Small Craft Advisory 667, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKDT TUE AUG 25 2009

.ANALYSIS AND UPPER LEVELS...
ALOFT...THE DEEP UPPER TROUGH REMAINS OVER MAINLAND ALASKA WITH
RIDGING OVER THE WESTERN AND CENTRAL ALEUTIANS. A DEVELOPING UPPER
LOW ASSOCIATED WITH THE REMNANTS OF TYPHOON VAMCO WILL TEMPORARILY
FLATTEN THIS RIDGE AND DEEPEN THE TROUGH THROUGH THE END OF THE WEEK.

AT THE SURFACE...THE BROAD LOW COMPLEX IS IN PLACE OVER THE NORTHEAST
PACIFIC WITH A WEAKENING LOW IN THE EASTERN GULF. VARIOUS EASTERLY
WAVES ARE ROTATING AROUND THE LOW COMPLEX. ELSEWHERE...HIGH PRESSURE
RIDGING IS OVER THE CENTRAL ALEUTIANS. FORMER TYPHOON
VAMCO...CURRENTLY SOUTHWEST OF SHEMYA...IS HEADING STEADILY TOWARD
THE WESTERN BERING.

.MODEL DISCUSSION...
MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH SATURDAY. SIMILAR
STORY TO THIS MORNING...WITH THE NAM CONTINUING TO BE TOO SLOW IN
HANDLING FORMER TYPHOON VAMCO AS IT MOVES ACROSS THE BERING AND INTO
THE NORTH PACIFIC. OTHERWISE...THE MAIN POINT OF CONTENTION IS
HANDLING THE LOW COMPLEX REMAINING IN THE GULF OF AK AND NORTHEAST
PACIFIC AS WE HEAD INTO THE WEEKEND. AS A RESULT OF THESE
DIFFERENCES...THE AFTERNOON PACKAGE WAS CONSTRUCTED MAINLY USING THE
GFS SOLUTION.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
MAIN FORECAST PROBLEM ACROSS SOUTHCENTRAL WILL BE TIMING EASTERLY
WAVES AND UPPER SHORTWAVES AS THEY PULSE ACROSS THE AREA TONIGHT AND
TOMORROW. A DEFORMATION ZONE LOOKS TO SET UP ACROSS THE AREA LATE
WEDNESDAY AS WELL. AS A RESULT...SHOWERS ARE EXPECTED TO BEGIN
FORMING TONIGHT ACROSS THE REGION...BECOMING MORE WIDESPREAD
WEDNESDAY AND WEDNESDAY NIGHT. GOOD ONSHORE FLOW ASSOCIATED WITH THE
LOW COMPLEX IN THE NORTHEAST PACIFIC WILL KEEP RAIN AND NUMEROUS
SHOWERS ACROSS COASTAL PORTIONS OF SOUTHCENTRAL AS WELL AS WE HEAD
THROUGH THE END OF THE WEEK.

.SOUTHWEST...
GENERALLY FAIR WEATHER WILL PERSIST ACROSS SOUTHWEST TONIGHT THROUGH
TOMORROW AS UPPER RIDGING REMAINS IN CONTROL. AS THE TYPHOON REMNANTS
MOVE ACROSS THE EASTERN ALEUTIANS...EXPECT RAIN AND GUSTY WINDS TO
IMPACT THE AKPEN WEDNESDAY NIGHT AND THURSDAY. SCATTERED SHOWERS
CANNOT BE RULED OUT ALONG BRISTOL BAY AS WELL.

.BERING SEA AND ALEUTIANS...
BIG STORY OVER THE NEXT SEVERAL DAYS REVOLVES AROUND FORMER TYPHOON
VAMCO MOVING ACROSS THE BERING...ACROSS THE EASTERN ALEUTIANS...AND
INTO THE NORTHERN PACIFIC. WIDESPREAD RAIN AND WINDS UP TO STORM
FORCE WILL ACCOMPANY THE LOW. PRECIP WILL BE MOST WIDESPREAD ACROSS
THE WESTERN AND CENTRAL ALEUTIANS THIS EVENING AND TONIGHT...MOVING
INTO THE EASTERN ALEUTIANS AND PRIBILOFS TOMORROW AND THURSDAY.

.LONG TERM FORECAST...
EXPECT THE LOW COMPLEX TO REMAIN IN THE GULF OF AK THROUGH THE
WEEKEND...KEEPING MOIST FLOW ALONG COASTAL PORTIONS OF SOUTHCENTRAL.
INLAND PORTIONS WILL LIKELY SEE MORE SCATTERED SHOWERS. SOUTHWEST AK
WILL REMAIN RELATIVELY FAIR AND DRY AS UPPER RIDGING REMAINS OVER THE
AREA. WHILE DETAILS REMAIN UNCLEAR...THE BERING SEA AND ALEUTIANS
LOOK TO RETURN TO A MORE ACTIVE PATTERN AS WE HEAD INTO NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORM 172 175 179
         GALE 155 165 170 176
FIRE WEATHER...NONE

NRH AUG 09