Small Craft Advisory 75, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
318 PM AKST THU JAN 21 2016

.SHORT TERM...SATELLITE IMAGERY THIS AFTERNOON SHOWING GALE FORCE
LOW OVER THE EASTERN AK GULF ON ITS NORTHWESTWARD TRACK TO THE
NORTHWEST GULF. THE LOW HAS BEEN WEAKENING THROUGH THE DAY WITH
DIMINISHING WINDS OVER THE GULF AND PANHANDLE. THE ASSOCIATED
FRONT IS MOVING OVER THE PANHANDLE AND WILL EXIT THE REGION
THROUGH THE EVENING. PRECIP HAS BEEN FALLING OVER MOST OF THE
PANHANDLE MAINLY AS RAIN, WITH THE EXCEPTION OF THE FAR NORTHERN
AREAS.

STORM FORCE WINDS OVER THE GULF DROPPED OFF THE GALES OVERNIGHT
AND WILL CONTINUE TO DIMINISH TO SMALL CRAFT THROUGH THE LATE
EVENING AND INTO THE NIGHT. THE 925 MB LOW LEVEL JET PRODUCED
GUSTS UPWARDS OT 45 MPG WITH OCCASIONAL 50 MPH GUSTS FOR THE
SOUTHERN PANHANDLE COAST TODAY. THE LOW LEVEL JET ALSO PRODUCE
WIND SHEAR FOR MOST AIRPORTS TODAY MAKING BUMPY TRAVEL. THE
EASTERLY GRADIENT OVER THE CENTRAL PANHANDLE WEAKENED EARLY IN
THE DAY SO THE DOWN DOWN JUNEAU WINDS DROPPED OFF EARLY IN THE
MORNING. NORTHERLY GRADIENT BETWEEN THE GULF LOW AND YUKON HIGH
ALONG WITH THERMAL GRADIENT KEPT STRONG WIND GUSTS FOR SKAGWAY
AND KEPT DOWN PRECIP. AS THE LOW MOVES MORE WESTWARD THE ISOBARS
WILL BECOME PARALLEL WITH A DROP OF IN WIND SPEEDS AND A SHIFT TO
THE SOUTH FOR THE CENTRAL AND NORTHERN PANHANDLE THROUGH THIS
AFTERNOON AND INTO THE EVENING. WINDS FOR FRIDAY WILL GENERALLY BE
IN THE 10 TO 20 MPH RANGE FROM THE SOUTHEAST.

RAIN FALL AMOUNTS GENERALLY LESS THAN ONE QUARTER OF AN INCH THE
PAST 24 HOURS. MODELS STILL A BIT HIGH WITH THE QPF AT LOWER
ELEVATIONS. WINTER STORM WARNING FOR THE HAINES HIGHWAY AND
ADVISORY FOR THE KLONDIKE HIGHWAY STILL IN EFFECT THROUGH 6 AM. AS
THE WINDS DROP OFF SNOW FALL RATES WILL INCREASE, THEN DROP AS THE
SOUTHER FLOW WARMS UP THE AIR COLUMN. KEPT WITH A 15 TO 1 RATIO
FOR THE HAINES HIGHWAY AND 10 TO 1 ELSEWHERE.

WHILE THE NAM INITIALIZED WELL AND MOST MODELS WERE IN GOOD
AGREEMENT FOR PRESSURE AND WINDS STARTED TO SEE MORE SPREAD FOR
FRIDAY WITH POP FIELDS. FOR WINDS NUDGED TO NAM12 ON THE OUTSIDE
WATERS AS THE NEW RUN SHOWED MORE OF THE WAVES AROUND THE LOW
CENTER. TIMING OF WINDS DIMINISHING AND SHIFTING TO THE SOUTH ALSO
DELAYED A FEW HOURS. KEPT A GENERAL COVERAGE OF PRECIP FOR FRIDAY
BUT MAY SEE A BREAK IN RAIN, ESPECIALLY OVER THE SOUTHERN
PANHANDLE IN THE LATE AFTERNOON. FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...NO CHANGES TO THE LONG RANGE WEATHER PATTERN.
UPCOMING WEEK FEATURES A SERIES OF LOWS THAT ENTER THE WESTERN
GULF FROM THE SOUTH OR SOUTHWEST. EACH SUCCESSIVE LOW WILL ROTATE
VARIOUS FRONTS AND TROUGHS NORTH OVER THE CENTRAL AND EASTERN GULF
AS WELL AS THE PANHANDLE, KEEPING SOUTHEAST ALASKA IN WET WEATHER.
DEEP LAYER SOUTHERLY FLOW WILL KEEP THE LOW LEVEL AIRMASS
SUFFICIENTLY WARM THAT PREDOMINANT PRECIP TYPE WILL BE RAIN.
EXCEPTIONS WILL BE THE FAR NORTHERN INNER CHANNELS - HAINES,
SKAGWAY, AND THE ASSOCIATED HIGHWAYS.

WINDS OVER THE EASTERN GULF WILL RANGE FROM SMALL CRAFT TO GALE
FOR THE UPCOMING WEEK WITH SEAS REMAINING AT 10 FEET OR HIGHER FOR
THE THE ENTIRE TIME FRAME.

NO CHANGE IN THE WEATHER PATTERN, HENCE NO NEED FOR MANY GRID
EDITS TODAY. UPDATED POP AND QPF VERY EARLY ON USING A BLEND OF
GFS22 AND GEM. OVERALL FORECAST CONFIDENCE IS AVERAGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 9 PM AKST THIS EVENING FOR AKZ027.
         WINTER STORM WARNING UNTIL 6 AM AKST FRIDAY FOR AKZ019.
         STRONG WIND UNTIL 6 PM AKST THIS EVENING FOR AKZ018.
         WINTER WEATHER ADVISORY UNTIL 6 AM AKST FRIDAY FOR AKZ018.
MARINE...GALE WARNING FOR PKZ041>043-051-052.
         GALE WARNING FOR PKZ022-036.
         SMALL CRAFT ADVISORY FOR PKZ043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ041.
         SMALL CRAFT ADVISORY FOR PKZ022.
         SMALL CRAFT ADVISORY FOR PKZ036.
         SMALL CRAFT ADVISORY FOR PKZ031-034.
         SMALL CRAFT ADVISORY FOR PKZ035.
         SMALL CRAFT ADVISORY FOR PKZ021.
         SMALL CRAFT ADVISORY FOR PKZ033.
         SMALL CRAFT ADVISORY FOR PKZ042.
         SMALL CRAFT ADVISORY FOR PKZ042.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ053.

&&

PRB/FRITSCH

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