High Wind in Alaska, January 12, 2012

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST THU JAN 12 2012

.ANALYSIS AND UPPER LEVELS...
THE LONGWAVE PATTERN ACROSS THE ALASKAN DOMAIN IS IN TRANSITION THIS
MORNING. THE PERSISTENT TROUGH ACROSS THE BERING SEA IS BEING
REPLACED BY A BUILDING RIDGE. AS THIS HAPPENS...THE PERSISTENT HIGH
PRESSURE OVER THE COAST OF BRITISH COLUMBIA IS RAPIDLY ERODING. A
SIGNIFICANT SHORTWAVE TROUGH IS DIGGING ACROSS SOUTHWEST ALASKA EN
ROUTE TO BECOMING A CLOSED UPPER LOW OVER THE WESTERN GULF BY THIS
EVENING. AHEAD OF THIS TROUGH...A WEAK SURFACE LOW IS LOCATED NEAR
PRINCE WILLIAM SOUND...SUPPLYING AMPLE MOISTURE TO SOUTHCENTRAL THAT
IS BEING REFLECTED BY WIDESPREAD SNOWFALL THIS MORNING ACROSS THE
AREA. OUT WEST...A VERY STRONG LOW SOUTH OF THE KAMCHATKA PENINSULA
OF RUSSIA IS SENDING A HURRICANE FORCE FRONT TOWARD THE WESTERN
ALEUTIANS THIS MORNING.

.MODEL DISCUSSION...
MODELS ARE IN EXCELLENT OVERALL AGREEMENT. SURFACE LOW IN THE
NORTHERN GULF STALLS SOMEWHERE NEAR THE SOUTHWEST CORNER OF PRINCE
WILLIAM SOUND BEFORE DRIFTING BACK TO THE SOUTHEAST THIS EVENING AND
ACCELERATING INTO THE EASTERN GULF. THE MODELS ARE ALSO IN GOOD
AGREEMENT WITH EACH OTHER ON THE LOCATION OF THE DEVELOPING UPPER LOW
IN THE WESTERN GULF...THOUGH ALL MODELS ARE A BIT FURTHER SOUTH WITH
THIS FEATURE THAN YESTERDAY.

.SHORT TERM FORECAST...
SOUTHCENTRAL...ADVERTISED SNOW EVENT IS GENERALLY ON TRACK. THE MOST
SIGNIFICANT DIFFERENCE FROM YESTERDAY IS THAT THE UPPER TROUGH WHICH
IS PROVIDING THE SYNOPTIC LIFT ACROSS THE AREA IS FURTHER SOUTH THAN
THE MODELS YESTERDAY SHOWED. THIS HAS SO FAR KEPT THE HEAVIEST SNOW
OVER THE NORTHERN KENAI PENINSULA. AS THE TROUGH CONTINUES TO MOVE
SLOWLY NORTHWARD MODERATE SNOW SHOULD CONTINUE TO PUSH NORTHWARD AS
WELL. EXPECTING LIGHT SNOW TO LINGER ACROSS MUCH OF THE AREA DURING
THE OVERNIGHT HOURS TONIGHT...WITH ANOTHER INCH OR TWO OF
ACCUMULATION. OVERALL THIS IS STILL SHAPING UP TO BE A SIGNIFICANT
SNOWFALL FROM THE WESTERN KENAI TO THE MAT-SU VALLEY. COLD AND DRY
WITH NORTH WINDS BECOME THE PREVAILING CONDITION AS WE HEAD TOWARD
THE WEEKEND IN ALL AREAS.

SOUTHWEST AND BERING SEA...COLD AIR AND CLEAR SKIES WILL CONTINUE
OVER THE MAINLAND ZONES TODAY. WIND CHILL ADVISORIES ARE VERIFYING
WITH GUSTY NORTHWEST WINDS IN BOTH THE DELTA AND BRISTOL BAY ZONES.
OUT WEST...THE FULL FORCE OF THE STRONG FRONT IS IMPACTING THE
WESTERN ALEUTIANS. THE FRONT WILL REACH PEAK INTENSITY THIS MORNING
AND SLOWLY WEAKEN AS IT MOVES TO THE CENTRAL ALEUTIANS TONIGHT. A
HIGH WIND WARNING REMAINS IN EFFECT FOR THE WESTERN ALEUTIANS...AND A
HIGH WIND WATCH HAS BEEN ISSUED FOR THE CENTRAL ALEUTIANS FOR THE
OVERNIGHT TIME PERIOD.

.LONG TERM FORECAST...
AS MENTIONED ABOVE...MOST OF ALASKA SETTLES INTO A SUNNY AND
DRY...ALBEIT COLD...PATTERN BEGINNING THIS WEEKEND AND RUNNING
THROUGH THE END OF NEXT WEEK. EXPECT MAIN FORECAST CHALLENGES WILL BE
STRONG OUTFLOW NORTHERLY WINDS IN FAVORED AREAS SUCH AS THOMPSON PASS
AND THE MATANUSKA VALLEY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 191
         BLIZZARD WARNING 125
         HIGH WIND WATCH 187
         SNOW ADVISORY 101 111 121 145
         WIND CHILL ADVISORY 155 161
MARINE...HURRICANE 175 176
         STORM 130 132 150 172 185
         GALE 120 121 127 129 138 155 170 179
         HEAVY FREEZING SPRAY 120 121 125 126 127 128 129 130 132 138
                              140 141 150 155 165
FIRE WEATHER...NONE

AMD JAN 12