Small Craft Advisory 772, NWS Anchorage, AK

AREA FORECAST DISCUSSION...CORRECTION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM ADT WED SEP 19 2007

CORRECTION FOR TYPOS

.MODEL DISCUSSION...MODELS ARE IN GOOD ALIGNMENT WITH EACH OTHER FOR
THE BIG PICTURE. THE LARGE LOW IN THE NORTHERN BERING SEA IS RESOLVED
VERY SIMILARLY ON THE NAM GFS AND ECMWF. THE UPCOMING WEATHER FEATURE
THAT THE MODELS DIVERGE THE MOST ON IS A WAVE THAT WILL PROPAGATE
THROUGH THE GULF OF ALASKA THURSDAY. THE ECMWF IS MUCH FASTER THAN
THE GFS OR NAM. THE GFS SEEMS TO HAVE THE BEST SOLUTION AS THE NAM
LOOKS TO KEEP THIS FEATURE TOO WEAK AND TOO FAR SOUTH. A SIMILAR
ISSUE OCCURS WITH YET ANOTHER WAVE DEVELOPING IN THE SOUTHWEST FLOW
SATURDAY WITH THE MODELS ALL ACKNOWLEDGING THAT THIS FEATURE WILL
DEVELOP BUT THE SOLUTION BETWEEN THE GFS AND ECMWF ON SATURDAY
DIFFERS BY AROUND 600 MILES. THE GFS ENSEMBLE ALSO SHOWS THAT THE GFS
IS STRUGGLING TO RESOLVE THIS SYSTEM WHICH IS COMMON IN THIS PATTERN.

.ANALYSIS AND UPPER LEVELS...THE BIG WEATHER FEATURE REMAINS THE
LARGE LOW IN THE NORTHERN BERING SEA. IT HAS WEAKENED TO AROUND 988
MB AND WILL CONTINUE TO SLOWLY WEAKEN AS IT MOVES ON SHORE BETWEEN ST
MICHAELS AND UNALAKLEET THURSDAY AFTERNOON. THE JET STREAM IS NOSING
ITS WAY BACK INTO THE AREA OVER THE EASTERN ALEUTIANS AND THEN INTO
THE GULF OF ALASKA BUT WILL RECEDE INTO SOUTHEAST ALASKA BY FRIDAY AS
THE BERING SEA LOW REMNANTS MOVE INTO SOUTH CENTRAL ALASKA.

.SHORT TERM FORECAST...SOUTHWEST ALASKA WILL CONTINUE TO SEE NUMEROUS
SHOWERS AROUND THE BERING SEA LOW THROUGH TOMORROW. SNOW SHOWERS WILL
FALL AT HIGHER ELEVATIONS IN SOUTHWEST ALASKA. SNOW SHOWERS MAY ALSO
OCCUR IN MOUNTAIN PASSES SUCH AS BROAD PASS AS WELL AS ISABEL AND
MENTASTA PASSES. HIGHER PORTIONS OF THE DENALI HIGHWAY SAW SNOW
ACCUMULATIONS LAST NIGHT AND WILL LIKELY SEE SNOW SHOWERS AGAIN
TONIGHT AS FREEZING LEVELS REMAIN LOW.

.LONG TERM FORECAST...THE ACTIVE FALL SEASON IS UPON US. ANOTHER
LARGE LOW APPEARS SET TO MOVE INTO THE WESTERN BERING SEA THIS
WEEKEND. THIS LOW WILL BE SIMILAR IN STRENGTH TO THE ONE THAT JUST
WENT THROUGH...BUT COLD AIR IN EASTERN RUSSIA WILL GET ENTRAINED INTO
THIS LOW AND LOWER FREEZING LEVELS ALONG THE ALEUTIANS AND INTO
SOUTHWEST ALASKA EVEN LOWER THAN THEY ARE NOW.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 160 165 170 179 180.
FIRE WEATHER...NONE.

EZ/SAM
SEP 07