High Wind in Alaska, October 11, 2015

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
617 AM AKDT SUN OCT 11 2015

.SHORT TERM...A LOW PRESSURE SYSTEM IN THE NORTH PACIFIC CAN BE
SEEN ON IR SATELLITE WITH THE CENTER BECOMING WRAPPED UP/OCCLUDED
AND A LONG FRONT EXTENDING SOUTH. THE LOW HAS DEVELOPED TO AROUND
960MB OVERNIGHT AND WILL MOVE INTO THE EASTERN GULF THROUGH THE
AFTERNOON. PRESSURE HAS BEEN FALLING QUICKLY (2-4MB PER HOUR) AT
NORTH NOMAD BUOY 46184 WHICH THE LOW IS HEADING TOWARD.

THE SOUTHERN PANHANDLE ALREADY HAS CLOUDS ASSOC WITH THE LARGE
FRONTAL BAND EXTENDING FROM THE LOW EARLY THIS MORNING AND WILL
SEE RAIN MOVING IN IN THE NEXT COUPLE HOURS. SELY WINDS WILL
INCREASE THROUGH THE MORNING AS WELL. WIDESPREAD STORM FORCE WINDS
WILL BE FELT OVER THE OUTSIDE WATERS AND NEAR THE OCEAN ENTRANCES.
HAVE CONTINUED WITH THE HIGH WIND WARNING FOR PRINCE OF WALES
ISLAND WHERE WIND GUSTS OF 60MPH ARE EXPECTED...NAMELY IN
HYDABURG. HAVE LIMITED WIND GUSTS TO 55 MPH FOR SITKA AND ELFIN
COVE AS THOSE TOWNS SPECIFICALLY ARE BLOCKED FROM THE EAST. THE
CENTRAL PANHANDLE WILL SEE GUSTS OF 35-45MPH LATE THIS AFTERNOON
AND EVENING...STRONGEST WINDS WILL BE OUT OF THE EAST SUCH AS ON
THE SOUTH SIDE OF DOUGLAS ISLAND. WIND WILL INCREASE OUT OF THE
NORTH THROUGH THE NORTHERN INNER CHANNELS (LYNN CANAL/GLACIER BAY)
THIS MORNING THEN EASE TONIGHT BEFORE FLIPPING SOUTH AND
INCREASING AGAIN BY MORNING. BY THIS TIME THE LOW CENTER WILL BE
JUST SOUTH OF YAKUTAT. EXPECT THIS TO CAUSE WINDS TO INCREASE OUT
OF INTERIOR PASSES NEAR YAKUTAT AND DOWN THE CHILKAT VALLEY.

STILL SOME VARIATION BETWEEN MODELS ON LOW PLACEMENT AND STRENGTH
AS IT MOVES INTO THE GULF. THE LATEST ECMWF SHIFTED THE LOW CENTER
EAST CLOSER TO THE GFS/NAM WITH THE CANADIAN REGIONAL MODEL IN
BETWEEN. FROM THIS A CONSENSUS PRESSURE WAS MADE WHICH ALSO
SHIFTED THE OFFICIAL FORECAST EAST BUT NOT QUITE AS DEEP. DUE TO
THE MODEL SPREAD FORECAST CONFIDENCE ON SPECIFICS WITH THE LOW IS
SLIGHTLY BELOW NORMAL. CONFIDENCE IS ABOVE NORMAL FOR RAIN
DEVELOPING FROM SOUTH TO NORTH THROUGH THE DAY AND BECOMING HEAVY
AT TIMES.

.LONG TERM...FAIRLY QUIET LONG TERM PERIOD WITH MOSTLY S TO W FLOW
OVER THE PANHANDLE FOR THE NEXT WEEK. THIS IS COURTESY OF A MEAN
500 MB LONG WAVE TROUGH THAT IS SITUATED OVER WESTERN ALASKA.
THERE ARE SOME FLUCTUATIONS IN ITS STRUCTURE AS VARIOUS SHORT
WAVES MOVE AROUND IT BUT IT MOSTLY STAYS PUT THROUGH MOST OF THE
NEXT WEEK.

