Small Craft Advisory 813, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
352 PM AKST MON NOV 16 2015

.SHORT TERM...VIGOROUS SHORTWAVE IMPULSE WAS MOVING ACROSS HAIDA
GWAII DURING MIDDAY MON. PRONOUNCED MIDLEVEL DEFORMATION ZONE WAS
PRESENT IMMEDIATE TO ITS N...ROTATING TOWARD A N-S ORIENTATION
OVER THE CNTRL/SRN PANHANDLE MON AFTERNOON. THIS FEATURE PRODUCED
A BURST OF MODERATE SNOW OVER KLAWOCK...AND IS AIDING IN
OCCASIONAL MODERATE SNOWFALL RATES AT PETERSBURG. THE WSW FOR THE
PETERSBURG/WRANGELL AREA WAS EXTENDED UNTIL 01Z TUE...BUT
HEAVIEST SNOW SHOULD QUICKLY COME TO AN END EARLY MON EVENING AS
THE BACK EDGE OF THE MIDLEVEL DEFORMATION ZONE PASSES E.
OTHERWISE...HYDER IS EXPECTED TO EXPERIENCE STEADY LIGHT TO
OCCASIONALLY MODERATE SNOW THROUGH MIDNIGHT.

A DEEP SURFACE LOW WILL CONTINUE TO TREK EWD AWAY FROM DIXON
ENTRANCE/SRN CLARENCE STRAIT THROUGH THIS EVENING...AND THEN EXIT
INTO BC TONIGHT. WNW SMALL CRAFT TO BORDERLINE GALE FORCE WINDS
WILL OCCUR OVER THE FAR SRN MARINE ZONES IN THE WAKE OF THE LOW.
IN ADDITION...TIGHT NLY GRADIENT IS PRESENT OVER LYNN
CANAL...WHICH WILL ALSO SUPPORT SMALL CRAFT WINDS THROUGH MON
EVENING.

A RELATIVE LULL IN PRECIPITATION IS EXPECTED TONIGHT AS
PREVIOUSLY MENTIONED DISTURBANCE MOVE E OF THE REGION. ANOTHER
SHORTWAVE TROUGH IS THEN FORECAST TO PROGRESS E ACROSS THE GULF ON
TUE...REACHING THE COAST OF THE PANHANDLE BY 00Z WED. SNOW SHOWERS
WILL INCREASE IN COVERAGE OVER MUCH OF THE AREA TUE AFTERNOON IN
RESPONSE TO THIS FEATURE.

.LONG TERM...SHORTWAVE TROF WILL MOVE ACROSS THE PANHANDLE TUE
NIGHT...WITH WEAKENING UPPER TROF PUSHING ACROSS THE AREA WED.
WEAK RIDGE WILL SLIDE ACROSS THE AREA WED NIGHT AND THU. A STRONG
OCCLUDED FRONT WILL MOVE INTO THE WRN GULF THU THEN SLOWLY PUSH
ACROSS THE ERN GULF AND SE AK THU NIGHT INTO FRI NIGHT. LOOKS LIKE
IT WILL WARM UP SIGNIFICANTLY WITH THIS SYSTEM...THEN COOL DOWN
SLOWLY OVER THE WEEKEND AFTER IT GOES BY. LARGER UPPER RIDGE LOOKS
LIKE IT WILL BUILD TO THE W OF THE AREA EARLY NEXT WEEK...AND THIS
WILL LIKELY DRIVE COLDER AND DRIER AIR SWD INTO THE AREA.

FOR TUE NIGHT AND WED...SHORTWAVE WILL CAUSE A LOT OF SHOWERS TO
MOVE ACROSS THE AREA WITH MOST OF THEM BEING SNOW. COULD GET A
COUPLE INCHES OF SNOW ESPECIALLY OVER THE NRN HALF OF THE AREA
TUE NIGHT. THE SHOWERS WILL CONTINUE WED AS UPPER TROF MOVES THRU.

FOR WED NIGHT AND THU...PRECIP WILL DIMINISH FROM THE W WED NIGHT
AS WEAK RIDGE MOVES IN. HOWEVER...LEADING EDGE OF PRECIP WITH THE
STRONG FRONT WILL PUSH INTO THE NRN GULF BY LATE WED NIGHT...AND
SOME OF THIS MAY GET INTO THE NRN PANHANDLE THU. THE SRN AREA
LOOKS TO REMAIN MAINLY DRY WITH DECENT BREAKS IN CLOUDS DEVELOPING
THERE.

FOR THU NIGHT-FRI NIGHT...PRECIP WILL BEGIN TO INCREASE OVER THE
NW HALF OF THE AREA THU NIGHT AND FRI MORNING...THEN POTENTIALLY
GET INTO THE SRN AREA BY FRI AFTERNOON OR EVENING. WARMER AIR WILL
BE ADVECTED IN ON STRONG S-SW FLOW...AND THIS WILL LIKELY CAUSE
ANY SNOW TO CHANGE OVER TO RAIN BY LATE FRI MORNING. RAISED TEMPS
A DECENT AMOUNT FOR THIS TIME FRAME. GIVEN THAT THE MOST PRECIP
WILL LIKELY FALL AFTER THE CHANGEOVER...NOT CURRENTLY EXPECTING
ANY HEAVY SNOWFALL NEAR SEA LEVEL...ALTHOUGH THE FAR N COULD BE
THE EXCEPTION TO THIS AS IT WILL TAKE LONGER FOR WARMER AIRMASS TO
MOVE IN. WINDS COULD BE STRONG NEAR SEA LEVEL AS FRONT MOVES
IN...WITH GALES LIKELY FOR MUCH OF THE AREA FRI INTO FRI NIGHT.

FOR SAT-SUN...IT WILL BEGIN TO SLOWLY COOL OFF AS COLD ADVECTION
DEVELOPS BEHIND THE FRONT. LOOKS LIKE MOST PRECIP WILL REMAIN RAIN
SAT...BIT BEGIN TO MIX WITH OR CHANGE OVER TO SNOW LATER SAT NIGHT
AND SUN MORNING FROM THE NW AS UPPER TROF MOVES IN.

FOR EARLY NEXT WEEK...EVEN COLDER AIR SHOULD PUSH IN BUT IT WILL
LIKELY DRY OUT AS WELL WITH STRONG UPPER RIDGE BUILDING TO THE W
AND DEEP LAYER N-NW FLOW DEVELOPING OVER SE AK.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY UNTIL 4 PM AKST THIS AFTERNOON FOR
     AKZ026.
         WINTER WEATHER ADVISORY UNTIL MIDNIGHT AKST TONIGHT FOR AKZ029.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-036-041>043.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

GARNER/RWT

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