Gale Warning 219, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
1235 PM AKDT SAT SEP 27 2008

.SHORT TERM...RAIN SHOWERS ARE SCATTERED ACROSS THE PANHANDLE
THIS MORNING AS A WEAK MID LEVEL RIDGE BUILDS ACROSS THE SOUTHERN
PANHANDLE. ON SATELLITE A WEAK MID LEVEL TROUGH CAN BE SEEN
ENHANCING THE CLOUD SHIELD SOUTHWEST OF YAKUTAT AND THIS WILL
HELP INCREASE THE MARINE LAYER AND PRECIP INTO THIS AFTERNOON
ACROSS THE NORTHERN GULF. THE BUILDING MID LEVEL RIDGE ACROSS THE
SOUTHERN PANHANDLE THIS AFTERNOON WILL ALLOW FOR MORE ONSHORE LOW
AND MID LEVEL FLOW INTO THE AFTERNOON AND EVENING AND THIS WILL
BRING MORE ENHANCED PRECIP INTO THE CENTRAL AND NORTHERN
PANHANDLE. A DEVELOPING SURFACE WAVE NOW NEAR 45N 150W IS
BEGINNING TO LOOK MORE ORGANIZED THIS MORNING AS THE BAROCLINIC
LEAF STRUCTURE NEAR 50N 151W IS LOOKING MUCH BETTER. WITH THE CAA
MOVING SOUTHEASTWARD INTO THE SURFACE WAVE IN THE NORTHERN
PACIFIC WILL CONTINUE TO SEE BAROCLINICITY INCREASE INTO THE
AFTERNOON AND THE SURFACE WAVE WILL CONTINUE TO DEEPEN TO 995 MB
BY TONIGHT. BOTH THE 12Z EUROPEAN COMMUNITY AND 12Z GFS WERE WELL
INITIALIZED THIS MORNING AND WENT WITH A 12Z GFS/UKMET FOR THE
SHORT TERM AS BOTH MODELS DO FAIRLY GOOD JOB WITH THE DEVELOPING
WAVE AND ITS MOVEMENT INTO TOMORROW AFTERNOON. THE 12Z GFS IS A
LITTLE BIT FASTER AND STRONGER DUE TO THE MORE PHASED MID LEVEL
PVA IN THE NORTHERN PACIFIC. THIS COULD LEAD TO WIND ADVY GUSTS
ACROSS THE SOUTHERN PANHANDLE TOMORROW WITH A 60 KNOT 850 MB LLJ
NORTH OF THE CHARLOTTES.

 FOR TONIGHT ONSHORE SURFACE AND MID LEVEL FLOW COMBINED WITH THE
WEAK MID LEVEL TROUGH NEAR YAKUTAT WILL ALLOW FOR PERIODS OF
LIGHT RAIN ACROSS THE PANHANDLE. WITH THE STRENGTHENING SURFACE
RIDGE ACROSS THE CENTRAL PANHANDLE AND WESTERN BRITISH COLUMBIA
AND A WEAK SURFACE LOW MOVING INTO THE YUKON WILL SEE THE
NORTH/SOUTH SURFACE PRESSURE GRADIENT INCREASE. WITH THAT THE
SOUTHERLY WINDS WILL INCREASE...ESPECIALLY IN THE NORTHERN
PANHANDLE TONIGHT WITH LOCALLY BREEZY CONDITIONS NEAR TAIYA
INLET.

 FOR TOMORROW THE DEVELOPING SURFACE LOW IN THE NORTHERN PACIFIC
WILL MOVE TO WEST OF DIXON ENTRANCE BY THE AFTERNOON AND THIS
WILL INCREASE THE SURFACE PRESSURE GRADIENT ALONG THE SOUTHERN
PANHANDLE AND EXPECT WINDY CONDITIONS ALONG PRINCE OF WALES BY
NOON TOMORROW. ATTM...THE 12Z GFS IS DEVELOPING A 60 TO 65 KNOT
850 MB LLJ ACROSS THE SOUTHERN PANHANDLE TOMORROW SO WILL WAIT TO
SEE IF THE 18Z RUN IS CONSISTENT FOR POSSIBLE WIND ADVY IN
AKZ027. ALSO WITH STRONG UPPER LEVEL DIVERGENCE AND MID LEVEL PVA
ACROSS THE SOUTHERN PANHANDLE TOMORROW WILL SEE LOCALLY HEAVY
RAINFALL. ACROSS THE CENTRAL AND NORTHERN PANHANDLE TOMORROW WILL
CONTINUE TO SEE LIGHTER PRECIP AMOUNTS AND MOSTLY CLOUDY SKIES
NEAR YAKUTAT WITH THE NORTHERLY WINDS IN THE AFTERNOON. IF THE
DEVELOPING SURFACE LOW IN THE NORTHERN PACIFIC MOVES FURTHER WEST
TOMORROW ALONG THE OUTER COAST COULD SEE BREEZY CONDITIONS INTO
THE CENTRAL PANHANDLE. SO THIS SYSTEM BEARS WATCHING INTO
TOMORROW AFTERNOON.

.LONG TERM...THERE STILL IS LARGE MODEL DIFFERENCES THROUGH MOST
OF THE WEEK SO THERE IS LOW CONFIDENCE IN THE FORECAST THIS COMING
WEEK. USED A BLEND OF THE 12Z GFS/EC/UKMET THROUGH MID WEEK BUT
THEN FOR THE REST OF THE WEEK USED THE HPC GRIDS AS IT USED A MIX
OF OPERATIONAL MODELS AND ENSEMBLES TO GET A CONSENSUS.

THE LARGE SCALE FLOW WILL REMAIN OUT OF THE SW WITH A MEAN
TROF OVER THE WESTERN GULF AND A RIDGE OVER THE WESTERN CONUS
THROUGH MOST OF THE WEEK. THE RIDGE WILL ADVECT WARM AIR NORTH OVER
THE PANHANDLE TO KEEP A TIGHT THERMAL GRADIENT OVER SE AK THROUGH
WED WITH RAIN BEING LIKELY TO CATEGORICAL. THERE WILL BE MULTIPLE
WAVES DEVELOPING ALONG THE BAROCLINIC ZONE OVER THE NORTHERN
PACIFIC AND MOVE INTO THE EASTERN GULF THROUGH THE WEEK. THESES WAVES
WILL INCREASE THE WINDS OVER THE EASTERN GULF TO SMALL CRAFT ON
MON THEN AGAIN ON THURSDAY AS A STRONGER LOW MOVES INTO THE SOUTHERN
GULF. THERE IS LOW CONFIDENCE ON THIS LOW SO LOWERED WINDS TO MIN SMALL
CRAFT ATTM AS THE GFS WAS SHOWING MIN GALES.

THE WARM FRONT WILL DRIFT TO THE WEST THROUGH THURSDAY AS THE
UPPER TROF OVER THE WESTERN GULF DIGS IN THE NORTH PACIFIC AND
ALLOWS THE FRONT TO MOVE OVER PAYA. BEFORE THE FRONT MOVES WEST
PAYA WILL BE ON THE DRY SIDE OF THE WARM FRONT AND BE ON THE
COOLER SIDE THROUGH THE EARLY WEEK. THE UPPER TROF WILL LIFT INTO THE
EASTERN GULF AND PUSH THE RIDGE EAST LATE IN THE WEEK INTO NEXT WEEKEND.
THIS WILL PUSH COLDER AIR OVER THE PANHANDLE FOR NEXT WEEKEND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ041>043-051-052.

&&

PSS/ABJ