Small Craft Advisory 244, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
229 PM AKDT FRI MAR 18 2011

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS THE PANHANDLE
UNDER MOSTLY CLEAR SKIES. WINDS OVER THE NORTHERN MARINE WATERS
ARE AROUND 20 KT WITH NORTHERN LYNN AND STEPHENS PASSAGE AROUND
MIN SMALL CRAFT. OVER LAND WINDS ARE ON THE LIGHT SIDE WITH MOST
STATIONS REPORTING WINDS LESS THAN 15 MPH BUT THERE ARE SOME
HIGHER GUSTS NEAR PAGY.

 DRY AND CLEAR WEATHER WILL CONTINUE THROUGH THE SHORT TERM
PERIOD WITH DEEP OFFSHORE FLOW. THE NORTHERLY PRESSURE GRADIENT
WILL CONTINUE TO INCREASE INTO SAT AS THE SURFACE HIGH IN THE
YUKON STRENGTHENS AND THE INVERTED TROF OVER THE SOUTHERN HALF OF
THE PANHANDLE PERSISTS. THIS WILL INCREASE OF PRESSURE GRADIENT
WILL CONTINUE TO INCREASE THROUGH LATE SAT MORNING THE N WINDS
RANGING FROM 25 TO 20 KT OVER N/S CHANNELS ALONG WITH CROSS
SOUND. NORTHERN LYNN WILL INCREASE TO MIN GALES EARLY SAT MORNING
BUT AS THE GRADIENT SLOWLY WEAKENS SAT AFTERNOON THOSE GALES
SHOULD DIMINISH TO MAX SMALL CRAFT.

&&

.LONG TERM...MODELS ARE IN GENERAL AGREEMENT THROUGH EARLY NEXT
WEEK WITH AN UPPER LEVEL BLOCKING RIDGE ACROSS THE FORECAST
DOMAIN...THEN MODELS DIVERT AS THE RIDGE BREAKS AND A WEAK
SHORTWAVE TROUGH MOVES ACROSS THE GULF AND THE PANHANDLE BY THE
MIDDLE OF NEXT WEEK. ON TUESDAY AND WEDNESDAY. SURFACE HIGH WILL
PERSIST ACROSS THE CENTRAL GULF AND NORTHERN CANADA WITH A WEAK
INVERTED TROUGH OF LOW PRESSURE ACROSS THE EASTERN GULF THROUGH
EARLY NEXT WEEK. AS A DEVELOPING LOW ENTERS THE FAR WESTERN GULF
ON TUESDAY...THE HIGH PROGRESSES EAST AND PUSHES THE INVERTED
TROUGH SOUTHEAST. MODEL SOLUTIONS DIVERT WITH THE POSITION AND
TIMING OF THE INCOMING LOW OVER THE WESTERN GULF...AND
CONSEQUENTLY THE TRACK OF THE FRONTAL BOUNDARY ASSOCIATED WITH THE
LOW. THE ECMWF KEEPS THE LOW FASTER THEN THE GFS AND MORE
SOUTHWARD TRACK THROUGH THURSDAY. THE GFS HAS SHOWN A BETTER RUN
TO RUN CONSISTENCY AND THUS WAS OPTED TO BLEND THE INHERITED GRIDS
THROUGH THE LONG TERM PERIODS. UNDER A WEAK PRESSURE
GRADIENT...ADDED THE NAM FOR THE EARLIER PORTION OF THE FORECAST
PERIODS TO HANDLE SOME WIND FIELDS WITH SOMEWHAT BETTER IN DETAIL.

 UNDER A PERSISTING RIDGE...GENERALLY DRY WEATHER WITH WEAK
OFFSHORE FLOW WILL CONTINUE ACROSS THE FORECAST DOMAIN THROUGH THE
WEEKEND AND EARLY NEXT WEEK. DEVELOPING FRONTAL BOUNDARIES WEST OF
THE RIDGE WILL WEAKEN AND DISSIPATE AS THEY MOVE EAST ACROSS THE
WESTERN GULF. ON TUESDAY...THE PERSISTING HIGH OVER THE PANHANDLE
WILL WEAKEN AND MOVE EAST AND THE INVERTED TROUGH OF LOW PRESSURE
ACROSS THE EASTERN GULF WILL DISSIPATE. A DEVELOPING LOW IN THE
WESTERN GULF WILL PUSH A FRONTAL BOUNDARY EAST ACROSS THE GULF
TUESDAY NIGHT INTO WEDNESDAY. THE LOW WILL CONTINUE TO TRACK
SOUTHEAST ACROSS THE SOUTHERN GULF THROUGH THURSDAY WITH ITS
TROUGH EXTENDING NORTHWEST TO THE NORTHERN GULF COAST. A PRE-
FRONTAL BOUNDARY MAY ARRIVE THE PANHANDLE COAST LATE MORNING OR
EARLY AFTERNOON ON TUESDAY FOLLOWED BY THE MAIN FRONT AFFECTING
THE COASTAL SECTIONS LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. AS
THE LOW TRACKS SOUTHEAST AND EXTENDS AN INVERTED TROUGH
NORTHWEST...THE FRONT WILL DRIFT NORTH TO THE NORTHERN PANHANDLE
AND SHEAR APART ACROSS THE SOUTHERN AREAS BY WEDNESDAY NIGHT INTO
THURSDAY. THE REMNANTS OF THE FRONT WILL CONTINUE TO AFFECT
YAKUTAT AREA THROUGH FRIDAY. WITH THE FRONTAL PASSAGE...SMALL
CRAFT TO GALE FORCE WINDS ARE EXPECTED ACROSS THE OUTER COASTAL
WATERS AND SOUTHERN AREAS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ012.
         SMALL CRAFT ADVISORY FOR PKZ011-013-022-031.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041>043.

&&

ABJ/AHN