Small Craft Advisory 69, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST FRI JAN 25 2008

.MODEL DISCUSSION...THE SYSTEM NOW AFFECTING SOUTHCENTRAL AND MOVING
TOWARD SOUTHEAST ALASKA IS PROGRESSING MUCH FASTER THAN WHAT ANY
MODEL HAD...FORECASTS WERE ADJUSTED TO THIS. MODELS ARE IN VERY GOOD
AGREEMENT THROUGH THE WEEKEND. THE MODELS THEN DIVERGE ON THE TRACK
AND STRENGTH OF A NORTH PACIFIC LOW ENTERING THE EASTERN BERING.

.ANALYSIS AND UPPER LEVELS...UPPER LOW IS NORTH OF MACKENZIE BAY WITH
A TROUGH EXTENDING DOWN INTO THE GULF. AT THE BOTTOM...A SURFACE LOW
IS TRAVELING EAST ACROSS THE GULF CONTINUING TO SPREAD SNOW OVER
SOUTHCENTRAL. AN UPPER LEVEL RIDGE STRETCHING OVER EASTERN SIBERIA
AND SOUTHEAST THROUGH THE ALEUTIANS IS MOVING EAST ALONG WITH ITS
SURFACE COUNTERPART. A WEAKENING LOW WEST OF SAINT LAWRENCE ISLAND
CONTINUES TO BRING SNOW SHOWERS TO THE BERING AND PRIBILOFS. A LARGE
LOW SOUTH OF THE KAMCHATKA PENINSULA IS PRODUCING A TRIPLE POINT LOW
JUST WEST OF THE WESTERN ALEUTIANS AND PUSHING ITS WARM FRONT OVER
THE CHAIN.

THE UPPER RIDGE WILL CONTINUE MOVING EAST THROUGH THE WEEKEND TO BE
OVER THE MAINLAND AND CENTRAL GULF BY SUNDAY NIGHT. A LARGE UPPER LOW
WILL FOLLOW BEHIND AND POSITION ITSELF OVER THE WESTERN BERING.

.SHORT TERM FORECAST...
SOUTH AND EAST OF THE ALASKA RANGE...A SHORTWAVE IN THE UPPER TROUGH
WILL DEEPEN THE LOW IN THE GULF WHILE HIGH PRESSURE OVER THE NORTHERN
MAINLAND STRENGTHENS AND PUSHES SOUTH. COMBINED WITH COLD ADVECTION
ON THE BACKSIDE OF THE UPPER LOW...NORTHERLY WINDS WILL BE PICKING UP
AS THE PRESSURE GRADIENT TIGHTENS. LOOK FOR WINDS NEAR THE COPPER
RIVER DELTA AND THOMPSON PASS TO BE OBSERVING SOME OF THE HIGHEST
WINDS TONIGHT AND TOMORROW. THE HIGH PRESSURE FROM THE NORTH AND THE
WEST WILL BRING CLEAR AND DRY CONDITIONS TO THE REGION BY LATE
TONIGHT TO LAST THROUGH THE WEEKEND. SUNDAY THE NEXT SYSTEM FROM THE
WEST WILL PUSH A FRONT OVER KODIAK SUNDAY THEN HEAD NORTHEAST THROUGH
THE GULF.

WESTERN MAINLAND AND ALASKA PENINSULA...SNOW SHOWERS FROM THE
WEAKENING BERING LOW WILL CONTINUE TODAY FOR MUCH OF THE AREA THEN
CLEAR TONIGHT. SATURDAY WILL BRING CLEAR SKIES OVER THE MAINLAND
WHILE A FRONT BRINGS A MIX OF RAIN AND SNOW TO THE PENINSULA.
TEMPERATURES THAT HAD COOLED FROM THE COLD ADVECTION ON THE BACKSIDE
OF THE UPPER LOW WILL HOLD STRONG ENOUGH TO KEEP ALL PRECIPITATION IN
THE FORM OF SNOW OVER THE WESTERN MAINLAND SATURDAY NIGHT THROUGH
MONDAY. A WEAK RIDGE BUILDS IN BEHIND THIS.

BERING/ALEUTIANS/PRIBILOFS...SNOW SHOWERS WILL CONTINUE OVER THE
PRIBILOFS TODAY FROM THE WEAKENING LOW. VERY WARM TEMPERATURES WITH
THE FRONTAL SYSTEM OVER THE WESTERN ALEUTIANS WILL SPREAD RAIN ACROSS
THE CHAIN AND BERING TODAY AND SATURDAY. SNOW SHOWERS WILL FILL IN
BEHIND AS COLD AIR REPLACES FROM THE NORTHWEST AND SLIGHT RIDGING
FILLS IN.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 120 121 130 132 150 172 175 176 179
         HEAVY FREEZING SPRAY 121 130 141 185
FIRE WEATHER...NONE

LR JAN 08