Small Craft Advisory 942, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AST FRI NOV 9 2007

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL TROUGH EXTENDS FROM THE BERING STRAIT TO SOUTH OF
KODIAK ISLAND THIS AFTERNOON. A VERTICAL MODERATELY STRONG SURFACE
LOW IS CENTERED OVER EASTERN BRISTOL BAY. A STATIONARY WEAKENING
FRONT EXTENDS FROM COOK INLET SOUTHEASTWARD OVER THE GULF OF ALASKA.

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GENERAL AGREEMENT THROUGH SUN NIGHT. THE
MAIN FEATURES INCLUDE THE BRISTOL BAY LOW MOVING SLOWLY EAST THEN
STALLING AND WEAKENING NEAR MIDDLETON ISLAND SUN...A STORM DEVELOPING
SOUTH OF THE ALEUTIANS AND BECOMING AN INTENSE LOW NEAR THE SOUTHERN
PANHANDLE SUN...AND A LARGE LOW MOVING FROM EASTERN SIBERIA TO THE
NORTHERN BERING OVER THE WEEKEND PRODUCING MODERATELY STRONG WESTERLY
WINDS ACROSS THE ENTIRE ALEUTIAN CHAIN SAT AND SUN. MODEL SOLUTIONS
ARE DIVERSE AND VARIED AFTER MON.  THE COMMON THEME OF THE GFS AND
ECMWF FOR NEXT WEEK IS TO DEVELOP A MAJOR PATTERN CHANGING LOW OVER
THE MID PACIFIC AND BRING IT TO THE NORTHERN GULF OF ALASKA BY LATE
NEXT WEEK. IF THIS HAPPENS IT WILL BE A SIGNIFICANT SHIFT IN THE
PATTERN MOVING AN ANCHOR CIRCULATION CENTER TO THE GULF OF ALASKA.

.SHORT TERM FORECAST...
IN THE BERING AND ALEUTIANS...RAIN AND SNOW SHOWERS WILL DIMINISH
OVER THE ALEUTIANS TONIGHT AND INCREASE OVER THE NORTHERN AND CENTRAL
BERING TONIGHT AND SAT WITH THE LOW MOVING IN FROM SIBERIA. THE
SHOWER ACTIVITY WITH THE SIBERIAN LOW WILL REACH THE ALASKA PENINSULA
LATE SAT AND SOUTHWEST ALASKA SUN AND MON. WESTERLY GALE FORCE WINDS
ARE EXPECTED OVER THE SOUTHERN BERING AND THE ENTIRE ALEUTIAN CHAIN
SAT AND SUN.

OVER SW AK SHOWERS WILL DIMINISH AND END TONIGHT AS THE BRISTOL BAY
LOW MOVES ACROSS THE ALASKA PENINSULA. A WEAK RIDGE WILL DRY OUT THE
AREA TEMPORARILY SAT NIGHT INTO SUN. THE SIBERIAN LOW MOVING INTO THE
BERING WILL SET UP AN OVERRUNNING SCENARIO SUN AFTERNOON THROUGH
EARLY MON MORNING. TEMPERATURES ALOFT WILL REMAIN SUFFICIENTLY COLD
FOR THIS TO BE AN ALL SNOW EVENT. SNOW SHOWERS WILL THEN CONTINUE
BEHIND THIS SYSTEM INTO THE MIDDLE OF NEXT WEEK AS A LOW DEVELOPS
ALONG THE BERING COLD FRONT AND REACHES THE COAST DURING
THE PERIOD.

SOUTH AND EAST OF THE AK RANGE...THE GULF FRONT WILL SLOWLY MOVE EAST
AND WEAKEN.  RAIN AND SNOW ALONG THE COAST AND IN THE INTERIOR WILL
DIMINISH BUT PERSIST ON SOUTHEAST UPSLOPE REGIONS THROUGH TONIGHT.
PRECIPITATION WILL MOVE TO THE NORTHEAST GULF COAST AND EASTERN
PRINCE WILLIAM SOUND TONIGHT WITH SOME SNOW POSSIBLY MAKING IT ACROSS
THE CHUGACH INTO THE COPPER RIVER BASIN AND TALKEETNA
MOUNTAINS. THIS WILL ALL TAPER OFF SUN AS THE BRISTOL BAY LOW CROSSES
THE ALASKA PENINSULA AND BRINGS RAIN TO KODIAK ISLAND.

.LONG TERM FORECAST...
CONFIDENCE IS LOW DUE TO DIVERGENCE OF MODEL SOLUTIONS.  A POSSIBLE
SHIFT IN THE PATTERN IS INDICATED.  IF THIS HAPPENS LOOK FOR AN
ANCHOR LOW IN THE GULF OF ALASKA.  RESULTANT WEATHER WILL BE A STRONG
COOLING TREND ESPECIALLY OVER WESTERN ALASKA AND THE EASTERN BERING
BY LATE NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES 120 125 150 155 165 180 185 414
FIRE WEATHER...NONE

RHH NOV 07