Small Craft Advisory 59, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AST THU JAN 19 2006

.DISCUSSION...
UPPER LEVELS...POLAR LOW SETTLING INTO THE INTERIOR TODAY WITH COLDER
AIR FILTERING INTO THE EASTERN BERING EASTWARD TO SOUTH CENTRAL
ALASKA. SHORT WAVE DIGGING SOUTH IN THE BERING SEA WILL BRING COLDER
AIR INTO THE TROUGH OF LOW PRESSURE ALL THE WAY TO THE ALEUTIAN
CHAIN. THIS WILL DEVELOP A TROUGH AXIS FROM THE NORTHERN COAST TO THE
EASTERN ALEUTIAN CHAIN BY FRIDAY. EXTREME EASTERN ALASKA WILL REMAIN
UNDER A SLIGHTLY WARMER SOUTHWEST FLOW ALOFT IN THIS SCENARIO. TWO
SEPARATE SHORT WAVE TROUGHS TO WORK THROUGH THE UPPER LEVEL TROUGH
THROUGH THE WEEKEND. ONE IS CURRENTLY NEAR 170W AND WILL MOVE EAST TO
NORTHEAST ON THE FRONT SIDE OF THE TROUGH INTO THE GULF OF ALASKA
FRIDAY. IT WILL WEAKEN WHEN IT HITS PANHANDLE FRIDAY NIGHT. AS THE
TROUGH DEEPENS OVER THE EASTERN BERING...ANOTHER SHORT WAVE TROUGH
LIFTS THROUGH THE GULF SATURDAY. THIS ONE HELPS TO PULL THE UPPER
LEVEL TROUGH EAST OVER SOUTH CENTRAL. THE TROUGH TO REMAIN OVER SOUTH
CENTRAL ALASKA THROUGH EARLY NEXT WEEK. IN THE MEANTIME...THE RIDGE
OF HIGH PRESSURE OVER THE BERING SEA IS PUSHED WESTWARD WITH THE
DEVELOPMENT OF THE TROUGH OVER THE EASTERN BERING FRIDAY. THE RIDGE
REMAINS OVER THE WESTERN ALEUTIAN CHAIN THROUGH SUNDAY. IT IS
EVENTUALLY PUSHED EASTWARD AS A SHORT WAVE TROUGH ROTATING AROUND
ANOTHER KAMCHATKA LOW WORKS TOWARD SHEMYA MONDAY.

SOUTH CENTRAL SURFACE...WEAK LOW IN WESTERN PRINCE WILLIAM SOUND THIS
MORNING PRODUCING AREAS OF LIGHT SNOW FROM CORDOVA TO WASILLA TO
CANTWELL AND POINTS EAST. SHORT WAVE TROUGH ROUNDING POLAR LOW
DROPPING INTO THE STATE WILL SWEEP OUT MOST LOW LEVEL MOISTURE OVER
THE INLAND AREAS LATER TODAY AND TONIGHT. WITH THE POLAR LOW MOVING
INTO THE INTERIOR...VERY COLD AIR FILTERING INTO WESTERN ALASKA AND
BERING SEA TODAY EVENTUALLY WORKING TO SOUTH CENTRAL TOMORROW. TEMPS
WILL NOT DIP TOO FAR BELOW NORMAL IN THE COPPER RIVER AS THE UPPER
LOW REMAINS WEST OF THAT AREA. OTHER PORTIONS OF THE MAINLAND WILL BE
WELL 5 TO 10 DEGREES BELOW NORMAL INLAND. HOWEVER...TEMPS WILL
REBOUND LATE FRIDAY NIGHT AND SATURDAY AS A LOW WORKS TOWARD KODIAK.
THIS LOW TO MOVE INTO THE SOUND LATE FRIDAY BRINGING MODERATE WINDS
AND PRECIPITATION TO SOUTH CENTRAL ALASKA. WITH THE PATH OF THIS
FIRST LOW...IT LOOKS AS THOUGH PRECIPITATION WILL MOVE INTO THE
ANCHORAGE AREA FRIDAY NIGHT LASTING THROUGH SATURDAY MORNING. A
STRONGER LOW TO MOVE IN AFTER THE FIRST EARLY SATURDAY NEAR KODIAK
AND INTO THE SOUND SATURDAY NIGHT. THIS ONE IS ALONG THE SAME PATH
BUT STRONGER WINDS. PRECIPITATION WILL BE ROUGHLY THE SAME AMOUNTS AS
THE FIRST ONE COMING THROUGH THE AREA. HOWEVER...LOW TO WEAKEN AND
HANG OUT IN THE SOUND THROUGH EARLY NEXT WEEK ALLOWING FOR SHOWERS TO
CONTINUE OVER MUCH OF SOUTH CENTRAL. HOWEVER...TROUGH AXIS TO MOVE
THROUGH SUNDAY NIGHT/MONDAY CAUSING SHOWERS TO END FROM THE WEST
STARTING MONDAY.

