Small Craft Advisory 941, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AKST THU NOV 27 2008

.MODEL DISCUSSION...THE MODELS SEEM TO BE HANDLING THE LARGE LOW
SOUTH OF THE ALASKA PENINSULA THAT IS HEADING FOR PRINCE WILLIAM
SOUND ON SATURDAY QUITE WELL. THERE IS SOME DIFFERENCES ON SATURDAY
WITH THE SPEED THIS LOW WILL MOVE THROUGH THE SOUND. THE GFS IS
REALLY BLASTING IT THROUGH QUICKLY WHILE THE NAM HOLDS PROBABLY TOO
FAR BACK. THE UKMET SOLUTION ACTUALLY LOOKS THE BEST WITH IT HOLDING
THE LOW IN THE SOUND UNTIL SUNDAY MORNING. THE NAM KEEPS IT IN THE
VICINITY OF THE SOUND EVEN LONGER. THERE IS NO REASON TO EXPECT THIS
LOW TO MOVE THROUGH THE SOUND QUICKLY AND IT IS EXPECTED TO LINGER A
LITTLE AND WEAKEN THROUGH THE WEEKEND.
THE NEXT LOW OF NOTE WILL ENTER THE WESTERN BERING SEA FRIDAY
AFTERNOON AND THEN BE ABSORBED INTO A LARGE LOW MOVING TOWARD THE
ALEUTIANS FROM THE SOUTHWEST THIS WEEKEND. THE MODELS ARE IMPROVING
WITH THE SOLUTION TO THIS BERING SEA LOW. HOWEVER THERE IS STILL A
SIGNIFICANT DIFFERENCE BETWEEN THE GFS AND EUROPEAN MODELS. THE GFS
IS KEEPING THE LOW MOVING INTO THE BERING SEA INTACT FOR TOO LONG.
THE DYNAMICS SUPPORT THIS LOW BEING WASHED OUT INTO A TROUGH AS THE
UKMET AND ECMWF SHOW SO THOSE SOLUTIONS ARE PREFERRED FROM SATURDAY
ONWARD IN THE BERING SEA AREAS.

.ANALYSIS AND UPPER LEVELS...THE MAJOR WEATHER FEATURE IS THE 955 MB
LOW THAT IS SOUTH OF THE ALASKA PENINSULA. THIS LOW IS BEGINNING TO
WEAKEN AS IT MOVES NORTHEAST AFTER BEING DOWN TO 947 MB ON THE
SURFACE ANALYSIS FROM YESTERDAY AFTERNOON. THE JET STREAM IS SOUTH OF
THE FORECAST AND QUITE STRONG AT 250 MB WITH WINDS NEARING 200 KT IN
PLACES. THIS JET STREAM WILL REMAIN ZONAL ALONG 40N AND SOUTH OF THE
ALEUTIANS FOR THE NEXT FEW DAYS. THIS WILL ALLOW ANOTHER STRONG LOW
TO DEVELOP AND THEN HEAD TOWARD THE ALEUTIAN ISLANDS THIS WEEKEND.
IN SHORT...A VERY ACTIVE WEATHER PATTERN WILL REMAIN WELL INTO NEXT
WEEK.

.SHORT TERM FORECAST...THIS SYSTEM IS BRINGING LOTS OF WEATHER AND
LOTS OF QUESTIONS AS TO PRECIPITATION TYPE IN THE GULF OF ALASKA
COASTAL AREAS AND INTO THE COOK INLET AREA. KODIAK ISLAND IS GETTING
THE FIRST DOSE OF THIS SYSTEM IN THE GULF AREA AND IS REMAINING SNOW
AS COLD AIR IN THE INTERIOR OF THE ISLAND IS STILL BEING ENTRAINED
OVER THE COAST. WHEN WINDS GET SHIFTED FROM OVER THE WATER THE RAIN
WILL BEGIN TO MIX IN...PROBABLY SOMETIME THIS EVENING. THIS SYSTEM
HAS ENOUGH WARM AIR TO TURN THE SNOW IN THE PRINCE WILLIAM SOUND AREA
INTO RAIN. SNOW WILL BE THE PREDOMINANT PRECIPITATION TYPE IN THE
COOK INLET REGION THOUGH THERE IS ALSO A CHANCE OF FREEZING RAIN IN
THE ANCHORAGE AREA FRIDAY NIGHT WITH THIS SYSTEM. THERE IS ALSO A
GOOD CHANCE OF RAIN MOVING INTO THE HOMER AREA FRIDAY.

FARTHER WEST THIS SYSTEM IS BRINGING IN STRONG WINDS TO THE ALASKA
PENINSULA AND THE ALEUTIAN ISLANDS. THERE HAS BEEN SOME CONSIDERATION
GIVEN AS TO WHETHER BLIZZARD CONDITIONS MAY DEVELOP IN THE EASTERN
ALEUTIANS OR THE ALASKA PENINSULA. AT THIS TIME IT LOOKS LIKE THE LOW
WILL TRACK FAR ENOUGH SOUTH THAT THE ALASKA PENINSULA WILL NOT GET
THESE CONDITIONS. WHILE IT STILL LOOKS LIKE THE THE EASTERN ALEUTIANS
WILL NOT GET DOWN TO BLIZZARD CONDITIONS DUTCH HARBOR SHOULD BE
WATCHED THROUGHOUT THE AFTERNOON AND EVENING AS THERE IS STILL A
POSSIBILITY THESE CONDITIONS COULD DEVELOP.

.LONG TERM FORECAST...AS THE LOW MOVES INTO THE SOUND ON SATURDAY
THERE IS A GOOD CHANCE THAT IT WILL BRING SIGNIFICANT SNOWFALL TO THE
ANCHORAGE AREA.
THE OVERALL PATTERN WILL KEEP MOVING STORMS INTO THE BERING SEA.
THERE IS A GOOD CHANCE THAT THERE WILL BE A RIDGE BUILDING ALONG THE
NORTH AMERICAN COAST AND SOUTHEAST ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 130 138 140 150 155 160 165 170 171 172 179 180.
         HEAVY FREEZING SPRAY 160 179 180.
FIRE WEATHER...NONE.

NOV 08