Gale Warning 34, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST SUN JAN 3 2010

.ANALYSIS AND UPPER LEVELS...
A PATTERN SHIFT IS IN THE WORKS THIS MORNING..WITH THE LONGWAVE TROUGH
MOVING OVER THE CENTRAL BERING AND AN UPPER LEVEL RIDGE BUILDING OVER
THE PANHANDLE.  REFLECTING DOWN TO THE SURFACE...A 965 MB LOW IN THE
NORTH PACIFIC IS SLOWLY MAKING ITS WAY TOWARD THE STATE.  AS IT MOVES
NORTHWARD IT WILL BEGIN TO RECURVE TO THE WEST AS IT IS PUSHED THAT
DIRECTION BY THE UPPER LEVEL RIDGE. A SIGNIFICANT AMOUNT OF WARM AIR
WILL MOVE UP FROM THE NORTHERN PACIFIC...BRINGING WARMING TEMPERATURES
TO THE STATE AND AMPLIFYING THE UPPER LEVEL RIDGE.

.MODEL DISCUSSION...
MODELS WERE IN GOOD AGREEMENT OVER THE SHORT TERM.  THE 06Z RUNS OF
THE NAM/GFS DID DIFFER A LITTLE FROM THE 00Z RUNS ON TIMING OF THE
SHORTWAVE INTO THE SOUTHERN PORTION OF THE STATE.  THE 00Z MODEL RUN
SHOWED THE SHORTWAVE MOVING THROUGH IN THE AFTERNOON...WHILE THE 06Z
RUNS INDICATED MORE PRECIPITATION IN THE MORNING.  AS OF THIS
ISSUANCE...THE 00Z RUNS APPEAR TO BE VERIFYING A LITTLE BETTER THIS
MORNING AND THE INITIAL PANELS OF THE 12Z NAM CONCUR.  IN THE LONG
TERM HPC GUIDANCE WAS BLENDED WITH THE ECMWF FOR THIS MORNINGS
FORECAST.

.SHORT TERM FORECAST...
IN THE EAST...TEMPERATURES ARE EXPECTED TO RISE OVER THE NEXT COUPLE
OF DAYS AS THE LOW MOVING TOWARD THE CENTRAL ALEUTIANS BRINGS WARM
MOIST AIR IN.  THIS WILL BRING SOME SNOW TO THE SOUTHCENTRAL REGION
INITIALLY WITH OVERRUNNING AHEAD OF THE MAIN FRONT. BY MONDAY NIGHT
WARMER TEMPERATURES WILL CAUSE MIXED PRECIPITATION MAINLY ALONG THE
COAST...WHILE DOWNSLOPING WILL PREVENT MUCH PRECIP FROM FALLING IN THE
ANCHORAGE BOWL AND THE WESTERN KENAI PENINSULA.  IN THE SUSITNA VALLEY
PRECIPITATION WILL BE A LITTLE HEAVIER...ESPECIALLY WEST OF THE PARKS
HIGHWAY.  EXPECT STRONG WINDS THROUGH ALL THE USUAL CHANNELED AREAS
SUCH AS THE TURNAGAIN ARM AND HIGHER ELEVATIONS.

WEST OF THE ALASKA RANGE...BIG WARM UP EXPECTED OVER THE NEXT COUPLE
DAYS FOR THE WESTERN ZONES.  THE STRONGEST WINDS WILL BE CIRCULATING
RIGHT AROUND THIS LOW...SO A DOWNSLOPE EFFECT CAN BE EXPECTED JUST
WEST OF THE ALASKA RANGE.  PILOTS CAN EXPECT TO SEE WIND SHEAR IN THE
TAFS WITH A STRONG LOW LEVEL JET AROUND THIS LOW...ESPECIALLY JUST
AHEAD OF THE WARM FRONT WHEN THE SURFACE WINDS WILL BE FROM THE NORTH.
BY TONIGHT THERE MAY BE SOME LOCALIZED AREAS OF FREEZING RAIN WEST OF
THE ALASKA RANGE...WITH THE NORTHEAST FLOW BRINGING IN COLD
TEMPERATURES AT THE SURFACE BUT SOUTHERLY FLOW BRINGING WARM AIR
ALOFT.  EXPECT THE WARMER TEMPERATURES TO MAKE IT ALL THE WAY TO THE
KUSKOKWIM DELTA BY MONDAY NIGHT.  THESE SHOULD BE SHORTLIVED WITH A
RETURN TO A SNOW FORECAST FOR THE K DELTA BY TUESDAY.

BERING SEA/ALEUTIANS...WITH THAT STRONG WEATHER FRONT MOVING IN TODAY
THE USUAL STRONG WINDS CAN BE EXPECTED ALONG THE ALEUTIANS AND IN THE
PRIBILOFS.  RIGHT NOW WINDS WILL REMAIN GALE FORCE FOR THE SHORT TERM
MARINE FORECAST...WITH SOME STORM FORCE WINDS MAKING IT INTO THE ST
MATTHEW ISLAND WATERS IN THE MID RANGE.  AHEAD OF THE FRONT THE STRONG
NORTHEAST WINDS WILL BRING COLD TEMPERATURES AND SNOW TO THE
PRIBILOFS...MAKING A GOOD CHANCE FOR A BLIZZARD TONIGHT.  OF COURSE
THIS IS HIGHLY DEPENDENT ON HOW FAST THE FRONT MOVES THROUGH AND THE
TEMPS WARM UP...SO IF THAT OCCURS TO QUICKLY A BLIZZARD WOULD BE SHORT
LIVED AT BEST.  AT THIS POINT IT IS STILL QUESTIONABLE ENOUGH TO MAKE
IT A WATCH FOR TONIGHT...NOT A WARNING.  THIS WILL BE REEXAMINED ON
THE DAY PACKAGE.

.LONG TERM FORECAST...
LONG TERM FORECAST IS UNCERTAIN AS ALWAYS BUT AT THIS POINT LOOKS TO
REMAIN STORMY.  A NEW LOW IS FORECAST TO MOVE INTO THE ALEUTIANS ON
THURSDAY BRINGING MORE WINDS AND MOST LIKELY RAIN TO THE WESTERN ZONES
WITH THE WARM TEMPERATURES ALOFT.  IN THE EAST...MORE DOWNSLOPING CAN
BE EXPECTED ON THE WEST SIDES OF THE MOUNTAINS WITH MIXED
PRECIPITATION OR EVEN RAIN ALONG THE GULF COAST.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH 195
MARINE...GALES 130 132 138 150 155 160 165 180
               170 171 172 175 176 185 179
         HEAVY FREEZING SPRAY 160 180 185 179
FIRE WEATHER...NONE

LEWF JAN 10