Small Craft Advisory 977, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AKST MON NOV 30 2009

.MODEL DISCUSSION...MODELS ARE HOLDING TOGETHER WELL WITH THE OVERALL
PATTERN. THE BIG ISSUE BETWEEN THEM HAS TO DO WITH HOW MUCH WARM AIR
MOVES INTO SOUTH CENTRAL ALASKA. THE NAM IS COLDER THAN THE GFS OR
ECMWF SOLUTIONS...WHICH ARE VERY SIMILAR IN THEIR SHORT TERM
TEMPERATURE PROFILES. WHERE THIS MAY IMPACT THE FORECASTS IS WHEN AN
AREA MY TURN TO RAIN OR IF IT DOES AT ALL. THE FORECASTS HAVE BEEN
MORE WEIGHTED TO THE WARMER GFS/ECMWF TEMPERATURES. THIS COULD CAUSE
MORE SNOWFALL OVER A GREATER AREA IF IT TURNS OUT THE NAM IS MORE
CORRECT.

.ANALYSIS AND UPPER LEVELS...THE MAJOR STORM CENTERS AROUND THE LARGE
LOW IN THE BERING SEA AND THE FRONT ASSOCIATED WITH IT. THE LOW
CENTER IS NOW VERTICALLY STACKED AND THE MAJORITY OF THE ENERGY IS
RIDING THE JET STREAM ALONG THE FRONT FROM ABOUT 40N 160W RIGHT INTO
THE GULF OF ALASKA AND THEN NORTHWEST.
THERE IS A TRIPLE POINT ON THE FRONT TO THE NORTHWEST OF KODIAK WITH
THE WARM FRONT MOVING INTO THE COOK INLET REGION THIS AFTERNOON. THE
JET STREAM WILL MOVE EASTWARD AND INTO CANADA BY WEDNESDAY BUT THEN
REDEVELOP TO THE WEST OVER THE ALASKA PENINSULA AND INTO BRISTOL BAY
AS AN UPPER LEVEL RIDGE BUILDS INTO THE EASTERN PART OF SOUTH CENTRAL
ALASKA.

.SHORT TERM FORECAST...THE LOCATION OF THE TRIPLE POINT PUTS THE WARM
SECTOR OF THE SYSTEM JUST UPSTREAM FROM MOST OF SOUTH CENTRAL ALASKA
AND IS WHY IT IS BELIEVED THAT THE SNOW WILL TURN TO RAIN IN MOST OF
THE COASTAL AREAS. AS THE WARM SECTOR OF THE STORM TURNS THE SNOW TO
RAIN ALONG THE NORTH GULF COAST AND EASTERN KENAI PENINSULA THE WINDS
ARE EXPECTED TO REMAIN UP IN THE TIGHT PRESSURE GRADIENT. THE
GRADIENT WILL EASE FROM THE WEST TO EAST AND THEN LINGER ALONG THE
NORTH GULF COAST FROM PRINCE WILLIAM SOUND EAST...CAUSING THE BARRIER
JET TO REMAIN ALONG THE COAST EAST OF MONTAGUE ISLAND INTO TUESDAY
NIGHT.
THE OCCLUDED PORTION OF THE FRONT HAS NOW MOVED THROUGH THE FORECAST
AREA WEST OF THE ALASKA RANGE AND HAS ALLOWED THE WINDS TO
DIMINISH...ENDING THE BLIZZARD CONDITIONS THERE. THE EXCEPTION TO
THIS IS THE PRIBILOF ISLANDS REGION WHERE THE FRONT HAS STALLED AND
WILL KEEP BLIZZARD CONDITIONS AROUND THROUGH TUESDAY MORNING.

.LONG TERM FORECAST...ANOTHER STRONG LOW WILL MOVE INTO THE BERING
SEA LATE IN THE WEEK AS AN UPPER LEVEL RIDGE BUILDS FROM SOUTHEAST
ALASKA INTO THE EASTERN PART OF SOUTH CENTRAL ALASKA. THIS WILL
PRODUCE STRONG AND WARM SOUTH AND SOUTHEASTERLY FLOW OVER THE EASTERN
BERING SEA REGION IN THE LATER PART OF THE WEEK AND INTO THE WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 131 195.
         WINTER STORM WARNING 125 145.
         HIGH WIND WARNING 101 135.
MARINE...GALE 121 129 155 172 175 176 179 180 185.
         STORM 120 125 130.
         HEAVY FREEZING SPRAY 180 185.
FIRE WEATHER...NONE.

NOV 09