Small Craft Advisory 116, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST TUE FEB 3 2009

.MODEL DISCUSSION...
AGREEMENT NOT SO GREAT WITH THE NUMERICAL GUIDANCE EVEN BY 36 HOURS.
DIFFERENCES IN THE LOCATION AND STRENGTH OF THE LOW FORMING IN THE
GULF ON WEDNESDAY ARE SIGNIFICANT ENOUGH TO CAUSE SOME FORECASTING
UNCERTAINTY. THE GENERAL UPPER LEVEL PATTERN IS IN FAIR AGREEMENT
FOR A WHILE...BUT BY 00Z SATURDAY (FRIDAY AFTERNOON) THE DIFFERENCES
BECOME LARGE.

.ANALYSIS AND UPPER LEVELS...
UPPER LOW OVER OVER THE STATE WITH AN ELONGATED TROUGH SOUTH THROUGH
THE EASTERN GULF OF ALASKA. ANOTHER LOW OVER THE SOUTHWEST BERING
SEA WITH A FLANKING TROUGH OVER THE SEA OF OKHOTSK. STRONG NEARLY
FULL LATITUDE RIDGE JUST EAST OF 140 DEGREES WEST LONGITUDE AND A
TRANSITORY FLATTENING RIDGE SOUTH OF KODIAK ISLAND.

.SHORT TERM FORECAST...
EXPECT SHOWERS TO DIMINISH ACROSS SOUTH CENTRAL ALASKA TODAY AS THE
UPPER TROUGH AXIS SWINGS NORTHEAST. THIS WILL OPEN UP PROGRESSIVELY
MORE ZONAL SOUTHWESTERLY FLOW DURING THE NEXT COUPLE OF DAYS. THE
FIRST SYSTEM TO RIDE THIS RIVER IS A WEAKENING OCCLUDED FRONT THAT
WILL MOVE INTO SOUTHWEST ALASKA AND KODIAK ISLAND TONIGHT. A TRIPLE
POINT LOW WILL FORM ALONG THIS FRONT ON WEDNESDAY AND PICK UP STEAM
AS IT MOVES INTO SOUTH CENTRAL ALASKA.

BY THURSDAY MORNING THE SOUTHWESTERLY FLOW ALOFT WILL BECOME QUITE
PRONOUNCED AND A STRONGER SYSTEM WILL MOVE INTO SOUTHERN AND WESTERN
ALASKA.

.LONG TERM FORECAST...
UPPER LEVEL FLOW WILL BECOME AMPLIFIED AGAIN LATER IN THE WEEK AS
ANOTHER TROUGH SETTLES INTO ALASKA. HOW LONG THIS WILL REMAIN OVER
THE STATE IS A HOTLY CONTESTED ITEM AMONGST THE MAJOR GUIDANCE. THE
GFS WOULD LIKE TO KICK IT OUT QUICKLY...BY MONDAY MORNING WHILST THE
ECMWF WOULD PREFER TO HOLD ON TO IT WELL INTO NEXT WEEK. THE MORNING
FORECAST PACKAGE REFLECTS THIS UNCERTAINTY WITH A FORECAST OF
TEMPERATURES AND CHANCES OF PRECIPITATION NEAR CLIMATOLOGY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING 172 175 176.
         GALE WARNING 155 160 170 185.
         HVY FRZ SPRY WARNING 121 125 129 130 132 138 140 141.
FIRE WEATHER...NONE.

LUDWIG FEB 09