Gale Warning 377, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
209 PM AKST SUN NOV 22 2009

.SHORT TERM...STRONG STORM IN THE WORKS OUT IN THE SOUTHWESTERN
GULF TODAY. AS IT MOVES NORTH THROUGH THE WESTERN GULF IT WILL
SEND A STRONG FRONT INTO THE PANHANDLE FOR LATE TONIGHT AND
MONDAY. RESENT MODEL RUNS HAVE BEEN SHIFTING THE LOW TRACK JUST A
BIT WEST OF PREVIOUS FORECASTS. CURRENTLY THE GFS IS THE FARTHEST
EAST WITH MOST OF THE REST OF THE MODELS CLUSTERED ABOUT 200 TO
300 MILES FURTHER WEST. IN OUR NECK OF THE WOODS, TIMING OF THE
FRONT IS RATHER GOOD BETWEEN THE VARIOUS MODELS WITH THE FIRST OF
THE FRONTAL BANDS HITTING THE SOUTHWEST OUTER COAST LATE TONIGHT.
THE FRONT WILL BE KICKING UP HIGHER WINDS AHEAD OF IT SO HAVE
KEPT THE WIND ADVISORIES THAT WERE POSTED BY THE MID SHIFT THE
SAME EXCEPT THAT THE ADV FOR 23 NOW STARTS AT MIDNIGHT INSTEAD OF
3 AM.

 AS THE FRONT PUSHES THROUGH THE PANHANDLE LATE TONIGHT AND
MONDAY, IT WILL SPREAD SOME MODERATE PRECIP ACROSS THE AREA. TYPE
WILL MAINLY BE LIQUID SOUTH OF A LINE FROM JUNEAU TO HOONAH TO
CROSS SOUND, WITH ALL SNOW ALONG AND NORTH OF THAT LINE LATE
TONIGHT AND INTO TOMORROW. BELIEVE THAT SNOW LEVELS WILL BE LOW
ENOUGH AND QPFS HIGH ENOUGH FOR ADVISORY LEVEL SNOW ACCUMULATIONS
FOR THE NORTHERN INNER CHANNELS STARTING EARLY TOMORROW MORNING.
HAVE POSTED WINTER WEATHER ADVISORIES FOR GUSTAVUS, HOONAH,
JUNEAU, HAINES AND SKAGWAY FOR MOST OF THE DAY TOMORROW. SNOW
LEVELS SHOULD RISE HIGH ENOUGH BY MONDAY AFTERNOON FOR THE SNOW
TO BEGIN TO MIX WITH RAIN IN GUSTAVUS, HOONAH, AND JUNEAU.

 ONE STICKY POINT IS A DEVELOPING WAVE ON THE FRONT BEFORE IT
MAKES IT INTO THE PANHANDLE. THIS COULD CAUSE A BRIEF INCREASE IN
WINDS FOR THE SOUTHERN ZONES. DID NOT HAVE ENOUGH CONFIDENCE IN
THIS TO ISSUE A WIND WARNING HOWEVER.

 SHORT TERM FORECAST WAS UPDATED USING A BLEND OF THE UKMET AND
NAM TODAY. WITH RELATIVELY GOOD INITIAL PLACEMENT AND A SCENARIO
THAT WAS SUPPORTED BY THE GFS ENSEMBLE MEAN, FELT THAT THE UKMET
WAS THE MODEL OF CHOICE TODAY. THE EXCEPTION WAS THAT I USED THE
HIGHER WIND MAGNITUDES OF THE GFS IN THE WIND FORECAST. FORECAST
CONFIDENCE IS A LITTLE ABOVE AVERAGE TODAY DUE TO UNCERTAINTY
WITH HOW THE DEVELOPING WAVE ON THE FRONT WILL AFFECT THE SYSTEM.

