Heavy Snow in Alaska, November 26, 2005

SOUTHEAST ALASKA FORECAST DISCUSSION
630 AM AST SAT NOV 26 2005

.SHORT RANGE...LATEST GOES IR SATELLITE IMAGERY LOOP SHOWS A
TROUGH EXTENDING FROM A LOW CENTERED SOUTH OF PRINCE WILLIAM
SOUND TO STRETCH EAST TO COVER THE EASTERN GULF COAST BEFORE
CURVING SOUTHEAST TO LIE ALONG THE OUTER COAST OF SOUTHEAST
ALASKA. CONVECTIVE CELLS ASSOCIATED WITH THIS TROUGH HAVE
ORGANIZED INTO LINES. WHILE THE CELLS MOVE NORTHWEST ALONG
THE TROUGH...THE TROUGH ITSELF CONTINUES TO SWING EAST TOWARD
THE INNER CHANNELS OF SOUTHEAST ALASKA. SNOW CONTINUES TO FALL
LIGHTLY OVER THE EASTERN GULF COAST AND YAKUTAT AREA WHERE
A SNOW ADVISORY REMAINS IN EFFECT. A FEW MIXED RAIN AND SNOW
SHOWERS ARE OCCURRING OVER PARTS OF SOUTHERN SOUTHEAST ALASKA.

MODELS SHOW THE LOW SOUTH OF PRINCE WILLIAM SOUND WEAKENING AND
BEGINNING A DRIFT TOWARD THE SOUTHEAST THIS AFTERNOON THAT WILL
TAKE THE CENTER OF THE LOW TO A POSITION 200 NM WEST OF THE
QUEEN CHARLOTTE ISLANDS BY SUNDAY MORNING. EASTWARD SWINGING
TROUGH AHEAD OF THE LOW WILL BRING MAINLY SNOW SHOWERS...
EXCEPT MIXED RAIN AND SNOW SHOWERS OVER THE SOUTH HALF OF
SOUTHEAST ALASKA LATER THIS MORNING THROUGH THIS AFTERNOON.
ON THE OTHER HAND...THE MAIN LOW DROPPING SOUTHEAST WILL
PRODUCE AN OFFSHORE FLOW ALONG THE EASTERN GULF COAST WEAKENING
THE SNOW SHOWER ACTIVITY THERE. AS A RESULT THE SNOW ADVISORY
WILL EXPIRE AROUND NOON AS THE SNOW SHOWER ACTIVITY ALONG THE
EASTERN GULF COAST BEGINS TO TAPER OFF.

HIGH PRESSURE BUILDING OVER BRITISH COLUMBIA AT THE SAME TIME THE
GULF OF ALASKA LOW IS MOVING TOWARD THE SOUTHEAST WILL CREATE AN
EAST OFFSHORE FLOW OVER THE SOUTHEAST ALASKA PANHANDLE. THIS WILL
LIMIT THE INTENSITY OF THE SNOW AND RAIN SHOWER ACTIVITY
OVER MUCH OF SOUTHEAST ALASKA THIS AFTERNOON.

TEMPERATURES WILL BE COLD ENOUGH FOR ALL SHOWER ACTIVITY TO
BE IN THE FORM OF SNOW ALONG THE EASTERN GULF...CENTRAL AND
SOUTHERN SOUTHEAST ALASKA TONIGHT WITH ONLY LIGHT ACCUMULATIONS
EXPECTED. SOME CLEARING BEGIN FROM THE NORTH OVER NORTHERN
SOUTHEAST ALASKA LATER TONIGHT. THIS CLEARING TREND WILL SPREAD
SOUTH TO INCLUDE THE NORTH HALF OF CENTRAL SOUTHEAST ALASKA
SUNDAY WHILE SCATTERED SNOW AND RAIN SHOWERS CONTINUE OVER THE
SOUTH HALF OF SOUTHEAST ALASKA THROUGH SUNDAY.

.LONG RANGE...MODELS ARE IN AGREEMENT THAT A 1011 MB LOW SUN
EVENING WILL CONTINUE TO MOVE TO ABOUT 200 NM WEST OF NORTHERN
VANCOUVER ISLAND BY MON MORNING AS IT INTENSIFIES TO 1000 MB.
THIS WILL INCREASE NORTHEAST OFFSHORE FLOW OVER ALL OF SOUTHEAST
ALASKA BY MON...FOR MOSTLY CLEAR SKIES...COLD NIGHTS AND COOLER
DAYS THROUGH THU NIGHT. THEN A 1010 MB LOW IS FORECAST TO MOVE
OUT OF  SOUTH CENTRAL ALASKA AND INTENSIFY TO 985 MB BY THE TIME
IT IS JUST WEST OF DIXON ENTRANCE NEXT SAT AFTERNOON. THIS WOULD
BRING A GOOD SNOW EVENT TO THE YAKUTAT AREA FRI AND THE PANHANDLE
FRI NIGHT AND SAT AS RELATIVELY WARMER MOISTER AIR IS DRAWN UP
OVER THAT ESTABLISHED COLD DRY AIRMASS.

ECMWF AGREES WITH THE LOW COMING OUT OF SOUTH CENTRAL ALASKA
ALTHOUGH LOCATION AND TIMING ARE SLIGHTLY DIFFERENT.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...SNOW ADVISORY...ZONE 17 UNTIL NOON

MARINE...SMALL CRAFT ADVISORY...
          ALL OUISIDE WATERS
          INSIDE WATERS...PKZ022-031-034-035-036

DED/LN