Small Craft Advisory 330, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
344 PM AKDT WED MAY 4 2011

.SHORT TERM...SATELLITE IMAGERY SHOWS A WEAKENING LOW IN THE
EASTERN GULF SLOWLY DRIFTING NORTH WITH ITS OCCLUDED FRONT
WRAPPING AROUND THE LOW. THE LEADING EDGE OF THE FRONTAL BOUNDARY
APPROACHES THE SOUTHERN PANHANDLE COASTAL SECTIONS HAS BROUGHT UP
GUSTY SOUTHEAST WINDS UP TO 30 KNOTS. STEADY RAIN PREVAILS MOST
OF THE FORECAST DOMAIN WITH OCCASIONAL MODERATE RAINFALL OVER THE
SOUTHERN AREAS. WINDS OVER THE MARINE ZONES ARE QUITE STRONG WITH
GALE FORCE WINDS OVER CLARENCE STRAIT AND SOUTHERN OUTER WATERS
WITH SMALL CRAFT WINDS FOR THE REST OF OUTSIDE WATERS...CROSS
SOUND AND OCEAN ENTRANCES.

MODELS ARE IN GENERAL AGREEMENT WITH THE NAM APPEARS THE BEST ON
HANDLING THE LOW IN THE EASTERN. THE WEAKENING LOW IN THE EASTERN
GULF WILL BECOME A TROUGH AS IT MOVES ONSHORE THE PANHANDLE BY
EARLY THURSDAY MORNING. THE OCCLUDED FRONT WILL MOVE ONSHORE THE
PANHANDLE TONIGHT THEN WEAKEN AND SHEAR APART THROUGH THURSDAY
EVENING. BEFORE THE LOW BECOMES A TROUGH...THE LOW WILL SLOWLY
DRIFT NORTH AND EASTERLY LOW LEVEL FLOW WILL INCREASE ACROSS THE
NORTHERN PANHANDLE WITH SMALL CRAFT WINDS ACROSS THE NORTH CENTRAL
INNER CHANNELS THIS EVENING. ALONG THE APPROACHING FRONTAL
BOUNDARY...GALE FORCE WINDS WILL CONTINUE OVER THE SOUTHERN
COASTAL WATERS THIS EVENING...BEFORE DECREASING TO SMALL CRAFT
LATER TONIGHT. ROUGH SEAS WILL LIKELY TO CONTINUE ACROSS THE
OUTSIDE WATERS ON THURSDAY.

THE FRONT WILL CONTINUE WEAKEN AS IT MOVES ONSHORE THE PANHANDLE
WITH LIKELY TO CATEGORICAL POPS FOR TONIGHT AND THURSDAY MORNING.
THEN THE FRONT WILL FURTHER WEAKEN EARLY THURSDAY AFTERNOON AND
SHEAR APART OVER THE CENTRAL PANHANDLE LATE IN THE AFTERNOON INTO
EARLY EVENING HOURS. THIS WILL LEAVE NORTHERN MOST AREAS FROM
HAINES TO SKAGWAY UNDER HIGHER POPS...AND TO THE SOUTH FROM
KETCHIKAN AND HYDER ZONES WITH CATEGORICAL POPS THROUGH THE LATE
AFTERNOON HOURS. GUSTY FRONTAL WINDS WILL SLOWLY DIMINISH THIS
EVENING AS THE LOW LEVEL JET WEAKENS EARLY THIS EVENING.

.LONG TERM...CHANGES TO THE LONG RANGE PACKAGE ARE SMALL, INCLUDING
THAT MOTHERS DAY ON SUNDAY IS TO BE MOSTLY CLOUDY BUT GEN DRY.

THE COMPUTER GRAPHICS SYSTEM HAS EXPERIENCED TECHNICAL DIFFICULTIES
THAT HAVE LIMITED THE PREPARATION TIME FOR THIS PRODUCT. THE
FORECAST PRODUCTS HAVE BEEN PRODUCED AND THE DIFFICULTIES ARE NOW
BELIEVED TO BE FIXED.

MODEL CONSENSUS FOR THE WEEKEND IS NOT IMPROVING. BETWEEN THE
ECMWF AND GFS, A SIGNIFICANT BREAKDOWN FOR CENTRAL GULF MSLP
FIELDS IS IN PLACE AT 06Z SUN. THE MOST RECENT RUNS OF EC AND
UKMET HAVE A CONSENSUS THROUGH 12Z SAT AND WERE BOTH USED. EC WAS
USED AS PRIMARY GUIDANCE THROUGH 06Z SUN, WITH THE GEFS VIA HPC
USED AS THE PRIMARY GUIDANCE THEREAFTER.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ036.
         SMALL CRAFT ADVISORY FOR PKZ021-022-032>035-041>043.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

AHN/JBT