Small Craft Advisory 483, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
353 PM AKDT FRI AUG 31 2012

.SHORT TERM...MOST REGIONS IN THE PANHANDLE ARE ENJOYING A VERY
NICE DAY TODAY WITH MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS. THE
TWO EXCEPTIONS ARE THE EXTREME SOUTHERN PANHANDLE AROUND ANNETTE
ISLAND AND SOUTHERN CLARENCE STRAIT (WHERE LOW CLOUDS AND FOG
PLAGUED THAT AREA THIS MORNING AND SOME LINGERING LOW CLOUDS ARE
STILL AROUND) AND WEST OF CAPE FAIRWEATHER (LEADING FRONTAL BANDS
FROM THE NEXT SYSTEM ARE ALREADY BRINGING RAIN TO YAKUTAT AND
GENERALLY OVERCAST SKIES THROUGHOUT THAT AREA). WINDS AND WAVES
ARE GENERALLY LOW AS WELL. THERE IS AN EXCEPTION TO THIS AS WELL.
BUOY 82 NEAR CAPE SUCKLING HAS BEEN REPORTING 30 KT SOUTHEASTERLY
WINDS AND 9 FT SEAS DUE TO THE BARRIER JET THAT HAS ALREADY SET
UP THERE.

 SHORT RANGE FORECAST IS A BIT UNCERTAIN AS WE TRANSITION FROM A
GENERALLY CLOUDLESS AND DRY SCENARIO TO A CLOUDY, BREEZY AND WET
SCENARIO BY TOMORROW AFTERNOON. MAIN UNCERTAINTY LIES WITH HOW A
WAVE THAT IS DEVELOPING ALONG THE APPROACHING FRONT, CURRENTLY
SOUTH OF KODIAK, WILL MOVE INTO THE NORTHERN GULF TONIGHT AND
SAT. RESENT MODEL RUNS HAVE HAD DIFFERING OPINIONS ON THIS. THE
12Z NAM FAVORED A SLOWER AND MORE EASTWARD TRACK SENDING THE LOW
UP TO NEAR YAKUTAT BY SAT AFTERNOON. THE GFS WENT FOR A FASTER
AND FARTHER WEST TRACK SENDING IT UP TOWARD PRINCE WILLIAM SOUND
BY SAT MORNING. THE ECMWF WENT FOR A MIDDLE OF THE ROAD APPROACH
WITH THE 18Z NAM LATER JUMPING ON BOARD. GENERALLY FAVORED THE
NAM AND ECMWF ON THIS AS I THOUGHT THE GFS WAS TOO FAST AND WAS
TOO FLAT WITH THE TROUGH ALONG THE FRONT FARTHER EAST ESPECIALLY
GIVEN HOW DECENTLY ORGANIZED THE WAVE LOOKS ON SATELLITE AT THE
MOMENT.

 THE RESULTING FORECAST HAS INCREASING CLOUDS OVER MOST OF THE
PANHANDLE TONIGHT AND INTO TOMORROW MORNING WITH RAIN CONTINUING
AT YAKUTAT. LOW TEMPERATURES WILL BE A BIT TRICKY TO PIN DOWN AS
THEY WILL DEPEND ON WHEN THE CLOUD COVER ARRIVES OVER A CERTAIN
AREA. THE SOONER THE CLOUD COVER ARRIVES THE WARMER OVERNIGHT
LOWS WILL BE. I AM GENERALLY GOING ON THE COLDER SIDE OF TEMPS
TONIGHT AS I THINK THE CLEARER SKIES WILL STICK AROUND UNTIL
EARLY MORNING FOR AREAS EAST OF CHATHAM STRAIT. TOMORROW'S HIGHS
WILL GENERALLY BE COOLER THEN TODAY'S GIVEN THE CLOUDS AND
POSSIBLE PRECIP. THE MARINE LAYER AND FOG WILL ALSO MAKE A RETURN
TONIGHT TO THE SOUTHERN PANHANDLE AS WELL.

