Gale Warning 19, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
542 AM AKST MON JAN 3 2011

.SHORT TERM...DIFLUENT SSW FLOW ALOFT WILL INCREASE THROUGH
TODAY  WITH THE LEADING EDGE OF A 100 KT JET CORE PUSHING INTO
EASTERN GULF TONIGHT. AN OCCLUDED FRONT ACROSS THE CENTRAL GULF
WILL STRENGTHEN AS IT PUSHES INTO THE EASTERN GULF LATE THIS
AFTERNOON AND EVENING THEN WEAKEN AS IT MOVES ACROSS SOUTHEAST
ALASKA TONIGHT.

 STRONG SSW FLOW IN MID AND UPPER LEVELS PERPENDICULAR TO TERRAIN
EXPECTED TO FORM BARRIER GALES ACROSS NORTHERN COASTAL WATERS AS
EARLY AS THIS MORNING AND CONTINUE WELL INTO EVENING. SE
GRADIENTS INCREASING ACROSS SOUTHEAST ALASKA IN ADVANCE OF
APPROACHING FRONT AND WILL SEE SMCR THROUGH MANY OF INNER
CHANNELS. FOR PUBLIC ZONES COASTAL AND SOUTHERN AREAS WILL SEE
WINDS INCREASE AND BECOME BREEZY THROUGH THE EVENING WITH GUSTS
EXPECTED TO FALL JUST SHORT OF ADVISORY LEVELS. HEAVIEST PRECIP
EXPECTED OVER NE GULF COAST AND SHOULD BE AT MODERATE LEVELS IN
PAYA LATE AFTERNOON AND EVENING. TEMPS CONTINUE TO WARM THROUGH
DAY AND EXPECT PRECIP TO FALL AS RAIN EXCEPT WILL LEAVE MIXED FOR
HYDER WHERE ACCUMS MAY REACH 1 INCH. THINKING SNOW LEVEL TOO HIGH
ON THE HAINES HIGHWAY FOR SNOW AND NOT SEEING ENOUGH PRECIP ON
THE KLONDIKE HIGHWAY FOR AN ADVISORY.

 MODELS IN GOOD AGREEMENT THROUGH SHORT TERM BUT STILL PREFERRED
EC FOR PRESSURE WHICH HAD MIDDLE OF THE ROAD GRADIENTS FOR
NORTHERN INNER CHANNELS BUT EC WINDS STILL SEE TOO LIGHT OVER
GULF AND ADDED UP TO 5 KT. FOR MASS FIELDS BLENDED IN NAM AND GFS
FOR GOOD MEASURE.

.LONG TERM...LARGE SCALE PATTERN WILL BE IN TRANSITION THIS WEEK
AS THE DEEP TROF OVER WRN AK AND ERN BERING SEA WILL BE REPLACED
BY A FAIRLY STRONG RIDGE BY NEXT WEEKEND. THE MODELS REMAIN
SOMEWHAT INCONSISTENT ON HOW FAR N AND E THE RIDGE WILL
BUILD...AND HOW STRONGLY CLOSED OFF ALOFT IT WILL GET. LA NINA
CLIMATOLOGY FAVORS RIDGE OVER ERN BERING SEA AND WRN PUBLIC...WHICH
WILL TEND TO SUPPORT AN ARCTIC AIRMASS MOVING S INTO THE AREA.
AFTER COORD WITH WFO PAFC...DECIDED TO USE THE 00Z ECMWF THRU 12Z
FRI...THEN GO WITH LATEST HPC THE REST OF THE WAY OUT TO DAY 8.
THE BIG PROBLEM WITH THE 00Z GFS WAS IT DID NOT INITIALIZE THE
LARGE LOW S OF THE ALEUTIANS VERY WELL AND THIS AFFECTED ITS
TRACK OF THIS FEATURE ALONG WITH OTHER DEVELOPMENTS FURTHER E.

 DURING THE MIDWEEK TIME FRAME...A FRONT WILL MOVE THRU THE AREA
TUE THEN STALL JUST S OF THE AREA TUE NIGHT. LOOKS LIKE A LOW
WILL DEVELOP AND MOVE NE INTO THE FAR ERN GULF WED. LOW WILL
LIKELY BE AN INSTANT OCCLUSION TYPE AS THE MAIN FRONT WILL REMAIN
S OF THE AREA. EXACT TRACK AND INTENSITY OF THIS FEATURE IS A BIT
UNCERTAIN AT THIS POINT AND THIS COULD HAVE PTYPE
RAMIFICATIONS...BUT FOR NOW WENT WITH THE EC TRACK TO THE FAR
SERN GULF BY WED MORNING THEN TURNING NWD ALONG THE OUTER COAST
WED AFTERNOON AND EVENING...WHICH WOULD LEAD TO MOSTLY RAIN FOR
THE AREA. COULD BE SOME SNOW OVER THE FAR N AS LOW LEVEL FLOW
TEMPORARILY TURNS NLY AHEAD OF THE LOW BUT ONCE IT MOVES BY
THEM...A QUICK RETURN TO SLY FLOW SHOULD OCCUR. THE PASSAGE OF
THIS LOW SHOULD BRING IN SOME COOLER AIR FROM THE WEST WED NIGHT
AND ESPECIALLY THU...BUT TEMPS WILL STILL BE MARGINAL FOR SNOW.
SHOULD ALSO BECOME A MORE SHOWERY PATTERN BY EARLY THU AS
WELL...AND MADE ADJUSTMENT TO PRECIP CHARACTER IN THIS FORECAST
FOR THU ONWARD.

 FOR LATE WEEK INTO THE WEEKEND...WEAKENING LOW WILL TRACK EWD
ACROSS THE GULF THU THEN TURN SE FRI AS UPPER TROF SHIFTS EWD.
THIS IS WHEN RIDGE WILL BE BUILDING TO THE W OF THE AREA...AND
THIS WILL START COLD AIRMASS SWD INTO THE NRN AREA FRI. ONCE THE
LOW MOVES SE OF THE AREA AND DEEP LAYER NLY FLOW DEVELOPS LATER
FRI...THE COLDER AIR WILL SPEED UP ITS SWD MOVEMENT THRU THE
AREA. STILL A BIT UNCERTAIN HOW INTENSE THE COLD AIR WILL BE AS
THIS WILL DEPEND ON WHERE THE UPPER RIDGE SETS UP. DID CONTINUE
THE DOWNWARD TREND TO TEMPS ESPECIALLY FOR THE WEEKEND...AND
DECREASED CLOUD COVER A LITTLE FASTER THAN PREVIOUS FORECAST DID.
WHILE HPC WAS USED FOR THE PRES FIELDS NEXT WEEKEND...DID BOOST
WINDS UP A BIT OVER THE NRN INNER CHANNELS FROM WHAT THE HPC PRES
GRADIENT WOULD SUPPORT AS TYPICALLY THESE COLDER OUTBREAKS FROM
THE N TEND TO COME IN ON AT LEAST SCA LEVEL NLY WINDS.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ042-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011-012-021-022-032>036-041.

&&

MM/RWT