Small Craft Advisory 52, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE JUNEAU AK
309 PM AKST FRI JAN 15 2016

.SHORT TERM...LOW CLOUDS AND AREAS OF FOG LINGERED ACROSS LARGE
PORTIONS OF SOUTHEAST ALASKA LATE INTO THE DAY TODAY, WHICH PUT A
DAMPER ON WHAT WAS SUPPOSE TO HAVE BEEN OUR ONE MOSTLY SUNNY AND
DRY DAY BEFORE WINTER RAINS RETURN. AS OF THIS AFTERNOON, A CIRRUS
SHIELD IS EVIDENT IN SATELLITE IMAGERY AND IS MOVING NORTH. IN
FACT, THE CLOUD SHIELD IS THICK ENOUGH THAT IT IS CASTING A
SHADOW ON THE SURFACE...ALSO SEEN IN SATELLITE IMAGERY. APART FROM
THE INCREASING CLOUDS ALOFT, THERE WILL BE WIDESPREAD AREAS OF FOG
THIS EVENING. THEN, AS A GALE FORCE FRONT APPROACHES FROM THE
WEST-SOUTHWEST, INCREASING WINDS WILL STIR UP THE SURFACE LAYER
AND MIX OUT THE FOG INTO AN ELEVATED STRATUS LAYER. GALE FORCE
WINDS WILL SPREAD GENERALLY FROM SOUTHWEST TO NORTHEAST IN ADVANCE
OF THE FRONT OVER THE EASTERN GULF THROUGH THE NIGHT. TYPICAL
INNER CHANNEL RESPONSES WILL ALSO BEGIN TONIGHT WITH INCREASING
SOUTHERLIES OVER CLARENCE STRAIT, EASTERLIES OVER SUMNER STRAIT,
ICY STRAIT, AND CROSS SOUND, AND NORTHERLIES ELSEWHERE.

PEAK CONDITIONS IN TERMS OF WIND ARE EXPECTED LATE TONIGHT
THROUGH TOMORROW MORNING. HAVE A STRONG WIND HEADLINE OUT FOR ZONE
27 FOR THIS TIME FRAME. AS THE PRE-FRONTAL WINDS BEGIN TO
DIMINISH, CATEGORICAL POP WILL MOVE NORTH, GETTING AS FAR NORTH AS
GUSTAVUS AND JUNEAU BY TOMORROW AFTERNOON. WITH OVERNIGHT LOWS IN
SOME LOCATIONS GETTING DOWN TO NEAR OR BELOW FREEZING UNDER MOSTLY
CLEAR SKIES, PRECIP MAY BEGIN AS SNOW IN SOME COLDER SPORTS BEFORE
TRANSITIONING BACK TO RAIN. NO SIGNIFICANT ACCUMULATIONS EXPECTED
ANYWHERE.

NO CHANGES TO INHERITED PRESSURES. SOME WIND DIRECTIONS ADJUSTED,
BUT ALSO REMAIN UNCHANGED FOR THE MOST PART. POP AND QPF UPDATED
WITH A BLEND OF GFS22 AND GEM. TEMPS AND SNOW LEVELS ADJUSTED
PER GFS MOS. OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...AN UPPER DISTURBANCE LOCATED OVER THE N CNTRL PAC
FRI AFTERNOON IS FORECAST TO ROTATE AROUND A LARGE UPPER-LEVEL
CYCLONE...ENTERING THE NERN PAC SAT...AND THEN EJECTING NNW TO THE
ERN GULF DURING SUN. MODEL GUIDANCE SHOWS STRONG SURFACE
CYCLOGENESIS OCCURRING BENEATH THE DISTURBANCE AS A COUPLED JET
STRUCTURE EVOLVES BETWEEN THE LEFT EXIT REGION OF A 100 KT 300 MB
SPEED MAX OVER BC AND A 50-60 KT JETLET OVER THE CNTRL GULF.

GFS AND ECMWF ARE IN CLOSE AGREEMENT TRACKING A DEEP LOW FROM THE
SERN GULF LATE SUN AFTERNOON NNW ALONG THE THE COAST OF SERN AK
DURING SUN NIGHT. BOTH THE 12Z AND 18Z NAM ARE OUTLIERS PRODUCING
A MUCH SLOWER PROGRESSION. BASED ON THE GFS/ECMWF...A 65 KT ESELY
925 MB JET WILL SPREAD OVER THE SRN PANHANDLE/MARINE WATERS BY 00Z
MON...AND THEN SPREAD ACROSS THE CNTRL PANHANDLE/MARINE WATERS BY
12Z MON...WITH WEAKENING TAKING PLACE THEREAFTER. IN ADDITION...
STRONG HEIGHT/PRESSURE RISES OCCUR IN THE WAKE OF THE LOW PRESSURE
CENTER. BOTH OF THESE FACTORS WILL SUPPORT GALE STRENGTH WINDS
OVER MOST OF THE INNER AND OUTSIDE WATERS...WITH MINIMUM STORM
FORCE WINDS POSSIBLE OVER THE FAR SRN MARINE ZONES. IN
ADDITION...POTENTIAL EXISTS FOR WIND GUSTS IN EXCESS OF 50 KT OVER
AKZ027-028. THUS...A HIGH WIND WATCH HAS BEEN ISSUED FROM SUNDAY
AFTERNOON THROUGH SUN EVENING. STRONG WIND ADVISORY APPEARS
WARRANTED ELSEWHERE ALONG THE GULF COAST...AS WELL AS AKZ018 AND
025.

PRIMARY FOCUS WITH THIS LONG TERM PACKAGE WAS SUN/MON...REMAINDER
OF THE FORECAST DOES NOT DEVIATE SIGNIFICANTLY FROM WHAT WAS
INHERITED. PROGRESSIVE PATTERN CONTINUES THROUGH NEXT WEEK...AS A
SERIES OF WAVES MOVE ACROSS THE REGION...YIELDING EPISODES OF
RAIN/SNOW OVER THE PANHANDLE. PRESSURE GRIDS WERE WEIGHTED TOWARD
THE 12Z ECMWF THROUGH MON...THEN TRANSITIONED TO WPC. UPDATES TO
THE REMAINDER OF THE FORECAST WERE MADE WITH ENSEMBLE GUIDANCE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM MIDNIGHT AKST TONIGHT THROUGH SATURDAY MORNING
     FOR AKZ027.
         HIGH WIND WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR
     AKZ027.
         HIGH WIND WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR
     AKZ028.
MARINE...GALE WARNING FOR PKZ012-022-034-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011-013-021-031>033-035-036-053.

&&

FRITSCH/GARNER

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