Small Craft Advisory 103, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST FRI FEB 1 2013

.ANALYSIS AND UPPER LEVELS...

A STRONG UPPER LEVEL RIDGE REMAINS OVER THE SOUTHERN INTERIOR OF THE
STATE EARLY THIS AFTERNOON...WITH A BROAD AND BAGGY UPPER LEVEL LOW
LOCATED SOUTH OF THE WESTERN ALEUTIANS. FROM THIS LOW EXTENDS AN
UPPER LEVEL TROUGH EASTWARD ACROSS THE ALASKA PENINSULA AND THEN
SOUTHEAST INTO THE PACIFIC OCEAN.

THE UPPER LEVEL RIDGE WILL CONTINUE TO PUSH TOWARDS THE NORTHERN HALF
OF THE STATE THIS WEEKEND WHILE THE MEAN UPPER LEVEL LOW POSITION
WORKS ITS WAY NORTH AND EAST TOWARDS BRISTOL BAY BY SUNDAY NIGHT
BEFORE WEAKENING. AN ACCOMPANYING 974 MB LOW SOUTH OF THE EASTERN
ALEUTIANS WILL DRIFT NORTH AND STRENGTHEN TO 966 MB SATURDAY MORNING
BEFORE WEAKENING TO 980 MB OVER THE ALASKA PENINSULA SUNDAY
AFTERNOON. NUMEROUS EMBEDDED DISTURBANCES IN THE FLOW AROUND THIS
CENTER OF ACTION WILL MEAN AT LEAST A CHANCE OF PRECIPITATION ACROSS
THE NEARLY THE ENTIRE FORECAST AREA FOR AT LEAST SOME PERIOD DURING
THE WEEKEND.

.MODEL DISCUSSION...
MODELS ARE LOCKED IN ON THE OVERALL PATTERN AND ARE SHOWING MUCH
BETTER AGREEMENT AND CONSISTENCY THAN YESTERDAY. THERE ARE STILL SOME
DIFFERENCES WORTH NOTING. THE ECMWF AND GFS ARE VERY CLOSE IN THE
SOLUTION IN THE BERING SEA AND SEEM TO HAVE A BETTER HANDLE ON THE
MOVEMENT OF THE LARGE LOW IN THE REGION THAN THE NAM. IN THE GULF OF
ALASKA THE NAM AND GFS DEVELOP A TRIPLE POINT LOW SOUTH OF KODIAK
ISLAND FRIDAY AND MOVE IT TOWARD MONTAGUE ISLAND BY SUNDAY WHILE THE
ECMWF DOES NOT DEVELOP THIS LOW AS MUCH AND MERELY HINTS AT THAT
FEATURE ALONG THE ALEUTIAN RANGE. THE GFS AND NAM SOLUTION FITS THE
DYNAMIC PATTERN BETTER AND WILL BE PREFERRED IN THE GULF DURING THAT
TIME PERIOD. AFTER THAT THE GFS AND ECMWF ARE IN RELATIVELY GOOD
AGREEMENT INTO LATE NEXT WEEK.

.SHORT TERM FORECAST...
SOUTHCENTRAL...WIDESPREAD FOG ACROSS THE AREA THIS MORNING HAS
LARGELY DISSIPATED AS THE NEXT FRONT HAS MOVED INTO THE REGION AND
INCREASED THE MIXING OF THE AIRMASS. THIS FRONT IS ONCE AGAIN
BRINGING WARMER AIR INTO THE REGION AND WILL CAUSE MOSTLY RAIN ALONG
THE COASTAL AREAS. AREAS FARTHER INLAND WILL LARGELY BE DOWN SLOPED
OUT. HOWEVER THERE DOES REMAIN A SMALL CHANCE OF FREEZING RAIN IN THE
UPPER COOK INLET REGION AS COOLER NORTHEASTERLY SURFACE FLOW WILL
KEEP TEMPERATURES BELOW FREEZING AT NIGHT AND WARMER AIR ALOFT THAT
IS ABOVE FREEZING IS OVER-RUNNING THIS COOLER AIR.

SOUTHWEST...THE FRONT MOVING THROUGH SOUTHWEST ALASKA IS RAPIDLY
WEAKENING BUT IS STILL PROVIDING ENOUGH LIFT TO PRODUCE SOME SNOW IN
THE BRISTOL BAY AREA WEST OF KING SALMON. AREAS CLOSER TO THE
ALEUTIAN RANGE WILL CONTINUE TO SEE THE PRECIPITATION DOWN SLOPED OUT
WITH WARMER TEMPERATURES AS WELL.

BERING SEA/ALEUTIANS...THE STRONG LOW MOVING NORTHWARD OUT OF THE
PACIFIC TOWARD THE CENTRAL ALEUTIANS WILL CONTINUE TO SLOWLY WEAKEN
AND ELONGATE AS IT MOVES INTO THE RIDGE IN THE NORTHERN BERING SEA.
AREAS ALONG THE ALEUTIANS WEST OF THIS LOW WILL SEE SNOW SHOWERS
WHEREAS IT WILL BE MOSTLY RAIN IN THE ALEUTIANS EAST OF THE LOW.

.LONG TERM FORECAST...
THE EXTENDED FORECAST THROUGH EARLY NEXT WEEK LOOKS SIMILAR TO THE
CURRENT WEATHER MAP WITH THE JET STREAM DISPLACEMENT FURTHER SOUTH
AND WEAK DECAYING FRONTS APPROACHING THE MAINLAND. HOWEVER A MORE
ACTIVE PATTERN IS ON THE HORIZON WITH A DEEP LOW MOVING OVER THE
BERING SEA SENDING ANOTHER ROUND OF DISTURBANCES TOWARD THE MAINLAND
IN THE MIDDLE TO LATER PART OF NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 130 140 172 175 176 185.
         HEAVY FREEZING SPRAY WARNING 185.
FIRE WEATHER...NONE.

FEB 13