Small Craft Advisory 362, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
311 PM AKDT SUN JUN 10 2012

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS A WEAKENING LOW
PRESSURE SYSTEM OVER THE CENTRAL GULF THAT WILL DRIFT TO THE WEST
THROUGH MON AND CONTINUE TO WEAKEN. THE ASSOCIATED OCCLUDED FRONT
IS PUSHING OVER THE PANHANDLE THIS AFTERNOON WITH PERIODS OF
LIGHT RAIN OVER THE NORTHERN HALF WITH MORE STEADY RAIN OVER THE
SOUTHERN HALF. WINDS ARE MAINLY ON THE LIGHT SIDE OVER THE INNER
CHANNELS WITH SOME STRONG WINDS WITH THE FRONT ALONG THE SOUTHERN
AND COASTAL AREAS. THERE IS SOME SMALL CRAFT WINDS OVER THE
NORTHEAST AND NORTHERN GULF WITH THE FRONT BUT THOSE WINDS WILL
SLOWLY DIMINISH THROUGH THIS EVENING TO BE LESS THAN 20 KT BY
LATE TONIGHT.

 THE LIGHT RAIN WILL PERSIST OVER MOST OF THE FORECAST AREA
THROUGH TONIGHT WITH THE EXCEPTION TO THE PAYA AND THE FAR
NORTHERN AREAS WILL SEE THE LIGHT RAIN DIMINISH BY LATE TONIGHT.

 AN UPPER LEVEL TROF WITH STRONG UPPER LEVEL DYNAMICS WILL DRIFT
OVER THE FORECAST AREA EARLY MON MORNING AND DRIFT NE INTO CANADA
BY THE AFTERNOON. RAIN WILL BE LIKELY OVER MOST OF THE FORECAST
AREA IN THE MORNING BUT IT WILL DIMINISH AND BECOME MORE SHOWERY
AS THE ATMOSPHERE BECOMES UNSTABLE. SCATTERED TO ISOLATED SHOWERS
WILL MOVE OVER MOST OF THE AREA BY THE AFTERNOON BUT SHOWERS WILL
LINGER OVER THE COAST MOUNTAINS SO AREAS ALONG THE COAST RANGE
WILL SEE MORE SHOWERS THAN AREAS TO THE WEST.

 THE WINDS WILL REMAIN ON THE LIGHT SIDE BUT AS THE HIGH PRESSURE
BUILDS OVER THE PANHANDLE THROUGH MON SOUTHERLY. SO WITH THAT
SAID WINDS WILL INCREASE TO 15 KT OVER MOST OF THE AREA WITH
20 T0 25 KT OVER LYNN CANAL.

 THERE IS ABOUT AVERAGE FORECASTER CONFIDENCE FOR THE NEXT 24HRS
AND USED A BLEND OF THE GFS/EC IN THE SHORT TERM PERIOD.

&&

.LONG TERM...MODELS ARE IN FAIR AGREEMENT THROUGH THE MID WEEK
WITH A NEAR STATIONARY LOW IN THE NORTHERN GULF. THE LOW WILL
CONTINUE TO WEAKEN THROUGH LATE TUESDAY BEFORE BECOMING BROAD BY
EARLY WEDNESDAY. AS THE LOW WEAKENS...A RIDGE OF HIGH PRESSURE
WILL REBUILD ACROSS THE PANHANDLE. USED THE GFS ENSEMBLE MEANS AND
ECMWF BLEND THROUGH THURSDAY AS THEY MADE THE BEST FIT TO THE
SYNOPTIC CONDITIONS.

 BEGINNING ON LATE THURSDAY...MODEL SPREADS BECOME LARGER AND
MODEL SOLUTIONS FOR THE SYNOPTIC PATTERN STRUGGLE. LEANED OVER THE
HPC OUTPUTS FROM LATE THURSDAY ONWARD. THE HPC APPROACH TO THE
MODEL SOLUTION RESULTED USING THE ECMWF AND EC ENSEMBLE WITH
CURRENT AND PREVIOUS GFS RUNS.

 AS THE LOW IN THE NORTHERN GULF WEAKENS AND BECOMES NEAR
STATIONARY...WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT LEVELS
ACROSS THE OUTSIDE WATERS. THE FRONTAL PASSAGE ASSOCIATED WITH THE
LOW WILL SLOWLY WEAKEN...BUT STILL BRING LIKELY TO CATEGORICAL
POPS...ESPECIALLY ACROSS THE NORTHEAST GULF COAST AND CLOSER TO
THE COAST MOUNTAINS THROUGH TUESDAY MORNING. A RIDGE OF HIGH
PRESSURE WILL CONTINUE TO BUILD ACROSS THE PANHANDLE WITH
INCREASING SOUTHERLY PRESSURE GRADIENT. SOUTHERLY WINDS WILL EASE
A BIT ON MONDAY NIGHT OVER NORTHERN LYNN CANAL...BUT WILL BE
ENHANCED AGAIN FOR SMALL CRAFT WINDS ON TUESDAY.

 CONDITIONS WILL IMPROVE LATER THIS WEEK AS THE RIDGE OF HIGH
PRESSURE CONTINUES BUILDING ACROSS SOUTHEAST ALASKA WITH
RELATIVELY WARM DAYTIME HIGHS ON THURSDAY AND FRIDAY. NO CONCRETE
CONFIDENCE BUT THE LONG RANGE MODELS HINT AN UPPER LEVEL SHORTWAVE
TROUGH WILL APPROACH THE EASTERN GULF AND SOUTHEAST ALASKA TOWARD
THE WEEKEND. AS THE SYSTEM NEARS THE EASTERN GULF...IT APPEARS
THAT THE MAIN DYNAMICS WILL WEAKEN AND SHEAR APART...LEAVING A
WEAK SURFACE LOW IN ITS WAKE ONSHORE OVER THE PANHANDLE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ012.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041-042.

&&

ABJ/AHN