Small Craft Advisory 910, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST MON NOV 9 2009

.ANALYSIS AND UPPER LEVELS...
LARGE HIGH PRESSURE SYSTEM JUST EAST OF THE DATE LINE WITH A DEEP
LOW OVER THE NORTHEAST GULF OF ALASKA AND AN EVEN DEEPER LOW OVER
NORTHEAST SIBERIA. VERY FAST POLAR JET EXITING ASIA NEAR THE KURIL
ISLANDS AND KAMCHATKA PENINSULA THEN RACING ACROSS THE BERING SEA.
THE JET THEN SPLITS AND WEAKENS SLIGHTLY WITH SOME ENERGY GOING
ACROSS CENTRAL ALASKA BUT MOST DROPPING SOUTH INTO THE
GULF...CIRCLING THE LOW AND REACHING THE WEST COAST ALONG THE
OREGON/WASHINGTON BORDER. THE UPPER TROUGH AXIS EXTENDS FROM JUST
OFF THE PANHANDLE THROUGH ANCHORAGE AND UP TO POINT HOPE.

.SHORT TERM FORECAST...
THE UPPER TROUGH AXIS WILL SHIFT EAST RAPIDLY TODAY AND SNOWFALL
WILL END FROM WEST TO EAST ACROSS SOUTH CENTRAL ALASKA TODAY.
ANOTHER SYSTEM RIDING THE JET IS ALREADY MOVING INTO SOUTHWEST
ALASKA BRINGING ANOTHER SHOT OF SNOW. THIS WILL CROSS INTO SOUTH
CENTRAL ALASKA TONIGHT AND SHIFT EAST OF THE AREA TUESDAY NIGHT. YET
ANOTHER AND EVEN STRONGER SYSTEM (THE JET CONSOLIDATES VERY STRONGLY
BY THIS TIME) WILL AT THIS POINT ALREADY BE AFFECTING SOUTHWEST
ALASKA AND BY WEDNESDAY SHOULD BE IN SOUTH CENTRAL ALASKA.

.LONG TERM FORECAST...
BY THURSDAY THE NUMERICAL GUIDANCE IS ALL OVER THE PLACE WITH THE
WEATHER SYSTEMS...THE MODELS DO NOT USUALLY DO TOO GOOD WITH VERY
FAST FLOW AS VERY SMALL PERTURBATIONS CAN BE QUICKLY RAMPED UP INTO
MAJOR STORMS. BUT THE OVERALL PICTURE IS THE MEAN TROUGH POSITION
WILL BE WELL SETTLED IN OVER ALASKA FOR A COOLER THAN NORMAL PATTERN
AND NEAR NORMAL PRECIPITATION.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING 130.
         GALE WARNING 121 129 132 138 150 170 172 175 185.
FIRE WEATHER...NONE.

LUDWIG NOV 09