Gale Warning 398, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
336 PM AKST WED DEC 10 2014

.SHORT TERM...ACTIVE WEATHER PATTERN CONTINUES OVER THE NEXT 24
HOURS AS ANOTHER STRONG LOW COMES SHOOTING UP INTO THE SE GULF
TONIGHT. VERY WELL DEFINED CIRCULATION SHOWN ON SATELLITE IMAGES
THIS AFTERNOON BUT THAT APPEARS TO BE THE UPPER LEVEL CIRCULATION. THE
SURFACE LOW SEEMS TO BE JUST WEST OF WHERE THE UPPER LOW IS BASED
ON BUOY OBS NEAR THE SYSTEM. STRETCHING TO THE NORTH IS A FRONTAL
BAND THAT HAS ALREADY BROUGHT SOME WINDS AND RAIN TO THE SOUTHERN
HALF OF THE PANHANDLE. THE NORTHERN PANHANDLE MEANWHILE HAS HAD A
FOGGY DAY IN THE CLEARER SKIES NORTH OF THE SYSTEM. MOST
OBSERVATIONS SITES AT SOME POINT HAD VISIBILITIES BELOW A MILE WITH
JUNEAU AIRPORT AND THE MENDENHALL VALLEY SOCKED IN WITH 1/4 MILE
ALL DAY LONG. THE REMAINING FOG SHOULD DISSIPATE THIS EVENING AS
THE FRONTAL BAND CONTINUES TO MOVE FARTHER NORTH BRINGING SOME
WIND AND PRECIP THAT WILL FINALLY MIX THE LOWER LAYERS OUT.
CONSEQUENTLY THE DENSE FOG ADVISORY OUT FOR THE JUNEAU AREA HAS
EXPIRED.

FOR TONIGHT AND TOMORROW, THE SOUTHERN PANHANDLE IS THE MAIN FOCUS AS THAT
STRONG LOW PUSHES UP INTO THE SE GULF. MODEL AGREEMENT STILL HAS A
FEW SNAGS WITH THE GFS BEING WAY TO FAST TRACKING THIS LOW NORTH.
THE NAM, GEM, AND ECMWF MEANWHILE HAVE FALLEN INTO A COMFORTABLE
AGREEMENT OF IT BOTTOMING OUT AROUND 960MB WEST OF HAIDA GWAII
EARLY WED EVENING BEFORE SLOWLY TRACKING N WEAKENING AS IT GOES.
IT IS SCHEDULED TO MAKE LANDFALL SOMEWHERE BETWEEN SOUTHERN
BARANOF ISLAND AND CROSS SOUND THU EVENING. THE MAIN CONCERN WITH
THIS IS THE WIND. 850 MB LOW LEVEL JET IS AROUND 50 TO 60 KT OVER
THE SOUTHERN PANHANDLE TONIGHT. CURRENT THINKING IS THAT HIGHEST
WINDS WILL BE OVER THE SOUTHERN OUTER COAST AND JUST OFF PRINCE OF
WALES ISLAND. AS A RESULT A HIGH WIND WARNING REMAINS UP FOR ZONE
27 TONIGHT AND EARLY TOMORROW WITH STRONG WIND HEADLINES UP FOR 28
AND 23 FOR MOST OF TONIGHT AND TOMORROW.

AS FOR PRECIP, MOST AREAS REMAIN TOO WARM FOR SNOW AND WILL REMAIN
TOO WARM AS MOST OF THE PANHANDLE REMAINS ON THE EAST SIDE OF THE
LOW TRACK FOR THE NEXT 24 HOURS. INSTEAD RAIN IS THE MAIN ORDER OF
THE DAY. MOST AREAS WILL SEE RAIN START UP SOMETIME OVERNIGHT.
QPF AMOUNTS OVER THE NEXT 24 HOURS WILL BE IN THE .5 TO 1.5 INCH
RANGE FOR THE SOUTHERN PANHANDLE AND LOWER AMOUNTS THE FARTHER
NORTH YOU ARE. THE EXCEPTION TO THIS WILL BE YAKUTAT WHERE THEY
WILL REMAIN MOSTLY DRY FOR THE NEXT 24 HOURS AS THEY ARE TOO FAR
WEST TO BE IMPACTED BY THE PRECIP BUT WILL SEE SOME CLOUDS ROLL
OVER THEM. YAKUTAT MAY ALSO BE THE ONLY PLACE THAT RETAINS SOME FOG
OVERNIGHT AS WELL.

