Small Craft Advisory 706, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
349 PM AKST FRI NOV 23 2012

.SHORT TERM...THE STORM SYSTEM THAT CAUSED HIGH WINDS OVER
PORTIONS OF THE PANHANDLE YESTERDAY REMAINS OVER THE EASTERN
CENTRAL GULF AND IS STILL A POTENT LOW. ALTHOUGH THE SYSTEM IS
BEGINNING TO WEAKEN, IT IS ALSO BEGINNING TO DRIFT EAST TOWARDS
THE OUTER COAST. END RESULT IS THAT, ALTHOUGH THERE ARE NO HIGH
WIND WARNING AND ONLY A FEW STRONG WIND HEADLINES IN THE
AFTERNOON FORECAST, A SIGNIFICANT OFFSHORE PRESSURE GRADIENT
REMAINS BETWEEN THE LOW IN THE GULF AND HIGH PRESSURE OVER
WESTERN CANADA. GALE WARNINGS REMAIN FOR MOST OF THE INNER
CHANNELS TONIGHT AS WELL AS THE OUTER COAST FROM THE DIXON
ENTRANCE TO CAPE FAIRWEATHER

ONCE THE LOW DRIFTS EAST OVER LAND AND FILLS MORE QUICKLY,
SOMEWHERE NEAR CAPE DECISION TOMORROW LATE AFTERNOON, AN INVERTED
TROUGH WILL SET UP OFF THE OUTER COAST, BUT THE OFFSHORE PRESSURE
GRADIENT WILL WEAKEN SIGNIFICANTLY AND WIND SPEEDS WILL DIMINISH
BY ONE CATEGORY OR MORE...ESPECIALLY OVER THE SOUTHERN PANHANDLE.

LOW LEVEL AIR TEMPS REFLECTING A FAIR SHOT OF WARM AIR ADVECTION
ASSOCIATED WITH THE FRONT AND VERY LITTLE DIURNAL TEMPERATURE
VARIATION WAS SEEN TODAY. TEMPS REMAINING LOW ENOUGH TO SUPPORT
SNOW AS FAR SOUTH AS FREDERICK SOUND. AS WITH YESTERDAY, SNOW
AMOUNTS TOTALING TO 3 INCHES OR LESS TONIGHT AND TOMORROW WITH
MOST OF THE SHOWER ACTIVITY REMAINING SOUTH OF ICY STRAIT.

USED NAM FOR PRESSURE. WIND BASED ON NAM BUT STRONGER OVER THE
GULF BY 3 TO 7 KTS. BLENDED GFS, ECMWF, AND GEM FOR POP AND QPF
BUT ADJUSTS THOSE FIELDS TO ACCOUNT FOR WIND AFFECT. TEMPS
ADJUSTED USING BIAS CORRECTED NAM AND SREF. SNOW LEVELS NUDGED
USING GFS. FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...CHANGES TO THE PACKAGE ARE SMALL. CONFIDENCE IS
AVERAGE.

THE LOW IN THE EASTERN GULF IS DISCUSSED IN THE SHORT RANGE
SECTION ABOVE. THE REMAINS OF THIS LOW WILL REDEVELOP ABOUT ABOUT
100 NM NE OF KETCHIKAN 12Z SUN AND DRIFT AWAY TO THE EAST.

AT 00Z MON AND 500H: SPLIT IN LARGE-SCALE FLOW WILL BE COMING
TOGETHER OVER N GULF COAST AND CENTRAL PANHANDLE. BRANCH FROM
THE NNW FROM THE ARCTIC OCEAN ENTRANCE TO ONSHORE THE N AK COAST
E OF BARROW.

THE BRANCH FROM THE SW INCLUDES A 500N RIDGE THAT AT THAT TIME
WILL EXTEND FROM THE NW ABOUT 200 NM SW OF THE PANHANDLE TOWARD
COL ABOUT 100 NM S OF SEWARD.

12Z WED IS THE BEGINNING OF A STRONGER ARCTIC OUTBREAK AND THOSE
ORIGINAL BRANCHES WILL PROVIDE THE DEEPER ARCTIC AIRMASS AND THE
SW BRANCH WILL BECOME ASSOCIATED WITH THE LOWS S OF THE GULF THAT
WILL ENHANCE THE N WIND OUTFLOW IN THE BOUNDARY LAYER.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL MIDNIGHT AKST TONIGHT FOR AKZ027.
         STRONG WIND UNTIL 6 PM AKST THIS EVENING FOR AKZ020-022-023.
         STRONG WIND THROUGH SATURDAY AFTERNOON FOR AKZ019.
         STRONG WIND THROUGH SATURDAY AFTERNOON FOR AKZ018.
MARINE...GALE WARNING FOR PKZ011>013-021-022-031>036-041>043-051.
         SMALL CRAFT ADVISORY FOR PKZ052.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ053.

&&

FRITSCH/JBT