Small Craft Advisory 254, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT THU MAR 15 2007

.DISCUSSION...

MODELS IN GENLY GOOD AGREEMENT THROUGH 60 HOURS. WINTERTIME PATTERN
HOLDING THROUGH AT LEAST 180 HOURS.

UPPER LEVELS...
THE HIGH PRESSURE RIDGE ALOFT OVER BERING SEA WILL SHIFT
NORTHWARD...REPOSITIONING ITSELF OVER SIBERIA AND THE RUSSIAN FAR
EAST BY FRI EVENING.
THE CUT OFF UPPER LEVEL LOW OVER THE NORTHERN GULF OF ALASKA WILL
MIGRATE WESTWARD...MOVING OVER BRISTOL BAY BY SAT AFTERNOON.
NET EFFECT OF UPPER LEVEL PATTERN CHANGE WILL BE TO STEER MORE
SURFACE LOWS INTO THE SOUTHERN GULF AND TOWARDS THE SOUTHEAST
PANHANDLE.
JET STREAM WILL REMAIN WELL SOUTH OF MAINLAND ALASKA AND THE BERING
SEA...SO LITTLE CHANGE EXPECTED IN THESE AREAS.

SURFACE EAST OF 160W...
COMPLEX LOW PRESSURE WILL CONTINUE OVER THE GULF OF ALASKA THROUGH
SUN AFTERNOON. NAM HANDLES MULTIPLE LOW CENTERS BEST THROUGH 48
HOURS. GFS PREFERRED BEYOND 48 HOURS.
1001 MB LOW 90 NM SOUTH OF CAPE YAKATAGA WILL DISSIPATE 300 NM SOUTH
OF MIDDLETON ISLAND FRI MORNING. NEW 999 MB LOW DEVELOPS 150 NM
SOUTHEAST OF MIDDLETON FRI MORNING THEN DEEPENS TO APPROX 991 MB AS
IT MOVES TO 75 NM SOUTHWEST OF YAKUTAT FRI NIGHT.
NORTHERLY GAP WINDS WILL DIMINISH TODAY AS FIRST LOW CENTER
DISSIPATES. WINDS WILL REDEVELOP TOMORROW AS SECOND LOW CENTER
STRENGTHENS AND TAKES ITS PLACE.
COLD AIR MASS OVER MAINLAND ALASKA WILL HOLD. TEMPERATURES REMAINING
10 TO 20 DEGREES BELOW CLIMO THROUGH THE WEEKEND.

SURFACE WEST OF 160W...
INVERTED RIDGE OF HIGH PRESSURE OVER THE CENTRAL BERING SEA WILL
GRADUALLY WEAKEN AND FLATTEN THROUGH FRI NIGHT. BROAD EASTERLY FLOW
WILL DEVELOP ACROSS THE BERING SEA FRI NIGHT. OFF CONTINENT FLOW
WILL REDUCE SNOW SHOWER DEVELOPMENT OVER THE EASTERN BERING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE  120 130 150 175 176
         SPRAY 120 121 129 130 138 141 150 155 165 171 179
FIRE WEATHER...NONE

ASB MAR 07