WEST OF THE ALASKA RANGE SURFACE...LOW SOUTH OF THE CENTRAL ALEUTIAN
CHAIN ALONG WITH HIGH PRESSURE OVER THE BERING SEA CREATING TIGHT
PRESSURE GRADIENT ALONG THEN CHAIN AND BERING SEA. AS A
RESULT...EASTER TO NORTHEAST WINDS ARE RATHER STRONG OVER THOSE
AREAS. IN FACT...SEEING SOME AREAS OF BLOWING SNOW REDUCING
VISIBILITY QUITE A BIT. ANOTHER LOW TO MOVE UP TO THE CHAIN
FRIDAY...MAINTAINING THE PRESSURE GRADIENT. WITH A POLAR LOW SETTING
UP OVER THE INTERIOR TODAY AND TROUGH AXIS DIGGING IN THE EASTERN
BERING TONIGHT...TEMPS WILL FALL FAR BELOW NORMAL IN WESTERN ALASKA
TO THE EASTERN ALEUTIANS STARTING TONIGHT. ANYWHERE FROM 5 TO 10
DEGREES IN THE ALEUTIAN CHAIN TO 15 TO 25 DEGREES IN THE INTERIOR.
THE HIGH PRESSURE OVER THE BERING SEA IS PUSHED WEST BY FRIDAY NIGHT
BUT A GOOD GRADIENT IS MAINTAINED OVER THE EASTERN BERING TO THE
COAST. THIS PATTERN TO REMAIN THROUGH THE WEEKEND UNTIL A FRONT
PUSHES TO THE WESTERN ALEUTIAN CHAIN LATE SUNDAY SHIFTING THE WHOLE
PATTERN EAST OVER TIME. WINDS WILL THEN PICK UP WITH THE LOW MOVING
INTO THE WESTERN ALEUTIAN CHAIN. MOST PRECIPITATION FROM THE LOW
ALONG THE CHAIN AND THE ONE COMING UP TOMORROW WILL REMAIN ALONG THE
CHAIN. EXPECT SOME MODERATE AMOUNTS OF SNOW AND RAIN TO MOST OF THE
ALEUTIAN CHAIN WITH THESE TWO SYSTEMS OVER THE NEXT 36 HOURS. AFTER
THE TROUGH DIGS IN THE EASTERN BERING...EXPECT MOST PRECIPITATION TO
BE CUT OFF OUTSIDE OF INSTABILITY SHOWERS IN THE BERING SEA HITTING
THE NORTHERN SIDE OF THE CHAIN OVER THE WEEKEND. THEN PRECIP ARRIVING
WITH THE FRONT IN THE WESTERN ALEUTIAN CHAIN LATE SUNDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...HEAVY FREEZING SPRAY 130 138 140 150 160 165 179
         STORM 175 176
         GALE 165 170 172 179
FIRE WEATHER...NONE

JN JAN 06