Gale Warning 213, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
143 PM AKDT SAT AUG 15 2009

.SHORT TERM...NC TO RAIN FCST, ONLY SMALL CHGS TO THE WIND
FCSTS.  NOTE THE GALES ARE BEING KEPT FOR NRN LYNN CANAL AND A
WIND ADVISORY GUSTS SHOULD BEGIN TO OCCUR AT PAGY ABT 6 PM THIS
EVENING.

 WELL ESTABLISHED POLAR FRONT ZONE EXTENDS SW FOR OVER A  1500 NM
SW OF THE YAKUTAT ZONE.  NO REASONS TO CHG TO PRECIP  FCSTS. RAIN
HEAVY AT TIMES FOR YAKUTAT, STEADY RAIN IN THE  PNHDL NORTH OF
FREDERICK SOUND AND RAIN DEVELOPING S.   THE PAYA RAOB AT 12Z WAS
SATURATED FOR THE BOTTOM THREE  MILES.  PRECIPITABLE WATER VALUES
OF ABOUT 1.3 INCHES EXISTS UPSTREAM FOR 1000 NM, AND LARGER
FURTHER UPSTREAM.   MEASURABLE RAINFALL RATES WILL SPREAD SE
ACROSS THE PNHDL S OF FREDERICK SOUND FROM ABOUT 6 PM THIS
EVENING TO 6 AM SUNDAY.

 THE STRONGEST WINDS WILL CONTINUE TO OCCUR IN THE NRN PNHDL.
PRESS FALLS IN SRN YUKON TRRTY ARE ASSOCD WITH SHORT WV THAT
TRACKED NE BYD THE AK RANGE THIS MORNING, AND HAS RAISED THE
GUSTS IN PAGY TO ALMOST 40 MPH.  FOLLOWING WV THAT IS UPSTREAM
SHOULD CAUSE PRESSURE FALLS TO RAISE THE WINDS FURTHER AND PAGY
SHOULD REACH WIND THE G40 KT THRESHOLD FOR WIND ADVISORIES THIS
EVENING.

 THE NAM TO GFS CONSENSUS IS GOOD AND BOTH HAVE BEEN APPLIED. THE
SREF WAS THE PRIMARY GUIDANCE FOR POP.

 &&

 .LONG TERM...WET FORECAST IN SIGHT FOR THE PANHANDLE FOR THE
NEXT FEW DAYS. STRONG ONSHORE MOISTURE PLUME THROUGH A DEEP LAYER
OF THE ATMOSPHERE WILL CONTINUE TO BRING RAIN TO MOST OF THE AREA
THROUGH MONDAY NIGHT. THE HEAVY RAINS AND HIGH FREEZING LEVELS
WILL KEEP CONCERN ON HIGH RIVER LEVELS THROUGHOUT THE AREA. BY
TUESDAY WITH UPPER RIDGING MOVING INTO THE AREA PRECIP WILL BEGIN
TO TAPER OFF A BIT, BUT ONSHORE FLOW WILL KEEP A LEAST A CHANCE
OF PRECIP IN THE FORECAST. NAM WAS PRIMARY MODEL USED EARLY ON
WITH SOME GFS THROWN IN. WINDS WILL ALSO BE AN ISSUE EARLY THIS
WEEK WITH SCA WINDS EXPECTED IN THE SOUTHERN COASTAL MARINE ZONES
AND LYNN CANAL EARLY NEXT WEEK. SEAS IN THE OUTSIDE WATERS WILL
ALSO BE HIGH WITH WAVE HEIGHTS OF UP TO 14 FT IN THE OFFSHORE
AREAS EARLY NEXT WEEK.

 BY WEDNESDAY, A STRONG UPPER TROUGH WILL BE MOVING EAST ACROSS
THE GULF. AT THE SURFACE THIS WILL TAKE THE FORM OF A WEAK LOW
MOVING FROM THE NORTH PACIFIC INTO THE NORTHERN PANHANDLE ONCE
AGAIN BRINGING A GOOD CHANCE OF RAIN TO THE AREA. MODELS ARE
HAVING SOME TROUBLE WITH THIS SYSTEM. RUN TO RUN CONSISTENCY HAS
BEEN BAD AS OF LATE ON THE TIMING AND STRENGTH LEADING TO A BELOW
AVERAGE CONFIDENCE ON THE FORECAST FOR MIDWEEK AND BEYOND. GFS IS
TAKING A 1010 MB LOW AND SENDING IT NORTHEAST INTO CAPE SPENCER
BY WEDNESDAY EVENING. THE PREVIOUS RUN HAD THE LOW FARTHER NORTH,
FASTER, AND STRONGER THEN THE CURRENT RUN. MEANWHILE, THE EC IS
BOUNCING AROUND MORE THEN THE GFS. THE 12Z RUN ON THE 14TH HAD A
SOLUTION THAT WAS SOMEWHAT SIMILAR TO WHAT THE CURRENT GFS IS
SHOWING. THE NEXT RUN FEATURED A MUCH FASTER SYSTEM, EVEN FASTER
THEN THE 6Z RUN OF THE GFS WAS SUGGESTING. THE CURRENT 12Z RUN OF
THE EC, NOW FEATURES A MUCH SLOWER, STRONGER (995MB), AND
SLIGHTLY FARTHER NORTH SYSTEM, AND IT KEEPS THE LOW IN THE
NORTHERN GULF MUCH LONGER. IN THIS TIME PERIOD, AFTER SOME
TALKING WITH THE HPC ALASKA DESK, DECIDED TO FALL IN WITH TODAYS
HPC GRIDS AS THEY PROVIDED A VERY GOOD MIDDLE GROUND TO WORK
WITH. STILL HAD TO DO SOME HAND EDITING TO GET WHAT I HAD IN MIND
INTO THE GRIDS.

 AFTER THURSDAY, THE CURRENT THINKING IS THAT AN UPPER RIDGE WILL
BUILD INTO THE AREA FOR FRIDAY AND SATURDAY. STILL HAVE CHANCE TO
SLIGHT CHANCE POPS OUT FOR MOST OF THE AREA AT THIS TIME, AS
THERE IS STILL SOME UNCERTAINTY ON WHETHER THE SYSTEM MIDWEEK
WILL STICK AROUND IN THE GULF OR NOT. BY EARLY THE FOLLOWING WEEK
MODELS SUGGEST THAT ANOTHER FRONTAL FEATURE WILL BE ARRIVING IN
THE PANHANDLE AGAIN GIVING US A HIGHER CHANCE OF PRECIP.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY FROM 6 PM THIS EVENING TO 6 PM AKDT SUNDAY FOR
     AKZ018.
MARINE...GALE WARNING FOR PKZ012.
         SMALL CRAFT ADVISORY FOR PKZ011-013-022-031-032-043-051-052.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041-042.

&&

JBT/EAL