Small Craft Advisory 208, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
346 PM AKDT WED MAR 14 2012

.SHORT TERM...975 MB LOW W OF HAIDA GWAII WILL MOVE N INTO THE
SE GULF THIS EVENING...THEN DRIFT TO THE NE GULF THU. ANOTHER LOW
DEVELOPING OVER THE NE PAC WILL MOVE NE TO HAIDA GWAII BY LATE
THU BUT WILL BE WEAKENING BY THAT TIME. USED BLEND OF 12Z EC/UK
FOR THEIR BETTER HANDLING OF BOTH LOWS...ESPECIALLY THE FIRST
ONE.

MAIN FORECAST ISSUES WILL BE PRECIP POTENTIAL AND WINDS. RIGHT
NOW SOME LIGHT PRECIP IS FALLING OVER THE S...BUT AS IT TRIES TO
MOVE FURTHER N IT WILL ENCOUNTER INCREASING OFFSHORE FLOW. THIS
WILL LOCALIZE PRECIP TO THE MORE ERN SLOPES OVER THE N
TONIGHT...AND HAVE HIGHEST POPS ALONG ERN SIDE OF
BARANOF/CHICHAGOF ISLANDS IN THE CENTRAL INNER CHANNEL ARE
TONIGHT. EVENTUALLY FLOW WILL BECOME MORE SELY AS LOW MOVES
FURTHER N INTO THE GULF LATE TONIGHT AND THU MORNING...WHICH WILL
INCREASE THREAT TO OTHER AREAS BUT STILL KEEPING POPS LIMITED TO
CHANCE ALONG THE PAJN-PAHN CORRIDOR. THE PAYA AREA WILL HAVE NELY
DOWNSLOPE FLOW GOING ON KEEPING POPS LOW LATE TONIGHT INTO THU
MORNING...THEN A MORE ESE FLOW WILL BRING BETTER CHANCE INTO THERE
THU AFTERNOON. THE S WILL REMAIN UNDER LIKELY OR BETTER POPS MOST
OF THE TIME TONIGHT AND THU. MAY BE A BRIEF BREAK IN PRECIP EARLY
THU HOWEVER...BEFORE MORE PRECIP FROM SECOND LOW MOVING IN FROM
THE S ARRIVES LATER THU MORNING. PTYPE TONIGHT SHOULD BE MOSTLY
RAIN FAR SOUTH AND MOSTLY SNOW S-CENTRAL TO HYDER AREA...WITH UP
TO 1 INCH OF SNOW IN THOSE AREAS. ON THU WARMER AIR MOVING IN ON
SE FLOW SHOULD CAUSE PRECIP TO BECOME MAINLY RAIN OVER THE S HALF
OF THE AREA BY LATE THU MORNING.

WIND WISE...RIGHT NOW HAVE SCA LEVEL NLY TO ELY FLOW OVER MUCH OF
THE INNER CHANNELS AND SCA TO GALE FORCE ELYS OVER THE SE AND
E-CENTRAL GULF. EXPECT THE GALE FORCE WINDS TO WEAKEN TO MAX SCA
THIS EVENING AS FRONT ASSOCIATED WITH LOW WEAKENS SOME. AS FIRST
LOW MOVES FURTHER NE LATE TONIGHT AND THU THE NLY WINDS SHOULD
WEAKEN OVER THE NRN INNER CHANNELS 6 OR SO HOURS BEFORE THE ELY
WINDS DO. THE SRN AREA WINDS WILL DROP OFF THU AS FIRST LOW MOVES
AWAY FROM THEM AND SECOND LOW IS STILL WELL S OF THE AREA. ABOUT
THE ONLY AREA NOT EXPECTED TO SEE SCA LEVEL WINDS IS THE FAR NRN
GULF FROM PAYA WWD...BUT SEAS WILL SLOWLY BUILD TO SCA LEVELS BY
THU AS LARGER SWELLS MOVE IN FROM THE S AND SE.

&&

.LONG TERM...MODELS STRUGGLING TO DEAL WITH FEATURES IN THE LONG
WAVE TROUGH ALOFT AS IT LINGERS OVER THE EASTERN GULF. THE UPPER
LEVEL REMAINING GENERALLY SOUTH OF 50 NORTH LATITUDE. THE ORIGINAL
TROUGH IS EXPECTED TO WEAKEN THROUGH SUNDAY AND MAY TRY TO LIFT
INTO THE SOUTHERN PORTION OF THE PANHANDLE. A NEW TROUGH WILL
REPLACE THIS AS IT MOVES SOUTH OF THE INTERIOR PORTION OF THE
STATE AND STRENGTHENING THE TROUGH AGAIN AS A HIGH AMPLITUDE RIDGE
IS EXPECTED TO BUILD OVER BERING SEAS AND CENTRAL PACIFIC.

OVERALL THIS PATTERN SHOULD KEEP THE AREA COOLER SIDE AND
PRECIPITATION TENDS TO BE SNOW OR MIX ACROSS THE FORECAST AREA
NEXT WEEK AFTER THE WEEKEND. USED HPC FOR THE LATER PERIODS WHICH
RELIED HEAVILY I THINK ON BLEND OF THE ENSEMBLE MEANS. CONFIDENCE
IN THE LATER PORTIONS OF THE FORECAST IS LOW DUE TO THE POOR
CONSISTENCY AND AVERAGE AT BEST FOR THE WEEKEND PORTION OF THE
FORECAST.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ036-041-042.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035-043.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

RWT/BEZENEK