Gale Warning 262, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
601 AM AKDT SUN OCT 19 2008

.SHORT TERM...THE GALE FORCE LOW IN THE WESTERN GULF CONTINUES TO
FILL AND WEAKEN THIS MORNING...HOWEVER IT CONTINUES TO WRAP LARGE
AMOUNTS OF COLD AIR AT MID LEVELS EASTWARD INTO THE EASTERN GULF
AS SEEN ON SATELLITE. THIS COLD AIR ALONG WITH UPPER LEVEL JET ENERGY IN
THE NORTHEASTERN PACIFIC HAS ALLOWED A SECOND SURFACE LOW TO FORM
WITHIN THE TRIPLE POINT JUST WEST OF DIXON ENTRANCE. THIS SECOND
SURFACE LOW AND ASSOCIATED MID LEVEL FRONTOGENETICAL STRUCTURE
WILL ADVECT NORTHWARD ACROSS THE PANHANDLE THIS MORNING CONTINUING
TO BRING RAIN. THE WINDY CONDITIONS WILL CONTINUE ALONG THE
SOUTHERN PANHANDLE THIS MORNING AS A 60 KNOT LLJ AT 850 MB
CONTINUES MIX WIND ADVY GUSTS DOWN TO THE SURFACE. EXPECT THESE
WINDY CONDITIONS TO CONTINUE INTO THE AFTERNOON...HOWEVER THE 850
MB LLJ WILL WEAKEN AND BE CONFINED TO JUST ALONG CLARENCE STRAIT
BY THE LATE MORNING. THEREFORE BELIEVE WIND ADVY GUSTS WILL
DIMINISH BY MID MORNING IN THE HYDABURG AREA AND ALONG WESTERN
PRINCE OF WALES ISLAND. ELSEWHERE SMCR ADVY WINDS WILL DIMINISH
EARLY THIS MORNING WITHIN THE CENTRAL PANHANDLE...BUT GALES WILL
CONTINUE ALL DAY WITHIN CLARENCE STRAIT WITH THE 850 MB LLJ
LOCATED DIRECTLY OVERHEAD. THE RAIN WILL CONTINUE TO BE HEAVY AT
TIMES NEAR KETCHIKAN AS STRONG UPPER LEVEL DIVERGENCE IN THE LEFT
EXIT REGION OF THE UPPER LEVEL JET WILL CONTINUE TO REMAIN OVER
THE SOUTHERN PANHANDLE INTO THE EARLY AFTERNOON. USED THE 00Z GFS
IN TODAYS PACKAGE AS IT HAS BEEN THE MORE CONSISTENT MODEL OVER
THE PAST FEW RUNS AND IT WAS A GOOD COMPROMISE BETWEEN THE 00Z
UKMET AND 00Z ECMWF.

FOR TONIGHT EXPECT THE PRECIPITATION TO BECOME MORE CONVECTIVE AS
CAA OCCURS FROM 850 THROUGH 500 MB EARLY THIS EVENING ACROSS THE
EASTERN GULF AND PUSHES INTO THE CENTRAL PANHANDLE. THIS MID
LEVEL CAA COMBINED WITH PVA IN THE ADVANCED OF ANOTHER SHORTWAVE
TROUGH ADVECTING ACROSS THE PANHANDLE WILL ALLOW FOR NUMEROUS SHOWERS
ACROSS THE PANHANDLE TONIGHT. EXPECT THE SHOWERS TO BE MORE
SCATTERED TO ISOLATED NEAR SKAGWAY AS IT WILL TAKE LONGER FOR THE
MID LEVEL PVA TO MOVE ACROSS THE EXTREME NORTHERN PANHANDLE. WITH
WINDS DIMINISHING ACROSS THE NORTHERN AND CENTRAL PANHANDLE
TONIGHT AND A FEW BREAKS IN THE CLOUD COVER COULD SEE AREAS OF FOG
AND DRIZZLE FORMING...HOWEVER WITH A MORE CONVECTIVE ENVIRONMENT
THIS WILL BE DIFFICULT. THE WINDY CONDITIONS ACROSS THE SOUTHERN
PANHANDLE WILL CONTINUE TO DIMINISH THROUGH TONIGHT AS THE SURFACE
PRESSURE GRADIENT CONTINUES TO RELAX AND THE 850 MB LLJ FINALLY
ADVECTS INTO WESTERN BRITISH COLUMBIA BY LATE TONIGHT. ELSEWHERE
SMCR WILL CONTINUE WITHIN THE COASTAL WATERS AS SEAS WILL REMAIN 9
TO 14 FEET WITH THE SW SWELL.

