Small Craft Advisory 307, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
100 PM ADT SAT MAR 31 2007

.DISCUSSION...

MODELS...MODELS INITIALIZED WELL AND SHOW VERY GOOD RUN-TO-RUN
CONSISTENCY AND MODEL-TO-MODEL CONSISTENCY THROUGH 48 HOURS. MODEL
SOLUTIONS BEGIN TO DIVERGE AFTER THIS POINT WITH LOW COMPLEX SOUTH
OF THE ALEUTIANS. WILL TREND TOWARD THE GFS/UKMET SOLUTION OF
TRACKING SHORT-WAVE AND ASSOCIATED SURFACE LOW WESTWARD ACROSS
ALEUTIANS MONDAY NIGHT.

UPPER AIR...A HIGH AMPLITUDE RIDGE IS CENTERED OVER MAINLAND ALASKA.
A SHORT-WAVE TROUGH IS TRACKING NORTH-NORTHEAST ACROSS THE EASTERN
BERING SEA (AND UP THE WEST SIDE OF THE RIDGE). A CUT-OFF LOW
SOUTHWEST OF THE ALEUTIANS IS BEING FORCED NORTHWARD BY THE UPPER
JET...WHICH IN TURN IS CAUSING AMPLIFICATION OF SHORT-WAVE RIDGE
OVER THE WESTERN BERING. THIS PATTERN WILL SLOWLY EVOLVE THE NEXT
FEW DAYS. THE SHORT-WAVE TROUGH OVER THE EASTERN BERING WILL PUSH
INTO TOP OF MAINLAND ALASKA RIDGE CAUSING IT TO WEAKEN A BIT.
MEANWHILE...WESTERN BERING RIDGE WILL CONTINUE TO AMPLIFY AND
BECOME A DOMINANT CUT-OFF RIDGE CENTERED OVER FAR EASTERN RUSSIA
ON MONDAY. WEAKNESS TO THE SOUTH WILL LET THE SUBTROPICAL JET
PUNCH EASTWARD ACROSS THE NORTH PACIFIC...EXTENDING THE TROUGH
EASTWARD. WHAT DOES ALL THIS MEAN TO THE FORECAST? WELL...IN THE
SHORT-TERM NOT MUCH. THE ALEUTIANS AND WESTERN BERING WILL CONTINUE
TO SEE MOST OF THE STORMY WEATHER. HOWEVER...THIS SETS THE STAGE
FOR A MORE SIGNIFICANT PATTERN CHANGE HEADING INTO NEXT
WEEKEND...WITH A HUGE AREA OF CYCLONIC FLOW SETTING UP OVER THE
REGION...A MORE FAVORABLE PATTERN FOR PRECIP AND WARMER TEMPERATURES.

SOUTHCENTRAL ALASKA FORECAST...VERY WEAK UPPER FORCING WILL RESULT
IN SOME CLOUDS THE NEXT FEW DAYS...BUT CONDITIONS WILL REMAIN DRY
THROUGH AT LEAST EARLY THIS WEEK. THE CHANCE OF PRECIP WILL INCREASE
MID TO LATE WEEK...ESPECIALLY FOR KODIAK ISLAND...AS UPPER FLOW
SHIFTS TO THE EAST TO SOUTHEAST...BRINGING MOISTURE FROM THE PACIFIC.

SOUTHWEST ALASKA/AKPENN FORECAST...RADAR SHOWS A BAND OF SNOW ALONG
THE KUSKOKWIM COAST. THIS WILL MOVE INLAND A BIT AND THEN TAPER OFF
TONIGHT AS UPPER-SHORT-WAVE MOVES OFF TO THE NORTH. LOW-LEVEL
SOUTHWEST FLOW WILL ADVECT STRATUS (EVIDENT IN LATEST SATELLITE
IMAGERY) AND POSSIBLY FOG FROM THE BERING SEA. THE REST OF SOUTHWEST
ALASKA WILL REMAIN DRY WITH VARIABLE CLOUDS.

ALEUTIANS/BERING SEA FORECAST...WIND SPEEDS ARE ON THE WAY UP ACROSS
THE ALEUTIANS WITH STORM FORCE WINDS EXPECTED BEGINNING THIS
AFTERNOON AS STRONG LOW PASSES TO THE WEST. FRONTAL BOUNDARY WILL
TRACK EASTWARD TO THE PRIBILOFS AND EASTERN ALEUTIANS AND THEN
BEGIN TO SHEAR APART ALONG THE WEST SIDE OF THE RIDGE. THE NEXT
COUPLE LOWS LOOK LIKE THEY WILL REMAIN SOUTH OF THE ALEUTIANS AS
UPPER JET DRIVES THEM EASTWARD. HOWEVER..SOME ENERGY WILL ROTATE
NORTHWARD TOWARD ALEUTIANS...MAINTAINING A CHANCE OF PRECIP THROUGH
THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORMS 175 176. GALES 172.
FIRE WEATHER...NONE.

SEB MAR 07