Small Craft Advisory 573, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
400 PM AKDT SAT OCT 6 2012

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS A BROAD AREA OF
SEA STRATUS OVER THE EASTERN GULF AND NEAR CROSS SOUND. THE
NORTHERN AREAS ARE CLOUDY WITH THE SOUTHERN TWO THIRDS MOSTLY
CLEAR. WINDS ARE MAINLY ON THE LIGHT SIDE BUT THERE IS SOME
INCREASED SOUTHERLY WINDS OVER NORTHERN LYNN TO 25 KT BUT THE
THINKING IS THAT THE WINDS WILL DIMINISH IN THE EARLY EVENING.
CROSS SOUND IS SEEING AN STIFF 20 KT FROM THE NORTHWEST BUT AS
THE SUN GOES DOWN THE WINDS WILL SLOWLY DIMINISH TO 15 KT. THE
NORTHERN GULF COAST IS SEEING SOME LIGHT RAIN FROM AN EMBEDDED
SHORTWAVE MOVING OVER THE TOP OF THE UPPER RIDGE OVER THE GULF.
THIS SHORTWAVE WILL INCREASE THE THREAT OF PREICP OVER THE
EASTERN GULF COAST THROUGH TONIGHT BUT ANY PRECIP WILL BE LIGHT.

THERE WILL NOT BE THAT MUCH OF A SYNOPTIC PATTERN CHANGE IN THE
NEXT 24HRS WITH THE UPPER HIGH OVER THE NORTH PACIFIC SLOWLY
DRIFTING INTO THE CENTRAL GULF BY SUNDAY AFTERNOON. THE SURFACE
HIGH WILL FOLLOW THE UPPER FEATURE BUT A INVERTED TROF WILL MOVE
OVER THE SOUTHERN AREAS THROUGH THE DAY ON SUNDAY.

WITH LARGE SCALE SUBSTANCE AND PLENTY OF LOW LEVEL MOISTURE FOG
WILL AGAIN FORM OVER THE INNER CHANNELS WITH SOME AREA GOING TO
SEE DENSE FOG. ALSO WITH DEEP ONSHORE FLOW AFTER THE UPPER
SHORTWAVE PASSES TO THE EAST AREAS OF DRIZZLE WILL ACCOMPANIED THE
FOG OVER THE NORTH CENTRAL AREAS. VISIBILITIES OVER THE WATER WAYS
AND THE GULF WILL BE REDUCED TO LESS THAN 1 MILES AT TIMES. THE
DENSE FOG WILL BE OVER THE CENTRAL INNER CHANNELS TO THE SOUTHERN
COASTAL AREAS FROM LATE THIS EVENING THROUGH LATE SUNDAY MORNING.

THE FOG AND DRIZZLE WILL SLOWLY DISSIPATE THROUGH THE MORNING AND
THE SOUTHERN AREAS WILL SEE ANOTHER SUNNY DAY BUT IT DEPENDS ON
WHEN THE LOW CLOUDS/FOG LIFTS. THE NORTHERN AREAS WILL SEE MOSTLY
CLOUDY SKIES BUT THERE WILL BE BREAKS IN THE CLOUD COVER.

THE INVERTED TROF MENTIONED ABOVE WILL INCREASE THE NORTHERLY
WINDS FROM CHATHAM STRAIT SOUTHWARD TO 15/20KT BY THE AFTERNOON
WHILE LYNN CANAL WILL SEE A SOUTHERLY WIND INCREASE TO BE 15/20
KT. THE EASTERN GULF WILL MAINLY SEE NW WINDS BUT GENERALLY LESS
THAN 15 KT.

THERE IS ABOVE AVERAGE FORECASTER CONFIDENCE WITH PERSISTENCE AS
A GUIDE.

.LONG TERM...SOME RECENT HISTORY ON THE LARGE SCALE: WHAT USED TO
BE TYPHOON REACHED THE POLAR FRONT ZONE IN THE WEST PACIFIC, AND
UNDERWENT EXPLOSIVE CYCLOGENESIS TO HURRICANE FORCE WINDS. THIS
SYSTEM IS NOW CROSSING THE DATELINE, AND IS CURRENTLY DISINTEGRATING
AN OMEGA BLOCK. THE OMEGA'S CENTRAL HIGH ALOFT IS THE REASON FOR
OUR MINIMAL PRECIPITATION, WITH LARGE AREAS OF SEA STRATUS.
NOTE THE FOG WILL CONTINUE TO REDEVELOP EACH NIGHT UNTIL THE
CLOUD COVER INCREASES BEGINNING TUE NIGHT AND WED. CONFIDENCE IS
AVERAGE.

THE LONG RANGE PACKAGE CONTINUES TO BE GENERALLY DRY UNTIL LATE
IN THE WEEK WHEN THE THE SYSTEM CURRENTLY AT THE DATELINE SENDS
POLART FRONT ZONE WAVES NE INTO THE GULF.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...DENSE FOG ADVISORY FROM 11 PM THIS EVENING TO 11 AM AKDT SUNDAY
     FOR AKZ024-026-027.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ052.

&&

ABJ/JBT