Small Craft Advisory 37, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST FRI JAN 11 2013

.MODEL DISCUSSION...
FORECAST GUIDANCE IS NOT IN VERY GOOD AGREEMENT PAST 24 HOURS INTO
THE FORECAST. MAIN DIFFERENCES CENTER AROUND THE ALEUTIANS AND
BERING SEA WITH HOW THEY HANDLE THE VARIOUS FEATURES IN THE
SOUTHERLY FLOW. IN GENERAL THE GFS IS SLOWER THAN THE OTHER MODELS
WITH THE SURFACE LOWS...AND THEN KEEPS A LOW SOUTH OF THE CENTRAL
ALEUTIANS...WHICH THE OTHER MODELS BRING INTO THE BERING SEA
SATURDAY AFTERNOON. THE AFTERNOON FORECASTS FOR THE AREAS WEST OF
KODIAK ISLAND USE MAINLY THE ECMWF...WITH THE GFS USED FROM KODIAK
ISLAND EASTWARD.

.ANALYSIS AND UPPER LEVELS...
A LARGE UPPER LEVEL RIDGE IS OVER THE NORTHEAST PACIFIC AND GULF OF
ALASKA AND EXTENDING ACROSS EASTERN MAINLAND ALASKA. A WEAK SHORT
WAVE TROUGH STRETCHES FROM SOUTH CENTRAL ALASKA NORTHWESTWARD TO AN
UPPER LEVEL LOW NEAR THE BERING STRAIT. A STRONG DEVELOPING LOW IS
LOCATED JUST SOUTH OF THE CENTRAL/EASTERN ALEUTIANS AND MOVING
RAPIDLY NORTH.

.SHORT TERM FORECAST...
THE UPPER LEVEL LOW SOUTH OF THE ALEUTIANS WILL MOVE NORTH FOR THE
NEXT COUPLE OF DAYS WITH THE SURFACE CENTER NEAR SAINT LAWRENCE
ISLAND SUNDAY AFTERNOON. THE OCCLUDED FRONT AND WARM FRONT WILL MOVE
NORTHEASTWARD...PUSHING THE RIDGE OVER ALASKA EASTWARD. THE JET
STREAM IS SITTING OVER THE "COLD" FRONT (IN QUOTATIONS BECAUSE OF
THE LACK OF DECENT COLD AIR) AND WILL PUSH A STREAM OF WARM MOIST
INTO THE AREA THROUGH MONDAY.

SOUTHWEST ALASKA AND THE ALEUTIANS/BERING SEA...THE WARM FRONT WILL
BE MOSTLY OCCLUDED BY THIS EVENING AND WILL PUSH ACROSS THE EASTERN
BERING SEA TONIGHT AND ACROSS SOUTHWEST ALASKA SATURDAY. THERE IS
PLENTY OF WARM AIR WITH THIS SYSTEM AND PRECIPITATION IN SOUTHWEST
ALASKA WILL TURN TO RAIN/FREEZING RAIN DURING THE DAY SATURDAY.
PRECIPITATION WILL BE MORE SHOWERY SATURDAY NIGHT INTO
MONDAY...MOSTLY RAIN NEAR BRISTOL BAY AND A MIX OF RAIN AND SNOW
FURTHER NORTH.

SOUTH CENTRAL ALASKA...THE WEAK SYSTEM OVER SOUTH CENTRAL ALASKA
THIS EVENING WILL MOVE EASTWARD INTO CANADA BY LATE TONIGHT. THE
WARM/OCCLUDED FRONT WILL PUSH INTO THE AREA SATURDAY. PRECIPITATION
SHOULD START AS SNOW MOST AREAS EXCEPT ALONG THE COAST THEN CHANGE
TO RAIN LATER IN THE DAY...WITH A POSSIBILITY OF SOME POCKETS OF
FREEZING RAIN DURING THE TRANSITION. BY SUNDAY PRECIPITATION SHOULD
BE ALL RAIN EXCEPT AT HIGHER ELEVATIONS AND AREAS FAR FROM THE
COAST. THERE WILL BE A SURGE OF WARM AND MOIST AIR SUNDAY AFTERNOON
INTO MONDAY. RAIN AMOUNTS WILL BE FAIRLY HIGH FOR THIS TIME OF
YEAR...RANGING FROM A HALF INCH IN INLAND VALLEYS TO POSSIBLY AROUND
THREE INCHES COASTAL AND MOUNTAINOUS AREAS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...FLOOD WATCH 101 111 121 125 131 135 145.
MARINE...STORM WARNING 170.
         GALE WARNING 130 150 155 160 165 171 172 175 179 180 185.
         HEAVY FREEZING SPRAY 185.
FIRE WEATHER...NONE.

LUDWIG JAN 13