Small Craft Advisory 281, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
203 PM AKDT FRI MAR 25 2016

.SHORT TERM...AN OCCLUDED FRONT WILL MOVE N INTO THE EASTERN GULF
TONIGHT. A COMPLEX LOW PRESSURE AREA WILL MOVE N INTO THE EASTERN
GULF SAT. BLENDED THE 12Z ECMWF WITH PREVIOUS FORECAST...MAINLY
TO MAKE SLIGHT SYSTEM INTENSITY TWEAKS.

MAIN FORECAST CONCERNS WILL BE PRECIP POTENTIAL AND WINDS. THE
SHOWERY REGIME CURRENTLY OVER THE INNER CHANNELS WILL BE REPLACED
BY STEADIER RAIN LATE THIS AFTERNOON AND EARLY EVENING AS FRONT
MOVES IN. THIS RAIN WILL CONTINUE INTO SAT WITH THE COMPLEX LOW
PRESSURE AREA MOVING INTO THE EASTERN GULF.

WINDS WILL BE A TRICKIER FORECAST. BETWEEN TERRAIN EFFECTS ON THE
LOW LEVEL WIND FIELDS AND SMALLER SIZE OF SYSTEMS COMING
IN...HITTING THE HIGHEST WINDS AT THE RIGHT TIME WILL BE
DIFFICULT. LOOKS LIKE STRONGEST WINDS WILL BE ALONG THE FAR ERN
GULF AND ADJACENT INNER CHANNEL AREAS AHEAD OF THE FRONT...WITH
25-30 KT WINDS EXPECTED. CLARENCE STRAIT WILL BE EVEN STRONGER
WITH WINDS UP TO 35 KT BY LATE TONIGHT. THINK THE WINDS WILL DROP
OFF SOME ON SAT...BUT THIS WILL DEPEND ON EXACT TRACK AND STRENGTH
OF THE VARIOUS SMALL LOWS OVER THE EASTERN GULF. MODELS HAVE BEEN
STRUGGLING WITH THIS SO THE FORECAST CONFIDENCE LOWERS ON SAT OVER
THE GULF. OTHER AREA OF CONCERN IS AROUND NORTHERN LYNN
CANAL...WHICH IS SEEING SOME ENHANCED WINDS DUE TO MID-LEVEL SW
FLOW INDUCING A LEE TROF NEAR PAGY. DECIDED TO START THEM AT 20
KT BUT THEY COULD REACH SCA LEVEL LATE IN THE AFTERNOON. AS THE
MID-LEVEL FLOW BACKS FROM SW TO S TONIGHT...THE LEE TROF NEAR PAGY
WILL WEAKEN AND WINDS AROUND NORTHERN LYNN CANAL SHOULD DECREASE
TO 10-15 KT.

OTHERWISE...IT SHOULD REMAIN FAIRLY MILD TONIGHT WITH TEMPS
REMAINING IN THE 40S FOR MUCH OF THE AREA. MAY NOT SEE MUCH RISE
IN TEMPS ON SAT WITH THE RAIN CONTINUING THROUGH THE DAY.
CURRENTLY NOT EXPECTING ANY SIGNIFICANT FOG GIVEN STRENGTH OF LOW
LEVEL FLOW KEEPING NEAR SURFACE LAYER MIXED.

.LONG TERM...MODELS REMAIN IN VERY GOOD AGREEMENT ON PATTERN
EVOLUTION OVER THE NEXT WEEK. THERE REMAINS LITTLE SPREAD IN THE
ENSEMBLE MEMBERS LEADING TO ABOVE AVERAGE FORECASTER CONFIDENCE.
THEREFORE FEW CHANGES WERE MADE TO THE PREVIOUS FORECAST. USED THE
12Z ECMWF FOR UPDATES THROUGH DAY 4 THEN TRANSITIONED TO THE
LATEST WPC GUIDANCE FOR THE REMAINDER OF THE LONG RANGE.

THE BEGINNING OF THE LONG RANGE FEATURES A TROUGH LIFTING INTO
CANADA ON SATURDAY NIGHT WITH PERIODS OF LIGHT RAIN ONGOING OVER
THE PANHANDLE. PRECIPITATION WILL DIMINISH THROUGH THE DAY SUNDAY
AS THE UPPER LEVEL DYNAMICS PUSH EAST OF THE AREA. A VERY STRONG
UPPER RIDGE WILL BUILD OVER THE GULF NEXT WEEK FROM THE SOUTH AND
DRIFT TO THE EAST AS IT STRENGTHENS. THE PATTERN WILL EVOLVE INTO
AN OMEGA BLOCK BY THE END OF THE WEEK WITH AN UPPER LOW ANCHORED
SOUTH OF ALEUTIANS AND ANOTHER OVER THE WESTERN CONUS. THIS HIGH
WILL ADVECT VERY WARM TEMPERATURES INTO SOUTHEAST ALASKA FROM MID
NEXT WEEK THROUGH THE END OF THE WEEK. MODELS HAVE REMAINED
CONSISTENT OVER THE PAST SEVERAL DAYS INDICATING 850 MB
TEMPERATURES WILL RANGE FROM 6 TO 12 C WHICH IS ABOUT 3-5 STD DEV
ABOVE NORMAL FOR LATE MARCH. TO GO ALONG WITH THE VERY WARM
TEMPERATURES MOST OF THE FORECAST AREA WILL BE ON THE DRY SIDE
WITH VERY STRONG SUBSIDENCE UNDER THE RIDGE. YAKUTAT WILL BE ON
THE ONSHORE SIDE OF THE HIGH EARLY IN THE WEEK AND HAS A CHANCE OF
SEEING HEAVY RAINFALL ON MONDAY BEFORE THE STREAM OF MOISTURE GETS
PUSHED TO THE WEST AS THE HIGH CONTINUES TO STRENGTHEN.

A QUICK LOOK AT RECORD DAILY HIGH TEMPERATURES FOR MID TO LATE
NEXT WEEK INDICATES THERE IS A HIGH LIKELIHOOD FOR A SIGNIFICANT
PORTION OF THE AREA TO BREAK THESE. CURRENTLY HAVE FORECASTED
HIGHS RANGING FROM THE UPPER 50S TO MID 60S FOR WEDNESDAY-FRIDAY.
AT THIS TIME...THE WARMEST DAYS LOOK LIKE THEY WILL BE THURSDAY
AND FRIDAY. IT SHOULD ALSO BE NOTED THE RECORD HIGH TEMPERATURE
EVER RECORDED FOR THE MONTH OF MARCH AT THE JUNEAU AIRPORT IS 61
DEGREES. THE EXPECTED SYNOPTIC SETUP WITH VERY WARM AIR ALOFT
COULD PUT THIS RECORD IN JEOPARDY NEXT THURSDAY. STAY TUNED...

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ036.
     SMALL CRAFT ADVISORY FOR PKZ022-033>035-041>043-051.
&&

RWT/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU