Small Craft Advisory 817, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
540 AM AKST SAT DEC 10 2011

.SHORT TERM...RATHER QUIET SHORT RANGE PERIOD FOR THE NEXT
24 HOURS AS WE ARE IN BETWEEN SYSTEMS AT THE MOMENT. YESTERDAY'S
SYSTEM IS ON ITS WAY THROUGH BRITISH COLUMBIA AT THE MOMENT
LEAVING THE PANHANDLE UNDER THE REMAINING SHOWERS IT ITS WAKE.
TEMPERATURES ARE WARM ENOUGH THAT MOST OF THE SHOWERS ARE FALLING
AS RAIN. THAT ISN'T THE ONLY CONCERN THROUGH. FOG IS ALSO
CROPPING UP IN SOME PLACES AS BREAKS IN THE CLOUDS ARE
DEVELOPING. PETERSBURG HAS ALREADY SEEN QUARTER MILE OR LESS
VISIBILITY EARLIER THIS MORNING AND VARIOUS OTHER OBSERVATION
SITES HAVE RECORDED LESS THEN 1 MILE VISIBILITY AT SOME POINT
OVERNIGHT.

FOR TODAY AND TONIGHT, CLOUDS WILL CONTINUE TO DECREASE AS A
RIDGE BUILDS IN THE GULF AND MOVES EAST. SHOWERS WILL ALSO
DECREASE AS THE VORT MAX AND COOL AIR ALOFT SUPPORTING THEM MOVE
OFF TO THE SE TODAY. BY THIS EVENING, MOST OF THE PANHANDLE SHOULD
BE UNDER PARTLY CLOUDY SKIES.

THE CLEARER SKIES TONIGHT WILL PROMPT TWO THINGS TO HAPPEN ACROSS
THE PANHANDLE. IN WIND SHELTERED AREAS TEMPERATURES WILL START TO
DROP DUE TO RADIATIONAL COOLING. SOME AREAS AWAY FROM THE WATER
AND IN WIND SHELTERED AREAS MAY DROP INTO THE TEEN TONIGHT. THE
OTHER POSSIBILITY IS THE DEVELOPMENT OF FOG IN THE INNER CHANNEL
AREAS AS THE ATMOSPHERE IS NEAR SATURATION FROM ALL THE RECENT
PRECIP. VISIBILITIES COULD DROP TO BELOW 1 MILE AT TIMES LATE
TONIGHT.

WINDS ARE NOT MUCH OF A PROBLEM ACROSS THE AREA AT THE MOMENT AS
MOST AREAS HAVE LESS THEN 20 KT WINDS. THIS TREND WILL CONTINUE
THROUGH THE SHORT TERM PERIOD. THE ONLY EXCEPTION EXPECTED IS OUT
IN THE CENTRAL AND NORTHERN GULF WHERE SE WINDS WILL BE INCREASING
TONIGHT AHEAD OF THE NEXT FRONT THAT IS COMING ACROSS THE GULF.

FORECAST MODELS WERE IN DECENT AGREEMENT. DECIDED TO USE THE EC
WITH A BIT OF THE GFS FOR FORECAST UPDATES TODAY AS THEY SEEMED TO
INITIALIZE THE BEST OUT OF THE SHORT RANGE MODELS. FORECAST
CONFIDENCE IS ABOVE AVERAGE.

&&

.LONG TERM...THE UPPER LEVEL RIDGE AXIS WILL PUSH EAST OF THE
PANHANDLE ON SUNDAY. A DEVELOPING 980 MB LOW LIFTS NNE INTO THE
NORTH CENTRAL GULF BY SUNDAY EVENING AND ONSHORE AND WEAKENING
NEAR CAPE SUCKLING BY MONDAY AFTERNOON. THE ASSOCIATED OCCLUDED
FRONT MOVES TO THE EASTERN GULF SUNDAY EVENING AND WEAKENS OVER
SOUTHEAST ALASKA THROUGH MONDAY. THERE IS A WAVE DEVELOPING ALONG
THE FRONT MOVES TO NEAR CAPE DECISION EARLY MONDAY. UPPER TROUGH
MOVES ACROSS PANHANDLE TUESDAY WITH A FLAT RIDGE BUILDING OVER THE
GULF. NEXT UPPER LEVEL RIDGE MOVES OVER SOUTHEAST ALASKA ON THURSDAY.

PRECI ASSOCIATED WITH NEXT FRONT SPREADS TO THE NORTHEAST GULF SUNDAY
AFTERNOON AND ACROSS NORTHERN SOUTHEAST ALASKA SUNDAY NIGHT. WILL
HAVE SOLID GALES IN COASTAL WATERS AND NEAR OCEAN ENTRANCES WITH
SOLID SMCR SE WINDS FOR REMAINDER OF INNER CHANNELS. DO HAVE SOME
COLD AIR IN PLACE SO EXPECT PRECIP HERE TO BEGIN AS SNOW WITH
SEVERAL INCHES POSSIBLE OVERNIGHT. AS FRONT MOVES THROUGH
SOUTHEAST ALASKA EXPECT SNOW TO GO TO ALL RAIN BY MONDAY
AFTERNOON. WINDS SHIFT TO WESTERLY SMCR MONDAY NIGHT. A MIX OF
RAIN AND SNOW SHOWERS FOLLOWS IN WESTERLY FLOW MONDAY NIGHT AND
TUESDAY.

TROUGH DIGS SOUTH TUESDAY NIGHT AND WEDNESDAY AND TURNS THE FLOW
OVER SOUTHEAST ALASKA OFFSHORE. WILL LIKELY SEE DECREASING CLOUDS
WITH SOME COLD AIR SPILLING INTO THE INNER CHANNELS ON WEDNESDAY.
DO NOT EXPECT ANY PRECIP ON WED WITH HIGH TEMPS STAYING NEAR
FREEZING AND DROPPING OFF INTO THE LOWER 20S AT NIGHT. PARTLY
CLOUDY CONDITIONS CONTINUE THURSDAY AS UPPER RIDGE BUILDS OVER THE AREA.

ANOTHER STRONG OCCLUSION SPREADS GALES INTO THE EASTERN GULF
THURSDAY WITH FRONT WEAKENING AS IT MOVES ACROSS SOUTHEAST ALASKA
FRIDAY NIGHT AND SAT. AGAIN WILL HAVE SOLID S-SE GALES IN COASTAL
WATERS AND POSSIBLE ACROSS SOUTHERN INNER CHANNELS AS WELL. THIS
FRONT DOES HAVE A FAIRLY STRONG WARM SECTOR SO EXPECT TEMPS TO BE
WARMING WITH RAIN AS PRIMARY TYPE.

MODELS DIVERGE RATHER EARLY WITH HANDLING OF WAVE LIFTING IN THE
GULF AS EARLY AS MONDAY. EC WAS DEEPEST AND A BIT FARTHER WEST
THAN GFS OR NAM AND WAS THE PREFERRED SOLUTION THROUGH MONDAY.
BEYOND MONDAY THERE IS LITTLE AGREEMENT OR RUN TO RUN CONSISTENCY
SO CONFIDENCE FALLS OFF QUICKLY FOR DAY 5-8 USED HPC GRIDS.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ041-042-052.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ043-051.

&&

EAL/MM