Small Craft Advisory 10, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
725 PM AST THU JAN 3 2008

.UPPER LEVELS...UPPER LEVEL PATTERN DOMINATED BY A COLD CORE LOW
ANCHORED OVER MAINLAND ALASKA WITH A BROAD TROUGH EXTENDING SOUTHWARD
INTO THE GULF OF ALASKA AND NORTHEAST PACIFIC. WELL DEFINED UPPER
LEVEL RIDGES EXIST BOTH OVER WESTERN CANADA AND THE BERING SEA.

.ANALYSIS AND SHORT TERM FORECAST...AT THE SURFACE A WELL DEFINED
CYCLONIC CIRCULATION WILL BECOME ESTABLISHED AROUND A SMALL LOW IN
THE NORTH PACIFIC BY SATURDAY MORNING. EASTERLY FLOW ALONG THE
NORTHERN AND EASTERN FLANKS OF THE LOW WILL SPREAD LIGHT SNOW ALONG
THE GULF COAST AND ACROSS THE KENAI PENINSULA. NORTHWESTERLY FLOW
ACROSS THE SOUTHWEST MAINLAND AND KODIAK ISLAND WILL HAVE A DRYING
EFFECT.

MEANWHILE OUT WEST STRATUS WILL PERSIST ACROSS THE CENTRAL AND
EASTERN BERING SEA. GUSTY NORTHWEST WINDS THROUGH CHANNELED AREAS
ALONG THE EASTERN ALEUTIANS AND ALASKA PENINSULA WILL DIMINISH THIS
EVENING AS THE GRADIENT RELAXES FROM THE WEST.

A SMALL 985 MB LOW ABOUT 120 NM EAST OF SHEMYA IS PROGGED TO
DISSIPATE ABOUT 60 NM SOUTH OF DUTCH HARBOR BY FRIDAY MORNING.
MINIMAL WIND AND PRECIPITATION ASSOCIATED WITH THIS SYSTEM.

.MODEL DISCUSSION...MODELS IN OKAY AGREEMENT. ECMWF MODEL PREFERRED
DUE TO BETTER INITIALIZATION AND RUN TO RUN CONSISTENCY. NAM IS THE
LEAST RELIABLE SOLUTION. GFS SOLUTION IS CLOSE TO ECMWF BUT WITH A
COUPLE OF NOTABLE DIFFERENCES.

GFS DOES NOT INITIALIZE THE LOW APPROACHING KODIAK TODAY AS DEEPLY AS
IT SHOULD AND DOES NOT MOVE IT AS CLOSE TO THE ISLAND TONIGHT AS THE
ECMWF OR UKMET. THUS GFS IS LIKELY UNDER FORECASTING THE NORTHWEST
WINDS ACROSS KODIAK ISLAND FOR TODAY TONIGHT AND TOMORROW. GFS IS
ALSO OVERDOING PRECIP FOR THE ISLAND. BEWARE.

OUT WEST GFS SOLUTION DIFFERS NOTABLY FROM ECMWF ONLY IN ITS HANDLING
OF A SMALL LOW IN THE NORTHWEST PACIFIC. THE GFS RECOGNIZES A WEAK
1000 MB NEAR 46N 176E FRIDAY AFTERNOON AND ARCS IT TOWARD THE CENTRAL
ALEUTIANS ON SATURDAY. ALL OTHER MODELS RECOGNIZE A SIGNIFICANTLY
STRONGER LOW AND KEEP IT WELL SOUTH OF THE ALEUTIAN CHAIN. THIS
FEATURE BEARS MONITORING BUT FOR THE TIME BEING WILL KEEP THE MARINE
FORECAST FOR CENTRAL ALEUTIANS SUB GALE IN ACCORDANCE WITH ECMWF
SOLUTION.

.EXTENDED FORECAST...THE LOW IN THE NORTHERN GULF OF ALASKA SATURDAY
IS EXPECTED TO REMAIN NEARLY STATIONARY AND GRADUALLY DISSIPATE. A
MODERATE LOW IS PROGGED TO BE ABOUT 330 NM WEST OF SHEMYA AT 00Z SUN.
MODELS DISAGREE ON STRENGTH BUT DO AGREE ON POSITION. FEATURE MAY
MOVE INTO WESTERN ALEUTIANS BUT WILL NOT LIKELY PROGRESS PAST ADAK
DUE TO A LACK OF UPPER LEVEL SUPPORT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 132 150 155 160 165 172 175
         HEAVY FREEZING SPRAY 130 132 138 150 155 160 165 179 180 185
FIRE WEATHER...NONE.

ASB JAN 08