Gale Warning 143, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
211 PM AKDT THU MAR 12 2009

.SHORT TERM... A 990 MB LOW LOCATED 100 NM S OF YAKUTAT WILL
MOVE INLAND JUST WEST OF THE FAIRWEATHER RANGE TONIGHT. AS OF
EARLY THIS AFTERNOON...THE ASSOCIATED FRONT WAS LOCATED JUST OFF
THE COAST AND WILL GRADUALLY PUSH INLAND TONIGHT AND ACROSS THE
PANHANDLE BY FRI MORNING.

PRECIP TYPE CONTINUES TO BE MAIN FORECAST CONCERN. FOR
PAYA...EXCEPT PRECIP TO REMAIN ALL SNOW AS THEY WILL REMAIN ON NW
SIDE OF LOW PREVENTING THEM FROM SEEING ANY ONSHORE FLOW. AS A
RESULT...ISSUED WINTER WEATHER ADVISORY UNTIL 8 PM FOR THEM AS
SNOWFALL RATES REMAIN FAIRLY STEADY THROUGH THE AFTERNOON.
PAEL/PAGS/PAOH/PAJN WILL SEE RAIN MIXING WITH SNOW THROUGH THE
EVENING THEN CHANGE BACK TO SNOW LATER TONIGHT AFTER THE FRONT
PASSES. EXPECT CENTRAL AND SOUTHERN COASTAL ZONES TO REMAIN ALL
RAIN THROUGH TONIGHT AND MIXING WITH SNOW AT TIME EARLY FRI
MORNING.

WIND WAS THE OTHER CONCERN FOR THE SHORT TERM. ISSUED WIND
ADVISORY FOR AKZ028 AS GUSTY SE WINDS WERE OBSERVED THIS
AFTERNOON IN PAKT/PANT. WINDS EXPECTED TO GRADUALLY DIMINISH ALONG
THE SOUTHERN ZONES THIS EVENING AT THE FRONT MOVES ONSHORE AND
TREND WILL CONTINUE NORTHWARD ALONG THE OUTER COAST THROUGH EARLY
FRI. GALE FORCE WINDS OVER THE OUTER WATERS AND ICY STRAIT/CROSS
SOUND WILL DIMINISH LATER THE EVENING LEAVING SCA.

MODELS WERE IN FAIR AGREEMENT THIS MORNING. HOWEVER...THEY DID
HAVE A HARD TIME DECIDING WHETHER OR NOT THE LOW IN THE NE GULF
WOULD MOVE E OR W OF THE FAIRWEATHER RANGE. EARLY THINKING WAS
THAT LOW WOULD MOVE FURTHER EAST TOWARDS CROSS SOUND. AFTER
LOOKING AT UPR LEVEL STEERING CURRENTS AND LATEST MODEL DATA...IT
APPEARED THAT UPR LEVEL SUPPORT WOULD MOVE AHEAD OF THE LOW ALLOW
IT TO DRIFT EASTWARD A LITTLE THEN RESUME A MORE NORTHERLY TRACK.

.LONG TERM...A LONG WAVE UPPER TROUGH HAS SET UP OVER THE GULF AND
SOUTHEAST ALASKA WILL REMAIN IN PLACE FOR THE DURATION OF THE
EXTENDED RANGE FORECAST. THIS FEATURE WILL GET AMPLIFIED THROUGH
MID WEEK AS AT LEAST THREE SHORT WAVES ROUND THE BASE OF THE UPPER
TROUGH. FINALLY...LATE IN THE WEEK A VERY STRONG SHORT WAVE WILL
DIG SOUTH AND REORIENT THE UPPER TROUGH AXIS TO THE SOUTHWEST AND
EXTEND WELL INTO THE PACIFIC. AT THE SURFACE...THIS WILL PRODUCE A
BROAD AREA OF LOW PRESSURE CENTERED OVER THE GULF WITH NUMEROUS
SMALLER SURFACE CIRCULATIONS EMBEDDED IN THE OVERALL FLOW. NO WELL
ORGANIZED SYSTEMS ARE EXPECTED UNTIL WEDNESDAY AND SO SNOW AND
RAIN WILL BE LIKELY FOR MOST PLACES BUT ON THE LIGHT SIDE UNTIL
THAT TIME.

MODELS ARE INDICATING A LOW APPROACHING THE SOUTHERN PANHANDLE
WEDNESDAY MORNING BUT BEGIN TO DIVERGE SIGNIFICANTLY AS THIS
FEATURE CLOSES THE COAST. GFS CONTINUES TO DEEPEN THIS SYSTEM AND
PUSHES A WELL DEFINED FRONT THROUGH THE CENTRAL PANHANDLE WHILE
ECMWF DISSIPATES THIS FEATURE OVER THE DIXON ENTRANCE. HPC AND
GRIDS REFLECT THE MIDDLE GROUND AS CONFIDENCE IN THIS PORTION OF
THE EXTENDED RANGE FORECAST IS LOW.

BLENDED NAM AND GFS THROUGH SUNDAY MORNING AND USED GFS FOR THE
REMAINDER OF SUNDAY. NO CHANGES TO THE LONG RANGE FORECAST BEYOND
THAT POINT.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL 6 PM AKDT THIS AFTERNOON FOR AKZ027-028.
         WIND ADVISORY UNTIL 4 AM AKDT FRIDAY FOR AKZ022-023.
         WINTER WEATHER ADVISORY UNTIL 6 PM AKDT THIS AFTERNOON FOR
     AKZ018-020-021-029.
         WINTER STORM WARNING UNTIL 6 PM AKDT THIS AFTERNOON FOR AKZ019.
         WINTER WEATHER ADVISORY UNTIL 8 PM AKDT THIS EVENING FOR AKZ017.
MARINE...GALE WARNING FOR PKZ021-022-036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011-013-031>035-051-052.

&&

MAM/FRITSCH