Gale Warning 149, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE JUNEAU AK
129 PM AKST TUE FEB 14 2012

.SHORT TERM...EARLY AFTERNOON SATELLITE LOOP REVEALS A WEAKENING
OCCLUDED FRONT OVER THE NORTHERN PANHANDLE WITH LIGHT RAIN/SNOW
MIX FALLING ACROSS THE CENTRAL PANHANDLE. CLOUDS ARE THINNING OUT
OVER THE SOUTHERN AREAS WITH FREQUENT SUNNY BREAKS. A WEAK RIDGE
OF HIGH PRESSURE BUILDS OVER THE EASTERN GULF...PUSHING THE
WEAKENING FRONT EASTWARD. SOUTHERLY PRESSURE GRADIENT BEGINS TO
RELAXING WITH DECREASING WINDS OVER SKAGWAY AND NORTHERN LYNN
CANAL.

 MODELS ARE IN GENERAL AGREEMENT WITH THE WEAKENING FRONT OVER
THE NORTHERN PANHANDLE DISSIPATING LATE TONIGHT. REFRESHED THE
INHERITED FORECAST PACKAGE WITH THE MOST PERSISTENT ECMWF FOR
TONIGHT AND WEDNESDAY. A DEVELOPING LOW IN THE FAR SOUTHWESTERN
GULF WILL SLIGHTLY DEEPEN AND DRIFT NORTHWARD TO NEAR KODIAK
THROUGH WEDNESDAY MORNING. THE LOW WILL PUSH ANOTHER OCCLUDED
FRONT INTO THE EASTERN GULF EARLY WEDNESDAY MORNING. THEN THE
FRONTAL BOUNDARY WILL MOVE ONSHORE OVER THE PANHANDLE THROUGH
WEDNESDAY NIGHT.

 SOUTHEAST WINDS WILL INCREASE AND BECOME GALE FORCE ACROSS THE
WESTERN HALF OF THE OFFSHORE AND NORTHERN OUTSIDE WATERS LATE
TONIGHT IN RESPONSE TO THE INCOMING FRONT. THE WINDS WILL SHIFT
TO SOUTH BEHIND THE FRONTAL PASSAGE AND DECREASE TO SMALL CRAFT
WINDS BY WEDNESDAY AFTERNOON. ACROSS THE INNER CHANNELS...SMALL
CRAFT WINDS WILL AFFECT NEAR OCEAN ENTRANCES ON WEDNESDAY WITH
THE ARRIVAL OF THE FRONTAL PASSAGE.

 WITH THE DISSIPATING FRONTAL BOUNDARY...LIGHT RAIN/SNOW MIX WILL
CONTINUE TO TAPER OFF OVER THE NORTHERN PANHANDLE TONIGHT. THE
INCOMING FRONT WILL BRING THE FORECAST AREAS BACK TO WET WITH
CATEGORICAL POPS BY WEDNESDAY AFTERNOON. PRECIPITATION WILL BE
MOSTLY RAIN OVER THE SOUTHERN HALF OF THE PANHANDLE. SNOW/RAIN
MIX OVER THE NORTHERN AREAS WILL BECOME ALL RAIN...HEAVY AT
TIMES...IN THE AFTERNOON AS THE EMBEDDED WARMER AIR MOVING INTO
THE AREA WITH THE FRONTAL PASSAGE.

 &&

 .LONG TERM...EXTENDED RANGE MODELS ARE STILL HAVING A FEW
PROBLEMS BEGINNING AS SOON AS THURS. FIRST PROBLEMS BEGIN SHOWING
UP WITH THE SPEED OF A FRONT MOVING THROUGH THE PANHANDLE ON
THURS. GFS, 12Z EC, AND NAM ARE THE FASTER OF THE VARIOUS
SCENARIOS WITH THE 00Z EC NOT FAR BEHIND. THE UKMET IS GOING OUT
ON A LIMB WITH A DEVELOPING LOW THAT SMACKS INTO THE SOUTHERN
OUTER COAST THURS NIGHT. THE DIFFERENCES DON'T END THERE. THE
NEXT SYSTEM IN LINE VARIES BETWEEN BEING A WEAK SECONDARY LOW IN
THE WESTERN GULF TO THE MAIN BERING SEA LOW (0Z AND 12Z EC)
BEFORE THE BERING LOW WEAKENS EARLY FRIDAY, OR IT EVOLVES INTO
THE DOMINATE LOW OF THE TWO AND THE BERING SEA LOW WEAKENS AWAY
(6Z AND 12Z GFS). NAM PUTS ANOTHER SPIN ON IT AND TAKES THAT
SECONDARY LOW INTO THE CENTRAL GULF INSTEAD OF LETTING IT WEAKEN
NEAR KODIAK ISLAND AND THE UK DOESN'T EVEN LET THE FEATURE INTO
THE GULF INSTEAD SENDING IT OVER TO VANCOUVER ISLAND BY FRIDAY.
AT LEAST FOR THE GFS, EC, AND NAM THEY ALL SEND A WEAK FRONT INTO
THE PANHANDLE SOMETIME EARLY FRIDAY. THE DIFFERENCES CONTINUE
THROUGH THE EXTENDED PERIOD. NEEDLESS TO SAY THE CONFIDENCE FOR
THE LONG RANGE FORECAST IS NOT VERY HIGH. SO FAR NEWER MODELS
RUNS HAVE JUST BEEN REINFORCING WHAT THE PREVIOUS RUNS FOR THAT
PARTICULAR MODEL HAVE BEEN SAYING ESPECIALLY WITH THE GFS AND EC.

 NOT EVERYTHING IS NOT AGREEING WITH EACH OTHER HOWEVER. THE
OVERALL LARGE SCALE PATTERN REMAINS WELL REPRESENTED WITH A BROAD
UPPER TROUGH DOMINATING THE NORTHERN PACIFIC, AND BERING SEA. AN
EMBEDDED UPPER LOW AND ITS SURFACE REFLECTION IN THE BERING WILL
WEAKEN AWAY THURS NIGHT ONLY TO BE REPLACED BY ANOTHER UPPER LOW
A LITTLE FARTHER TO THE WEST BY FRI. WE ARE LEFT WITH A WEST TO
SW FLOW PATTERN WHICH WILL CONTINUE TO MAKE FORECASTING PRECIP
TYPE DIFFICULT WITH THE CONTINUED SWITCHING BETWEEN WARM AND COLD
ADVECTION.

 FOR FORECAST UPDATES DECIDED TO GO WITH A BLEND OF THE GFS AND
12Z EC AS BOTH APPEARED TO BE REASONABLY CLOSE ENOUGH TO EACH
OTHER TO GET A REASONABLE MIDDLE GROUND OUT OF THE BLEND. THAT
AND BOTH SHOWED REASONABLE RUN TO RUN CONSISTENCY FOR THERE
RESPECTIVE SCENARIOS. SAT AND BEYOND PUT MORE WEIGHT ON THE HPC
DATA FOR ITS USE OF ENSEMBLE DATA. FORECAST CONFIDENCE IS ABOUT
AVERAGE IN THE MID RANGE AND BELOW AVERAGE PAST FRIDAY.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ052.
         SMALL CRAFT ADVISORY FOR PKZ012-022-033>036-041>043-051.

&&

AHN/EAL