Gale Warning 362, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
250 PM AKST TUE NOV 25 2014

.SHORT TERM...AFTERNOON SATELLITE IMAGERY REVEALS SCATTERED SHOWERS
CONTINUING TO MOVE ONSHORE. THESE SHOWERS ARE EXPECTED TO DISSIPATE
THIS EVENING AS COOLER AND DRIER AIR FILTER IN FROM THE NORTH AS AN
AREA OF HIGH PRESSURE OVER YUKON BUILDS SOUTH TOWARDS THE
PANHANDLE. CLOUDS WILL ALSO BE DECREASING OVERNIGHT. MOSTLY CLEAR
SKIES ARE EXPECTED ACROSS THE NORTHERN PANHANDLE, WHILE SOME CLOUDS
WILL LINGER OVER THE SOUTHERN PANHANDLE. WITH REMNANT LOW-LEVEL
MOISTURE, LIGHT AND VARIABLE WINDS TONIGHT, DO EXPECT PATCHY FOG TO
FORM OVER PART OF THE PANHANDLE INCLUDING JUNEAU, PETERSBURG,
WRANGELL, ANGOON, HOONAH, GUSTAVUS, AND ELFIN COVE. MOSTLY SUNNY
SKIES WILL BE FOUND ACROSS THE PANHANDLE ON WEDNESDAY.

 AS THE YUKON HIGH BUILDS IN OVERNIGHT, WINDS WILL SHIFT TO THE
NORTH AND INCREASE DURING THE DAY ON WEDNESDAY AS THE NORTH-SOUTH
PRESSURE GRADIENT TIGHTENS. NORTHERLY GALE FORCE WIND IS EXPECTED
IN NORTHERN LYNN CANAL. STRONG WIND GUSTS TO 40 MPH WILL DEVELOP IN
SKAGWAY AREA BY WEDNESDAY AFTERNOON. LOCALLY WINDY CONDITIONS WILL
ALSO DEVELOP NEAR DOWNTOWN JUNEAU AND DOUGLAS AREA STARTING
WEDNESDAY AFTERNOON. STRONGER OUTFLOW WINDS WILL DEVELOP OUT OF
MOUNTAIN PASSES. BEYOND THE SHORT TERM PERIOD, WINDS WILL CONTINUE
TO INCREASE ACROSS THE PANHANDLE.

 WITH MOSTLY CLEAR SKIES, OVERNIGHT LOW TEMPERATURES FOR YAKUTAT
AREA WILL DIP TO THE LOW 20S. THE LOW TEMPERATURES IN SKAGWAY WILL
REMAIN IN THE LOW 30S, AS NORTHEASTERLY WIND WILL LEAD TO DOWNSLOPE
COMPRESSIONAL WARMING FOR THE AREA. FOR THE REST OF THE PANHANDLE,
DO EXPECT LOWS TO BE IN THE LOW TO MID 30S. FOR WEDNESDAY, HIGHS
WILL RANGE FROM MID 30S IN THE NORTHERN PANHANDLE, TO THE MID 40S
IN THE SOUTHERN PANHANDLE. APPROXIMATELY AVERAGE HIGH TEMPERATURES
WILL PERSIST OM WEDNESDAY.

 FORECAST CONFIDENCE IS ABOVE NORMAL. NUMERICAL MODELS ARE ALL
SUGGESTING A BUILDING HIGH FROM YUKON INTO THE PANHANDLE THROUGH
WEDNESDAY. UTILIZED A BLEND OF GEM/NAM WHEN REFRESHING THE
INHERITED GRIDS.

