Small Craft Advisory 185, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST WED FEB 21 2007

.SYNOPSIS...

CLEAR COLD AND WINDY WEATHER CONTINUES ACROSS MUCH OF ALASKA THIS
MORNING IN RESPONSE TO NORTHERLY FLOW. SATELLITE IMAGERY SHOWS A
WEAKENING LOW IN THE NORTHEAST GULF OF ALASKA THAT IS SLOWLY MOVING
SOUTHEAST...AND A UPPER RIDGE/TROUGH COUPLET ACROSS THE NORTHERN
PACIFIC BEING DRIVEN EAST FROM THE DATELINE TO WEST COAST OF THE
CONUS WITH SURFACE LOW TO THE SOUTH OF THE ALEUTIANS.

OVER THE EAST THE MODELS HAVE A GOOD HANDLE ON THE STABLE PATTERN
ACROSS THE ENTIRE DOMAIN THROUGH DAY 3...THE INHERITED FORECAST LOOKS
ON TRACK AND NO MAJOR CHANGES HAVE BEEN MADE TO THE CURRENT PACKAGE.
A STEERING UPPER LEVEL LOW JUST SOUTH OF THE MCKENZIE RIVER DELTA
BEGINS TO PULL NORTH BUT NOT BEFORE THE NORTHERN BRANCH OF THE JET
ACTS TO REINFORCE THE ALREADY GUSTY WINDS ACROSS PRINCE WILLIAM SOUND
AND THE COPPER RIVER DELTA THROUGH TOMORROW EVENING. THOMPSON PASS
CONTINUES TO GUST TO 75 MPH EARLY THIS MORNING AND WITH CONTINUED
COLD AIR ADVECTION FROM THE NORTH HAVE KEPT THE HIGH WIND WARNING AND
THE WIND CHILL ADVISORY FOR THE COPPER RIVER DELTA AND THOMPSON PASS
RESPECTIVELY...DESPITE THE WEAKENING PRESSURE GRADIENT. WITH GUSTY
WINDS AND TEMPERATURES BELOW ZERO ACROSS THE COPPER RIVER
BASIN...MATSU BOROUGH...AND THE KENAI PENINSULA HAVE MAINTAINED WIND
CHILL ADVISORIES AND STRONG WIND HEADLINES IN THESE AREAS.

IN THE WEST...CLEAR AND COLD WEATHER DOMINATES SOUTHWEST ALASKA
BEFORE A LOW DROPS SOUTH OUT OF SIBERIA CARRYING ITS FRONT ACROSS THE
Y/K DELTA FRIDAY WITH CLOUDS AND SOME SNOW SHOWERS. THE GFS SOLUTION
WAS FOLLOWED IN THE NEAR TERM WITH THE LOW CURRENTLY SOUTH OF THE
ALEUTIANS STAYING SOUTH OF THE AREA...THIS IS FOLLOWED BY A STRONG
SURFACE HIGH AND UPPER RIDGE OVER THE BERING.

EXTENDED...BEYOND DAY 3 THE MODELS ARE HAVING A TOUGH TIME RESOLVING
THE FEATURES OUT WEST. THE EUROPEAN SOLUTION DEEPENS A LOW SOUTH OF
THE ALEUTIANS MUCH DEEPER THAN THE GFS NAM AND ENSEMBLE MEAN
SOLUTIONS. FOR THE PURPOSES OF THE FORECAST...HAVE NOT TWEAKED THE
EXTENDED GRIDS MUCH OVERNIGHT. IN THE EAST THE MODELS HINT AT A
SLIGHT MODERATION OF TEMPERATURES ACROSS THE AREA BY MIDWEEK NEXT
WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...WIND CHILL ADVISORY FOR THOMPSON PASS
         HIGH WIND WARNING FOR COPPER RIVER DELTA
         WIND CHILL ADVISORY FOR 141 AND 145
MARINE...GALE WARNING 120 121 172 176
         HEAVY FREEZING SPRARY 120 121 125 129 130 138 140 141 150
         160 165 179 180 185
FIRE WEATHER...NONE.

SDM FEB 07