Small Craft Advisory 750, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT FRI OCT 19 2012

.ANALYSIS AND UPPER LEVELS...THE UPPER LEVEL RIDGE IS MOVING EASTWARD
AND IMPACTING THE WEATHER OVER THE STATE MORE AS IT PUSHES THE UPPER
LEVEL LOW INTO THE SOUTHEAST ALASKA PANHANDLE. THIS WILL CONTINUE
THROUGH THE WEEKEND AS THE UPPER LEVEL RIDGE WILL MOVE OVER THE
WESTERN PART OF THE STATE AT THAT TIME. THIS WILL INCREASE THE
NORTHERLY FLOW IN SOUTH CENTRAL ALASKA AND PROVIDE MORE UPPER LEVEL
SUPPORT FOR GUSTY WINDS...ESPECIALLY ALONG THE NORTH GULF COAST.
AT THE SURFACE THE HIGH IS CENTERED NEAR DUTCH HARBOR WITH THE RIDGE
EXTENDING INTO THE EASTERN BERING SEA. THE SURFACE LOW IS IN THE
EASTERN GULF OF ALASKA AND IS CONTINUING TO WEAKEN AND DRIFT TO THE
SOUTHEAST.

.MODEL DISCUSSION...MODELS ARE DOING WELL OVER SOUTH CENTRAL ALASKA
AND MOST OF SOUTHWEST ALASKA BUT ARE STRUGGLING A LITTLE WITH A FRONT
THAT WILL MOVE THROUGH THE BERING SEA THIS WEEKEND. THE BIGGEST ISSUE
WITH THE FRONT IS THE STRENGTH AND ORIENTATION THE ECMWF HAS WITH IT
IN THE EASTERN BERING SEA ON SUNDAY. THE GFS.NAM SOLUTIONS LOOK
BETTER WITH THE WAY THIS FRONT IS SLAMMING INTO THE LARGE RIDGE OVER
THE STATE.

.SHORT TERM FORECAST...WITH THE HIGH PRESSURE BUILDING OVER THE
MAINLAND PART OF THE STATE THERE WILL BE LITTLE WEATHER OF NOTE
EXCEPT FOR WINDS. THE PRESSURE GRADIENT IS INCREASING IN THE GULF OF
ALASKA AREA AND DECREASING IN SOUTHWEST ALASKA THROUGH THE ALASKA
PENINSULA. TYPICAL GAP WINDS SUCH AS THE THROUGH THE MATANUSKA RIVER
VALLEY AND THROUGH THOMPSON WILL PERSIST THROUGH SATURDAY NIGHT.
AREAS NEAR COOK INLET WILL ALSO SEE WINDS PERSIST. AREAS FARTHER
INLAND AND NOT NEAR CHANNELED TERRAIN WILL PROBABLY SEE THE
ATMOSPHERE DECOUPLE OVERNIGHT AND SEE WINDS BECOME LIGHT...ALLOW AN
STRONG INVERSION DEVELOP AND THEREFORE SEE TEMPERATURES DROP RAPIDLY.
THERE WILL BE A LARGE DIFFERENCE IN TEMPERATURE BETWEEN WINDY AREAS
AND AREAS WHERE THE WIND DIES DOWN TONIGHT.

.LONG TERM FORECAST...THE RIDGE BUILDING INTO WESTERN ALASKA THIS
WEEKEND WILL BRIEFLY WEAKEN AS A FRONT IN THE BERING SEA MOVES INTO
IT. HOWEVER THIS RIDGE WILL QUICKLY REDEVELOP MONDAY OVER THE EASTERN
BERING SEA AND SOUTHWEST ALASKA WHERE IT WILL PARK ITSELF FOR THE
MAJORITY OF NEXT WEEK IN A STRONG BLOCKING PATTERN THAT WILL SENT THE
STORM TRACK WELL SOUTH OF THE STATE. THEREFORE EXPECT A SIGNIFICANT
AMOUNT OF CLEAR SKIES WITH BELOW NORMAL OVERNIGHT TEMPERATURES.
TEMPERATURES DURING THE DAY MAY E NEAR NORMAL AS THE SUN IS STILL
STRONG ENOUGH THIS TIME OF YEAR TO WARM SURFACES...ESPECIALLY ONES
NOT COVERED IN SNOW.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 130 132 150 175 176 185.
FIRE WEATHER...NONE.

OCT 12