Small Craft Advisory 110, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST MON FEB 4 2013

.MODEL DISCUSSION...
GUIDANCE IN SURPRISINGLY GOOD AGREEMENT THROUGH THE SHORT TERM AT
THE SURFACE. AT THE UPPER LEVELS THERE IS SOME DISAGREEMENT ON HOW
SHARP THE TROUGH THAT CROSSES SOUTHERN ALASKA ON WEDNESDAY WILL BE
BUT OTHERWISE ARE IN GOOD AGREEMENT.

.ANALYSIS AND UPPER LEVELS...
THERE IS A WEAK UPPER LEVEL TROUGH STRETCHING FROM CHIGNIK NORTHWEST
INTO EXTREME NORTHEAST RUSSIA. ANOTHER LOW JUST SOUTH OF THE CENTRAL
ALEUTIANS IS MOVING EAST/SOUTHEAST. A LARGE UPPER LOW IS NEAR THE
KAMCHATKA PENINSULA AND IS BEGINNING TO SPIN UP A POWERFUL SYSTEM
SOUTHWEST OF THE WESTERN ALEUTIANS. THERE IS AN EAST-WEST ORIENTED
RIDGE BETWEEN THE CENTRAL ALEUTIAN SYSTEM AND THE CHIGNIK/RUSSIA LOW
AND A RIDGE ALONG THE NORTH AMERICAN WEST COAST WHICH NOSES INTO
ALASKA.

.SHORT TERM FORECAST...
SOUTH CENTRAL ALASKA...THE CHIGNIK/RUSSIA LOW WILL SLOWLY MOVE
NORTHEAST THROUGH TUESDAY. WITH SLOWLY DECREASING MOISTURE AND
DYNAMICS OVER THE AREA PRECIPITATION WILL END IN MOST AREAS BY
TUESDAY AFTERNOON. THEN THE LOW WILL BECOME AN OPEN WAVE TROUGH AND
MOVE EASTWARD. CHANCES OF PRECIPITATION WILL INCREASE AGAIN OVER
SOUTH CENTRAL ALASKA FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
WITH LIMITED MOISTURE TO WORK WITH ANY PRECIP WILL BE FAIRLY
LIGHT...BUT WITH COLDER AIR ALOFT MOST OF THE PRECIP WILL BE IN THE
FORM OF SNOW. ANOTHER WARM AND MOIST SYSTEM WILL MOVE INTO THE AREA
FROM THE SOUTHWEST ON THURSDAY.

SOUTHWEST ALASKA...WITH THE UPPER LOW OVERHEAD AND THUS CYCLONIC
FLOW...SHOWERS WILL CONTINUE OVER THE AREA THROUGH TUESDAY NIGHT.
THERE WILL BE A BREAK OVER THE AREA ON WEDNESDAY BEFORE A BERING
SEA/ALEUTIAN SYSTEM PUSHES INTO THE AREA FROM THE SOUTHWEST ON
WEDNESDAY NIGHT AND THURSDAY.

BERING SEA AND ALEUTIANS...THE LOW JUST SOUTH OF THE CENTRAL
ALEUTIANS WILL MOVE EAST/SOUTHEAST OUT OF THE AREA BY LATER TONIGHT.
THE NEXT SYSTEM OF NOTE IS A LOW SOUTHWEST OF THE WESTERN ALEUTIANS
THAT WILL "BOMB OUT" TONIGHT AND TUESDAY...WITH THE LOWEST SURFACE
PRESSURE EXPECTED TO BE AROUND 950 MB. THE MAIN FRONT ASSOCIATED
WITH THIS SYSTEM WILL MOVE INTO THE WESTERN ALEUTIANS TUESDAY...THE
CENTRAL ALEUTIANS TUESDAY NIGHT AND INTO THE EASTERN ALEUTIANS AND
ALASKA PENINSULA WEDNESDAY. BY WEDNESDAY THIS WILL BE THE DOMINANT
UPPER LOW AND CENTERED SOUTH OF THE WESTERN ALEUTIANS. IT WILL THEN
SLIDE TO THE CENTRAL ALEUTIANS THURSDAY WHILE THE ASSOCIATED WEATHER
WILL HAVE PUSHED TO THE CANADIAN BORDER WITH SOUTH CENTRAL ALASKA BY
THURSDAY AFTERNOON.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING 175 176.
         GALE WARNING 170 172 185.
         HEAVY FREEZING SPRAY 179.
FIRE WEATHER...NONE.

LUDWIG FEB 13