Small Craft Advisory 348, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT SAT APR 20 2013

.ANALYSIS AND UPPER LEVELS...
A CLOSED UPPER LEVEL HIGH BUILDING OVER THE SOUTHERN HALF OF MAINLAND
ALASKA CONTINUES TO SUPPORT GENERALLY PLEASANT CONDITIONS ACROSS THE
REGION. A COMPACT UPPER LEVEL LOW CENTERED BETWEEN KODIAK ISLAND AND
THE NORTHERN AKPEN IS SPREADING CLOUDY SKIES OVER THE SOUTHWESTERN
GULF WHILE ANOTHER UPPER LOW OVER THE NORTHERN PACIFIC REMAINS NEARLY
STATIONARY WELL TO THE SOUTH OF THE AKPEN. A DEVELOPING SURFACE LOW
ON THE NORTHERN PERIPHERY OF THIS FEATURE WILL TRACK NORTHWARD
TOWARDS KODIAK ISLAND TONIGHT. MEANWHILE...A SHORTWAVE TROUGH
DROPPING RAPIDLY SOUTHWARD THROUGH THE CENTRAL/EASTERN BERING SEA IS
BRINGING A FEW SNOW SHOWERS TO THE PRIBILOFS THIS AFTERNOON WHILE
UPPER LEVEL RIDGING CONTINUES TO BUILD ACROSS THE WESTERN HALF OF THE
BERING.

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT WITH RESPECT TO THE OVERALL SYNOPTIC
PATTERN INTO THE MIDDLE OF NEXT WEEK BUT CONTINUE TO STRUGGLE IN
HANDLING THE LOW AND ASSOCIATED FRONT MOVING INTO THE GULF LATER THIS
WEEKEND. THE 12Z NAM HAS SHIFTED THE LOW FURTHER WEST AND SLOWED THE
PROGRESSION OF THE FRONT OVER THE NORTHERN GULF WHEREAS THE GFS HAS
SHIFTED FURTHER EAST TO COME INTO BETTER AGREEMENT WITH THE EC
SOLUTION...WHICH REMAINS THE MOST CONSISTENT. THEREFORE...UTILIZED
THE EC/GFS FOR THE TIMING OF PRECIPITATION OVER SOUTHCENTRAL AK.
OTHERWISE...MODELS ARE IN GOOD AGREEMENT REGARDING THE EVOLUTION OF
THE OVERALL PATTERN OVER THE NEXT SEVERAL DAYS. THE SHORTWAVE OVER
THE BERING WILL CONTINUE TO MOVE QUICKLY SOUTHWARD TONIGHT AND MERGE
WITH THE AFOREMENTIONED UPPER LOW OVER THE NORTH PACIFIC ON SUNDAY.
THE LOW AFFECTING THE NORTHERN GULF COAST THIS WEEKEND WILL DEPART BY
MONDAY EVENING...ALLOWING BROAD UPPER LEVEL RIDGING TO BECOME
ESTABLISHED OVER THE BERING AND MAINLAND ALASKA INTO THE MIDDLE PART
OF THE WEEK.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
PRECIPITATION WILL RETURN TO PORTIONS OF SOUTHCENTRAL AK TONIGHT AND
SUNDAY AS THE DEVELOPING SURFACE LOW AND ASSOCIATED FRONT ADVANCE
NORTHWARD INTO THE GULF. RAIN AND SNOW WILL OVERSPREAD KODIAK ISLAND
THIS AFTERNOON AND EVENING AND THEN MOVE TO THE GULF COAST LATE
TONIGHT INTO SUNDAY. THE BULK OF THE ACTIVITY WILL BE CONFINED TO
COASTAL PORTIONS OF THE AREA...WITH ONLY ISOLATED SHOWERS FOR INLAND
LOCATIONS. PRECIPITATION WILL BEGIN TO TAPER OFF SUNDAY NIGHT INTO
MONDAY MORNING AS THE UPPER LOW DEPARTS TO THE EAST AND HIGH PRESSURE
ONCE AGAIN BECOMES ESTABLISHED OVER THE AREA.

SOUTHWEST ALASKA...
PLEASANT CONDITIONS MARKED BY CLEAR SKIES AND WARMING TEMPERATURES
WILL CONTINUE OVER THE NEXT SEVERAL DAYS AS HIGH PRESSURE REMAINS
OVERHEAD. A FEW RAIN AND SNOW SHOWERS WILL BE POSSIBLE TONIGHT INTO
SUNDAY ALONG THE ALEUTIAN RANGE AND NORTHERN AKPEN IN THE VICINITY OF
THE UPPER LOW OVER THE SOUTHWESTERN GULF.

ALEUTIANS/BERING SEA...
A FEW RAIN AND SNOW SHOWERS WILL BE POSSIBLE INTO TONIGHT FROM THE
PRIBILOFS TO THE EASTERN ALEUTIANS AS THE SHORTWAVE CONTINUES ITS
SOUTHWARD PROGRESSION THROUGH THE BERING. A FRONT WILL SPREAD
PRECIPITATION OVER THE WESTERN ALEUTIANS TONIGHT INTO SUNDAY BEFORE
DISSIPATING SUNDAY NIGHT. OTHERWISE...HIGH PRESSURE WILL PROMOTE
GENERALLY BENIGN CONDITIONS THROUGH THE EARLY PART OF THE WEEK.

.LONG TERM FORECAST...
THE GENERAL PATTERN LOOKS TO BE CHARACTERIZED BY BROAD UPPER LEVEL
RIDGING INTO THE MIDDLE OF NEXT WEEK...WHICH WOULD RESULT IN A
CONTINUATION OF PLEASANT SPRING LIKE CONDITIONS OVER MUCH OF THE
REGION INTO THE EXTENDED TERM. MODELS DEPICT A WARM FRONT MOVING INTO
THE GULF ON TUESDAY...WHICH COULD POTENTIALLY BRING SOME ADDITIONAL
PRECIPITATION TO SOUTHCENTRAL AK DEPENDING ON HOW FAR NORTH THE FRONT
ULTIMATELY PROGRESSES.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE WARNING 120 130 138
FIRE WEATHER...NONE

CB APR 13