Small Craft Advisory 160, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AST TUE FEB 13 2007

.DISCUSSION...

SHORT TERM...WEAKENING SURFACE LOW OVER THE ALASKA PENINSULA WILL
CONTINUE TO FILL AND DRIFT NORTHWEST ALONG THE SOUTHWEST ALASKA COAST
OVERNIGHT. SNOWFALL WITH THE WEAK UPWARD VERTICAL MOTION FIELD
EXPECTED TO BE LIGHT IN WEST. WEAKENING NORTHWEST SOUTHEAST ORIENTED
FRONTAL BAND ACROSS BERING SEA FROM LOW IN WESTERN BERING SEA TO LOW
PRESSURE OVER THE ALASKA PENINSULA. TROUGHING EXTENDS EASTWARD ACROSS
SOUTH CENTRAL ALASKA. MOST OF THE PRECIPITATION FALLING AS SNOW OVER
THE INLAND KENAI PENINSULA. SNOW WILL DEVELOP ALONG THE COAST THIS
EVENING AS THE FLOW BACKS WITH THE UPPER TROUGH PASSAGE. DRIER AIR
MOVING IN WITH SHORT WAVE RIDGE OVERNIGHT.

LONG TERM...OTHERWISE PATTERN FAIRLY QUIET ACROSS THE FORECAST AREA
GIVEN THE TIME OF THE YEAR...WITH A MINIMUM OF MARINE WARNINGS OUT.
THE MOST SIGNIFICANT CHANGE SHOULD OCCUR OVER THE WEEKEND AS THE
BROAD TROUGHINESS THAT DOMINATES THE FORECAST AREA INTO THE WESTERN
BERING SEA GIVES WAY TO AMPLIFIED FLOW. THE LONG WAVE RIDGE APPEARS
TO WANT TO REESTABLISH OVER 160W SOMETIME NEXT WEEK WITH A COLD
NORTHWESTERLY FLOW ACROSS MAINLAND ALASKA.

MODELS....NCEP MODELS LOOKING WELL INITIALIZED AND FAIRLY CONSISTENT
THROUGH 72 HOURS. WRF THEN HAS TYPICAL BOUNDARY ISSUES WITH SYSTEM
MOVING OUT OF EXTREME WESTERN BERING SEA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 155 170.
FIRE WEATHER...NONE.

CAS FEB 07