Small Craft Advisory 436, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
529 AM AKDT SUN JUN 1 2014

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL COLD CORE LOW CENTERED OVER THE SOUTHWEST MAINLAND
IS SLOWLY MOVING TO THE EAST. WIDESPREAD RAIN SHOWERS ASSOCIATED
WITH THIS UPPER LOW COVER MUCH OF THE SOUTHWEST MAINLAND...AND ARE
BEGINNING TO DEVELOP OVER COOK INLET. TO THE EAST OF THESE
SHOWERS...WIDESPREAD RAIN STRETCHES FROM THE EXTREME WESTERN GULF
INTO THE GULF COAST. THIS RAIN WILL BECOMING REINVIGORATED LATER
TODAY AS THE UPPER LOW APPROACHES...KEEPING MUCH OF THE GULF COAST
UNDER A RISK OF RAINFALL INTO MONDAY AFTERNOON. WEAK MID LEVEL
RIDGING OVER THE WESTERN ALEUTAINS IS HELPING TO KEEP THE AREA
CLOUDY...BUT OTHERWISE VOID OF PRECIPITATION.

&&

.MODEL DISCUSSION...
THE MODELS HAVE ALL INITIALIZED WELL AND ARE IN GOOD AGREEMENT
WITH THE UPPER LEVEL LOW THAT WILL MIGRATE THROUGH THE SOUTHERN
MAINLAND...AND WILL BE THE MAIN DRIVER FOR ACTIVE WEATHER TODAY.
THIS MODEL AGREEMENT THEN STARTS TO BREAK DOWN MONDAY MORNING
WITH SPEED DIFFERENCES WITH THE UPPER LOW AS IT WEAKENS TO THE
EAST. THE GFS/EC ARE MUCH WEAKER AND FURTHER WEST...WHILE THE NAM
IS THE MOST PROGRESSIVE WITH BRINGING A FASTER AND DEEPER LOW
INTO THE NORTHERN PANHANDLE. THE MORNING PACKAGE USED A BLEND
BETWEEN THESE SOLUTIONS...WHICH IS CLOSEST TO THE CURRENT GEM
REGIONAL LOCATION. OUT WEST...THERE IS GOOD AGREEMENT THOUGH
MONDAY AS MID LEVEL RIDGING SPREADS OVER THE BERING AND A WESTERN
ALEUTIAN LOW APPROACHES. THIS HOWEVER ALSO STARTS TO BREAK DOWN AS
THE MODELS BEGIN TO STRUGGLE WITH A DEVELOPING SYSTEM SOUTH OF
DUTCH HARBOR.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...AS MENTIONED ABOVE...THE SHORT TERM FORECAST
THROUGHOUT SOUTHCENTRAL WILL BE DOMINATED BY THE UPPER LEVEL COLD
CORE LOW APPROACHING COOK INLET. SHOWERS WILL CONTINUE TO QUICKLY
DEVELOP FROM THE KENAI PENINSULA TO MATANUSKA VALLEY EARLY THIS
MORNING...WHICH WILL THEN BE CLOSELY FOLLOWED BY DEVELOPMENT OVER
THE SUSITNA VALLEY. AS IS INDICATED WITH A COOL 52 DEGREE
CONVECTIVE TEMPERATURE ON THE 12Z ANCHORAGE SOUNDING...THE
ATMOSPHERE IS PRIMED FOR CONVECTION TO FIRE THIS AFTERNOON WITH
VERY LIMITED DAYTIME HEATING. THE INLAND KENAI PENINSULA WILL BE
DIRECTLY UNDER THE COLDEST AIR ALOFT DURING ITS PEAK DAYTIME
HEATING TODAY WHICH WILL CAUSE FOR THE DEVELOPMENT ISOLATED
THUNDERSTORMS TODAY. CONVECTION OVER ANCHORAGE AND THE MATSU WILL
BE SOMEWHAT LIMITED IN COMPARISON DUE TO SLIGHTLY WARMER
ALOFT...HOWEVER THERE IS STILL A RISK OF SMALL HAIL MIXING IN
WITH THE RAIN SHOWERS THIS AFTERNOON/EVENING. SHOWERS WILL THEN REMAIN
IN THE AREA THROUGH LATE TONIGHT AS THE UPPER THROUGH SLOWLY
DISSIPATES OVERHEAD...AND WILL BEGIN TO CLEAR OUT MONDAY MORNING
AS SHORTWAVE RIDGING BUILDS IN.

SOUTHWEST ALASKA...
MOST OF THE SOUTHWEST MAINLAND WILL REMAIN CLOUDY WITH RAIN
SHOWERS INTO TUESDAY AS A WEAK SHORTWAVE WILL QUICKLY FOLLOW THE
DEPARTING COLD CORE LOW. TEMPERATURES WILL REMAIN BELOW NORMAL
UNDER CLOUDY SKIES DURING THIS TIME...BUT WILL THEN WARM BACK TO
NEAR TO ABOVE NORMAL ON WEDNESDAY WHEN MID LEVEL RIDGING WILL
RETURN TO THE AREA.

BERING SEA/ALEUTIANS...
THE WEAK SHORTWAVE TROUGH THAT IS CURRENTLY BRINGING RAIN SHOWERS
TO PRIBILOFS WILL BE THE MOST SIGNIFICANT FEATURE IN THIS AREA
THROUGH TUESDAY. OTHER AREAS WILL REMAIN UNDER THE INFLUENCE OF
MID LEVEL RIDGING WITH STRATUS AND LIGHT WINDS UNTIL THE NEXT LOW
APPROACHES THE CENTRAL AND WESTERN ALEUTIANS LATE MONDAY.

&&

.LONG TERM FORECAST...
THERE IS DECENT MODEL AGREEMENT THAT THE BERING RIDGE THAT WILL
BUILD OVER THE MAINLAND STARTING ON TUESDAY WILL KEEP MAJOR
SYNOPTIC SCALE SYSTEMS AWAY FROM THE MAINLAND FOR AT LEAST A FEW
DAYS. LATER IN THE WORK WEEK...THE MODELS REALLY BEGIN TO
STRUGGLE WITH THE WESTERN ALEUTIAN LOW AS IT UNDERCUTS THE BERING
RIDGE AND MOVES TOWARDS THE AKPENN ON FRIDAY. IT DOES APPEAR THIS
LOW WILL BE STRONG ENOUGH CONTINUE TO BRING A PERIOD OF ACTIVE
WEATHER TO THE MAINLAND INTO EARLY NEXT WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

DEK JUN 14