.LONG TERM...BEGINNING OF THIS PERIOD STARTS WITH THE REMNANT
LOW/TROUGH OVER THE PANHANDLE WHICH SHOULD BE IN THE RAPID
WEAKENING STAGE BY 06Z FRI. IT CONTINUES TO WEAKEN AND EDGE NORTHWARD
LATE ON THURSDAY NIGHT WITH ONLY REMNANT PRECIP AND SOME RESIDUAL
WIND. SOME CHANGES WERE MADE EARLY IN THE PERIOD ON WINDS IN
NORTHERN LYNN WHICH APPEARED NOT TO WEAKEN RAPIDLY ENOUGH IN THE
06Z-12Z PERIOD EVEN WITH A BIAS TOWARDS TYPICAL LATENESS IN THAT
AREA. MADE CHANGES CONSERVATIVELY BASED ON CURRENT PRESSURE
GRADIENT PROGS...AND WITH SYSTEM WEAKENING GRADIENTS SHOULD BE
DOING THE SAME. GEM MODEL IS THE STRONGEST ON THIS EXITING LOW
FOR THURS. NIGHT AND IS A BIT OF AN OUTLIER.

WE REMAIN ON THE WARM SIDE OF THE DEEP LONGWAVE TROUGH OVER THE
ALEUTIANS AND SOUTHWARD THROUGH EARLY NEXT WEEK. AS A RESULT...NO
EXTENSIVE SNOW IS FORESEEN WITH ONLY OCCASIONAL MIXED EPISODES ON
THE NORTHERN FRINGES AND IN THE HYDER VICINITY. THE SURFACE LOW
TRACKS WILL REMAIN GENERALLY THE SAME UP THROUGH THE CENTRAL GULF
AND THEN NNWWD OUT OF THE AREA. SATURDAY'S NEW STORM FRONT WITH
ENHANCED GRADIENTS BEGINNING ABOUT 09-12Z LOOKS POTENT WITH 980ISH
CENTRAL GULF LOW AND STRONG GRADIENTS BETWEEN THAT AND THE
INTERIOR COLD AIR DEVELOPING. LOOKS TO BE GALE-FORCE FOR OUTER WATERS AND
PORTIONS OF INNER CHANNELS WITH MORE MODERATE RAIN AMOUNTS FOR THE
PANHANDLE...WITH GRADIENTS PEAKING IN THE SAT PM - SUN AM PERIOD.
THE NEXT L ON MON- TUES TAKES AN ALMOST IDENTICAL TRACK. MADE AN
ENSEMBLE APPROACH WITH THE QPF/POP GRIDS THROUGH THE WEEKEND USING
MOSTLY NAM/EC PROGS. GENERAL MODEL AGREEMENT IS PRESENT THROUGH
ABOUT MONDAY BETWEEN THE EC AND GEM MODELS AND EARLY ON IN THE
NAM. OVERALL THE GFS ONCE AGAIN IS THE OUTLIER ON SURFACE PRESSURE
GRADIENTS DURING THE DAYS 3-5 PORTION...BUT ALOFT IT MOSTLY AGREES
WITH THE EC/GEM EVEN INTO DAYS 5-6. MID- LEVEL HEIGHT FIELDS ON
THE 3 MAJOR MODELS ALL SHOW A WEST- EAST JET JUST SOUTH OF THE
GULF WHICH WILL CONTINUE OUR ACTIVE WET AND WINDY WX PATTERN. WPC AK
SEEMS TO BE LEANING TOWARDS A STATUS QUO APPROACH WITH THE
LONGWAVE REMAINING OVER THE ALEUTIANS IN THE EXTENDED...THIS
KEEPS PANHANDLE IN THE WARM SECTOR AND SEE NO REASON AT THIS POINT
TO DISAGREE. WENT WITH HPC GUIDANCE FROM LATE ON DAY 4 ONWARDS
THROUGH THE EXTENDED WHICH AT THIS POINT IS WET THROUGH DAY 8.
MODEL CONFIDENCE WAS AVERAGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING FROM 9 PM THIS EVENING TO 5 AM AKST THURSDAY
     FOR AKZ027.
         STRONG WIND UNTIL 9 PM AKST THIS EVENING FOR AKZ027.
         STRONG WIND FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON FOR
     AKZ027.
         STRONG WIND FROM 9 PM AKST THIS EVENING THROUGH THURSDAY MORNING
     FOR AKZ023.
         STRONG WIND THROUGH THURSDAY MORNING FOR AKZ028.
MARINE...STORM WARNING FOR PKZ041.
         GALE WARNING FOR PKZ012-033-036-042.
         SMALL CRAFT ADVISORY FOR PKZ013-021-022-031-032-034-035-043.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

EAL/WESLEY

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