Blizzard Watch 12, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
410 AM AST WED FEB 13 2008

.MODEL DISCUSSION...MODELS INITIALIZED WELL WITH NORTH PACIFIC LOW
AND ARE IN GOOD AGREEMENT WITH THE PROGRESSION OF THIS LOW TO KODIAK
ISLAND THURSDAY MORNING. THERE IS SLIGHT DIVERGENCE IN LOW TRACKS
AS THE LOW THEN MOVES INLAND...BUT SOLUTIONS ARE CENTERED AROUND
COOK INLET...AND FORECAST WOULD NOT VARY MUCH WITH ANY OF THESE
SOLUTIONS...SO DECIDED TO STICK CLOSE TO THE GFS TRACK. CONFIDENCE
QUICKLY DROPS BEHIND THIS SYSTEM AS MODEL SOLUTIONS RAPIDLY DIVERGE.
THEREFORE...WILL STICK CLOSE TO CURRENT FORECAST FROM THIS POINT
ONWARD.

.ANALYSIS AND UPPER LEVELS...SATELLITE SHOWS A STRONG VERTICALLY
STACKED LOW SOUTH OF DUTCH HARBOR. THIS SYSTEM HAS PRODUCED BLIZZARD
CONDITIONS ACROSS THE EASTERN ALEUTIANS AND INTO THE PRIBILOFS. THE
OCCLUSION IS MOVING INTO BRISTOL BAY..KODIAK ISLAND AND THE KENAI
PENINSULA WITH PRECIP PUSHING INLAND. STRONG SOUTH TO SOUTHEAST FLOW
SETTING UP OVER SOUTHCENTRAL IN ADVANCE OF THE LOW.

.SHORT TERM FORECAST...
EAST OF THE ALASKA RANGE...SOUTHCENTRAL ALASKA WILL BE ON THE WARM
SIDE  OF THE STORM SYSTEM. MOST AREAS MAY SEE A BRIEF PERIOD OF SNOW
AHEAD OF THE FRONT BEFORE WINDS COME UP. EXPECT HEAVIER AMOUNTS WEST
OF THE PARKS HIGHWAY WITH UPSLOPE WINDS AND COLDER TEMPS. STRONG
EASTERLIES WILL THEN DEVELOP AS THE FRONT NEARS TODAY AND PRODUCE
DOWNSLOPE DRYING ALONG THE LEE SIDE OF THE MOUNTAINS. WARM AIR
ADVECTION WILL TURN PRECIPITATION TO MAINLY RAIN FOR COASTAL AREAS BY
THIS AFTERNOON. WARM AIR WILL ALSO MOVE OVER TOP OF THE SURFACE COLD
LAYER INLAND...SO PRECIPITATION AT HIGHER ELEVATIONS MAY TURN TO RAIN
LATE TODAY AND LOW LEVELS MAY SEE SOME AREAS OF FREEZING RAIN. COLD
AIR WILL QUICKLY MOVE BACK IN THURSDAY NIGHT CHANGING ALL
PRECIPITATION BACK TO SNOW. ALSO EXPECT VERY STRONG WINDS ACROSS THE
KODIAK ISLAND WATERS AS THE COLD AIR ADVECTS BACK IN. SNOW WILL BEGIN
TO TAPER OFF FRIDAY...BUT NEXT FRONT WILL BE ON THE WAY WITH ANOTHER
CHANCE OF SNOW BY FRIDAY NIGHT.

BERING SEA/ALEUTIANS/AKPENN...EXPECT BLIZZARD CONDITIONS TO CONTINUE
ACROSS THE EASTERN ALEUTIANS AND PRIBILOFS THIS MORNING. WINDS WILL
PICK UP OUT OF THE NORTH BEHIND THE SYSTEM. STRONG COLD ADVECTION
BEHIND THE SYSTEM WILL RESULT IN SNOW SHOWERS AND BLOWING SNOW ACROSS
THE CENTRAL TO EASTERN BERING AND ALEUTIANS AS WELL AS THE SOUTHERN
ALASKA PENINSULA. STORM FORCE GUSTS ARE LIKELY THROUGH CHANNELED
AREAS TODAY. THE ICE EDGE WILL ALSO CONTINUE ITS MARCH SOUTHWARD.
CONDITIONS WILL GRADUALLY IMPROVE WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT AS THE LOW WEAKENS OVER INLAND SOUTHWEST ALASKA. THE NEXT STORM
SYSTEM WILL MOVE TO SOUTH OF THE ALEUTIANS THURSDAY AND REMAIN THERE
FRIDAY. THE MAIN IMPACT WILL BE GALE FORCE EASTERLIES ALONG THE
ALEUTIANS.

SOUTHWEST ALASKA...THE FRONT ASSOCIATED WITH THE PACIFIC LOW WILL
MOVE FROM EAST TO WEST ACROSS SOUTHWEST ALASKA WEDNESDAY...BRINGING
WARM AIR ALOFT OVER EASTERN PORTIONS OF BRISTOL BAY AND THE KUSKOKWIM
VALLEY. AREAS IMMEDIATELY ALONG THE MOUNTAINS WILL SEE DOWNSLOPE
DRYING SO DO NOT EXPECT ANY SIGNIFICANT PRECIPITATION. FARTHER FROM
THE MOUNTAINS THERE IS THE POTENTIAL FOR FREEZING RAIN AS LOW LEVEL
NORTHERLY FLOW MAINTAINS BELOW FREEZING SURFACE TEMPERATURES. FOR
NOW WILL ADD IN A CHANCE OF FREEZING RAIN. WESTERN PORTIONS OF
SOUTHWEST ALASKA WILL SEE ALL SNOW AND GUSTY WINDS RESULTING IN
REDUCED VISIBILITIES DUE TO BLOWING SNOW. MAY NEED BLIZZARD ALONG THE
COAST OF 161 AND 155. LOOKS LIKE BULK OF PRECIPITATION WILL REMAIN
EAST OF THERE...WITH MAINLY SNOW SHOWERS ALONG THE COAST.COLD AIR
WILL MOVE BACK INTO ALL OF SOUTHWEST ALASKA THURSDAY NIGHT CHANGING
ALL PRECIPITATION BACK TO SNOW. SNOW AND WINDS WILL GRADUALLY END
FRIDAY AS THE LOW MOVES TO NORTHERN ALASKA.

.LONG TERM FORECAST...LONG-WAVE PATTERN OF TROUGH CENTERED OVER THE
BERING AND RIDGE OVER WESTERN NORTH AMERICA LOOKS LIKE IT WILL HOLD
THROUGH THE EXTENDED PERIOD. THEREFORE...STORM TRACK WILL REMAIN
SIMILAR WITH LOWS TRACKING SOUTH OF THE ALEUTIANS AND THEN MOVING
NORTH ACROSS THE GULF AND SOUTHCENTRAL. THIS WILL KEEP THE BERING
COLD AND BRING A CHANCE OF PRECIPITATION EVERY 2 TO 3 DAYS ALONG THE
STORM TRACK. MODELS ARE WARMING THE INTERIOR INTO EARLY NEXT WEEK BUT
THIS IS STILL VERY UNCERTAIN. WILL MAINTAIN BELOW FREEZING TEMPS FOR
NOW.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 185 195
MARINE...HEAVY FREEZING SPRAY 121 130 140 165 179 185
         STORMS 120 130 170 172
         GALES 125 132 138 140 141 150 155 160 165 171 175 176 179
FIRE WEATHER...NONE

RNW FEB 08