Small Craft Advisory 729, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
304 PM AKST THU NOV 29 2012

.SHORT TERM...NO SIGNIFICANT CHANGES TO THE FORECAST PACKAGE
THROUGH TONIGHT AND FRIDAY. THE LARGE VERTICALLY STACKED LOW
SOUTH OF THE GULF GENERALLY PERSISTENT THROUGH IT WILL BE
WEAKENING AND DRIFTING T THE NORTHEAST THROUGH FRIDAY. THE AREA
OF HIGH PRESSURE OVER THE ALASKAN INTERIOR AND NORTHWEST CANADA
WILL PERSIST. BETWEEN THESE TWO FEATURES STRONG OUTFLOW CONTINUES
ACROSS THE NORTHERN PANHANDLE. EXPECT THAT THESE WINDS WILL
PERSIST GENERA LY THROUGH THE SHORT TIME FRAME.

 A BAND OF LIGHT SNOW SNOW IS STRETCHED OUT ACROSS THE NORTH
CENTRAL PANHANDLE MAINLY DROPPING A FINE GRAIN SNOW FLAKES.
REPORTS OF AMOUNTS OF THE SNOW AS IT MOVES THROUGH THE AREA IS
1 TO 3 INCHES. THE FRONT SHOULD BE STRETCHING AND SHEERING OUT
ACROSS THE NORTHERN PANHANDLE AND ROTATING ABOUT NEAR YAKUTAT BY
EARLY FRIDAY MORNING. ANOTHER BAND OF PRECIPITATION WILL BE
PUSHING INTO THE SOUTHERN PANHANDLE OF FRIDAY.

 ANOTHER WORRY POINT WITH THE STRONG WINDS AND COLDER
TEMPERATURES IS AREAS OF FREEZING SPRAY FOR MARINERS FOR THE
NORTHERN PORTION OF THE PANHANDLE.

 &&

 .LONG TERM...THE BATTLE BETWEEN THE CANADIAN HIGH AND ITS
OUTFLOW VS THE LOW IN THE GULF STARTS TO DETERMINE A WINNER BY
THE END OF THE LONG RANGE PERIOD. THAT WINNER IS THE LOW IN THE
GULF FOLLOWING A ONE-TWO PUNCH OF SHORT WAVE TROUGHS ROUNDING THE
SOUTH SIDE OF AN UPPER LEVEL TROUGH IN THE GULF. THESE FEATURES
WILL BE SLAMMING INTO THE PANHANDLE FROM THE SOUTH BRINGING
PRECIP AND SOME WIND. THE FIRST OF WHICH WILL BE SLOWLY COMING
NORTH LATE IN THE WEEKEND FOLLOWED BY THE SECOND WHICH WILL NOT
SHOW UP UNTIL TUES.

 FROM BOTH SYSTEMS, WIND WILL NOT BE VERY MUCH OF A PROBLEM.
PRESSURE GRADIENT PATTERS AROUND BOTH ARE NOT VERY TIGHT UNTIL
YOU GET TO THE NORTHERN PANHANDLE AND ITS INTERACTION WITH THE
FALTERING CANADIAN HIGH. EXPECTING AT MOST SMALL CRAFT WINDS TO
MAYBE MIN GALE IN CLARENCE STRAIT SUN AFTERNOON INTO SUN EVENING.
THE PRECIP WILL BE THE BIGGER CONCERN AS THERE WILL STILL BE
SUBSTANTIAL COLD AIR TRAPPED IN THE INNER CHANNELS. AREAS AROUND
FREDERICH SOUND AND NORTHWARD WILL BE UNDER THE GUN FOR MORE SNOW
STARTING SUN. NOT EXPECTING A HUGE SNOW DUMP AS THERE IS NOT MUCH
OF A MOISTURE PLUME AVAILABLE FOR THIS SYSTEM TO WORK WITH. MOST
ACCUMULATION MAY BE DUE TO OVERRUNNING SNOW RATHER THAN LARGE QPF
AMOUNTS. LOCATION WILL ALSO PLAY A PART AS HIGHEST AMOUNTS LOOK
TO BE AROUND THE FREDRICK SOUND TO ICE STRAIT AREA. AREAS FARTHER
NORTH START TO GET INTO THE DIMINISHED BUT STILL PRESENT
NORTHERLY WINDS AND THE PRECIP WILL START TO BREAK UP. FARTHER
SOUTH AND IT WILL BE TOO WARM FOR SNOW.

