Gale Warning 666, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
100 PM AKDT SUN SEP 19 2010

.MODEL DISCUSSION...GFS AND NAM IN REASONABLE AGREEMENT ON SURFACE
FEATURES THROUGH ABOUT 60 HRS AND THEN SIGNIFICANT DIVERGENCE ON
ANOTHER PACIFIC SYSTEM MOVING INTO THE WESTERN ALEUTIANS. AS PER
USUAL THE GFS IS RUNNING 3 TO 5 MB DEEPER THAN THE NAM OR OLDER ECMWF
RUN.  RIDGE OF HIGHER PRESSURE OVER GULF AND MAINLAND AT 500 MB STILL
PROGED TO MOVE INTO THE CHUKCHI SEA BY MID-WEEK WITH SEVERAL
WEAKENING FRONTS MOVING INTO THE SOUTHERN GULF.

.ANALYSIS AND UPPER LEVELS...VISIBLE SATELLITE IMAGERY SHOWS PLENTY
OF STRATUS AND FOG OVER THE WESTERN HALF OF THE GULF WITH NEAR
COMPLETE CLOUD COVER OVER THE BERING AND ALEUTIANS.  ACTIVE WEATHER
CONSISTS OF A LOW OVER THE WESTERN ALEUTIANS WITH A WEAKENING WARM
FRONT OVER THE AK PEN.

.SHORT TERM FORECAST...BERING LOW IS PROGED TO MOVE NORTH OF ATKA
MONDAY MORNING AND THEN NORTHWARD INTO THE CENTRAL BERING AS IT BUTTS
UP ALONG THE WESTERN SIDE OF THE RIDGE. MODERATELY STRONG SOUTHWEST
WINDS CAN BE EXPECTED IN THE WESTERN AND CENTRAL ALEUTIANS OVER THE
NEXT 48 HOURS.  LITTLE CHANGE EXPECTED EAST OF 160W.

.LONG TERM FORECAST...AS NOTED ALREADY THERE IS CONSIDERABLE MODEL
DIVERGENCE REGARDING ALEUTIANS ON WEDNESDAY.  GFS PRODUCES A SURFACE
TROUGH NEAR AMCHITKA EARLY WEDNESDAY MORNING WHICH SUBSEQUENTLY MOVES
OVER THE EASTERN ALEUTIANS.  NAM SHOWS ZONAL FLOW WHILE OLDER ECMWF
LEANS TOWARD THE GFS SOLUTION...WOULD EXPECT A TROUGH/LOW TO MOVE
OVER THE CENTRAL ALEUTIANS ON WED WITH MODERATE SOUTH WINDS.

OVER MAINLAND...HIGH PRESSURE WEAKENS THROUGH THE WEEK WITH COOLER
AIR MOVING FROM THE ARCTIC INTO SOUTHCENTRAL BY FRIDAY.  LITTLE IN
THE WAY OF CLOUDS OR MOISTURE IS EXPECTED.

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

JMP SEP 10