Gale Warning 493, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
325 PM AKST THU DEC 8 2011

.SHORT TERM...THE LATEST SATELLITE SHOWS A WEATHER FRONT OVER
THE CENTRAL GULF WHICH IS SLOWLY DRIFTING TO THE EAST. THE
SURFACE RIDGE OVER THE SE AK THIS AFTERNOON WILL CONTINUE TO KEEP
SOUTH WINDS OVER THE FORECAST AREA THAT WILL KEEP MOST LAND
STATIONS ABOVE FREEZING. THE UPPER RIDGE WILL CONTINUE TO SLOWLY
DRIFT TO THE EAST WITH VERY STABLE CONDITIONS ACROSS THE AREA.
LIGHT RAIN WITH SOME DRIZZLE OVER THE SOUTHERN AREAS WILL PERSIST
THROUGH TONIGHT AS THE DEEP MOIST ONSHORE FLOW CONTINUES. THE
COLD FRONT WILL SLOWLY DRIFT THROUGH THE PANHANDLE FROM NW TO SE
FRIDAY. THE FRONT WILL BE OVER THE SOUTHERN THIRD OF THE FORECAST
AREA BY FRIDAY AFTERNOON WITH RAIN BECOMING SHOWERS BEHIND THE
FRONT. TEMPS WILL REMAIN STEADY ACROSS THE FORECAST AREA AND WILL
RANGE FROM THE MID 30S TO LOWER 40S. THERE IS SOME COLD AIR STILL
ALONG THE KLONDIKE HIGHWAY AND THEY HAVE RECEIVED ABOUT 3 INCHES
SO FAR TODAY. AS THE FRONT MOVES OVER THE AREA THE PRECIP RATES
WILL INCREASE AND 4 TO 6 INCHES WILL FALL OVER NIGHT WITH AN
ADDITIONAL 3 THROUGH FRI SO THE WINTER WEATHER ADVY IS STILL IN
EFFECT UNTIL NOON ON FRI. THE VISIBILITIES ARE VERY POOR DUE TO
FOG AND BLOWING SNOW...THESE CONDITIONS WILL CONTINUE THROUGH
TONIGHT.

 WIND WISE...THE SHARPING SURFACE RIDGE OVER THE INNER CHANNELS
IS PRODUCING STRONG WIND GUST OVER THE FAR NORTHERN INNER
CHANNELS AND OVER THE LYNN CANAL. THESE STRONG WINDS WILL
CONTINUE INTO FRI MORNING AS THE RIDGE WILL WEAKEN A THE FRONT
MOVES EAST OF THE AREA. THE WINDS OVER THE REST OF THE INNER
CHANNELS WILL REMAIN TO BE ON THE WINDIER SIDE AS THE FRONT
APPROACHES WITH SMALL CRAFT WINDS AND LOCALLY WINDY CONDITIONS
OVER LAND AREAS. THE WINDS OVER THE GULF WILL MIN SMALL CRAFT
WITH SEA HEIGHTS BUILDING TO 13 FT LATE TONIGHT.

&&

.LONG TERM...MODELS ARE IN GENERAL AGREEMENT WITH A MEAN UPPER
LEVEL SHORTWAVE TROUGH MOVES INTO THE EASTERN GULF ON FRIDAY NIGHT
AND DRIFTS EAST ACROSS SOUTHEAST ALASKA ON SATURDAY. AN UPPER
LEVEL RIDGE REBUILDING ACROSS THE GULF BEHIND THE TROUGH ON
SATURDAY NIGHT WILL BECOME A DOMINANT FEATURE THROUGH SUNDAY
NIGHT. THE ECMWF SOLUTIONS APPEAR TO BE MOST REPRESENTATIVE FOR
THE TRANSITION AND BEING USED TO REFRESH THE INHERITED FORECAST
PACKAGE THROUGH LATE SUNDAY. THE TRAILING EDGE OF EXITING FRONTAL
PASSAGE WILL REMAIN ACROSS THE SOUTHERN PANHANDLE THROUGH FRIDAY
NIGHT. WITH WARM AIR DOMINATING THE AREA...CATEGORICAL POPS FOR
RAIN WILL SLOWLY DIMINISH OVERNIGHT FRIDAY NIGHT ACROSS THE
SOUTHERN ZONES. AS THE RIDGE BUILDING ACROSS THE FORECAST
DOMAIN...GENERALLY DRY WEATHER IS EXPECTED THROUGH SATURDAY NIGHT
WITH COLDER TEMPERATURES. THE LEADING EDGE OF THE NEXT FRONTAL
PASSAGE WILL ARRIVE YAKUTAT AREA LATE SATURDAY NIGHT THEN QUICKLY
SPREAD SOUTHEASTWARD OVER ENTIRE SOUTHEAST ALASKA THROUGH SUNDAY
NIGHT. A DEVELOPING LOW ACROSS THE NORTHERN GULF OVER THE WEEKEND
AND THE EXITING RIDGE WILL GENERATE TIGHT EASTERLY PRESSURE
GRADIENT. THIS WILL PRODUCE EAST TO SOUTHEAST SMALL CRAFT WINDS
ACROSS THE INNER CHANNELS ON SUNDAY.

 FROM EARLY NEXT WEEK TO THE END OF THE LONG TERM PERIOD...THE
OPERATIONAL GFS AND ECMWF SHOWS RUN TO RUN TIMING AND INTENSITY
DIFFERENCES WITH SMALLER SCALE AND SURFACE SENSIBLE WEATHER
SYSTEMS WHILE STILL SHOWING A FAIR AGREEMENT WITH LARGER SCALE AND
UPPER LEVEL FEATURES. THE ENSEMBLE MEANS ESTABLISHES A BASELINE
FOR THE FORECAST PACKAGE AND THEREFORE...LEANED OVER THE HPC
ENSEMBLE MEAN APPROACH FROM MONDAY THROUGH THURSDAY. WITH BELOW
AVERAGE FORECAST CONFIDENCE...THE FRONT WILL EXIT SOUTHEAST SLOWLY
THROUGH TUESDAY...THEN A NEW DOOR WILL OPEN TO GREET THE NEXT
WEATHER SYSTEM ON THURSDAY. WITH AN EXCEPTION FOR THE NORTHERN
MOST ZONES...RELATIVELY WARM AIR MASS WILL PRIMARILY DOMINATE THE
FORECAST AREA...AND SO THE PRECIPITATION TYPE SHOULD BE RAIN WITH
POSSIBLE SNOW MIX AT NIGHTTIME. SMALL CRAFT SOUTHWESTERLY WINDS
WILL CONTINUE TO AFFECT THE OUTSIDE WATERS THROUGH THE
WEEKEND...AND CONTINUE OVER THE NORTHERN OUTER WATERS UNTIL EARLY
NEXT WEEK. DUE TO PERSISTING SOUTHWEST TO WEST LONG PERIOD
SWELLS...ROUGH SMALL CRAFT SEAS 10 TO 15 FEET WILL PREVAIL ACROSS
THE OUTER WATERS THROUGH EARLY NEXT WEEK.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 3 AM AKST FRIDAY FOR AKZ019.
         STRONG WIND THROUGH FRIDAY MORNING FOR AKZ018.
         WINTER WEATHER ADVISORY UNTIL NOON AKST FRIDAY FOR AKZ018.
MARINE...GALE WARNING FOR PKZ012-013.
         SMALL CRAFT ADVISORY FOR PKZ011-021-022-031>036-041>043-051.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ052.

&&

ABJ/AHN