Small Craft Advisory 274, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
401 PM AKDT MON MAR 21 2016

.SHORT TERM...AN UPPER TROUGH WAS POSITIONED FROM THE AK PENINSULA
SE TO THE NERN PAC MON AFTERNOON. AS A STRONGER TROUGH MOVES E
ACROSS THE NCNTRL PAC THROUGH TUE AFTERNOON...THE DOWNSTREAM
TROUGH WILL ADVANCE E AND DEAMPLIFY AS IT ENCOUNTERS A RIDGE OVER
THE PANHANDLE. AS THIS OCCURS...VERY LIGHT SHOWER ACTIVITY WILL
CONTINUE TO SPREAD NW OVER THE REGION. MIDLEVEL CLOUD COVER IS
EXPECTED TO BE ABUNDANT DURING THE SHORT TERM PERIOD...WHICH WHEN
COMBINED WITH WEAKENING OFFSHORE WINDS...WILL PRECLUDE ABOVE
NORMAL TUE AFTERNOON HIGHS EXPERIENCED THE PAST FEW DAYS...BUT
WILL ALSO AID IN GENERALLY MILD OVERNIGHT LOWS. OTHERWISE...A GALE
FORCE FRONT IS FORECAST TO ENTER SWRN PORTIONS OF MARINE ZONE 310
BY LATE TUE AFTERNOON. SELY WINDS WILL BEGIN TO STRENGTHEN OVER
THE OUTER MARINE WATERS AS A RESULT...WHILE REMAINING RELATIVELY
WEAK OVER THE INNER CHANNELS.

PRESSURE GRIDS WERE NUDGED SLIGHTLY TO THE 12Z NAM. REMAINDER OF
THE FORECAST WAS GENERALLY ON TRACK...THE FEW CHANGES MADE WERE
BASED ON A GFS/ECMWF/NAM ENSEMBLE BLEND.

.LONG TERM...MODELS IN BETTER AGREEMENT ON MOVEMENT OF LOW AND
FRONT ACROSS THE AREA FOR TUE NIGHT-THU TIME FRAME. USED THE 12Z
GFS FOR THE MOST PART AS IT WAS GOOD MIDDLE GROUND COMPROMISE
AMONGST THE MODELS WITH THE LOW TRACK ACROSS THE S GULF THEN
ACROSS N HAIDA GWAII. LOOKS LIKE RIDGE WILL BUILD ACROSS THE GULF
FOR LATE WEEK. MODELS DIFFER SOMEWHAT ON ANOTHER SYSTEM COMING IN
FOR THE WEEKEND. USED MAINLY WPC TO HANDLE THU NIGHT ONWARD. DID
TWEAK POPS FROM WPC THOUGH AS THE TIMING APPEARED SLOW GIVEN
POSITION OF SYSTEMS DURING THE DAY 4-7 PERIODS.

FOR TUE NIGHT AND WED...PRECIP WITH OCCLUDED FRONT WILL SPREAD N
ACROSS THE SRN AREA TUE NIGHT...THEN REACH MOST OF THE NRN AREA
FOR WED. HOWEVER...THE PRECIP BAND WILL BE DIMINISHING AS IT MOVES
N DUE TO THE OFFSHORE FLOW AND UPPER SUPPORT FOR FRONT WEAKENING.
KEPT MENTION OF LIKELY OR HIGHER POPS LIMITED TO THE PAJN-PAGS
AREAS SWD. WINDS WILL REACH GALE FORCE OVER THE GULF AHEAD OF THE
FRONT...AND SOME OF THESE GALES COULD AFFECT THE MORE E-W INNER
CHANNELS AS WELL. MOST INNER CHANNELS SHOULD PEAK AT SCA LEVELS
THOUGH. MAY NEED STRONG WIND HEADLINE FOR THE SRN COAST LATER TUE
NIGHT AND WED MORNING.

FOR WED NIGHT AND THU...PRECIP WILL DIMINISH OVER THE N AS FRONT
DISSIPATES...AND THE N WILL LIKELY SEE SOME CLEARING THU AS
OFFSHORE FLOW INCREASES WITH SFC LOW MOVING BY TO THE S OF THE
AREA. LOOKS LIKE A FAIRLY MILD DAY OVER THE N WITH SOME SUNSHINE
LIKELY AND OFFSHORE FLOW. THE SRN AREA WILL SEE PRECIP WITH THE LOW
CENTER WRAP INTO THAT AREA SO KEEPING LIKELY OR HIGHER POPS GOING
THERE WED NIGHT AND THU.

FOR THU NIGHT...LOW WILL MOVE OUT AND PRECIP THREAT SHOULD
DIMINISH OVER THE S.

FOR FRI ONWARD...WITH THE INCREASING MODEL DIFFERENCES...THE
PRECIP POTENTIAL FORECAST HAS LIMITED CONFIDENCE RIGHT NOW. THERE
MAY BE ANOTHER FRONT FOR LATE FRI INTO SAT SO AT LEAST A CHANCE
OF PRECIP FOR THAT TIME FRAME. FURTHER OUT...MAY SEE SOME STRONG
RIDGING BUILDING OVER THE AREA NEXT WEEK...SO POTENTIAL FOR A
DRIER AND WARMER PERIOD IS THERE ESPECIALLY BY MIDWEEK.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ051-052.
     SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041>043.
&&

GARNER/RWT

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