Gale Warning 410, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
121 PM AKST FRI DEC 4 2009

.SHORT TERM...A 1050 MB HIGH CONTINUES TO BUILD INTO THE ALASKAN
AND CANADIAN INTERIOR AS LONG WAVE RIDGE BUILDS OVER CENTRAL GULF
AND ALASKAN INTERIOR. ENTIRE PANHANDLE UNDER DRYING OFFSHORE FLOW
THIS AFTERNOON AND WILL CONTINUE INTO THIS EVENING. MOST
LOCATIONS AT VFR CONDITIONS TODAY WITH ONLY OCCASIONAL DROPS TO
IFR CONDITIONS WITH PATCHY FOG THIS MORNING. SCATTERED SKIES AND
RIDGE ALOFT WILL ALLOW INVERSIONS IN WIND SHELTERED LOCATIONS
SUCH AS THE MENDENHALL VALLEY TO DEVELOP AFTER SUNSET THIS
EVENING AND ALLOW TEMPERATURES IN THOSE LOCATIONS TO DROP INTO
THE LOW TO MID TEENS BY MORNING. PATCHY FOG POSSIBLE IN THE WIND
SHELTERED LOCATIONS.

 GAP WINDS INCREASE TONIGHT ESPECIALLY ACROSS THE NORTHERN ZONES
AS THE HIGH PRESSURE SYSTEM MOVES IN THE THE YUKON. WIND
ADVISORIES FROM MIDNIGHT TONIGHT THROUGH SATURDAY AFTERNOON FOR
PKZ 18 AND PKZ 19. INNER NORTHERN INNER CHANNELS BUMP UP TO SCA
WITH EXCEPTION OF BOTH NORTHERN AND SOUTHERN LYNN CANALS WHICH
BUMP TO GALES TONIGHT. WINDS WILL ABATE SOMEWHAT TOMORROW
AFTERNOON FOR THE NORTHERN ZONES AS GRADIENT ORIENTATION BECOMES
UNFAVORABLE AS HIGH PRESSURE SYSTEM MOVES SOUTH. GAP FLOW FROM
INTERIOR PASSES WILL INCREASE THROUGH THE DAY ON SATURDAY AND
INTO SATURDAY NIGHT FOR SOUTHERN ZONES.

 MODELS IN STRONG AGREEMENT THROUGH THE SHORT TERM. PREFERRED THE
NAM12 AS ITS RESOLUTION IS HANDLING GAP FLOWS FROM THE CANADIAN
INTERIOR BEST AND INITIALIZED WELL.

&&

.LONG TERM...UPPER LVL BLOCKING HIGH WILL REMAIN IN PLACE WELL
INTO NEXT WEEK. THIS PATTERN WILL BE DRY AND KEEP SKIES MOSTLY
CLEAR TO PARTLY CLOUDY OVER THE PANHANDLE. WINDS OVER THE
NORTHERN REGIONS WILL DIMINISH AS HIGH PRESSURE AND TEMPERATURE
GRADIENT SHIFTS FROM NS TO EW ORIENTATION. GAP FLOW WINDS WILL
KEEP INTERIOR AREAS WINDY WITH THE POSSIBILITY OF SOME ADVY LVL
WINDS IN PKZ25 AND PKZ29 INTO SAT NIGHT. ARCTIC AIR MASS WILL
BEGIN RETROGRADING INTO N CANADA AT THE START OF THE WEEK
TRACKING SW INTO THE YUKON AND N BRITISH COLUMBIA. TRACK OF THIS
AIR MASS IS STILL A BIT UNCERTAIN.

MODELS WERE IN GOOD AGREEMENT AND INITIALIZED WELL. USED A BLEND
OF NAM12 WITH INHERITED GRIDS THROUGH DAY 4 AS IT GAVE A BIT MORE
DETAIL TO THE PRESSURE GRADIENT. EC CONTINUED TO BE A BIT MORE
CONSISTENT THAN GFS FOR THE LONG RANGE BUT BOTH LOOKED FAIRLY
REALISTIC WITH THE TRACK OF THE ARCTIC AIR MASS. GFS TRACKING A
BIT MORE TO THE N INTO THE AK INTERIOR WITH THE EC A BIT FURTHER
S OVER N BC AND THE YUKON. OVER ALL NO MUCH CHANGE TO THE
FORECAST WITH THESE UPDATES. MODEL TEMPERATURES FOR SAT NIGHT
OVER THE NORTHERN AND CENTRAL REGIONS WERE A GOOD DEAL COLDER
THAN PREVIOUS RUNS SO DROPPED MIN TEMPS A BIT...POSSIBLY NOT
ENOUGH WITH THE CLEAR SKIES. EITHER WAY EXPECT COLD TEMPS OVER
THE WEEKEND THEN A SLIGHT WARM UP MID WEEK.

FORECAST CONFIDENCE WAS ABOVE AVERAGE FOR THE LONG TERM...WITH
SOME ISSUES WITH HOW LOW WILL TEMPS GO AND ARCTIC AIR MASS
LOCATION RESOLUTION AT THE END OF THE WEEK.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM AKST
SATURDAY FOR
     AKZ018-019.
MARINE...GALE WARNING FOR PKZ012-013.
         SMALL CRAFT ADVISORY FOR PKZ011-021-022-031-032-034>036.

         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ042-051-052.

&&

CCC/PRB