Small Craft Advisory 55, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST SAT JAN 19 2008

.MODEL DISCUSSION...
MODELS ARE IN FAIRLY GOOD AGREEMENT THIS MORNING AND HAVE BEEN PRETTY
CONSISTENT IN THE SHORT TERM. GFS WAS CHOSEN OUT WEST FOR THE
DURATION.  IN THE EAST NAM WAS CHOSEN IN THE SHORT TERM TO HANDLE THE
SMALLER FEATURES WHILE GFS WAS CHOSEN OVERALL FOR THE LONG TERM.

.ANALYSIS AND UPPER LEVELS...
VERY STRONG UPPER LEVEL JET THIS MORNING PUSHING ITS WAY STRAIGHT UP
THE WEST COAST.  12Z ANALYSIS INDICATES A JET MAX OF 120 KTS IS
SUPPORTING THE LOW CURRENTLY IN THE NORTHERN BERING WITH A SECOND JET
MAX OF 125 KTS SUPPORTING THE LOW SOUTH OF THE ALEUTIANS.  MEANWHILE
THE UPPER LEVEL RIDGE IS ENTRENCHED OVER THE MAIN PORTION OF THE
STATE.  AS THE GRADIENT TIGHTENS THE STRONG WINDS ARE REACHING ALL
THE WAY DOWN TO THE SURFACE.  WARM AIR ADVECTION IS ALSO VERY
SIGNIFICANT WITH THESE SYSTEMS...WHICH HELPED TO STRENGTHEN THE RIDGE
BUT ALSO ELIMINATED BLIZZARD CONDITIONS BY WARMING THE SURFACE.
MODELS ARE CURRENTLY FORECASTING THE LOW SOUTH OF THE ALEUTIANS TO
MOVE INTO THE ALEUTIANS THIS MORNING AT 1005 MB...SATELLITE IMAGERY
INDICATES THIS MAY BE SLIGHTLY UNDERDONE AND THE LOW MAY BE STRONGER
THAN FORECAST.

.SHORT TERM FORECAST...
EAST OF THE ALASKA RANGE...THE FORECAST REMAINS DRY FOR A VERY SHORT
TIME UNTIL THE FRONT MOVES THROUGH SUNDAY MORNING.  STRONG WINDS ARE
EXPECTED IN CHANNELED AREAS...IN PARTICULAR ALONG TURNAGAIN
ARM...WITH SOUTHEASTERLIES AHEAD OF THE FRONT.  WHILE THE FORECAST IS
FOR RAIN IN THE KODIAK AREA NORTHWARD THE COLD AIR IS ENTRENCHED AND
SNOW IS EXPECTED FOR THE SUSITNA VALLEY.  THIS IS A BORDERLINE
ADVISORY EVENT SO SNOW TOTALS SHOULD BE WATCHED CAREFULLY IN THE
UPCOMING FORECASTS. BY MONDAY THE MAIN TROUGH WILL HAVE MOVED THROUGH
THE EASTERN ZONES.  A SECOND FRONT IS EXPECTED TO MOVE THROUGH ON
MONDAY AFTERNOON BUT THIS IS CURRENTLY NOT EXPECTED TO BE AS STRONG.

WEST OF THE ALASKA RANGE...HIGH WIND WARNINGS ALONG THE COAST THIS
MORNING AS THOSE STRONG UPPER LEVEL WINDS MIX DOWN TO THE SURFACE.
AS MENTIONED PREVIOUSLY ALL THE WARM AIR ADVECTION HAS ALSO LED TO
SOME ANOMALOUS WARM TEMPERATURES THROUGHOUT THE REGION.  MIXED PRECIP
AND RAIN CAN BE EXPECTED ALONG THE WEST COAST BUT IN THE KUSKOKWIM
RIVER VALLEY SNOW IS MORE LIKELY WITH THE OVERRUNNING.  CONDITIONS
ARE EXPECTED TO IMPROVE TEMPORARILY THIS AFTERNOON AND INTO SUNDAY...
BUT AS MENTIONED ABOVE THE MODELS MAY HAVE UNDERFORECAST THE STRENGTH
OF THE SYSTEM CURRENTLY SOUTH OF THE ALEUTIANS.  BY SUNDAY AFTERNOON
ANOTHER STRONG SYSTEM IS EXPECTED TO MOVE UP FROM THE NORTH PACIFIC
AND THIS WILL BRING HIGH WINDS AGAIN TO THE ALEUTIANS AND POTENTIALLY
ALONG THE COAST AS WELL.

.LONG TERM FORECAST...
AFTER SUNDAYS LOW MOVES UP THE WEST COAST IT LOOKS LIKE A RETURN TO
COLDER TEMPERATURES FOR MUCH OF THE STATE.  A RIDGE BUILDS IN OVER
THE CENTRAL BERING AND THIS SHOULD BRING COLD AIR THROUGH THE
MAINLAND.  CONSEQUENTLY THE FORECAST STILL CALLS FOR A CHANCE OF SNOW
FOR MOST LOCATIONS TUESDAY NIGHT AND INTO WEDNESDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 155 161
MARINE...GALE 120 130 132 138 140 141 150 155 160
              165 180 170 171 176 185 179
         STORM 160
         HEAVY FREEZING SPRAY 160 185
FIRE WEATHER...NONE

LEWF JAN 08