Small Craft Advisory 99, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
251 PM AKST WED JAN 27 2016

.SHORT TERM...A RATHER STRONG LOW PRESSURE SYSTEM MOVING INTO THE
NORTH CENTRAL GULF ON THURSDAY WILL BE THE MAIN WEATHER MAKER OVER
THE NEXT 24 HOURS. THE ASSOCIATED WEATHER FRONT PUSHED ACROSS THE
PANHANDLE TODAY AND LED TO ANOTHER ROUND OF GUSTY WINDS AND
MODERATE RAINFALL. THE ONLY SUBFREEZING AIR IN SOUTHEAST ALASKA
REMAINS OVER THE HIGHEST ELEVATIONS OF THE KLONDIKE HIGHWAY. THE
WINTER WEATHER ADVISORY REMAINS IN EFFECT THROUGH 9 PM WITH AN
ADDITIONAL 2-4 INCHES THIS EVENING.

THERE WAS VERY LITTLE CHANGE TO THE PREVIOUS FORECAST. WINDS WILL
GRADUALLY DIMINISH THROUGH THURSDAY AFTERNOON AS THE PRESSURE
GRADIENT BEGINS TO RELAX. MOIST DEEP LAYER ONSHORE FLOW WILL
RESULT IN CONTINUED HIGH PRECIPITATION CHANCES AND UNSEASONABLY
WARM TEMPERATURES. SEAS OVER THE GULF ARE CURRENTLY IN THE 20-25
FT RANGE WITH GUSTY WINDS AND A SW SWELL. AS WINDS DIMINISH
THROUGH THE PERIOD EXPECT SEAS TO FALL TO 16-20 FT BY LATE
THURSDAY AFTERNOON.

USED THE 12Z NAM FOR UPDATES TO THE INHERITED FORECAST. VERY
FORECASTER CONFIDENCE IS ABOVE AVERAGE.

.LONG TERM...RATHER QUIET EXTENDED RANGE FORECAST PERIOD. SHOWER
ACTIVITY IN THE SHORT RANGE WILL CONTINUE INTO THE EXTENDED
PERIOD BUT BEGIN DIMINISHING IN EARNEST FRIDAY NIGHT WITH SOME
SHOWER ACTIVITY LINGERING ALONG THE OUTER COAST THROUGH SATURDAY
EVENING. AT THAT TIME, A SHARP SURFACE RIDGE WILL SHIFT EAST,
PRODUCING NORTHWESTERLY FLOW OVER THE EASTERN GULF. AT THIS SAME
TIME, AN INVERTED TROUGH WILL SET UP OVER THE PANHANDLE. RESULTING
WEAK OFFSHORE FLOW WILL FAVOR DIMINISHING CLOUD COVER FROM NORTH
TO SOUTH. PARTLY CLOUDY TO MOSTLY CLEAR SKIES AND DRY WEATHER ARE
EXPECTED TO LAST INTO NEXT WEEK. LONG RANGE MODEL INDICATING THE
NEXT SIGNIFICANT FRONT WILL NOT ARRIVE ON THE OUTER COAST UNTIL
LATE NEXT WEDNESDAY.

UNSEASONABLY WARM TEMPERATURES WILL FALL SLOWLY BACK TO NORMAL
OVER THE COURSE OF THE UPCOMING WEEK AS A RESULT OF COOLER LOW
LEVEL AIRMASS ADVECTING IN FROM THE WEST AS WELL AS NIGHTTIME
RADIATIONAL COOLING UNDER PARTLY CLOUDY TO MOSTLY CLEAR SKIES AT
NIGHT.

THE EXTENDED RANGE MARINE FORECAST IS MOSTLY DEVOID OF SMALL CRAFT
CONDITIONS AS WELL. EXCEPTIONS TO THIS GENERALIZATION WILL BE AN
AREA OF NORTHWESTERLY SMALL CRAFT WINDS OVER MARINE ZONE 310
FRIDAY MORNING THROUGH SATURDAY MORNING. THE OTHER AREA OF
POTENTIAL SMALL CRAFT WINDS WILL BE NORTHERN LYNN CANAL BEGINNING
SUNDAY AFTERNOON AS THE INVERTED TROUGH RETREATS TO THE SOUTH AND
A STRONGER NORTHERLY PRESSURE GRADIENT BUILDS IN FROM CANADA.

UPDATED PRESSURE AND WINDS THROUGH FRIDAY NIGHT USING A BLEND OF
ECMWF AND CANADIAN NH TO BETTER CAPTURE THE WEAK LOW RESPONSIBLE
FOR NORTHWESTERLY SMALL CRAFT WINDS OVER THE EASTERN GULF EARLY
ON. ALSO REDUCED OVERNIGHT LOWS AND DAYTIME HIGHS TO REFLECT THE
COOLER AIRMASS MOVING IN FROM THE WEST. REMAINDER OF THE FORECAST
ESSENTIALLY UNCHANGED. OVERALL FORECAST CONFIDENCE IS AVERAGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY UNTIL 9 PM AKST THIS EVENING FOR AKZ018.
     STRONG WIND UNTIL 3 PM AKST THIS AFTERNOON FOR AKZ028.
MARINE...GALE WARNING FOR PKZ036-042-043-051-052.
     SMALL CRAFT ADVISORY FOR PKZ021-022-031>035-041-053.
&&

TPS/FRITSCH

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