000
WTNT45 KNHC 290254
TCDAT5
TROPICAL STORM SHARY DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL202010
1100 PM AST THU OCT 28 2010
 
SATELLITE...SHIP...AND BUOY DATA INDICATE THAT THE CIRCULATION
ASSOCIATED WITH THE LOW PRESSURE AREA SOUTHEAST OF BERMUDA HAS
BECOME BETTER DEFINED.  THE SYSTEM HAS MAINTAINED ORGANIZED
CONVECTION THROUGHOUT MOST OF THE DAY AND HAS ENOUGH ORGANIZATION
TO BE CLASSIFIED AS A TROPICAL CYCLONE.  THE CENTER OF THE CYCLONE
HAS PASSED JUST SOUTHWEST OF NOAA BUOY 41049 DURING THE PAST COUPLE
OF HOURS.  THE BUOY REPORTED PEAK 1-MINUTE SUSTAINED WINDS OF 33 KT
AT BOTH 0000 AND 0200 UTC.  BASED ON THE WIND OBSERVATIONS FROM THE
BUOY...THE SYSTEM IS STARTED AS A 35-KT TROPICAL STORM....THE
EIGHTEENTH OF THE 2010 ATLANTIC HURRICANE SEASON.  SINCE THERE IS
ENOUGH SEPARATION BETWEEN SHARY AND THE UPPER-LOW TO THE
SOUTHWEST...AND THERE IS A SMALL RADIUS OF MAXIMUM WINDS...THE
SYSTEM IS DESIGNATED AS A TROPICAL RATHER THAN A SUBTROPICAL
CYCLONE.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 310/20.  IT APPEARS THAT
THE CENTER HAS REFORMED TO THE NORTHWEST DURING THE PAST SEVERAL
HOURS...MAKING IT DIFFICULT TO DETERMINE A MORE PRECISE MOTION.
SHARY HAS BEEN MOVING BETWEEN A MID-LEVEL RIDGE TO THE NORTHEAST AND
THE LARGE UPPER-LEVEL LOW ITS SOUTHWEST.  THE TROPICAL STORM IS
EXPECTED TO TURN TOWARD THE NORTH AND THEN NORTHEAST DURING THE
NEXT 24-36 HOURS AS THE RIDGE MOVES EAST AND A MID-LATITUDE TROUGH
MOVES OFF THE EAST COAST OF THE UNITED STATES.  THE TRACK GUIDANCE
IS IN GOOD AGREEMENT...ALTHOUGH THERE ARE SOME DIFFERENCES IN THE
FUTURE FORWARD SPEED OF SHARY.  THE GFS...UKMET...AND ECMWF ARE
SLOWER THAN THE NOGAPS...GFDL...AND HWRF.  FOR NOW THE SLOWER
SOLUTION IS PREFERRED...AND THE OFFICIAL FORECAST IS SLOWER THAN
THE DYNAMICAL MODEL CONSENSUS.

IT APPEARS THAT SHARY WILL BE A RELATIVELY SHORT-LIVED TROPICAL
CYCLONE.  MODERATE SOUTH TO SOUTHEASTERLY SHEAR IS FORECAST TO
DECREASE DURING THE NEXT 12-24 HOURS...WHICH COULD ALLOW FOR SOME
STRENGTHENING.  AFTER 24 HOURS...SHARY WILL BE TRANSITIONING TO AN
EXTRATROPICAL CYCLONE AS IT MERGES WITH A COLD FRONT.  THE GLOBAL
MODELS DO NOT SHOW ANY ADDITIONAL INTENSIFICATION OF THE SYSTEM AS
AN EXTRATROPICAL CYCLONE.  IN FACT...THEY INDICATE THAT THE CYCLONE
SHOULD WEAKEN IN 3-4 DAYS AND DISSIPATE BY 96 HOURS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/0300Z 27.3N  63.7W    35 KT
 12HR VT     29/1200Z 29.6N  65.4W    40 KT
 24HR VT     30/0000Z 32.8N  63.9W    45 KT
 36HR VT     30/1200Z 35.5N  60.0W    45 KT...POST-TROP/EXTRATROP
 48HR VT     31/0000Z 39.3N  54.0W    40 KT...POST-TROP/EXTRATROP
 72HR VT     01/0000Z 43.5N  45.0W    30 KT...POST-TROP/EXTRATROP
 96HR VT     02/0000Z...DISSIPATED
 
$$
FORECASTER BROWN/BERG