Gale Warning 80, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
239 PM AKST FRI FEB 5 2016

.SHORT TERM...QUIETER WEATHER DAY ACROSS SOUTHEAST ALASKA TODAY.
CONVECTIVE ENVIRONMENT IS VERY EVIDENT ON SATELLITE EARLY THIS
AFTERNOON WITH NUMEROUS CELLS OVER THE GULF OF ALASKA. THERE WERE
EVEN A FEW LIGHTNING STRIKES AND REPORTS OF PELLETS EARLIER THIS
MORNING. THESE SHOWERS ARE ASSOCIATED WITH A TROUGH THAT WILL LIFT
OVER THE PANHANDLE TONIGHT. THE WEAK RIDGE OF HIGH PRESSURE WILL
SHARPEN ON SATURDAY IN RESPONSE TO AN APPROACHING GALE FORCE FRONT
THAT WILL BE JUST SOUTH OF THE AREA AT THE END OF THE SHORT TERM
SECTION ON SATURDAY AFTERNOON.

BREAKS IN THE CLOUD COVER ARE SEEN ON WEBCAMS AND SATELLITE
IMAGERY EARLY THIS AFTERNOON WITH A LULL IN THE SHOWER ACTIVITY.
HAVE INCLUDED PATCHY FOG THIS EVENING FOR MANY INLAND LOCATIONS AS
THERE REMAINS AMPLE LOW LEVEL MOISTURE AND RELATIVELY LIGHT
WINDS. CLOUD COVER AND SHOWER COVERAGE WILL INCREASE LATER THIS
EVENING AND OVERNIGHT AHEAD OF THE TROUGH. WITH SOME COOLER AIR
ALOFT RESIDING OVER THE PANHANDLE EXPECT WE WILL SEE SOME SNOW MIX
IN AT SEA LEVEL FOR PORTIONS OF THE CENTRAL AND NORTHERN INNER
CHANNELS. HOWEVER, DO NOT EXPECT ANYTHING MORE THAN AN INCH OR TWO
DUE TO LOW QPF AMOUNTS AND A STILL RELATIVELY WARM BOUNDARY LAYER.
SHOWER ACTIVITY WILL BE ON THE DECREASING TREND THROUGH SATURDAY
AND ESPECIALLY DURING THE AFTERNOON AS FLOW BEGINS TO TURN MORE
EASTERLY WITH THE INFLUENCE OF THE APPROACHING FRONT TO THE SOUTH.
THE SHARPENING RIDGE WILL RESULT IN 15-20 KT SOUTHERLIES THROUGH
THE INNER CHANNELS ON SATURDAY BUT DO NOT FORSEE ANY SIGNIFICANT
WIND THROUGH THE TIMEFRAME.

USED THE 12Z NAM FOR UPDATES TO THE INHERITED FORECAST.

.LONG TERM...IMPRESSIVE UPPER DISTURBANCE WAS OBSERVED IN WV
IMAGERY OVER THE NCNTRL PAC FRI AFTERNOON. THIS FEATURE IS
FORECAST TO EVOLVE INTO A DEEP-LAYER CYCLONE BY SAT...AT WHICH
POINT IT WILL MOVE N TOWARD KODIAK ISLAND THROUGH SUN. AS THIS
TAKES PLACE...A GALE FORCE FRONT WILL PROGRESS TO COASTAL PORTIONS
OF SERN AK. IN ADDITION TO HAZARDOUS MARINE WINDS...SELY GUSTS
FROM 40-50 MPH WILL BE POSSIBLE FOR COASTAL COMMUNITIES...AS WELL
AS THE KETCHIKAN AREA.

A MOIST AIRMASS /PW VALUES FROM 0.5 TO 0.7 INCH/ WILL SPREAD N
TOWARD THE SRN PANHANDLE WITH THE FRONT...AND PERSIST THROUGH AT
LEAST MON NIGHT. THIS WILL FAVOR PERIODS OF HEAVY RAIN FOR SRN
AREAS...AND POTENTIALLY WET HEAVY SNOW OVER HYDER SUN-SUN NIGHT.
HOWEVER...DUE TO UNCERTAINTY IN LOW-LEVEL TEMPERATURE
PROFILES...CONFIDENCE IS NOT HIGH ENOUGH ATTM FOR WINTER STORM
WATCH ISSUANCE.

AN UPPER-LEVEL RIDGE BUILDING NNW WILL TEMPORARILY SHUT DOWN THE
WET WEATHER DURING PART OF TUE...BUT THIS BREAK WILL QUICKLY BE
FOLLOWED BY ANOTHER FRONTAL SYSTEM TUE NIGHT/WED. WARM AIRMASS
WILL SPREAD N WITH THIS SYSTEM...WITH MILD TEMPERATURES EXPECTED
TO PERSIST OVER THE REGION THROUGH THE REMAINDER OF THE LONG TERM
PERIOD.

PRESSURE GRIDS WERE UPDATED WITH AN ECMWF/NAM/GFS/INHERITED BLEND
THROUGH 00Z TUE...FOLLOWED BY WPC THEREAFTER. REMAINDER OF THE
LONG TERM FORECAST WAS ALSO REFRESHED WITH ENSEMBLE GUIDANCE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ031-043-052.
     SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-041-042-051-053.
&&

TPS/GARNER

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