Gale Warning 373, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT SUN APR 21 2013

.ANALYSIS AND UPPER LEVELS...
A COMPACT UPPER LOW OVER KODIAK ISLAND ALONG WITH AN ATTENDANT
SURFACE REFLECTION JUST TO ITS EAST ARE DRIFTING SLOWLY TOWARDS THE
NORTHEAST THIS AFTERNOON...WITH AN ASSOCIATED FRONT OVER THE NORTHERN
GULF OF ALASKA BRINGING RAIN AND SNOW TO KODIAK ISLAND AND COASTAL
PORTIONS OF SOUTHCENTRAL AK. FURTHER INLAND...SURFACE HIGH PRESSURE
CONTINUES TO PROMOTE CLEAR SKIES AND MILD CONDITIONS OVER MUCH OF THE
SOUTHERN MAINLAND...ALTHOUGH HIGH CLOUDS HAVE BEGUN TO SPREAD
NORTHWARD INTO THE ANCHORAGE BOWL AND MATANUSKA VALLEY. A DEEPENING
NORTH PACIFIC UPPER LOW IS ADVANCING RAPIDLY SOUTHWARD ALONG
170W...ALLOWING UPPER LEVEL RIDGING TO BUILD EASTWARD OVER THE BERING
SEA.

.MODEL DISCUSSION...
MODELS CONTINUE TO COME INTO BETTER AGREEMENT IN THE HANDLING OF THE
SYSTEM CURRENTLY AFFECTING THE NORTHERN GULF AND REMAIN IN GENERALLY
GOOD AGREEMENT WITH RESPECT TO THE OVERALL SYNOPTIC PATTERN THROUGH
THE MIDDLE OF THE WEEK. THE UPPER LOW OVER KODIAK ISLAND WILL MOVE TO
THE NORTHERN GULF COAST JUST EAST OF PRINCE WILLIAM SOUND LATE
TONIGHT AS THE SURFACE LOW WEAKENS AND THEN DISSIPATES...THEN DEPART
TO THE EAST ON MONDAY WHILE TRANSITIONING INTO AN OPEN WAVE. THIS
WILL ALLOW HIGH PRESSURE TO BECOME REESTABLISHED OVER SOUTHCENTRAL AK
ON MONDAY. HIGH PRESSURE WILL CONTINUE TO DOMINATE THE BERING THROUGH
THE MIDDLE OF THE WEEK WITH A STRONG NORTH PACIFIC LOW REMAINING WELL
SOUTH OF THE ALEUTIAN CHAIN AND A SURFACE FRONT EXTENDING EASTWARD
INTO THE GULF.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
RAIN AND SNOW WILL CONTINUE INTO TONIGHT ALONG THE GULF COAST AS THE
LOW NEAR KODIAK ISLAND TRAVERSES THE NORTHERN GULF. THE IMPACTS FROM
THIS SYSTEM FURTHER INLAND WILL LARGELY BE LIMITED TO INCREASING MID
AND AND UPPER LEVEL CLOUDINESS DURING THE EVENING AND NIGHTTIME
HOURS... ALTHOUGH A FEW SHOWERS ARE POSSIBLE AS WELL. PRECIPITATION
WILL BEGIN TO TAPER OFF ON MONDAY MORNING AS THE LOW DEPARTS TO THE
EAST AND HIGH PRESSURE BUILDS BACK INTO THE AREA. PRECIPITATION WILL
RETURN TO SOUTHCENTRAL AK ON TUESDAY AS ANOTHER FRONT MOVES INTO THE
GULF...WITH PRECIPITATION ONCE AGAIN MOST LIKELY OVER KODIAK ISLAND
AND ALONG THE GULF COAST WITH A FEW SHOWERS INLAND.

SOUTHWEST ALASKA...
CALM AND PLEASANT CONDITIONS WILL PREVAIL FOR THE EARLY PART OF THE
WEEK AS THE SOUTHWEST MAINLAND REMAINS ON THE EASTERN PERIPHERY OF
HIGH PRESSURE OVER THE BERING. A CHANCE FOR PRECIPITATION WILL RETURN
TO THE SOUTHERN PART OF THE AREA LATE MONDAY AS A FRONT ASSOCIATED
WITH A NORTH PACIFIC LOW APPROACHES THE AKPEN...WITH SHOWERS
SPREADING NORTHWARD TO THE BRISTOL BAY REGION ON TUESDAY.

ALEUTIANS/BERING SEA...
PRECIPITATION WILL TAPER OFF THIS EVENING ACROSS THE WESTERN
ALEUTIANS AS A WEAK FRONT CONTINUES TO DISSIPATE.
OTHERWISE...GENERALLY BENIGN CONDITIONS WILL PREVAIL THROUGH THE
MIDDLE OF THE WEEK AS HIGH PRESSURE DOMINATES THE REGION.

.LONG TERM FORECAST...
A DEVELOPING REX BLOCK WILL DICTATE THE UPPER LEVEL PATTERN INTO THE
MIDDLE TO LATER PART OF THE WEEK WITH HIGH PRESSURE OVER THE BERING
AND A LARGE UPPER LOW SOUTH OF THE ALEUTIAN CHAIN. MODELS ARE HINTING
AT THE POLAR VORTEX DROPPING SOUTHWARD FROM THE CANADIAN ARCTIC AND
CLIPPING THE EASTERN HALF OF MAINLAND ALASKA LATE IN THE WEEK...BUT
CONFIDENCE IN THIS SOLUTION IS RELATIVELY LOW AT THIS POINT IN TIME.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE WARNING 120 130 150 155 170
         HEAVY FREEZING SPRAY 180
FIRE WEATHER...NONE

CB APR 13