Gale Warning 237, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
207 PM AKDT TUE SEP 8 2009

.SHORT TERM...THE LEFTOVERS OF TODAYS SYSTEM IS THE MAIN CONCERN
IN THE SHORE TERM FORECAST TODAY. CURRENTLY, A WEATHER FRONT
ASSOCIATED WITH A 990 MB LOW IN THE CENTRAL GULF IS APPROACHING
THE SOUTHERN OUTER COAST. CLOUDS AND RAIN HAS SPREAD OVER THE
ENTIRE SOUTHERN PANHANDLE AND IS WORKING ITS WAY NORTH THROUGH
THE CENTRAL AND NORTHERN PANHANDLE NOW. STEADY PRECIPITATION HAS
YET TO SHOW AT PASI, PAGN AND AREAS FARTHER NORTH DUE TO
DOWNSLOPING WINDS AT THESE LOCATIONS. RAIN SHOULD BEGIN LATER
THIS AFTERNOON AS LOW LEVEL WINDS BECOME MORE ALONG SHORE. WIND
ADVISORIES ARE STILL UP FOR 23, 27 AND 28 FOR THIS AFTERNOON AND
INTO THE EARLY EVENING. SO FAR, WINDS IN THESE AREAS HAVE BEEN
GUSTING INTO THE HIGH 20 KT RANGE WITH A FEW IN THE LOWER 30S.
PAHY SO FAR IS THE ONLY OBSERVATION SITE TO REPORT AN ADVISORY
GUST WITH A GUST TO 36 KT LATE THIS MORNING. IN THE MARINE ZONES,
GALE WARNING IS UP FOR MARINE ZONE 36 AND SOME OF THE COASTAL AND
OFFSHORE ZONES FOR THIS AFTERNOON. MOST OF THE OTHER ZONES HAVE
SCA WINDS THIS EVENING.

FOR TONIGHT, WINDS WILL CONTINUE TO DIMINISH AS THE FRONT SHEARS
APART AND COMES ONSHORE. IN MOST PLACES WINDS WILL DROP BELOW WIND
ADVISORY AND SCA CRITERIA AS THE FRONT PASSES. THE RAIN HOWEVER,
WILL CONTINUE THROUGH TOMORROW AS SOUTHERLY FLOW CONTINUES AND A
SECOND SHORT WAVE TROUGH MOVES INTO THE PANHANDLE FOR WEDNESDAY.
YAKUTAT AND SKAGWAY WILL FINALLY SEE SOME RAIN BY LATE TONIGHT AND
WEDNESDAY AS THE REMAINS OF THE FRONT CONTINUE TO PUSH NORTH.

MODELS TODAY ARE, IN GOOD AGREEMENT WITH EACH OTHER. ALTHOUGH THE
CONSISTENCY WITH PREVIOUS SOLUTIONS IS A BIT LACKING. COMPARED TO
YESTERDAY, THE PAST FEW MODEL RUNS NOW SUPPORT THE TWO WAVE
STRUCTURE THAT THE SYSTEM IS DISPLAYING ON SATELLITE WITH MOST OF
THE ENERGY EARLY ON GETTING PUMPED INTO THE SOUTHERN MOST WAVE IN
THE NORTH PACIFIC. THIS HAS CAUSED THE LOW IN THE CENTRAL GULF TO
BE A BIT WEAKER THEN PREVIOUS SOLUTIONS INDICATED AND WINDS TO BE
A LITTLE LESS THEN FIRST THOUGHT. FORECAST WAS UPDATED WITH A
BLEND OF THE GFS AND NAM. AND FORECAST CONFIDENCE IS AVERAGE GIVEN
THE CHANGES IN THE MODEL SOLUTIONS OVER THE PAST 24 HOURS.

.LONG TERM...THE RAPID CYCLOGNESIS WILL OCCUR IN THE NPAC WED AND
TRACK INTO THE WRN GLFALSK WED NIGHT AND SEND A STRONG OCCLUSION
ONSHORE THE PNHDL THU. HEAVY RAIN, OR AT LEAST FMH1 MODERATE
THAT THE PUBLIC WOULD CONSIDER HEAVY RAIN, SHOULD OCCUR FOR MOST
THE PANHANDLE DAYTIME THU EXCEPT FOR ZONES 28, 29. THERE ARE
FEW CHANGES TO THE LONG TERM FCST PKG OTHER THAN ADDING THE
DESCRIPTION OF THE RAIN BEING HEAVY.

AT 00Z THU A 971 MB LOW 500 NM S OF PADQ WILL BE TRACKING NNE AT
30 KT. THE LOW CENTER WILL BE RAPIDLY DECELERATING AT THAT TIME
AND WILL REACH A GREATEST DEPTH OF 965 MB 400 NM S OF PAWD. THE
FNTL BNDRY WILL MOVE ONSHORE THE OUTER COAST S OF PASI ABT 00Z
FRI. THE LOW ITSELF HAS AN ASYMMETRICAL WARM-CORE THAT MAY
REPRESENT A STRONG REGION OF BAROCLINITY MOVING UP THE WARM-
FRONTAL BOUNDARY ON THE EAST SIDE ABT 06Z THU AND CREATING
A SECOND LOW CENTER OF ABT 970 MB 250 NM S OF PAMD 18Z THU.
THIS RAPID AND COMPLEX CYCLONE EVOLUTION WITH TWO CENTERS
IS THE MOST IMPORTANT DIFFERENCE BETWEEN THE GFS AND ECMWF.
THE MAX GALE IN MARINE ZONES 51 AND 52 IS BEING KEPT WITHOUT
CHANGE, ALTHOUGH IT IS POSSIBLE FOR A HIGHER WIND EVENT TO
OCCUR DUE TO A STRONGER ONSHORE FLOW AND BARRIER ENHANCEMENT
AS DEPICTED IN THE CURRENT GFS.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL 9 PM AKDT THIS EVENING FOR AKZ023-027.
         WIND ADVISORY UNTIL 6 PM AKDT THIS EVENING FOR AKZ028.
MARINE...GALE WARNING FOR PKZ036-043-051.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033-035-041-042-052.

&&

EAL/JBT