Small Craft Advisory 1055, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTH CENTRAL AND SOUTHWEST ALASKA
200 PM AST SAT DEC 15 2007

.ANALYSIS AND UPPER LEVELS...
A FAIRLY STABLE UPPER FLOW IS ESTABLISHED OVER ALASKA WITH AN UPPER
RIDGE EXTENDING FROM THE NORTHWEST BERING THROUGH THE EASTERN
ALEUTIANS AND AN UPPER TROUGH FROM NORTH OF BARROW TO THE CENTRAL
GULF OF ALASKA. THE TROUGH WILL REMAIN STATIONARY THROUGH THE WEEKEND
WITH A SHORT WAVE MOVING DOWN FROM THE ARCTIC CROSSING OVER BARROW
SUN NIGHT.  THIS WAVE WILL MOVE TO WEST CENTRAL INTERIOR ALASKA BY
TUE CAUSING THE TROUGH TO SLOWLY RETROGRADE WESTWARD.  THE UPPER
RIDGE WILL REMAIN STATIONARY WITH AN UPPER HIGH CUTTING OFF JUST WEST
OF ANADYR BY LATE MON AND WESTERLIES BREAKING THROUGH UNDER THE HIGH
OVER THE NORTH PACIFIC SOUTH OF THE ALEUTIANS BY TUE.

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT IN THE SHORT TERM.  DIFFERENCES SHOW UP
MON IN THE WESTERN ALEUTIANS.  THE GFS BRINGS THE NEXT LOW NORTH OF
THE ALEUTIANS LATE MON WHILE THE UKMET KEEPS THIS LOW SOUTH OF THE
CHAIN AND STRETCHES IT OUT ALONG 50N. WE WILL LEAN TOWARD THE UKMET
SOLUTION AS IT IS A BETTER FIT WITH THE UPPER LEVEL WESTERLIES
BREAKING THROUGH THE RIDGE SOUTH OF THE CHAIN.

.SHORT TERM FORECAST...
SOUTH CENTRAL...
COLD AND LOCALLY WINDY FOR SOUTH CENTRAL THROUGH MONDAY.
SLOW COLD ADVECTION WILL PERSIST SUNDAY AND MONDAY AS WILL
THE TIGHT PRESSURE GRADIENT WITH LOW PRESSURE IN THE NORTHERN GULF.
EXPECT LOCALLY STRONG WINDS AND COLD TEMPERATURES. SOME OF THE
STRONGEST WINDS WILL OCCUR IN THE WESTERN GULF FROM  SOUTH OF CHIGNIK
NORTHEAST TO KENNEDY ENTRANCE. MANY OTHER AREAS OF IN CHANNELED
TERRAIN SUCH AS RESURRECTION BAY WILL EXPERIENCE STRONG WINDS AS
WELL. HEAVY FREEZING SPRAY WILL BE AN ISSUE FOR MANY AREAS NEAR
SHORE. CONDITIONS WILL REMAIN GENERALLY DRY THROUGH MONDAY WITH
PARTLY CLOUDY SKIES.

SOUTHWEST MAINLAND...
PRETTY MUCH THE SAME SETUP FOR THE SOUTHWEST MAINLAND AS
SOUTH CENTRAL...EXCEPT THAT WINDS WILL GENERALLY NOT BE AS STRONG AS
SOUTH CENTRAL BUT TEMPERATURES WILL BE A LITTLE COLDER.

BERING SEA/ALEUTIANS...
ACTIVE WEATHER WILL PERSIST OVER THE CENTRAL AND WESTERN
BERING/ALEUTIANS TO THE WEST OF THE BERING SEA RIDGE. A MODERATELY
STRONG FRONT IS MOVING NORTHEAST THROUGH THE WESTERN BERING/ALEUTIANS
TODAY BRINGING GALES AND RAIN...OR SNOW CHANGING TO RAIN. THIS FRONT
WILL WEAKEN TONIGHT AND STALL SUNDAY AS IT RUNS INTO THE HIGH
PRESSURE IN THE EASTERN BERING/ALEUTIANS. A STRONG LOW WILL MOVE INTO
THE WESTERN ALEUTIANS SUNDAY NIGHT AND MONDAY WITH STORM FORCE WINDS
LIKELY.

.LONG TERM FORECAST...
THE UPPER AIR FLOW SHOULD PERSIST UNTIL WEDNESDAY. THINGS GET MORE
UNCERTAIN AFTER WEDNESDAY.  THE MODELS INDICATE RETROGRESSION OF THE
UPPER LEVEL ALASKA TROUGH TO THE EASTERN BERING BY FRI AND BUILDING
AN UPPER RDIGE OVER THE EASTERN GULF OF ALASKA. IF CORRECT THIS WILL
BRING WARMER AND WETTER FLOW FROM THE SOUTHEAST OVER MOST OF THE
SOUTHERN ALASKA MAINLAND BY LATE NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORM  130 352
         GALE  121 129 132 138 150 155 165 172 175 176 185 351 411
                 412 413
         HEAVY FREEZING SPRAY  121 125 129 130 132 138 140 141 150
                 160 165 180 185
FIRE WEATHER...NONE

RHH DEC 07