.LONG TERM...DRYING TREND FROM LATE WEDNESDAY ONWARD WILL BE
ACCOMPANIED BY AN ARCTIC FRONT AND STRONG WINDS IN MANY AREAS
THROUGH THURSDAY. COLDEST TEMPERATURES OF THE SEASON THUS FAR ARE
LIKELY BY LATE THURSDAY AREA-WIDE...BUT ATMOSPHERE WILL BE
RELATIVELY DRY DUE TO NORTHERLY/NORTHEASTERLY FLOW DOMINATING
BEGINNING LATE WEDNESDAY. STRONG CROSS-BARRIER OUTFLOW WINDS ARE
LIKELY FOR THE CENTRAL/NORTHERN FAVORED AREAS. AT THIS POINT
EXPECT MOSTLY BORA CONDITIONS IN THE TAKU-EXPOSED AREAS WITHOUT A
WELL-DEFINED CRITICAL LEVEL AT THIS POINT ON THE MODELS...AND
THIS MIGHT LIMIT THE MAXIMUM WINDS AND PREVENT SIGNIFICANT LOW-
LEVEL ACCELERATION AND WIND SHEAR. EVEN SO...WE ISSUED A HIGH WIND
WATCH FOR POTENTIAL OF LOCAL GUSTS UP TO 60MPH+ IN THE JUNEAU
ZONE FOR WEDNESDAY NIGHT AND THURSDAY, AND FOR STRONG WINDS IN THE
SKAGWAY AREA. GUSTS FOR EXPOSED AREAS MAY EXCEED 40 MPH IN THE
LATTER ZONE. FOR MARINE ZONES...FREEZING SPRAY MAY BE A PROBLEM
DEPENDING ON HOW COLD THE OFFSHORE AIR MASS ENDS UP...WATER
TEMPERATURES STILL IN MID-40S...WILL NEED TO MONITOR THIS. GUSTS
WILL GENERALLY BE LOWER FOR SOUTHERN AREAS ALTHOUGH THE ENTIRE
PANHANDLE WILL BE POST-FRONTAL BY WED EVENING. AT THIS POINT WE
HAVE SEVERAL GALES ANTICIPATED FOR NORTHERN CHANNELS AND STORM-
FORCE WINDS IN THE FORECAST FOR NORTHERN LYNN FOR WED NIGHT AND
THURSDAY...DEBATED ON THIS AND DECIDED THAT GRADIENTS MAY END UP
EVEN STRONGER THAN THE STRONG VALUES PREDICTED BY THE MODELS. THE
VALUE IS CURRENTLY 10MB FOR SKAGWAY- JUNEAU ON THE NAM12 AND 12MB
FOR JUNEAU- KETCHIKAN. OUTFLOW GUSTS TO 50-60MPH FROM THE TYPICAL
PASSES ADJACENT TO COMMUNITIES AND INNER CHANNELS WERE MENTIONED
IN ZONES.

TEMPERATURES WILL DROP OFF NORTH-TO-SOUTH LATE WED BUT WED-THURS NIGHT
LOWS WILL DEPEND HEAVILY ON LOCAL WINDS. TEMPERATURES IN THE
SINGLE DIGITS ARE POSSIBLE FOR FRI NIGHT OVER MANY AREAS IN THE
CENTRAL/NORTHERN PANHANDLE. UTILIZED NAM/EC GUIDANCE FOR DAYS 3-5
FOR SOME MINOR TWEAKS TO WINDS AND THERMAL FIELDS AND FOR QPF
UPDATES. AFTER THAT POINT MERGED TO WPC GUIDANCE FOR THE EXTENDED.
THE MODELS CONTINUE TO DIVERGE FROM LATE WEEKEND INTO EARLY NEXT
WEEK SO CONFIDENCE IN THE FIRST POST- COLD MOISTURE FIELDS IS LOW.
THE EC FOR EXAMPLE HAS SNOW MOVING IN LATE SUNDAY FOR THE NORTHERN
PANHANDLE BUT THE GFS NOW DELAYS THIS UNTIL MON- TUES. IT IS LIKELY
THAT MOISTURE WILL RETURN DURING EARLY WEEK AS LOW-LEVEL
TEMPERATURES BEGIN TO MODIFY BEGINNING OVER THE WEEKEND. MODEL
CONFIDENCE IS GENERALLY ABOVE AVERAGE FOR THE SYNOPTIC FLOWS
THROUGH THE WEEKEND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
     EVENING FOR AKZ025.
         STRONG WIND WEDNESDAY AFTERNOON FOR AKZ018.
MARINE...GALE WARNING FOR PKZ012.
         SMALL CRAFT ADVISORY FOR PKZ011-013-022-031-036-051-053.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041.

&&

RCL/WESLEY

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