Small Craft Advisory 360, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
335 PM AKDT SAT JUN 9 2012

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS THE SOUTHERN
PANHANDLE UNDER PARTLY TO MOSTLY CLOUDY SKIES WITH MID LEVEL
CLOUDS OVER THE NORTHERN AREAS. A DEVELOPING LOW PRESSURE SYSTEM
IS LIFTING OUT OF THE NORTH PACIFIC. WINDS OVER THE FORECAST
ALONG WITH MARINE AREAS ARE ON THE LIGHT SIDE WITH THE EXCEPTION
TO NORTH LYNN WHERE WINDS ARE 10 TO 20 MPH BUT THEY WILL DIMINISH
THROUGH THE EARLY EVENING HOURS.

 CLOUDS WILL INCREASE FROM SOUTH TO NORTH THROUGH TONIGHT AS THE
LOW PRESSURE SYSTEM LIFTS INTO THE SOUTHERN GULF THEN INTO THE
CENTRAL GULF BY SUN AFTERNOON. AN OCCLUDED FRONT WILL LIFT INTO
THE EASTERN GULF LATE TONIGHT WITH A CHANCE OF PRECIP ALONG THE
SOUTHERN COASTAL AREAS. THE RAIN WILL DEVELOP OVER THE SOUTHERN
AREAS THROUGH THE EARLY SUN MORNING HOURS AND SPREAD NORTHWARD
THROUGH THE DAY. THE FAR NORTHERN AREA WILL REMAIN ON THE DRY
SIDE WITH JUST A CHANCE BUT RAIN WILL BE LIKELY OVER THE NORTH
CENTRAL AREAS BY THE AFTERNOON. THERE IS SOME SE FLOW ALOFT THAT
MAY HOLD OFF THE RAIN OVER THE NORTH CENTRAL AREAS.

 THE WINDS OVER THE EASTERN GULF WILL INCREASE TO 30 KT THROUGH
TONIGHT WITH GALES DEVELOPING OVER THE OFFSHORE WATERS. THE BAND
OF GALES WILL MOVE INTO THE EASTERN GULF THROUGH SUN MORNING BUT
IT WILL NOT LAST LONG AS THE FRONT WEAKENS AS IT LIFTS NORTH AND
THE WINDS WILL RELAX THROUGH SUN AFTERNOON. OVER THE INNER
CHANNELS THE WINDS WILL BE ON THE LIGHT SIDE TONIGHT BUT BACK
AROUND TO THE SOUTH AND INCREASE TO 15 TO 20 KT OVER THE SOUTHERN
HALF. THE NORTHERN AREAS WILL REMAIN TO SEE LIGHT NORTH WINDS.
THROUGH SUN THE SOUTHERLY WINDS WILL SLOWLY INCREASE TO BE 15 TO
25 KT WITH THE STRONGEST WINDS NEAR CROSS SOUND AND CLARENCE
STRAIT.

 OVERALL THERE WAS NOT MUCH CHANGES IN THE SHORT TERM FORECAST
BUT THERE IS LOW FORECASTER CONFIDENCE ON THE PRECIP FORECAST AS
FORECAST MODELS ARE HAVING ISSUES WITH APPROACHING THE FRONT.
USED A BLEND OF THE NEW EC/NAM AS THEY INITIALIZED THE BEST AT
12Z.

&&

.LONG TERM...MODELS ARE IN GENERAL AGREEMENT THROUGH EARLY NEXT
WEEK WITH A CLOSED UPPER LEVEL LOW ACROSS THE GULF SLOWLY FILLS
AND DRIFTS EASTWARD THROUGH EARLY NEXT WEEK. A WEAKENING SURFACE
RIDGE OF HIGH PRESSURE ACROSS SOUTHEAST ALASKA DISSIPATES LATE
SUNDAY NIGHT AS A LOW IN THE CENTRAL GULF SLOWLY WEAKENS WHILE
DRIFTING FARTHER NORTH TO THE NORTHERN GULF THROUGH MONDAY
AFTERNOON. THE LOW WILL BECOME NEARLY STATIONARY AND CONTINUE
WEAKEN THROUGH TUESDAY MORNING BEFORE BECOMING BROAD BY TUESDAY
EVENING. AS THE LOW WEAKENS...A RIDGE OF HIGH PRESSURE WILL
REBUILD ACROSS THE PANHANDLE. USED THE GFS AND ECMWF BLEND
THROUGH TUESDAY NEXT WEEK AS THEY MADE A GOOD CONSENSUS ON
HANDLING THE LOW TRACK.

 BEGINNING ON WEDNESDAY...THE CLOSED UPPER LOW SHOULD BECOME
BROAD AND STALL OVER SOUTHEAST ALASKA WHILE A WEAK UPPER HIGH OVER
WESTERN ALASKA WEAKENS AND MOVES A LITTLE TO THE WEST THROUGH LATE
THURSDAY. THE IDEAL SYNOPTIC CONDITION WILL BE BRINGING THE BROAD
UPPER LOW BACK TO THE NORTHERN GULF TOWARD THE NEXT WEEKEND. MODEL
SOLUTIONS FOR THE SYNOPTIC PATTERN STRUGGLE FROM WEDNESDAY ONWARD.
THE HPC APPROACH TO THE MODEL SOLUTION RESULTED USING THE
OPERATIONAL ECMWF AND GFS PRIMARILY THROUGH FRIDAY WITH A LITTLE
ENSEMBLE MEANS. FOR THE NEXT WEEKEND...THE ECMWF BRINGS AN UPPER
RIDGE A BIT TOO FAST INTO THE GULF. THUS THE GFS WAS GIVEN HEAVIER
WEIGHTING FOR THE WEEKEND.

 THE LOW DRIFTING NORTHWARD ACROSS THE CENTRAL GULF WILL CONTINUE
MAINTAIN SMALL CRAFT WINDS FOR THE NORTHERN OUTSIDE WATERS EARLY
SUNDAY NIGHT. SOUTHERLY WINDS WILL REMAIN AROUND 20 KNOTS BUT 8 TO
9 FEET ROUGH SEAS WILL REMAIN ACROSS THE OUTSIDE WATERS THROUGH
EARLY NEXT WEEK. THE LOW AND ITS ASSOCIATED FRONTAL PASSAGE WILL
SLOWLY WEAKENS...BUT STILL BRING LIKELY TO CATEGORICAL POPS
ACROSS THE PANHANDLE SUNDAY NIGHT...EXCEPT NORTHERN MOST AREAS.
LIKELY POPS WILL CONTINUE MOST OF THE PANHANDLE MONDAY
MORNING...THEN DIMINISH IN THE AFTERNOON AS THE LOW FURTHER
WEAKENS AND MOVES FAR NORTHERN GULF. AS THE LOW WEAKENS OVER THE
NORTHERN GULF AND A RIDGE OF HIGH PRESSURE REBUILDS ACROSS THE
PANHANDLE...SOUTHERLY PRESSURE GRADIENT WILL BE ENHANCING AND
SMALL CRAFT WINDS WILL AFFECT THE NORTHERN LYNN CANAL ON MONDAY
AND TUESDAY. THE LOW THEN BECOMES NEARLY STATIONARY IN THE
NORTHERN GULF...BRINGING CATEGORICAL POPS FOR YAKUTAT AREA THROUGH
TUESDAY. AS THE LOW BECOMES BROAD BY TUESDAY EVENING...RAIN WILL
BEGIN TAPERING OFF ACROSS THE NORTHEAST GULF COAST.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ041>043.
         SMALL CRAFT ADVISORY FOR PKZ012-022-033-036-051-052.

&&

ABJ/AHN