.LONG TERM...IT WAS A VERY TRICKY DAY ON THE LONG TERM DESK AS THE
OVERNIGHTS MODELS DID NOT HAVE GOOD RUN TO RUN CONTINUITY. THE EC
FLIP FLOP ON THE WEATHER SYSTEM LIFTING INTO THE GULF ON TUE AND
THERE ARE OTHER ISSUES THROUGH THE WEEK WITH THE TRACK AND
STRENGTH OF THE SERIES LOW PRESSURE SYSTEMS MOVING INTO THE GULF.
ALSO THERE HAS BEEN A LARGE INCREASE IN ENSEMBLE MEMBER SPREAD
OVERNIGHT SO WITH THAT SAID THERE WAS NOT MANY CHANGES MADE TO THE
PREVIOUS FORECAST. WHERE CHANGES WERE MADE USED A BLEND OF THE
INHERITED GRIDS WITH THE GFS THROUGH TUE NIGHT AS IT HAS BEEN
CONSISTENT WITH THE ELONGATED LOW OVER THE WESTERN GULF WITH A
FRONT EXTENDING OVER THE EASTERN GULF. THEN FOR THE EXTEND
PORTIONS USED HPC GUIDANCE. OVERALL THERE IS LOW FORECASTER
CONFIDENCE IN ANY INDIVIDUAL SYSTEM THAT WILL MOVE INTO THE GULF
THIS WEEK. THERE IS FAIR FORECASTER CONFIDENCE THAT THERE WILL BE
3 TO 4 WEATHER FRONT THAT WILL MOVE OVER THE PANHANDLE THIS WEEK
ALONG WITH WARMING TEMPS.

AT THE START OF THE LONG TERM A SURFACE TROF WITH A FRONT WILL BE
LIFTING OVER THE PANHANDLE MON NIGHT. THIS FRONT WILL CONTINUE TO
SPREAD RAIN OVER THE SOUTHERN HALF OF THE AREA WITH A MIX OVER THE
CENTRAL AREAS THAT WILL CHANGE TO ALL RAIN OVER NIGHT. FURTHER
NORTH IT WILL BE SNOWING BUT AS THE FRONT MOVES THROUGH AND THE
SURFACE RIDGE BEGIN TO BUILD OVER THE PANHANDLE THE SOUTHERLY FLOW
WILL INCREASE AND MIX OUT THE COLD AIR. IT MAY STAY ALL SNOW ALONG
THE HIGHWAYS LONGER WITH SIGNIFICANT ACCUMULATION. AS THE RIDGE
BUILDS OVER THE AREA THE WINDS WILL INCREASE TO SMALL CRAFT OVER
THE NORTHERN INNER CHANNELS AND IT WILL BECOME BREEZY TO WINDY
NEAR PAGY AND PAHN.

SHOWERS WILL CONTINUE INTO TUE MORNING BUT A UPPER RIDGE WILL MOVE
OVER THE PANHANDLE AHEAD OF A LOW MOVING OUT OF THE NORTH PACIFIC
AND INTO THE WESTERN GULF THROUGH WED. THE ASSOCIATED WEATHER
FRONT WILL SPREAD RAIN FROM SOUTH TO NORTH THROUGH TUE AND THE
WINDS ALONG THE GULF WILL INCREASE TO GALES ALONG WITH SMALL
CRAFTS OVER INSIDE WATERS. THE WINDS OVER THE COASTAL AREAS MAY
NEED WIND ADVY BUT THERE IS LOW CONFIDENCE ATTM AS WITH THE LOW
CENTER OVER IN THE WESTERN GULF THINK THE STRONGEST WINDS WILL
REMAIN OVER THE GULF.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM AKST MONDAY FOR
     AKZ027.
         WINTER WEATHER ADVISORY FROM 3 AM TO 3 PM AKST MONDAY FOR AKZ020-
     021-025.
         WIND ADVISORY FROM MIDNIGHT TONIGHT TO NOON AKST MONDAY FOR
     AKZ023-028.
         WIND ADVISORY FROM 3 AM TO NOON AKST MONDAY FOR AKZ029.
         WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM AKST MONDAY FOR AKZ018-
     019.
MARINE...STORM WARNING FOR PKZ043-051-052.
         GALE WARNING FOR PKZ021-022-033>036-041-042.
         SMALL CRAFT ADVISORY FOR PKZ011>013-031-032.

&&

EAL/ABJ