AT THE SURFACE ONSHORE FLOW WITH SHOWERS WILL BE THE MAINSTAY
THROUGH AT LEAST MID WEEK. SOME SMALL CRAFT WINDS WILL STILL BE AN
ISSUE IN THE GULF AND NORTHERN LYNN CANAL FOR MON AND MON NIGHT
DUE TO LINGERING AFFECTS FROM SUNDAY'S LOW BUT THOSE WILL BE ON A
GRADUALLY DIMINISHING TREND AS NO ORGANIZED STRONG SYSTEMS ARE
EXPECTED THROUGH WED NIGHT. SUNDAY'S LOW HAS ALSO DRAWN DOWN SOME
COOLER AIR FROM THE BERING SEA IN ITS WAKE CAUSING THE ATMOSPHERE
ABOVE THE WARM GULF TO BECOME MORE UNSTABLE. THIS COMBINED WITH
SOME UPPER LEVEL VORTICITY MOVING THROUGH HAS CAUSED ME TO ADD
SOME SLIGHT CHANCE OF THUNDERSTORMS INTO THE GULF AND OUTER COAST
LAND AREAS FOR MON INTO TUE. WHILE MOST OF THE GULF COULD SEE SOME
LIGHTNING THE COASTAL AREAS ARE THE MOST LIKELY PLACES THAT IT
COULD OCCUR AS INTERACTIONS WITH TERRAIN ENHANCE THE STRONGER
SHOWERS.

FORECAST GETS A BIT MORE MURKY FROM MID WEEK ON AS A NEW PIECE OF
UPPER LEVEL ENERGY ROUNDS THE BASE OF THE MEAN TROUGH. DIVING SE
FROM THE CENTRAL ALEUTIANS IT WILL EVENTUALLY FORM AN UPPER LOW
AROUND 40N 155W. INITIALLY THE LOW WILL DRAW A FEW PIECES OF
ENERGY WESTWARD KEEPING THE PANHANDLE DRIER AS THE LOW AND TROUGH
START TILTING MORE NEGATIVELY THROUGH LATE WEEK. HOWEVER, BY THE
WEEKEND THAT TROUGH WILL BE MOVING THROUGH THE PANHANDLE BRINGING
MORE RAIN AND SOME WIND.

INITIALLY THE 0Z GFS WAS SHOWING THIS UPPER LOW HAVING LESS OF AN
EFFECT AND BRINGING A MODERATE STRENGTH SYSTEM INTO THE CENTRAL
GULF BY THU (THIS SOLUTION WAS NOT SUPPORTED BY ANY OTHER MODEL
AND EVEN IT'S OWN ENSEMBLE MEAN DID NOT AGREE WITH THIS.). THIS
HAS CHANGED WITH THE 6Z RUN WHICH NOW SHOWS THE SYSTEM HEADING
INTO THE SW GULF MUCH LIKE THE ECMWF AND CANADIAN MODELS WERE
SUGGESTING. WE WILL NOT BE COMPLETELY DRY HOWEVER, AS THEY ARE
STILL SUGGESTING THAT SOME PARTS OF THE FRONT FROM THIS SYSTEM
WILL AFFECT THE NORTHERN GULF THU WITH SOME SMALL CRAFT WINDS OR
EVEN GALES. MODEL SPREAD IS EVEN MORE SEVERE FOR THE WEEKEND AS
THE TROUGH MOVES THROUGH AFFECTING TIMING AND STRENGTH. SO DID NOT
CHANGE THE WEEKEND FORECAST TO AWAIT FUTURE MODEL RUNS.

&&

.AVIATION...WITH THE STORM FORCE LOW MOVING THROUGH THE GULF
AVIATION WEATHER WILL BE RATHER BUMPY TODAY AND TONIGHT. PLENTY OF
WIND SHEAR TO DEAL WITH AS MOST OF THE PANHANDLE WILL SEE 50 TO 70
KT WINDS AS FAR DOWN AS 2000 FT PARTICULARLY IN THE SOUTHERN
PANHANDLE AND ALONG THE OUTER COAST. THESE WINDS WILL DIMINISH SUN
NIGHT INTO MON AS THE LOW WEAKENS AND MOVES TOWARD THE NORTHERN
GULF COAST.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM 1 PM AKDT THIS AFTERNOON THROUGH LATE TONIGHT
     FOR AKZ026.
         HIGH WIND WARNING FROM 10 AM THIS MORNING TO 7 PM AKDT THIS
     EVENING FOR AKZ027.
         STRONG WIND UNTIL 10 AM AKDT THIS MORNING FOR AKZ027.
         STRONG WIND FROM THIS EVENING THROUGH LATE TONIGHT FOR AKZ027.
         STRONG WIND FROM 4 PM AKDT THIS AFTERNOON THROUGH LATE TONIGHT
     FOR AKZ025.
         STRONG WIND FROM 10 AM AKDT THIS MORNING THROUGH MONDAY MORNING
     FOR AKZ022-023.
         STRONG WIND FROM 10 AM AKDT THIS MORNING THROUGH THIS EVENING
     FOR AKZ028.
         STRONG WIND FROM THIS EVENING THROUGH MONDAY MORNING FOR AKZ017.
MARINE...STORM WARNING FOR PKZ022-036-041>043.
         GALE WARNING FOR PKZ021-031-033>035-051.
         SMALL CRAFT ADVISORY FOR PKZ011>013-032-052-053.

&&

EAL/FERRIN

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