Gale Warning 399, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
315 PM AKST WED NOV 9 2011

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS A LOW PRESSURE
SYSTEM LIFTING NORTH OVER THE FAR SOUTHERN AREAS WITH THE CLOUD
SHIELD EXTENDING NORTH NEAR PAPG. THE REST OF THE FORECAST AREA
HAS VARIABLE CLOUDINESS WITH MOSTLY CLOUDY CONDITIONS OVER THE
NORTHERN GULF COAST. CLOUDS FROM THE WEST WILL MOVE OVER THE
PANHANDLE AHEAD OF A LOW MOVING INTO THE NORTHERN GULF. THERE IS
SOME ISOLATED SHOWERS NEAR PAYA WITH STEADY RAIN OVER THE
SOUTHERN THIRD. THE REST OF THE FORECAST AREA IS ON THE DRY SIDE
WHICH WILL CONTINUE THROUGH MOST OF THE NIGHT. WINDS ARE
GENERALLY LESS THAN 20 KT FROM THE NNW. THE WINDS WILL REMAIN ON
THE LIGHT BUT AS A WEAK SURFACE RIDGE BUILDS OVER THE AREA THEY
WILL VEER AROUND TO THE S THROUGH TONIGHT.

 AS THE LOW FROM THE WEST DRIFTS INTO THE NORTHERN GULF A STRONG
WARM FRONT WILL MOVE OVER THE EASTERN GULF LATE TONIGHT AND BE
OVER THE PANHANDLE BY THE AFTERNOON. AS THE ONSHORE FLOW
INCREASES RAIN WILL SPREAD FROM THE NORTH TO SOUTH THROUGH THE
PANHANDLE THURSDAY. MOST OF THE FORECAST AREA WILL SEE RAIN BUT
THE FAR NORTHERN AREAS WILL START OUT AS SNOW WITH ACCUMULATIONS
FROM 1-3 INCHES BEFORE THE WARMER AIR MOVES IN A CHANGES TO RAIN.
THE RAIN WILL BE HEAVY AT TIMES OVER THE SOUTHERN THIRD FROM VERY
STRONG VERTICAL MOTION AND MOISTURE TRANSPORT. THE WINDS OVER THE
GULF WILL INCREASE FROM THE SE THROUGH THE MORNING HOURS TO BE
MAX SMALL CRAFT BUT WILL INCREASE FROM THE WEST ONCE THE COLD
FRONT OVER THE CENTRAL GULF DRIFTS EAST. A LOW WILL DEVELOP NEAR
THE TRIPLE POINT BY THE AFTERNOON NEAR CROSS SOUND. THIS WILL
INCREASE THE WINDS OVER THE INNER CHANNELS THROUGH THE DAY TO
RANGE FROM 15 TO 25 KT WITH THE STRONGEST WINDS OVER THE FAR
SOUTHERN AREAS WITH MIN GALE IN AREA 36. LAND AREAS WILL SEE THE
WINDS FROM THE SE TO BE FROM 10 TO 20 WITH SOME LOCALLY HIGH
GUSTS IN EXPOSED AREAS ALONG THE COAST. BY THE AFTERNOON THE
SOUTHERN AREAS WILL SEE WINDY CONDITIONS AS THE FRONT MOVES OVER
THEM AND MAY SEE GUSTS TO 35 MPH.

 USED A BLEND OF THE EC/GEM/UKMET FOR THE NEXT 24HRS AS THEY WERE
HOLDING THE FRONT BACK SOME AND WAS SHOWING THE TRIPLE POINT
FEATURE WELL. THE NEW GFS AND NAM IS NOW SHOWING THE SAME KIND OF
SOLUTION SO THERE IS SLIGHTLY ABOVE AVERAGE FORECASTER CONFIDENCE
FOR THE FIRST 24HRS.

&&

.LONG TERM...FOR THURSDAY EVENING THE LOW IN THE NORTHERN AK GULF
WILL MOVE TOWARD THE PANHANDLE COAST AND BEGIN TO DRIFT A BIT TO
THE SOUTH THEN MOVING EAST TOWARD BRITISH COLUMBIA. PRECIP WILL
BEGIN TO DIMINISH OVERNIGHT AND WITH COLD AIR PUSHING IN BEHIND
RAIN OVER THE NORTHERN PANHANDLE WILL BEGIN TO MIX WITH SNOW.
HAINES AND THE HAINES HIGHWAY COULD SEE SOME HIGHER SNOW
ACCUMULATION BUT PRECIP SHOULD END BEFORE ANY SIGNIFICANT
ACCUMULATION. HIGH PRESSURE RIDGE BEHIND THE LOW WILL CLEAR CLOUD
COVER FRIDAY WITH COLD MORNING TEMPS. WITH THE PREVIOUS NIGHTS
PRECIP MAY SEE SOME ICY ROADS FOR THE FRIDAY COMMUTE. THE NEXT LOW
WILL DEVELOP THE WESTERN AK GULF FROM TRIPLE POINT ASSOCIATED
WITH A 960 MB LOW IN THE BERING SEA 06Z SAT. THE LOW WILL TRACK
EAST WITH ASSOCIATED FRONT REACHING THE PANHANDLE BETWEEN 12Z AND
18Z SAT. EC HAS KEPT THIS LOW FURTHER TO THE NORTH WHILE THE GFS
HAS BEGUN TO TRACK IT FURTHER SOUTH FROM RUN TO RUN. GFS NOW
INDICATED A DEEPER LOW CENTER NEARING 965 MB WHILE THE EC HAS
KEPT THE CENTER NEAR 971 MB. MAIN DIFFERENCE WILL BE STRENGTH OF
WINDS IN THE AK GULF...FOR NOW BLENDED TOWARD THE HIGHER GFS
SOLUTION. FOR THE START OF NEXT WEEK LOOKING AT ANOTHER COLD AIR
MASS PUSHING EAST WITH 850 MB TEMPS NEARING -10C. WITH MORE ZONAL
FLOW NEXT LOW WILL TRACK ACROSS THE SOUTHERN AK INTERIOR WITH A
QUASI STATIONARY LOW DEVELOPING IN THE NORTHERN AK GULF.

DIFFERENCES BETWEEN THE MODELS AND DIFFERENCES RUN TO RUN LOOK
MINOR AT FIRST GLANCE BUT THESE INCONSISTENCIES ARE CAUSING FAIR
DIFFERENCES IN THE PRACTICAL FORECAST. WHILE THE EC WAS THE LEAST
CONSISTENT RUN TO RUN PREVIOUS DAYS NOW THE GFS IS SHOWING
INCREASED JUMPS FORM RUN TO RUN WHILE THE EC HAS BECOME A BIT MORE
CONSISTENT...ESPECIALLY WITH RESPECT TO THE LOW IN THE NORTHERN AK
GULF 12Z SAT. USED A BLEND OF 12Z ECMWF AND UKMET FOR THE START OF
THE LONG TERM THEN TRANSITIONED IN SOME 12Z GFS TO MATCH BETTER
WITH THE ANCHORAGE BORDER...AS THEY HAD THE LOW FURTHER SOUTH THAN
THE EC WITH WINDS A BIT STRONGER. FOR THE REST OF THE LONG TERM
SWITCHED TO THE NEW HPC GRIDS...WHICH WAS A BIT CLOSER TO THE
ECMWF BUT STILL MORE OF A SUPER BLEND. FORECAST CONFIDENCE IS
BELOW AVERAGE.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ036.
         SMALL CRAFT ADVISORY FOR PKZ022-031>035-041>043-051-052.

&&

ABJ/PRB