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FXAK67 PAJK 281422
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
622 AM AKDT FRI AUG 28 2015

.SHORT TERM...LOW PRESSURE OVER THE NORTHEAST GULF WILL STEADILY
DROP SOUTHEAST OFFSHORE OF BARANOF AND PRINCE OF WALES ISLAND BY
TONIGHT. BUT BEFORE DOING SO...A WAVE DEVELOPING ALONG THE FRONT
IN THE SOUTHEAST GULF WILL RIDE UP INTO BARANOF ISLAND THIS
AFTERNOON. MEANWHILE A WEAKENING FRONT ACROSS THE CENTRAL AND
SOUTHERN PANHANDLE WILL MAKE VERY LITTLE PROGRESS EASTWARD TODAY
AND WILL VIRTUALLY STALL TONIGHT...PROVIDING A FOCUS FOR SHOWERS
ACROSS THE PANHANDLE.

ON THE NORTH SIDE OF THE LOW HIGH PRESSURE OVER THE ALASKA
INTERIOR AND THE CANADIAN YUKON WILL TIGHTEN PRESSURE GRADIENTS
OVER THE NORTH CAUSING OUTFLOW WINDS FROM LYNN CANAL WEST TO THE
NORTHEAST GULF COAST THROUGH MOUNTAIN PASSES. HIGH RES MODELS
INDICATING SOME OF THIS SPREADS ACROSS THE COAST MOUNTAINS THIS
MORNING...BUT AT THIS POINT WE ARE NOT SEEING A LOT OF EVIDENCE
THAT WOULD JUSTIFY DOWNSLOPE WINDS INTO DOWNTOWN JUNEAU. BUT
HEDGED WINDS HERE WITH EAST 10 TO 15 MPH FOR MUCH OF TODAY AND
TONIGHT...EVEN THOUGH OUR BET THAT WINDS ARE LIGHTER...ESPECIALLY
TONIGHT. MORE CONFIDENT WE ARE OF A SMALL CRAFT DEVELOPING OVER
LYNN CANAL THIS MORNING BEFORE SLACKENING SOMEWHAT THIS EVENING.
IT SHOULD REAPPEAR LATE TONIGHT...AGAIN FROM THE NORTH AS
TEMPERATURES CHILL OVER CANADA.

ON THE FLIP SIDE...SOUTHERLIES WILL STILL DOMINATE THE SOUTH. A
LOW LEVEL JET OF UP TO 45 KT WILL ENHANCE STRONG GRADIENTS ACROSS
CLARENCE STRAIT...AND WAS CAUSE FOR RAISING GUSTS TO 40 MPH FOR
MUCH OF THE DAY. EVEN THOUGH THE JET PERSISTS TONIGHT...SURFACE
GRADIENTS WILL WEAKEN...THUS WE ALLOWED A DROP TO 20 KT...ALTHOUGH
THIS MAY BE PRECARIOUSLY LOW. IN ADDITION WIND SHEAR ACCOMPANIES
THE TAFS FROM PETERSBURG SOUTH.

FINALLY...BANDS OF HEAVY RAIN FALLS ALONG THE STALLED FRONT.
OVERNIGHT KLAWOCK AND KETCHIKAN HAVE RAINED UP TO A QUARTER-INCH
PER HOUR AT TIMES. JUNEAU`S HEAVIER BANDS RELENTED EARLY THIS BUT
AS THE WAVE TO THE SOUTH MOVES INTO BARANOF ISLAND THIS
MORNING...WE THINK WHERE RAIN OVER THE NORTH HAS STOPPED...IT
SHOULD REEMERGE INTO THE AFTERNOON AT LEAST. FINALLY...THE UPPER
LOW USHERS IN SOME COOLER AIR FROM THE BERING SEA THROUGH
TONIGHT...THUS RAIN WILL TURN TO SHOWERS OVER THE BULK OF THE
PANHANDLE.

06Z NAM AND 00Z ECMWF USED FOR UPDATES. FORECAST CONFIDENCE POOR
FOR WINDS OVER THE CENTRAL PANHANDLE...BUT STRONGER OVER THE FAR
NORTH AND FAR SOUTH.

