Gale Warning 131, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST MON FEB 18 2013

.MODEL DISCUSSION...MODEL SYNOPTIC INITIALIZATIONS REASONABLE. THE
ECMWF APPEARS TO HANDLE THE STORM TRACK BEST WITH THE NEXT LOW THE
MOVES TOWARD THE AK PEN TONIGHT/TUE. THE GFS ATTEMPTS TO TAKE THE
CENTER INTO BRISTOL BAY WHILE THE ECMWF KEEPS THE CENTER JUST SOUTH
OF THE AK PEN BEFORE SLIDING THE CENTER INTO THE GULF. THE ECMWF
TRACK SEEMS REASONABLE AS THE SOUTHERN EXTENT OF THE ICE EDGE AND
COLD DOME OVER THE SW MAINLAND SHOULD HELP TO HIGH PRESSURE IN PLACE
AND FORCE THE APPROACHING LOW CENTER TO STAY FURTHER SOUTH. AFTERNOON
PACKAGES WILL BE BASED ON PART ON THE ECMWF...WITH A LITTLE NAM IN
THE FIRST 24 HRS IN THE EAST.

.ANALYSIS AND UPPER LEVELS...
CLEARING SKIES ARE FOLLOWING A TROUGH WHICH IS MOVING EAST ACROSS THE
NORTH GULF AND COPPER RIVER BASIN TODAY. TEMPS SHOULD BE COLD ENOUGH
FOR TO SUPPORT SNOW WITH SYSTEM. THE DYNAMICS ARE NOT EVERY
STRONG...SO SHOULD NOT SEE SIGNIFICANT SNOWFALL WITH THIS SYSTEM.
MODERATE PRESSURE GRADIENTS ARE EXPECTED ALONG THE NORTH GULF COAST
WITH TROUGH PASSAGE. A STRONG LOW AND ITS ASSOCIATED FRONTAL
TROUGH OVER THE BERING SEA PRODUCED BLIZZARD CONDITIONS OVER THE
PRIBILOF ISLANDS OVERNIGHT AND THIS MORNING. THE LOW IS SLOWLY
WEAKENING AND DRIFTING NW. THE TEMPS ARE WARMING AS THE FRONTAL
TROUGH DRIFTS NORTH AND WEAKENS...SO CONDITIONS SHOULD CONTINUE TO
IMPROVE THROUGH THIS AFTERNOON. TEMPERATURES OVER THE SW MAINLAND
ARE MODERATING SOME THIS MORNING AS CLOUD COVER SPREADS OVER THE
AREA.

.SHORT TERM FORECAST...

.SOUTHCENTRAL ALASKA...CLEARING SHOULD SPREAD ACROSS MOST OF THE AREA
AS THE UPPER TROUGH CLEARS THE EASTERN COPPER RIVER BASIN OVERNIGHT.
INCREASING CLOUDS SPREAD TO THE WEST/SOUTH GULF AS WELL AS THE KENAI
PEN EARLY TUE MORNING WITH THE APPROACH OF THE LOW AND ACCOMPANYING
FRONTAL TROUGH. EXPECT THAT THE THE PRECIPITATION WILL START AS SNOW
AT KODIAK...BUT SHOULD SHIFT TO RAIN OR MIX BY AFTERNOON.
SNOW SHOULD IMPACT THE NORTH GULF TUE AFTERNOON/EVE WITH SOME
SPILLING OVER THE COLD AIR INLAND. TEMPS MAY WARM ENOUGH OVERNIGHT
TUE NIGHT ALONG THAT COASTS TO PRODUCE A SNOW/RAIN MIX. BLOWING SNOW
OVER THE EASTERN KENAI PEN(PORTAGE VALLEY/EASTERN TURNAGAIN ARM) MAY
BE A CONCERN...BUT IT IS FELT AT THIS POINT THAT THE TEMPS MAY WARM
TOO MUCH FOR BLIZZARD CONDITIONS.

.SW ALASKA...
WIND CHILLS OVER THE DELTA WILL MODERATE SOME THROUGH TONIGHT WITH
INCREASED CLOUD COVER EVEN THOUGH SURFACE WINDS WILL INCREASE SOME.
BLIZZARD CONDITIONS ARE LOOKING MORE DOUBTFUL OVER THE BRISTOL BAY
ZONE TUE AFTERNOON AS THE LOW TRACK IS EXPECTED TO GO FURTHER SOUTH.
HOWEVER...THERE IS STILL ENOUGH UNCERTAINTY IN THE LOW TRACK TO
CONTINUE THE BLIZZARD WATCH. PRECIPITATION WILL BE MIXED OVER THE AK
PEN WITH THE INITIAL APPROACH OF THE LOW TONIGHT...BUT SHOULD SEE
SNOW ON BLOWING SNOW BEHIND CENTER ON TUE AS THE CENTER TRACKS EAST.

.BERING SEA/ALEUTIANS...

STORM CENTER OVER THE EAST CENTRAL BERING SEA WILL MOVE NW AND WEAKEN
OVER THE NEXT 48 HRS. COLD AIR WILL WRAP AROUND THE SOUTHERN AND
EASTERN QUADS OF THE CENTER AS THE FLOW BACKS TO A MORE SOUTHERLY
DIRECTION. SO LOOK FOR UNSETTLED WEATHER WITH SHOWERS AS THIS CENTER
TRACKS NW.

.LONG TERM FORECAST...
THE ACTIVE WEATHER PATTERN FOR THE AREA LOOKS TO BREAK DOWN LATER
THIS WEEK AS MOST OF THE AREA WILL BE TRAPPED BETWEEN TWO STATIONARY
RIDGES OVER THE ARCTIC OCEAN AND CENTRAL PACIFIC. THIS SETUP WILL
CAUSE MUCH OF THE STATE TO MOVE INTO A STAGNANT WEATHER
PATTERN...WITH FEW FAST MOVING OR DEEP SYSTEMS TO SPEAK OF.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH 161 AND BLIZZARD WARNING 131(THOMPSON PASS)
MARINE...STORM...155 185 411 412 413
         GALE...120 125 132 138 140 150 160 165 170 172 175 176 180
                195 414.
FIRE WEATHER...NONE.

RMC FEB 13
120 125 132 138 140