.LONG TERM...GOOD AGREEMENT BETWEEN THE MODELS ON THE DEVELOPMENT
OF A STORM FORCE LOW ENTERING THE SOUTH CENTRAL GULF LATE TUESDAY
OR TUESDAY NIGHT. OTHERWISE MINOR MODEL DIFFERENCES IN TRACK AND
INTENSITY ARE BEING EXAGGERATED BY THE VERY DEEP CENTRAL PRESSURE
AND THE VERY STEEP PRESSURE GRADIENTS INVOLVED. BLENDED GFS AND
UKMET TO EXISTING GRIDS FOR THIS SYSTEM THROUGH WEDNESDAY. BEYOND
THIS TIME...DIFFERENCES BETWEEN GFS AND ECMWF WERE SO RADICAL THAT
NO COMPROMISE WAS POSSIBLE IN BLENDING...SO WENT WITH A BLEND OF
HPC AND ECMWF.

GALE FORCE WINDS WILL SPREAD NORTH OVER THE EASTERN GULF ON
TUESDAY MORNING AND INTENSIFY TO STORM FORCE BY TUESDAY AFTERNOON.
IN ADDITION TO WIDE SPREAD GALES OVER A MAJORITY OF THE INNER
CHANNELS...AM EXPECTING TO SEE ADVISORY LEVEL WIND GUSTS OVER THE
OUTER COAST FROM CAPE SPENCER SOUTH TO THE DIXON ENTRANCE THROUGH
TUESDAY NIGHT. AT THIS POINT...ADVISORIES FOR ZONES 26 AND 28 MAY ALSO
BE NEEDED THROUGH TUESDAY EVENING.

SOUTHEAST GALES DEVELOP OVER THE COASTAL WATERS AGAIN ON THURSDAY
AS ANOTHER VERY DEEP LOW TRACKS EAST ACROSS THE NORTHERN GULF. DO
NOT THINK THIS ONE WILL MAKE IT ALL THE WAY TO THE PANHANDLE BUT
RATHER WILL COME ASHORE VICINITY PRINCE WILLIAM SOUND AND FILL.
ASSUMING THIS...THE PANHANDLE WILL BE SPARED THE WORST OF THIS
SYSTEM. GFS IS CURRENTLY OFFERING A MUCH MORE PESSIMISTIC SOLUTION
WITH REGARD TO THIS LOW AND WILL HAVE TO BE WATCHED CLOSELY.

THE THIRD VERY DEEP LOW AND THIRD ROUND OF GALES OVER THE MARINE
ZONES IN THE LONG RANGE FORECAST PERIOD BEGINS NEXT WEEKEND WHEN A
LOW AND ASSOCIATED FRONT TRACKS NORTHEAST INTO HE GULF AND HEADS
FOR THE COAST VICINITY CAPE SUCKLING.

MODELS HAVE BEEN CONSISTENT FOR PAST THREE DAYS IN FORECASTING
HEAVY RAIN ACROSS MOST OF THE PANHANDLE ON TUESDAY AND TUESDAY
NIGHT SO HAVE INCLUDED THIS PHRASE IN THE MORNING FORECAST AND
EXPECT TO SEE FOUR TO SIX INCHES OF RAIN BETWEEN TUESDAY MORNING
AND WEDNESDAY MORNING. HEAVIEST RAIN EXPECTED TO FALL OVER THE
SOUTHERN ZONES. AFTER A BRIEF BREAK ON WEDNESDAY...ANOTHER ROUND
OF HEAVY RAINS IS EXPECTED ON THURSDAY.

ADJUSTED TEMPERATURES DOWN LATE IN THE WEEK AS AN ARCTIC BOUNDARY
SETS UP. SNOW LEVEL FORECAST ALSO REFLECTS THE FALLING TEMPS AND
AM EXPECTING TO SEE SOME SNOW IN YAKUTAT...HOONAH...AND JUNEAU BY
NEXT WEEKEND...WHICH WOULD BE ABOUT A WEEK EARLIER THAN CLIMATOLOGY.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL 9 AM AKDT THIS MORNING FOR AKZ027.
         WIND ADVISORY UNTIL 3 PM AKDT THIS AFTERNOON FOR AKZ028.
MARINE...GALE WARNING FOR PKZ036.
         SMALL CRAFT ADVISORY FOR PKZ035-041>043-051-052.

&&

PSS/FRITSCH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JUNEAU AK
320 AM AKDT SUN OCT 19 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0113 AM     NON-TSTM WND GST ANNETTE                 55.04N 131.59W
10/19/2008  M41 MPH                             AK   ASOS

0213 AM     NON-TSTM WND GST METLAKATLA              55.12N 131.58W
10/19/2008  M40 MPH                             AK   AWOS

&&

PRB