Small Craft Advisory 808, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
544 AM AKST WED DEC 7 2011

.SHORT TERM...HIGH PRESSURE OVER SE AK WILL DRIFT E OF THE AREA
TODAY. A WARM FRONT WILL MOVE NE TO THE ERN GULF TONIGHT. USED THE
06Z NAM FOR PRESSURE/WINDS AS MODELS WERE VERY CLOSE ON THE
MOVEMENT OF THE WARM FRONT AND WANTED THE BETTER DETAIL OF THE
NAM.

MAIN FORECAST CONCERN WILL BE PTYPE AND AMOUNTS. MODEL SOUNDINGS
SHOW A FAIRLY DEEP ISOTHERMAL LAYER DEVELOPING TONIGHT AHEAD OF
THE WARM FRONT. ALSO...THEY SHOW SOME MID-LEVEL DRYING OUT MAINLY
OVER THE SRN HALF OF THE AREA LATER TONIGHT. TEMPS WILL LIKELY BE
SLOWLY RISING OVERNIGHT MOST PLACES AS WELL. PRECIP SHOULD START
OUT AS SNOW MOST AREAS DURING THE EVENING...THEN CHANGE TO RAIN IN
THE PAEL/PASI AREAS OVERNIGHT AS TEMPS RISE WELL ABOVE FREEZING. PRECIP
WILL BE MAINLY RAIN FURTHER S ALONG THE COAST. INLAND...COMPLICATION
ARISES AS MID-LEVEL DRYING OUT OCCURS AND ICE CRYSTAL NUCLEATION
BECOMES UNLIKELY ACROSS THE CENTRAL AREA OVERNIGHT. LOOKS LIKE A
SET UP FOR FREEZING DRIZZLE IN THE PAGN AND PAPG ZONES LATER
TONIGHT. AM ISSUING A FREEZING RAIN ADVY FOR THOSE ZONES STARTING
AT 06Z TONIGHT. IT IS POSSIBLE THAT THE PAJN/PAOH AREAS COULD GET
INTO THIS AS WELL OVERNIGHT BUT MODEL SOUNDINGS SUGGEST CLOUDS
REMAIN DEEP AND COLD ENOUGH FOR ICE CRYSTAL NUCLEATION TO CONTINUE
OVERNIGHT. IF THEY ARE OVERDONE ON THE CLOUD DEPTH IN MID-LEVELS
THOUGH...MAY NEED TO MENTION FREEZING DRIZZLE FURTHER N. THE PAYA
AREA WILL START AS SNOW BY EARLY EVENING...THEN BECOME MIXED WITH
RAIN LATE AS TEMPS RISE ABOVE FREEZING. STILL...LOOKS LIKE A 4 TO
6 INCH SNOWFALL FOR THEM SO WILL ISSUE WINTER WX ADVY FOR TONIGHT.
GENERALLY EXPECT A 1 TO 4 INCH SNOWFALL OVER THE NRN INNER
CHANNELS TONIGHT.

OTHERWISE WINDS WILL PICK UP WITH GALES EXPECTED ALONG THE N GULF
COAST BY THIS EVENING...AND SCA FOR ALL THE REMAINING ERN GULF BUT
THE FAR SERN PART AND THE ICY STRAIT/CROSS SOUND/NW GLACIER
BAY/SRN CHATHAM STRAIT AREAS. WINDS ELSEWHERE WILL PICK UP TONIGHT
BUT SHOULD REMAIN BELOW SCA.

&&

.LONG TERM...WARMING CONTINUES OVER THE NORTHEAST GULF COAST AND
THE PANHANDLE WITH THE SNOW CHANGING OVER TO RAIN ALTHOUGH
NORTHERN LYNN CANAL MAY STILL SEE SOME MIXED OR SNOW POSSIBLY AS
WELL AS THE COOLER AIR MAY TAKE A BIT TO REMOVE. THE BAND OF
PRECIPITATION IS MOVING SOUTHEAST THROUGH EARLY FRIDAY. AM SEEING
SOME MINOR COOLING FOR THE END OF THE WEEKD OVER THE NORTHERN
GULF.

ANOTHER SYSTEM SPREADS INTO THE BERING SEA...THE FRONTAL BAND
SWEEPS INTO THE WESTERN GULF AND THE RIDGE BUILDING BECAUSE OF IT
REWARMS THE EASTERN GULF AND THE PANHANDLE AREA SUNDAY AND MONDAY.
THE BREAK IN THE PRECIPITATION LATE FRIDAY TO SUNDAY. LOOKS LIKE
THERE MAY BE ANOTHER LETUP IN THE PRECIPITATION EARLY NEXT WEEK.

FORECAST CONFIDENCE IS AVERAGE THROUGH THE TIME FRAME.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...FREEZING RAIN ADVISORY FROM 9 PM THIS EVENING TO 9 AM AKST
     THURSDAY FOR AKZ024-026.
         WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 5 AM AKST
     THURSDAY FOR AKZ017.
MARINE...GALE WARNING FOR PKZ043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011-021-022-033-042.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041.

&&

RWT/BEZENEK