Small Craft Advisory 189, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
430 PM AST WED FEB 21 2007

.DISCUSSION...
MODELS ARE IN BETTER AGREEMENT THOUGH THE GFS MODEL DEEPEN THE LOW
MOVING ACROSS THE NORTH PACIFIC MUCH MORE THAN THE NAM MODEL DOES. I
PREFER THE GFS MODEL BECAUSE IT HAS BEEN MORE CONSISTENT THE THE NAM
MODEL BUT CONFIDENCE IS NOT ROCK SOLID.

UPPER AIR...
THE GENERAL UPPER AIR PATTERN OVER MAINLAND ALASKA WILL NOT CHANGE
MUCH OVER THE NEXT 2 DAYS. THE UPPER LOW NEAR THE MCKENZIE DELTA WILL
REMAIN NEARLY STATIONARY THROUGH FRIDAY AFTERNOON. A HIGH AMPLITUDE
RIDGE OVER THE EASTERN BERING SEA WILL PERSIST THROUGH THURSDAY NIGHT
THEN BEGIN TO FLATTEN AS AN UPPER LOW MOVES OUT OF SIBERIA INTO THE
NORTHERN BERING SEA FRIDAY. A NORTHERLY FLOW WILL PERSIST OVER
EASTERN AND CENTRAL MAINLAND THROUGH FRIDAY.

A 300 MB NORTHERLY JET OVER THE WESTERN INTERIOR AND THE WESTERN GULF
OF ALASKA WILL MOVE INTO THE CENTRAL INTERIOR AND PRINCE WILLIAM
SOUND THURSDAY AFTERNOON THEN WILL DIMINISH FRIDAY.

EAST DOMAIN...
CLEAR AND COLD CONDITIONS WILL CONTINUE THROUGH FRIDAY. GUST WINDS
OVER THE SUSITNA VALLEY AND KENAI PENINSULA WILL CONTINUE TO DIMINISH
THROUGH TONIGHT. STRONG WINDS THROUGH CHANNELED AREAS ALONG THE
ALASKA RANGE AND CHUGACH MOUNTAIN WILL PERSIST THROUGH LATE THURSDAY
UNTIL THE UPPER JET SUPPORT MOVES OUT OF THE AREA.

WEST DOMAIN...
SOUTHWEST MAINLAND WILL REMAIN MOSTLY CLEAR AND COLD THROUGH THURSDAY
NIGHT. A WEAK 1013 MB LOW OVER SIBERIA WILL MOVE INTO THE WESTERN
SEWARD PENINSULA FRIDAY AFTERNOON. A WEAK WEATHER FRONT ASSOCIATED
WITH THE LOW WILL MOVE INTO THE KUSKOKWIM DELTA FRIDAY. CLOUDS AND
LIGHT SNOW WILL MOVE INTO THE KUSKOKWIM DELTA AND WESTERN BRISTOL BAY
FRIDAY.

THE WEATHER FRONT OVER THE CENTRAL BERING SEA DISSIPATE OVER THE
EASTERN BERING SEAS THURSDAY NIGHT.

THE LOW SOUTHWEST OF DUTCH HARBOR WILL MOVE EAST ALONG 51N LATITUDE
THROUGH FRIDAY.  GALE FORCE WINDS OVER THE CENTRAL ALEUTIANS ALONG
THE BACK SIDE OF THE LOW WILL DIMINISH THURSDAY MORNING. GALE FORCE
WINDS WILL ALSO DEVELOP ALONG THE PACIFIC SIDE OF THE EASTERN
ALEUTIANS AND ALASKA PENINSULA AS THE LOW PASSES SOUTH OF THE AREA.

A WEAK LOW SOUTH OF THE KAMCHATKA PENINSULA WILL MOVE SOUTH OF THE
WESTERN ALEUTIANS THURSDAY AND THURSDAY NIGHT AND WILL DISSIPATE
SOUTH OF THE CENTRAL ALEUTIANS FRIDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING FOR THOMPSON PASS.
         HIGH WIND WARNING FOR THE COPPER RIVER DELTA AND VALDEZ
         ZONE.
MARINE...HEAVY FREEZING SPRAY...120 121 125 129 130 140
                                160 165 179 180 185
         GALE...120 155 172
FIRE WEATHER...NONE.

NM FEB 07