Blizzard in Alaska, November 15, 2009

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST SUN NOV 15 2009

.ANALYSIS AND UPPER LEVELS...
IN THE UPPER-LVLS...A LARGE LONG-WAVE TROUGH IS DRAPED FROM THE
CENTRAL BERING/ALEUTIANS EAST TO THE GULF OF AK...WITH AN UPPER-LOW
OVER THE SOUTHERN MAINLAND. NUMEROUS SHORTWAVES ROTATE AROUND THE
TROUGH...ENHANCING SNOW SHOWER ACTIVITY OVER THE MARINE AREAS IN THE
BERING AND GULF...BUT ALSO COASTAL AREAS OF PRINCE WILLIAM SOUND AND
THE KENAI PENINSULA. AN UPPER-RIDGE IS BEGINNING TO BUILD THROUGH THE
FAR WESTERN BERING. AT THE SURFACE A WEAK WAVE OF LOW PRESSURE IS
DEVELOPING NEAR MIDDLETON ISLAND...AND DRIFTING SLIGHTLY TO THE EAST.
FURTHER WEST...A GALE FORCE FRONT IS ADVANCING TOWARDS THE WESTERN
ALEUTIANS.

.MODEL DISCUSSION...
MODELS ARE ACCEPTABLY CAPTURING THE MAJOR FEATURES THROUGH THE
SHORT-TERM FORECAST PERIOD. THE WAVE OF LOW PRESSURE OVER THE N GULF
WILL DRIFT TO THE EAST AND WEAKEN ON MONDAY...WITH ANOTHER ONE
RE-DEVELOPING JUST SOUTH OF CAPE SUCKLING ON TUESDAY. THE FRONT
MOVING INTO THE WESTERN ALEUTIANS LATE SUNDAY AND MONDAY WILL STALL
OVER THE CENTRAL ALEUTIANS AND BERING ON TUESDAY. A WAVE OF LOW
PRESSURE WILL DEVELOP ALONG THE FRONT NEAR DUTCH HARBOR ON TUESDAY
AND SLIP INTO THE NORTH PACIFIC. THE GFS WAS EMPLOYED FOR THE MORNING
FORECAST PACKAGE.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
COLD AND DRY CONDITIONS TO CONTINUE FOR MUCH OF THE SOUTHERN MAINLAND
AS THE UPPER-LOW AND TROUGH REMAIN THE PREDOMINANT FEATURES. FOCAL
POINT OF PRECIPITATION WILL RESIDE WITH THE WEAK WAVES OF LOW
PRESSURE OVER THE NORTHERN GULF AND SHORTWAVE ENERGY ENHANCING THE
SNOW SHOWER ACTIVITY OVER COASTAL AREAS OF PRINCE WILLIAM SOUND...AND
OVER THE MOUNTAINS OF THE EASTERN COPPER RIVER BASIN THROUGH TUESDAY.

.SOUTHWEST...
SCATTERED SNOW SHOWERS ALONG UPSLOPE AND COASTAL AREAS OF BRISTOL BAY
AND THE KUSKOWIM DELTA...OTHERWISE COLD AND MOSTLY DRY. BRISK
COLD-ADVECTION FLOW OVER THE AKPEN WEAKENS THROUGH MONDAY AS THE LOW
OVER THE GULF DRIFTS EAST AND DISSIPATES AND THE PRESSURE GRADIENT
RELAXES.

.BERING SEA/ALEUTIANS...
SHOWERS GIVE WAY TO A STEADIER PRECIPITATION AS THE GALE FORCE FRONT
ADVANCES EAST THROUGH THE ALEUTIANS. WARMER AIR WITH THE SYSTEM LOOKS
TO TRANSITION SNOW TO RAIN AS THE SYSTEM MOVES EAST. A LOW WILL
DEVELOP NEAR DUTCH HARBOR ON TUESDAY...AND THE LOW SLIPS SOUTH OF THE
AKPEN.

.LONG TERM FORECAST...
LOW CONFIDENCE CONTINUES IN TRACK OF INDIVIDUAL STORMS IN THE
EXTENDED PERIOD. THROUGH THE MEDIUM RANGE...COLD AND DRY ACROSS THE
SOUTHERN MAINLAND...WHILE REMAINING UNSETTLED OVER THE WESTERN AOR.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE...352 411 412 413 414 132 150 155 160 165 170 171 172
                175 176 179 180 185
HEAVY FREEZING SPRAY...412 414 121 130 132 138 160 165 180

JAM NOV 09