Small Craft Advisory 657, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM ADT WED JUL 26 2006

.DISCUSSION...
A CHANGE IN THE PREDOMINANT WEATHER PATTERN SOUTHERN ALASKA HAS BEEN
EXPERIENCING IS IN STORE FOR THE LATTER HALF OF THE WEEK. THE UPPER
LEVEL LOW IN THE GULF OF ALASKA IS WEAKENING AND MOVING INTO THE
NORTHERN PANHANDLE OF THE STATE. AN UPPER LEVEL RIDGE IN THE BERING
SEA WILL BUILD INTO BRISTOL BAY AND THE KUSKOKWIM VALLEY BY THURSDAY
AFTERNOON. THE RIDGE AXIS WILL THEN EXTEND OVER KODIAK ISLAND THROUGH
THE COPPER RIVER BASIN BY FRIDAY AFTERNOON. THIS PATTERN WILL CLEAR
OUT A LARGE PORTION OF SOUTH CENTRAL ALASKA FOR THE NEXT FEW DAYS.

THE ATMOSPHERE OVER SOUTHERN ALASKA WILL BE NO MORE THAN MODERATELY
UNSTABLE THE NEXT FEW DAYS WITH TODAY BEING THE MOST UNSTABLE. WITH
THE SUN BREAKING OUT OVER A NUMBER OF AREAS THIS AFTERNOON CUMULUS
CLOUDS ARE APPEARING OVER A GOOD PORTION OF THE AREA...ESPECIALLY
OVER MOUNTAINS. THOUGH THE LOW LEVEL HEATING IS GETTING THIS GOING
RELATIVELY EARLY THE INDICATIONS ARE THAT THIS WILL NOT RESULT IN A
LARGE CONVECTIVE OUTBREAK DUE TO THE STABILITY OF THE ATMOSPHERE
ABOVE THE LFC. LOW LEVELS OF CAPE WILL KEEP THE CUMULUS FROM BUILDING
INTO THUNDERSTORMS WITH THE POSSIBLE EXCEPTION OF THE WESTERN SUSTINA
VALLEY NEAR THE ALASKA RANGE. OTHER PLACE WILL SEE SOME SHOWERS
AROUND THIS AFTERNOON AND EVENING...ESPECIALLY NEAR MOUNTAINS.

A MODERATE LOW SOUTH OF SHEMYA THIS AFTERNOON WILL MOVE INTO THE
WESTERN BERING SEA BY THURSDAY AFTERNOON AND THEN NORTHWARD TO THE ST
LAWRENCE ISLAND AREA FRIDAY. THIS LOW WILL BRING GALE FORCE WINDS TO
THE ALUETIAN ISLANDS AND BERING SEA AS IT MOVES THROUGH THOSE AREAS.

WEST OF THE ALASKA AND ALEUTIAN RANGES THE FLOW WILL TURN SOUTHWEST
AS THE RIDGE MOVES BY. THIS WILL LIKELY BRING MARINE STRATUS TO
COASTAL AREAS AFTER THE RIDGE AXIS MOVE TO THE EAST.

MODELS ARE IN GOOD AGREEMENT WITH ALL OF THE MAIN FEATURES. THERE ARE
SOME MINOR DIFFERENCES BETWEEN THE HIGH RESOLUTION NAM MODEL AND THE
LOWER RESOLUTION GFS OVER THE LAND AREAS BUT NOTHING THAT WILL IMPACT
THE FORECASTS VERY MUCH.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 155 170 172 175 179 180 185.
FIRE WEATHER...NONE.

JUL 06