 AS FOR THE THE HIGH IN CANADA, IT WILL BE SUFFERING FROM
WITHDRAWAL. IN THIS CASE WITHDRAWAL OF REINFORCING SHOTS OF COLD
AIR FROM THE ARCTIC. THE UPPER LEVEL TROUGH THAT HAS BEEN
SUPPLYING THIS COLD AIR WILL BECOME MORE BROAD, AXIS DRIFTS A BIT
TO THE WEST, AND IT BECOMES LESS POSITIVELY TILTED BY THE TIME WE
GET TO EARLY NEXT WEEK. THE RESULT IS THE COLD SHOTS THAT WOULD
HAVE BEEN PUMPING UP OUR CANADIAN HIGH ARE NOW GETTING DIRECTED
TO WESTERN ALASKA AND THE BERING SEA. THE HIGH WILL REMAIN IN THE
YUKON THROUGH MOST OF THE LONG RANGE PERIOD BUT AT A WEAKER
STRENGTH THAN WHAT IT HAS BEEN SHOWING. THE ONLY THING SUSTAINING
IT IS THE LINGERING COLD AIR THAT REMAINS TRAPPED ON THE CANADIAN
SIDE OF THE COAST MOUNTAINS. FOR THE PANHANDLE THIS MEANS
GRADUALLY DECREASING NORTHERLY WINDS THROUGH MOST OF THE PERIOD.
BY THE END OF THE WEEKEND AND INTO NEXT WEEK ONLY MIN NORTHERLY
GALES SHOULD BE BLOWING IN LYNN CANAL WITH WEAKER OUTFLOWS OUT OF
TAKU INLET AND OTHER OUTFLOW AREAS.

 MODEL AGREEMENT HAS BEEN RATHER GOOD OVER THE PAST DAY OR TWO.
THERE HAS NOT BEEN MUCH DIVERGENCE BETWEEN RUNS EITHER. THE ONE
KINK IS THE DEPICTION OF THE WAVE COMING UP FROM THE SOUTH ON
TUES. THE LATEST EC HAS ABANDON IT IN FAVOR OF BEEFING UP A WAVE
ON MON EVENING THAT WAS PREVIOUSLY MUCH WEAKER. DECIDED ON USING
THE PREVIOUS EC RUN AS WELL AS HPC AS THE ENSEMBLE RUNS STILL ARE
FAVORING THE TUES WAVE. FORECAST CONFIDENCE IS A BIT ABOVE
AVERAGE.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING UNTIL 4 PM AKST THIS AFTERNOON FOR AKZ025.
         STRONG WIND THROUGH LATE FRIDAY NIGHT FOR AKZ025.
         STRONG WIND THROUGH LATE FRIDAY NIGHT FOR AKZ022.
         STRONG WIND FRIDAY AFTERNOON FOR AKZ020.
         STRONG WIND UNTIL 6 PM AKST THIS EVENING FOR AKZ029.
         STRONG WIND FROM FRIDAY MORNING THROUGH FRIDAY AFTERNOON FOR
     AKZ029.
         STRONG WIND FROM FRIDAY EVENING THROUGH LATE FRIDAY NIGHT FOR
     AKZ019-029.
         STRONG WIND THROUGH LATE TONIGHT FOR AKZ019.
         STRONG WIND THROUGH LATE FRIDAY NIGHT FOR AKZ017-018.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ012.
         STORM WARNING FOR PKZ012-022.
         GALE WARNING FOR PKZ011-013-021-031>035-043-051-053.
         SMALL CRAFT ADVISORY FOR PKZ036-041-042-052.

&&

BEZENEK/EAL