.LONG TERM...SHOWERS CONTINUE ON SATURDAY AS THE LOW REMAINS OVER
THE SOUTHERN SE GULF. HEAVIEST SHOWERS ON SATURDAY MORNING
CONTINUE TO BE OVER THE KETCHIKAN REGION AND UP ALONG THE SOUTHERN
COASTAL MOUNTAINS. COOL 850MB TEMPERATURES BEING DRAWN DOWN BY THE
LOW WILL CAUSE HIGHS IN THE LOW 50S AND CLOUDY SKIES/PRECIP WILL
KEEP A VERY SMALL DIURNAL RANGE BETWEEN MAX/MINS. THE LOW CENTER
WILL SHIFT NORTHWARD TO THE NE GULF THRU SAT EVENING THEN
REINTENSIFY. BY SUNDAY MORNING MODERATE RAIN CAN BE EXPECTED MOST
PLACES AND HEAVY AT TIMES OVER KETCHIKAN ONCE AGAIN THROUGH THE
AFTERNOON AND EVENING.

ON MONDAY THE LOW WILL START TO SHIFT SOUTHWARD (AGAIN). THIS WILL
ALLOW THE RAIN TO DIMINISH FROM NORTH TO SOUTH THROUGH MONDAY NIGHT
WITH INCREASING OFFSHORE FLOW. KETCHIKAN WILL SEE THE RAIN ENDING
MID MORNING TUESDAY. THE REMNANT INVERTED TROUGH WILL REMAIN OVER
THE PANHANDLE THROUGH WEDNESDAY AND KEEP NORTHERLY WINDS THROUGH THE
INNER CHANNELS.

LONG RANGE MODELS ARE IN GOOD AGREEMENT ON THE WET WEEKEND AND THE
DRYING TREND FOR THE SECOND HALF OF THE WEEK. THEY EVEN HAVE LARGER
SUNNY BREAKS AND 850MB TEMPERATURES WARM BACK UP THROUGH THE END OF
THE WEEK. SO HAVE TRENDED MAX TEMPS BACK UPWARD IN THAT
DIRECTION...HOWEVER WITH FEWER CLOUDS OVERNIGHT MINS WILL BE COOLER
CAUSING A LARGER DIURNAL RANGE.

&&

.HYDROLOGY...A FLOOD WATCH REMAINS IN EFFECT FOR THE TAIYA RIVER
UNTIL 4 PM. ALTHOUGH THERE WAS A CREST OF 16.1 FEET LATE THURSDAY
EVENING. SHOWERS MAY PICK BACK UP THIS MORNING AS THE WAVE OVER
THE SE GULF PUSHES A FRESH SURGE OF MOISTURE NORTHWARD. WATERS
WILL LIKELY REMAIN HIGH TODAY...BUT THE FRONT APPEARS TO SPREAD
MORE MOISTURE NORTHWARD LATER TONIGHT...POSSIBLY MANDATING A WATCH
EXTENSION. AFTER RE-EVALUATION...WATCH MAY BE CANCELLED TODAY BUT
RE-ISSUED TONIGHT FOR THE NEXT THREAT. IF SO...AN SPS WILL LIKELY
REPLACE THE WATCH. MONTANA CREEK INDEED ROSE TO BANKFULL...BUT NOW
THAT RAIN RATES HAVE FALLEN...IT HAS DROPPED HARD. A GENERAL SPS
NOW COVERS THE HIGH LAKE/RIVER LEVELS NEAR JUNEAU AS WELL AS
STREAM AND RIVER RISES AS WELL AS MUDSLIDE THREAT FOR THE SOUTHERN
PANHANDLE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...FLOOD WATCH UNTIL 4 PM AKDT THIS AFTERNOON FOR AKZ018.
         STRONG WIND UNTIL 4 PM AKDT THIS AFTERNOON FOR AKZ028.
MARINE...GALE WARNING FOR PKZ036.
         SMALL CRAFT ADVISORY FOR PKZ012-022-041-043-051-052.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ042.

&&

$$

ADKINS/FERRIN

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