 INTO TOMORROW, WINDS WILL BE INCREASING ACROSS THE GULF AND
PANHANDLE WITH GALES FORMING ALONG THE OUTSIDE WATERS TOMORROW
MORNING. WIND FOR THE OUTER COASTAL AND SOUTHERN LAND AREAS I
DON'T THINK WILL BE QUITE HIGH ENOUGH TO WARRANT ISSUING ANY
HEADLINES TOMORROW BUT WIND GUSTS TO 35 MPH OR SOME OCCASIONAL
GUSTS TO 40 MPH ARE NOT OUT OF THE QUESTION ESPECIALLY NEAR
SOUTHERN BARANOF ISLAND, HYDABURG, ANNETTE AND KETCHIKAN. INNER
CHANNEL WINDS WILL MAINLY CONSIST OF SMALL CRAFT WINDS FOR
CLARENCE STRAIT, SUMNER, SOUTHERN CHATHAM, CROSS SOUND, AND ICE
STRAIT TOMORROW. WINDS TO 20 KT ARE EXPECTED FOR THE REST OF THE
INNER CHANNELS AT SOME POINT SAT.

 AS FOR RAIN, MOST OF THE QPF IS EXPECTED TO IMPACT YAKUTAT
OVERNIGHT AND INTO TOMORROW ASSOCIATED WITH THE ENERGY FROM THE
FRONTAL WAVE. FOR THE REST OF THE PANHANDLE THE PRECIP IS NOT
EXPECTED TO START UP UNTIL TOMORROW WITH THE OUTER COAST GETTING
IT SAT MORNING AND THE REST OF THE PANHANDLE GETTING INTO IT BY
SAT AFTERNOON AND EVENING. EXPECTED QPF AMOUNTS WILL GRADUALLY
DIMINISH THE FURTHER EAST AND SOUTH YOU GO WITH INCREASING
DISTANCE FROM THE MAIN FRONTAL ENERGY. STILL EXPECTING UPWARDS
HALF AN INCH TO ONE INCH TOTAL IN NORTHERN AREAS.

&&

.LONG TERM...THE UPPER LEVEL LONGWAVE TROUGH OVER THE BERING SEA
WILL BE THE DOMINANT FEATURE FOR THE LONG RANGE PERIOD. AFTER THE
STRONG FRONTAL SYSTEM PUSHES INTO WESTERN CANADA SATURDAY NIGHT...
UPPER FLOW WILL BECOME MORE ZONAL WITH SEVERAL WEAK SHORTWAVES
CROSSING THE GULF THROUGH THE BEGINNING OF NEXT WEEK. ENSEMBLE
SPREAD IS FAIRLY LARGE IN THE WESTERN GULF TO THE EAST OF THE
UPPER LOW SUGGESTING CONSIDERABLE VARIANCE IN THE STRENGTH AND
MOVEMENT OF THESE SHORTWAVES. MODELS ARE HINTING ABOUT AN
AMPLIFYING RIDGE OVER THE PANHANDLE AROUND THE MIDDLE OF NEXT
WEEK. HOWEVER...MODEL CONFIDENCE IS LOW REGARDING THE ORIENTATION
AND MAGNITUDE OF THIS UPPER RIDGE.

GFS SOLUTION IS PREFERRED FOR THE MIDDLE PERIODS...BUT THEN A
TRANSITION TO HPC GUIDANCE WHICH FAVORS ENSEMBLE MEANS FOR THE EXTENDED
RANGE.

SHOWERS WILL PERSIST INTO SUNDAY BEHIND THE FRONTAL PASSAGE ON
SATURDAY NIGHT. STEADY RAIN IS LIKELY FOR LABOR DAY AS THE NEXT
UPPER TROUGH MOVES THROUGH THE PANHANDLE. SMALL CRAFT CATEGORY
WINDS ARE POSSIBLE IN THE OUTSIDE WATER ASSOCIATED WITH THIS
SYSTEM. THE REMAINDER OF THE WEEK WILL REMAIN WET WITH WESTERLY
ONSHORE FLOW.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ042-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ012-021-022-033-035-036-041-053.

&&

EAL/RCL