Gale Warning 292, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
630 AM ADT WED OCT 31 2007

.SYNOPSIS...
.SHORT RANGE...A WAVE ALONG THE FRONTAL BOUNDARY THAT MOVED
THROUGH THE PANHANDLE YESTERDAY HAS DEVELOPED INTO A 992 MB
CLOSED LOW AND IS CURRENTLY LOCATED OVER THE CENTRAL INNER
CHANNELS AND TRACKING NORTH. THIS FEATURE RESULTED IN EXTENSIONS
TO THE WIND ADVISORIES FOR ZONES 26...27...AND 28 AS WELL AS THE
ADDITION OF A WIND ADVISORY FOR ZONE 29. ADVISORIES FOR ZONES 27
THROUGH 29 ARE EXPECTED TO EXPIRE AT 9 AM. THE GENERAL TREND FOR
WINDS TODAY WILL SEE LIGHT AND VARIABLE WINDS OVER THE NORTHERN
HALF OF THE PANHANDLE BECOME GUSTY OUT OF THE SOUTH AS THE LOW
CONTINUES TO TRACK NORTH INTO BRITISH COLUMBIA AND THE YUKON.
SOUTH OF FREDERICK SOUND...SOUTHERLY WINDS WILL BECOME
SOUTHWESTERLY AND BEGIN TO DIMINISH AROUND MID MORNING.

SATELLITE IMAGERY IS REVEALING CLOUD TOP TEMPERATURES BETWEEN -40
AND -50 DEGREES F. GFS AND NAM ARE BOTH INDICATING SOME
SIGNIFICANT INSTABILITY THROUGHOUT THE DAY. HAVE THEREFORE
INCLUDED ISOLATED THUNDERSTORMS IN THE COASTAL MARINE ZONES...THE
OUTER COAST...AND A LARGE PORTION OF THE SOUTHERN PANHANDLE INTO
TONIGHT.

A SHORT WAVE WILL TRACK OVER THE OUTER COAST LATE IN THE DAY
TODAY. THIS FEATURE IS CURRENTLY LOCATED OVER PRINCE WILLIAM
SOUND AND EXTENDS INTO THE NORTH CENTRAL GULF. THIS FEATURE WILL
KEEP THE PANHANDLE UNDER SHOWERS TODAY AND TONIGHT IN ADVANCE OF
THE NEXT WEATHER FRONT.

BY THIS AFTERNOON...A 978 MB GALE FORCE LOW WILL BE LOCATED NEAR
160W SOUTH OF THE ALASKA PENINSULA AND TRACKING NORTHEAST. WINDS
IN ADVANCE OF THE ASSOCIATED OCCLUDED FRONT WILL INCREASE TO NEAR
GALE FORCE IN THE OFFSHORE MARINE ZONE BY THE END OF THE SHORT
TERM FORECAST PERIOD. FOR ADDITIONAL INFORMATION ON THIS NEXT LOW
PLEASE SEE THE EXTENDED RANGE DISCUSSION BELOW.

.LONG RANGE...MODELS CONTINUE TO BE IN SYNOPTIC AGREEMENT AND
FAIRLY CONSISTENT WITH PREVIOUS RUN. USED A BLEND OF 00Z NAM40
AND ECMWF FOR DAY 3 THEN BLENDED 00Z GFS AND MOS WITH OFFICIAL
GRIDS FOR DAYS 4 THROUGH 8.

978 MB LOW MOVES NORTH THROUGH THE WESTERN GULF THURSDAY AND
ONSHORE THE KENAI PENINSULA FRIDAY EVENING, THE ASSOCIATED
OCCLUSION MOVES THROUGH THE EASTERN GULF FRIDAY AFTERNOON AND
ACROSS SOUTHEAST ALASKA THURSDAY NIGHT AND EARLY FRIDAY MORNING.
EXPECT WIDESPREAD GALE FORCE WINDS ACROSS THE EASTERN GULF AND
MAX SMCR TO GALE FORCE WINDS THROUGH THE INNER CHANNELS THURSDAY
EVENING. WILL LIKELY NEED ANOTHER ROUND OF WIND ADVISORIES WITH
GUSTS TO 50 MPH EXPECTED IN ZONES. AGAIN RAINFALL WILL BE
MODERATE TO LOCALLY HEAVY SOUTHERN AND COASTAL.

BEHIND THIS LOW... A FAST WEST WIND SETS UP ACROSS THE GULF ON
FRIDAY AS PARENT LOW MOVES INTO ALASKA INTERIOR. THE PERSISTENT
W-SW WINDS WILL KEEP A LARGE SWELL IN THE GULF WITH SEAS HOLDING
OVER 20 FEET INTO FRIDAY. THICKNESS VALUES DROP OFF INTO THE
LOWER 520S BUT WITH LONG FETCH OVER WATER WILL KEEP
PRECIPITATION MAINLY RAIN SHOWERS EXCEPT FOR THE FAR NORTH.

A WAVE ALONG THE TRAILING FRONT PASSES SOUTH OF THE CHARLOTTE
ISLANDS FRIDAY NIGHT INTO EARLY SATURDAY. THINK IT WILL BE FAR
ENOUGH SOUTH TO KEEP THE STRONGEST WINDS SOUTH OF OUR FORECAST
AREA BUT DO EXPECT TO SEE PRECIPITATION REACH THE SOUTHERN ZONES.
IT IS POSSIBLE THAT HYDER COULD GO TO SNOW DURING THIS TIME AS
THICKNESS DROPS TO 525 WITH AN OFFSHORE WIND LATE FRIDAY NIGHT
BUT WILL HAVE TO CONTINUE TO MONITOR THIS SITUATION.

A RESIDUAL LOW AND TROUGH ACROSS THE NORTHERN GULF DIGS SE
THROUGH THE COASTAL WATERS SATURDAY AS  A 1030+ MB HIGH BUILDS
INTO THE GULF SATURDAY AFTERNOON  AND OVER SOUTHEAST ALASKA
SUNDAY. INITIALLY...SOUTHEAST ALASKA WILL MAINTAIN AN ONSHORE
FLOW OVER THE TOP OF RIDGE FOR CONTINUED CLOUDS AND A CHANCE OF
LIGHT SHOWERS. ONCE TROUGH DROPS SOUTH WINDS WILL TURN OFFSHORE
AND DO EXPECT A BRIEF DRYING TREND FROM THE NW PANHANDLE SATURDAY
NIGHT TO SE PANHANDLE SUNDAY NIGHT INTO MONDAY. WILL GO MOSTLY TO
PARTLY CLOUDY DURING THIS TIME WITH A COOLER AIR MASS SPILLING
INTO THE AREA.

A WETTER PATTER RETURNS BY MID WEEK AS UPPER RIDGE TILTS TO SE
AND ALLOWS LONG FETCH SW FLOW BACK INTO THE PANHANDLE.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...WIND ADVISORY AKZ027>029
MARINE...GALES PKZ041-036 SCA
PKZ012>013-021>022-031-033>035-042>043-051>052

FCF/MM