Gale Warning 558, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKDT SAT AUG 14 2010

.ANALYSIS AND UPPER LEVELS...AN UPPER LEVEL RIDGE COVERS MUCH OF
MAINLAND ALASKA WITH AN AXIS THAT CURVES ALONG THE BRITISH COLUMBIA
COAST AND INTO MAINLAND ALASKA. MEANWHILE A LOW CENTERED NEAR THE
PRIBILOFS COVERS THE EASTERN AND CENTRAL BERING. AN ASSOCIATED SHARP
UPPER LEVEL SHORTWAVE STRETCHES ACROSS THE EASTERN ALASKA PENINSULA
INTO THE NORTH PACIFIC.

.AT THE SURFACE...SURFACE HIGH PRESSURE EXISTS UNDERNEATH THE UPPER
LEVEL RIDGE ACROSS THE EASTERN GULF AND INTERIOR MAINLAND ALASKA. A
SURFACE LOW EXISTS UNDERNEATH THE UPPER LEVEL LOW NEAR BRISTOL BAY.
MEANWHILE A NEW TRIPLE POINT LOW IS FORMING SEVERAL HUNDRED MILES
SOUTH OF KODIAK ISLAND.  THIS LOW IS EXPECTED TO INTENSIFY AND MOVE
ACROSS KODIAK ISLAND AND THE SOUTHCENTRAL REGION INTO SUNDAY NIGHT.

.MODEL DISCUSSION...MODELS ARE IN GENERAL AGREEMENT IN THE SHORT
TERM. WHILE THE GFS WAS GENERALLY FAVORED...THE HIGH RESOLUTION NAM
HAS BEEN ABLE TO CAPTURE WEAK SHORTWAVE FEATURES OVER SOUTHCENTRAL.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...EASTERN PORTIONS OF THE SOUTHCENTRAL REGION REMAIN
ALONG THE BOUNDARY OF A WELL DEVELOPED RIDGE OVER THE GULF AND A LOW
PRESSURE SYSTEM OVER THE BERING. A SERIES OF WEAK SHORTWAVES ALONG
THIS BOUNDARY ARE RESULTING IN PERIODS OF SHOWERS AND SUNSHINE ACROSS
THE REGION. THE COPPER RIVER BASIN IS BENEATH THE UPPER LEVEL RIDGE
AXIS AND HAS REMAINED MOSTLY CLEAR TODAY. THE CHANCE FOR RAIN WILL
INCREASE BY SUNDAY AS A TRIPLE POINT LOW ASSOCIATED WITH GOOD
MOISTURE TRANSPORTATION PROGRESSES FROM THE WEST. CONDITIONS WILL
REMAIN UNSETTLED IN THE SHORT TERM AS ANOTHER LOW APPROACHES MONDAY.

.SOUTHWEST...
.LONG TERM FORECAST...A STRONG PRESSURE GRADIENT BETWEEN A BERING LOW
AND GULF HIGH ALONG WITH A DEVELOPING SURFACE LOW...ARE SUPPORTING
STRONG UPPER LEVEL WINDS ACROSS THE BRISTOL BAY REGION. GUSTS OF 48
KT HAVE BEEN MEASURED AT PORT HEIDEN AND 46 KT AT TOGIAK. RAIN
SHOWERS HAVE ALSO OCCURRED WITH THIS FRONT...AS BROAD SOUTHERLY FLOW
TRANSPORTS MOISTURE FROM THE TROPICS. THE PRESSURE GRADIENT IN THE
REGION WILL RELAX BY TOMORROW AS THE LOW PRESSURE MOVES TO THE
NORTHWEST AND THE LOW PROGRESSES EASTWARD. THIS SYSTEM WILL BRING
RAIN AND WINDS TO THE INTERIOR SOUTHWEST MAINLAND SUNDAY AS IT
PROGRESSES EASTWARD.

.ALEUTIANS...A WEAKENING SURFACE LOW PRESSURE IS BRINGING THE CHANCE
FOR RAIN SHOWERS TO THE WEST AND CENTRAL ALEUTIANS TODAY. THIS LOW IS
EXPECTED TO CONTINUE TO SLOWLY PROGRESS EASTWARD AND KEEP SHOWERS IN
THE FORECAST FOR MUCH OF THE ALEUTIANS. GALE FORCE WINDS ARE ALSO
POSSIBLE WITH THIS SYSTEM.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES...130 132 140 150 160 180 185 176
FIRE WEATHER...FINISHED FOR THE SEASON.

ELN AUG 10