Small Craft Advisory 436, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKDT WED MAY 27 2009

.ANALYSIS AND UPPER LEVELS...
A STACKED UPPER LEVEL LOW OVER NORTHWEST AK REMAINS STALLED.
AN ASSOCIATED FRONTAL BOUNDARY IS DRAPED ACROSS THE KUSKOKWIM VALLEY
WITH COOLER AND DRIER AIR TO THE WEST. STATIONARY LOW PRESSURE OVER
THE GULF OF ALASKA CONTINUES TO WEAKEN AND FILL. A SURFACE RIDGE
CONTINUES TO BUILD OVER THE EASTERN BERING. A WEATHER FRONT
ASSOCIATED WITH A POTENT STACKED LOW CENTERED TO THE WEST OF THE
ALEUTIAN ISLANDS IS RESPONSIBLE FOR LOW CLOUDS AND LIGHT
PRECIPITATION OVER THE ALEUTIANS AND BERING SEA.

.MODEL DISCUSSION...
MODELS ARE STILL SHOWING AGREEMENT IN THE SHORT TERM EVOLUTION OF
THE RIDGE BUILDING INTO THE GULF BY FRI NIGHT...AND THE ALEUTIAN LOW
MOVING SOUTH OF THE CHAIN. SECONDARY LOWS WILL PINWHEEL ACROSS THE
ISLANDS AS THE MAIN LOW DRIFTS INTO THE NORTH PACIFIC BY THE WEEKEND.
MODELS GENERALLY AGREE IN THE LONG TERM BUT BEGIN TO DISAGREE ON THE
PLACEMENT OF THE ALEUTIAN LOW AND ASSOCIATED SHORTWAVES BY MONDAY.
THE FORECAST RELIES HEAVILY ON THE GFS THROUGH THE ENTIRE FORECAST...
WITH ITS SOLUTION BEING A GOOD COMPROMISE EARLY NEXT WEEK.

.SHORT TERM FORECAST...
RAIN SHOULD PERSIST THROUGH MUCH OF THE DAY OVER THE ANCHORAGE BASIN
AND ALONG THE GULF COAST. PRECIPITATION WILL DECREASE AS THE RIDGE
BUILDS INTO THE REGION BEGINNING FRIDAY. WEST OF THE FRONT...
SOUTHWEST AK SHOULD REMAIN MOSTLY DRY WITH THE CHANCE OF AFTERNOON
SHOWERS THROUGH FRI. THE FRONT ASSOCIATED WITH THE LOW TO THE WEST OF
THE ALEUTIANS SHOULD KEEP SHOWERS OVER MUCH OF THE CHAIN THROUGH THE
WEEKEND.

.LONG TERM FORECAST...
THE ALEUTIAN LOW WILL BECOME STATIONARY SOUTH OF THE ISLANDS AND
IMPULSES WILL ROTATE ACROSS THE ISLANDS INTO THE MIDDLE OF NEXT WEEK.
THIS WILL BRING SHOWERS TO THE REGION THROUGH THE SAME PERIOD. FOR
SOUTHWEST AK...EXCEPT FOR A FEW SHOWERS OVER THE WEEKEND...HIGH
PRESSURE WILL BUILD INTO THE AREA BRINGING DRY CONDITIONS THROUGH THE
MIDDLE OF NEXT WEEK. SOUTHEAST OF THE AK RANGE...LINGERING SHOWERS
WILL END BY SAT NIGHT AS HIGH PRESSURE BUILDS INTO THE GULF. DRY
CONDITIONS WILL THEN PERSIST THROUGH MUCH OF NEXT WEEK.

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

EN/DS MAY 09