Gale Warning 362, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
559 AM AKST WED NOV 27 2013

.SHORT TERM...A SLOWLY DEVELOPING LOW PRESSURE AREA W OF HAIDA
GWAII WILL MOVE N INTO THE ERN GULF TODAY...THEN ACROSS NRN SE AK
TONIGHT. TRAILING COLD FRONT WILL SWEEP ACROSS SE AK TONIGHT.
MODELS WERE IN GOOD AGREEMENT ON THE MAIN FEATURES SO ENDED UP
USING THE 06Z NAM TO TAKE ADVANTAGE OF ITS HIGHER RESOLUTION.

 MAIN FORECAST CONCERNS WILL BE SNOWFALL AMOUNTS UP N...PRECIP
POTENTIAL ELSEWHERE...AND WINDS. BASED ON S-SE UPSLOPE FLOW ALOFT
AND SOME COLD AIR REMAINING OVER THE AREA...HAVE GONE AHEAD AND
ISSUED WINTER STORM WARNINGS FOR ZONES 18 AND 19 FROM NOON TODAY
TO 5 AM THU. DID LIMIT THE AREA TO NW OF PAHN IN ZONE 19 AND NEAR
WHITE PASS FOR ZONE 18...AS ELEVATIONS NEAR SEA LEVEL WILL BE A
LITTLE ABOVE FREEZING AND RAIN WILL BE MAIN PTYPE. WENT FOR 6 TO
12 INCHES OF SNOW DURING THE WARNING PERIOD...WITH HIGHEST
AMOUNTS NEAR THE CANADIAN BORDER IN 19 AND AT UPPER END OF WHITE
PASS FOR 18. PAHN COULD SEE A COUPLE OF INCHES OF SNOW LATER
TONIGHT ONCE LOW JUMPS INLAND AND SOME COOLER AIR FILTERS IN.

 AM EXPECTING PRECIP PRETTY MUCH EVERYWHERE OVER SE AK WITH THIS
SYSTEM. HIGHEST AMOUNTS WILL BE NEAR S FACING TERRAIN AND JUST NW
 OF THE LOW TRACK IN SMALL COMMA HEAD/DEFORMATION ZONE. PRECIP
SHOULD BECOME SHOWERY TONIGHT AFTER COLD FRONT MOVES THRU THE
AREA...ALTHOUGH INSTABILITY WILL INITIALLY BE ON THE WEAK
SIDE...SO EXPECT MOST SHOWERS ALONG THE COAST MTNS LATE TONIGHT.

 AS FOR WINDS...GRADIENT ORIENTATION WILL FAVOR THE MORE E-W
CHANNELS INITIALLY (EXCEPT OVER THE FAR N)...BUT THIS WILL SHIFT
TO THE MORE N-S CHANNELS LATER TODAY AS LOW GETS FURTHER N IN THE
GULF. EXPECT MAINLY SCA LEVEL WINDS IN THOSE AREAS...EXCEPT MAY
SEE GALES FOR CLARENCE STRAIT AND FOR THE FAR ERN GULF WATERS S
OF CROSS SOUND. DECIDED TO PUT OUT STRONG WIND HEADLINE FOR ZONE
27 THIS MORNING. THERE WILL BE A BURST OF WIND OVER THE N-CENTRAL
AREA TONIGHT AS LOW MOVES IN JUST N OF THERE...SO THINK GALES
WILL DEVELOP FOR NRN STEPHENS PASSAGE AND NRN END OF CHATHAM
STRAIT FOR A FEW HOURS LATE THIS EVENING. THERE IS POSSIBILITY OF
A BRIEF STRONG WIND EVENT NEAR PAJN LATE THIS EVENING. ALSO...AS
LOW AND FRONT PULLS INLAND...WLY FLOW WILL DEVELOP OVER THE ERN
GULF AND SOME OF THIS WILL GET INTO THE CROSS SOUND AND FAR SRN
ENDS OF CHATHAM AND SUMNER STRAITS AS TIP JETS DEVELOP. WENT FOR
GALE FORCE WLYS IN THOSE AREAS TONIGHT. FINALLY...THINK LYNN
CANAL AND GLACIER BAY WILL PICK UP TO SCA NLY WINDS THIS
MORNING...WITH A SHIFT TO SLY WINDS LATE TONIGHT.

 OTHERWISE...THE PESKY FOG SHOULD BE DIMINISHING AS PRECIP MOVES
IN EARLY THIS MORNING. MAY STILL HAVE SEVERAL HOURS OF IFR/LIFR
CEILINGS THIS MORNING THOUGH AS LOW LEVEL WINDS MAY BE SLOW TO
PICK UP IN SOME AREAS.

&&

.LONG TERM...MODELS REMAIN IN GENERAL AGREEMENT THROUGH THE MID
RANGE AND REFRESHED THE INHERITED FORECAST PACKAGE WITH THE 06Z
NAM AND 00Z ECMWF FOR THEIR GOOD CONSENSUS WITH THE LOW IN THE FAR
NORTHERN AREA AND A RIDGE OF HIGH PRESSURE IN THE SOUTHERN AREA
PROGRESSING EASTWARD ON THANKSGIVING DAY AND THE LOW REFORMS
ACROSS THE NORTHERN PANHANDLE FRIDAY AS AN ARCTIC HIGH EXPANDS
EASTWARD. THE NEWLY REFORMED LOW WILL CONTINUE TO DRIFT EAST
FOLLOWED BY ANOTHER LOW MOVING INTO THE PANHANDLE SATURDAY. AT
THIS TIME THE ARCTIC HIGH WILL BE IN FULL SWING AND PUSH THE LOW
SOUTHEAST ACROSS THE PANHANDLE INTO BRITISH COLUMBIA THROUGH
SUNDAY. THE HIGH WILL CONTINUE TO ENHANCE AND PUSH ARCTIC AIR MASS
OVER SOUTHEAST ALASKA THROUGH EARLY NEXT WEEK WITH GENERALLY DRY
WEATHER AND TIGHTENED NORTHERLY PRESSURE GRADIENT.

 MAINTAINED POSSIBLE 2 TO 4 INCHES OF SNOW ACCUMULATION ALONG THE
HAINES AND KLONDIKE HIGHWAYS ON THANKSGIVING DAY IN CONJUNCTION TO
THE WINTER STORM WARNING CARRIED BY THE SHORT TERM FORECAST
PACKAGE. OTHER THAN THAT PRECIPITATION WILL BE MOSTLY RAIN FOR THE
REST OF THE PANHANDLE THROUGH FRIDAY UNDERNEATH THE RIDGE OF HIGH
PRESSURE. WITH INCREASING OFFSHORE FLOW AHEAD OF THE ARCTIC AIR
MASS ENTRAINMENT SNOW CHANCE WILL INCREASE BUT POPS WILL DECREASE.
MAINTAINED SMALL CRAFT TO GALE FORCE WINDS ACROSS THE COASTAL
WATERS AS INHERITED THROUGH THE MID RANGE AND POSSIBLE STORM FORCE
WINDS OVER THE NORTHERN INNER CHANNELS OVER THE WEEKEND WITH
TIGHTENED NORTHERLY PRESSURE GRADIENT. KEPT THE WPC ENSEMBLE
SOLUTIONS FROM SATURDAY THROUGH THE END.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 9 AM AKST THIS MORNING FOR AKZ027.
         WINTER STORM WARNING FROM NOON TODAY TO 5 AM AKST THURSDAY FOR
     AKZ018-019.
MARINE...GALE WARNING FOR PKZ022-031-032-036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-033>035-051-052.

&&

RWT/AHN