High Wind in Alaska, November 26 to 28, 2014

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
333 PM AKST WED NOV 26 2014

.SHORT TERM....LOOKED CLOSELY AT STRONG WIND POTENTIAL FOR THE NOTORIOUS
TAKU AREAS AROUND JUNEAU AND BEST GUESS IS 40-50 MPH SUSTAINED
FOR THE GENERAL PERIOD LATE TONIGHT THROUGH POTENTIALLY AS LATE
AS THURSDAY EVENING. THIS ANALYSIS USED PRIMARILY THE MTNWMODEL
ROUTINE, DETAILED NAM CROSS SECTIONS, AND HI-RESW-ARW MODEL
PREDICTIONS. SOME MODELS SUGGESTED EVEN HIGHER BUT HISTORICALLY
THEY HAVE A BIAS TOWARD STRONGER WIND SPEEDS ACCORDING TO OTHERS
HERE WITH MORE EXPERIENCE USING THESE MODELS LOCALLY. BOTTOM
LINE...AT THIS POINT LOOKS LIKE STRONGEST GUSTS WILL BE IN THE
55-65 MPH RANGE AND THUS MARGINAL FOR THE HWW. TIME PERIOD OF RISK
SHOULD BE AROUND 10-12Z THURS (CONSISTENT WITH PREVIOUS FORECAST) TO
THURSDAY AFTERNOON. WOULD SUGGEST MONITORING THE WINDS CLOSELY
AROUND JUNEAU THIS EVENING, AS IT APPEARS THE ONSET OF WIND IS
ALREADY A BIT SLOW...AND MAKING MODIFICATIONS IF NECESSARY. WE
MAINTAINED THE HIGH WIND WARNING FOR DOUGLAS/JUNEAU. ALSO STRONG
WINDS FOR HYDER ZONE AND SKAGWAY/HAINES PER PREVIOUS FORECAST. FOR
MARINES...SLEW OF GALE WARNINGS WILL BE IMPLEMENTED TONIGHT AND
TOMORROW AND MAINTAINED STORM FORCE FOR NORTHERN LYNN WITH GUSTS
AS HIGH AS 70 KT. JPFCST CURRENTLY GIVES 10 MB GRADIENT FOR
SKAGWAY- JUNEAU, MAX 15Z THURS, 6 MB JUNEAU- SITKA, MAX 21Z, AND
11MB JUNEAU- KETCHIKAN, MAX 21Z. FREEZING SPRAY COULD BE A THREAT
FOR LYNN CANAL BUT THE CONSENSUS FOR NOW IS THAT IT WILL NOT GET
INTO THE MODERATE RISK CATEGORY WITH UPSTREAM AIR TEMPERATURES
LIKELY TO BE AT LEAST 30 DEGF IN THE WINDY SKAGWAY AREA. WE DID
NOT INCLUDE FREEZING SPRAY IN THE FORECAST.

GRIDS REQUIRED ONLY MINOR MODIFICATION FOR TODAY AND
TONIGHT AS NEW MODEL RUNS WERE VERY CONSISTENT ON THE LARGER-SCALE
FEATURES. WIND GRIDS WERE THE BIGGEST CHALLENGE AS SEVERAL ZONES,
ESP. 25 AND OTHERS IN PRIMARILY THE SOUTH, WILL EXHIBIT THE TYPICAL
LARGE SPREAD BETWEEN MAX AND MIN WINDS. THERMAL FIELDS REQUIRED
SOME TIME AND THOUGHT AS SPREADS WILL BE LARGE BETWEEN WIND-
PROTECTED AREAS AND EXPOSED AREAS LIKE SKAGWAY AND JUNEAU
DOWNTOWN. THE CHALLENGE WAS CHOOSING WHICH OF THE MARGINAL AREAS
WILL BLOW...WHICH WAS TOUGH AND SHOULD BE MONITORED TONIGHT.
EC/NAM WAS THE MODEL OF CHOICE FOR THE PERIOD WITH AVERAGE MODEL
CONFIDENCE FOR THE NON- MESOSCALE FEATURES.

.LONG TERM...HIGH PRESSURE CONTINUES TO BE THE DOMINATE FEATURE
AS IT MOVES SOUTHEAST THROUGH BRITISH COLUMBIA WITH A WEAK
INVERTED TROUGH ALONG THE OUTER COAST. HIGH PRESSURE OVER THE GULF
OF ALASKA WILL SLOWLY BUILD INTO THE WEEKEND. A WEAK AREA OF LOW
PRESSURE LOOKS TO DEVELOP OVER TH NORTHERN GULF NEAR CENTRAL GULF
CAST BY LAST SATURDAY AND WILL BRING A LOW CHANCE OF LIGHT
PRECIPITATION ALONG THE NORTHEAST GULF COAST INTO SUNDAY. BY
MONDAY AM LOOKING AT AN STRONG AREA OF LOW PRESSURE OVER THE
WESTERN BERING SEA THAT WILL BE TRYING TO SPREAD A WEATHER BAND
AND PRECIPITATION ACROSS THE GULF TO THE PANHANDLE BY EARLY NEXT
WEEK. BEST ESTIMATE FOR THE START OF PRECIPITATION AGAIN IS
TUESDAY...AND MAY BE STARTING AS SNOW. WILL HAVE TO KEEP AN EYE TO
SEE IF IT WILL BE A SIGNIFICANT SNOW AMOUNT.

FIRST FORECAST ISSUE WILL BE OUTFLOW WINDS BEGINNING TO DIMINISH
THURSDAY NIGHT AND EARLY FRIDAY TO A MORE NORMAL SET OF WINDS. THE
TEMPERATURES WILL BE THE COLDEST FRIDAY NIGHT TO SATURDAY MORNING.
UNDER THE CLEAR SKIES.

&&

.MARINE...

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING FROM 3 AM THURSDAY TO MIDNIGHT AKST THURSDAY
     NIGHT FOR AKZ025.
         STRONG WIND THROUGH THURSDAY EVENING FOR AKZ019.
         STRONG WIND THROUGH THURSDAY EVENING FOR AKZ018.
         STRONG WIND THROUGH LATE TONIGHT FOR AKZ029.
MARINE...STORM WARNING FOR PKZ012.
         GALE WARNING FOR PKZ011-013-022-031-032-034-036-043-051-053.
         SMALL CRAFT ADVISORY FOR PKZ021-033-035-041-042.

&&

WESLEY/BEZENEK

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU