Small Craft Advisory 1063, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTH CENTRAL AND SOUTHWEST ALASKA
200 PM AST MON DEC 17 2007

.ANALYSIS AND UPPER LEVELS...
TODAYS FEATURES INCLUDE AN UPPER LEVEL TROUGH OVER WESTERN ALASKA
WITH ONE CENTER OVER BARROW AND ONE CENTER OVER THE NORTHERN GULF OF
ALASKA..AN UPPER RIDGE FROM DUTCH HARBOR TO WEST OF ANADYR..AN UPPER
LOW OVER THE WESTERN ALEUTIANS AND A BAND OF WESTERLIES IN THE NORTH
PACIFIC NEAR 50N.  THE UPPER CENTER OVER BARROW WILL MOVE SLOWLY
SOUTH TO THE SEWARD PENINSULA BY THURSDAY. A SHORT WAVE IN THE POLAR
WESTERLIES WILL MOVE FROM OFF JAPAN TO NEAR UNALASKA AND LINK UP WITH
THE SEWARD PENINSULA CENTER BY THURSDAY. THE UPPER RIDGE WILL
RETROGRADE WEST ABOUT 15 DEGREES LONGITUDE BY THURSDAY. THE NORTHERN
GULF UPPER LOW WILL WEAKEN AND MOVE ONSHORE OVER THE NORTHEASTERN
GULF WEDNESDAY AND A RIDGE WILL BUILD OVER THE EASTERN GULF OF ALASKA
THURSDAY.

.MODEL DISCUSSION...
THE MODELS ARE CONVERGING AND GETTING INTO CLOSER AGREEMENT.  THE GFS
UKMET AND ECMWF ARE ALL WITHIN 6 HOURS OF EACH OTHER THURSDAY MORNING
AT 72 HOURS OUT. THE GFS AND ECMWF ARE IN GOOD AGREEMENT OVER THE
MAINLAND AND BERING SEA OUT THROUGH FRIDAY AFTERNOON. IN THE SHORT
TERM THE NAM IS IN GOOD AGREEMENT WITH THE OTHER MODELS ESPECIALLY
EAST OF 170W.

.SHORT TERM FORECAST...
THE LOW PRESSURE IN THE GULF OF ALASKA AND ASSOCIATED STRONG SURFACE
PRESSURE GRADIENT OVER SOUTH CENTRAL WILL REMAIN NEARLY STATIONARY
AND SLOWLY WEAKEN THROUGH WEDNESDAY NIGHT WITH VERY LITTLE CHANGE IN
THE WEATHER PATTERN. THE LOCALLY GUSTY SOUTH CENTRAL WINDS WILL
GRADUALLY DIMINISH THROUGH WEDNESDAY.  BANDS OF SNOW SHOWERS WILL
MOVE EAST OVER THE NORTH GULF REACHING PRINCE WILLIAM SOUND THROUGH
WEDNESDAY.

SOUTHWEST MAINLAND...
QUIET AND COLD WEATHER WILL PERSIST THROUGH WEDNESDAY NIGHT
OVER THE SOUTHWEST MAINLAND. GUSTY WINDS ESPECIALLY NEAR THE ALASKA
RANGE WILL DIMINISH BY WEDNESDAY. FURTHER WEST HIGH PRESSURE WILL
BUILD IN BRINGING LOW -40F TEMPERATURES TO THE KUSKOKWIM VALLEY
TUESDAY NIGHT AND ESPECIALLY WEDNESDAY NIGHT.

BERING/ALEUTIANS...
TWO STRONG AREAS OF LOW PRESSURE WILL AFFECT MAINLY THE WESTERN
PORTION OF THE REGION OVER THE NEXT FEW DAYS. THE FIRST LOW PRESSURE
IS NEAR KISKA TODAY AND IS BRINGING STORM FORCE WINDS TO THE
REGION AND RAIN AND SNOW. THIS LOW WILL MOVE NORTHWEST TOWARD
KAMCHATKA AS ANOTHER STRONG LOW MOVES UP FROM THE NORTH PACIFIC.
THE NEXT LOW WILL REACH THE CENTRAL ALEUTIANS WEDNESDAY AND THEN MOVE
EASTWARD ALONG THE CHAIN TO NEAR UNALASKA BY LATE THURSDAY. THIS LOW
WILL LIKELY BRING STORM FORCE WINDS TO THE CENTRAL AND EASTERN
ALEUTIANS WEDNESDAY AND THURSDAY. HIGH PRESSURE WILL PERSIST OVER THE
EASTERN BERING UNTIL WEDNESDAY.

.LONG TERM FORECAST...
THE TWO LONGER RANGE MODELS BOTH TREND TOWARD A LOW OVER SOUTHWEST
ALASKA BY SATURDAY.  THIS TRANSLATES TO A WARMING TREND FOR SOUTHERN
ALASKA WITH STRONG SOUTHEAST WINDS LIKELY IN PRINCE WILLIAM SOUND AND
TURNAGAIN ARM AND A GOOD CHANCE OF PRECIPITATION WITH HEAVIEST
AMOUNTS IN SOUTHEAST UPSLOPE EXPOSURES.  MODEL SOLUTIONS DIVERGE OVER
THE NORTH PACIFIC AND EASTERN GULF OF ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...HEAVY FREEZING SPRAY  121 125 129 130 132 138 140 141 150
                                 160 165 180 185
         STORM  172 175 176 411 412 413
         GALE  121 129 130 132 150 185 352
FIRE WEATHER...NONE.

RHH DEC 07