPPER LEVEL SHORT WAVES DOWN ACROSS THE NORTHERN GULF
COAST...THE FIRST OF A FEW CROSSED OVERNIGHT BRINGING STRONG WINDS
THROUGH CHANNELED TERRAIN. OUT WEST...A WEAKENING LOW NEAR SHEMYA IS
QUICKLY MOVING NORTHWEST TO THE KAMCHATKA PENINSULA. THE FRONT
ASSOCIATED WITH THE LOW IS DRAPED ACROSS THE CENTRAL AND WESTERN
ALEUTIANS BUT IS WEAKENING AS THE UPPER LEVEL SUPPORT VACATES THE
REGION.

.MODEL DISCUSSION...EXCELLENT MODEL AGREEMENT OVER MOST OF THE STATE.
DIFFERENCES ARISE IN THE MEDIUM RANGE ALONG THE OLD FRONTAL BOUNDARY
OUT WEST.

.SHORT TERM FORECAST...

SOUTHCENTRAL...THE MAIN CONCERNS IN THE SHORT TERM OVER SOUTHCENTRAL
WILL BE WINDS INCREASING THIS EVENING THROUGH CHANNELED TERRAIN. THE
NEXT IN A SERIES OF UPPER LEVEL SHORT WAVES WILL MOVE OVER THE
REGION...STRENGTHENING THE GRADIENT ALONG THE GULF COAST. THE UPPER
LEVEL WINDS ASSOCIATED WITH THIS WAVE ARE A BIT MORE IMPRESSIVE SO WE
ARE ANTICIPATING WARNING LEVEL WINDS FOR A FEW OF THE TYPICAL
CHANNELED AREAS INCLUDING THE MATANUSKA VALLEY...VALDEZ...AND THE
COPPER RIVER DELTA. ELSEWHERE...WINDS WILL INCREASE AND BECOME
BLUSTERY OVERNIGHT AND ESPECIALLY TOWARD WEDNESDAY MORNING. THE WINDS
WILL INITIALLY MIX DOWN WARMER AIR ALOFT BRINGING TEMPERATURES TO THE
UPPER 30S TO LOWER 40S IN PARTS. COLD AIR ADVECTION ON THE BACK SIDE
OF THE SHORT WAVE FROM THE NORTHEAST WILL EVENTUALLY FILTER ACROSS
THE REGION...BRINGING TEMPERATURES BACK DOWN TO NEAR NORMAL FOR THIS
TIME OF YEAR LATER IN THE WEEK.

THE GRADIENT STAYS STRONG THROUGH THE WEEK...SO WILL NEED TO WATCH
FOR ADDITIONAL SHORT WAVES AND UPPER LEVEL SUPPORT TO BRING OTHER
POTENTIAL WARNING LEVEL WINDS.

SOUTHWEST ALASKA...WEATHER IS MUCH MORE BENIGN OUT WEST WHERE HIGH
PRESSURE AND A GRADUAL COOLING IS UNDERWAY. COLD AIR WILL SLOWLY
ADVECT ACROSS THE REGION BEHIND EACH SHORTWAVE...BRINGING
TEMPERATURES BACK TO CLIMATOLOGICAL NORMAL OR BELOW FOR THE REST OF
THE WEEK.

BERING SEA/ALEUTIANS...HIGH PRESSURE WILL SLOWLY RETROGRADE NORTH AND
WEST ALLOWING FOR THE COLD AIR AND SHORT WAVES TO EVENTUALLY INVADE
THE EASTERN BERING LATER IN THE WEEK. UNTIL THEN...A SERIES OF WEAKER
LOWS WILL DEVELOP ALONG THE OLD FRONTAL BOUNDARY SOUTH OF THE CHAIN.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNINGS ZONE 111 131 135.
MARINE...STORM WARNING 127
         GALE WARNINGS 120 121 126 128 172 175 176
FIRE WEATHER...NONE.

AB JAN 11