Small Craft Advisory 783, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT FRI SEP 30 2005

.DISCUSSION...
SHORT TERM...
THE LOW IN THE NORTHERN GULF IS EXPECTED TO REMAIN STATIONARY THROUGH
TONIGHT THEN SLOWLY DRIFT NORTHWEST INTO THE SOUND AND WEAKEN. THE
MAIN UPPER LEVEL LOW IS CENTERED OVER NORTHWEST ALASKA AND THIS WILL
SLOWLY DROP SOUTH ACROSS WESTERN ALASKA. ANOTHER UPPER LOW WILL
ROTATE AROUND THIS MAIN CENTER INTO THE GULF OF ALASKA TONIGHT. A
WEAK LOW IS FORMING OVER THE KUSKOKWIM DELTA AND THIS WILL MOVE SOUTH
IN RESPONSE TO THE UPPER LEVEL LOW. THE POLAR FRONT CURRENTLY EXTENDS
THROUGH THE KUSKOKWIM VALLEY TO THE LOW IN THE DELTA. WE EXPECT THE
COLD AIR TO REMAIN WEST OF THE RANGE THROUGH TONIGHT. THE SOUTHERN
END OF THE POLAR FRONT WILL PUSH ACROSS THE ALEUTIAN MOUNTAINS AND
KAMISHAK GAP TONIGHT AND THUS WE EXPECT THIS TO INDUCE SHOWERS ACROSS
THOSE REGIONS. THE MOISTURE NOW OVER THE KUSKOKWIM VALLEY WILL IS
FALLING OUT AS SNOW OR RAIN AND SNOW ALONG THE ALASKA RANGE. MORE
MOISTURE WILL ROTATE IN FROM THE NORTHEAST TO KEEP SHOWERS GOING
THROUGH SAT NIGHT THEN DRY OUT BY SUN.

A LOW 300 NM WEST OF THE PRIBILOFS WILL MOVE SOUTH OF THE PRIBILOFS
LATE TONIGHT. AS IT DOES THE GUSTY NORTHWEST WIND WILL DIMINISH. HE
MOISTURE ASSOCIATED WITH THIS LOW WILL TRACK ACROSS UNALASKA LATE
TONIGHT RESULTING IN A GOOD SHOT OF SHOWERS. FOLLOWING THIS LOW A
WEAK RIDGE WILL BUILD INTO THE CENTRAL BERING SEA INCREASING THE
LIKELYHOOD OF FOG.

LONGER TERM...
BY SUN NIGHT THE UPPER LOW OVER WESTERN ALASKA DROPS INTO THE GULF.
THIS WILL RESULT INT HE SURFACE LOW DROPPING SOUTH AS WELL AND A
RIDGE OF HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT BUILDS INTO THE
BERING SEA THEN WESTERN ALASKA. BY SUN AFTERNOON THE FLOW ALONG THE
NORTH GULF COAST AND SOUTH CENTRAL ALASKA WILL BE DRIER NORTHERLY
FLOW.

THE NEXT STORM MOVING INTO THE PICTURE FOR THE ALEUTIANS IS A LOW NOW
WELL SOUTH OF THE ALEUTIANS. WE EXPECT THIS TO INTENSIFY TO AROUND
990 MB JUST SOUTH OF UNALASKA MON.

BEYOND MONDAY THE LEVEL OF UNCERTAINTY FOR THE FORECAST POSITION OF
THIS LOW IS HIGH AS THE MODELS HAVE MADE A MAJOR CHANGE FROM THE
PREVIOUS FEW CYCLES. CURRENTLY WE WILL MAINTAIN THE EXPECTED
CONDITIONS FROM THE PREVIOUS FORECAST PACKAGE FOR DAYS 5 ON OUT UNTIL
THE MODELS SETTLE UPON A SOLUTION.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...DONE.

SAM SEP 05