000
WTNT41 KNHC 221432
TCDAT1
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
1100 AM AST THU SEP 22 2011
 
OPHELIA REMAINS QUITE DISORGANIZED IN ITS APPEARANCE ON SATELLITE
IMAGES.  EVEN WITH VISIBLE PICTURES THE LOW-LEVEL CENTER...SUCH AS
IT IS...IS DIFFICULT TO DISCERN.  MOST OF THE DEEP CONVECTION IS
SHEARED TO THE NORTHEAST AND EAST OF THE ESTIMATED CENTER.  FROM A
DVORAK PERSPECTIVE...THE SYSTEM IS RATED AS A LOW-END TROPICAL
STORM.  HOWEVER...BUOY...SHIP...AND SCATTEROMETER DATA HAVE BEEN
SAYING OTHERWISE AND THE CURRENT INTENSITY ESTIMATE REMAINS 55 KT. 
AS OPHELIA APPROACHES AN UPPER-LEVEL TROUGH TO ITS NORTHWEST...THE
SOUTHWESTERLY SHEAR THAT HAS BEEN IMPACTING THE STORM IS LIKELY TO
INCREASE FURTHER.  SLOW WEAKENING IS PREDICTED THROUGH 48 HOURS DUE
TO THE STRONG SHEAR.  AFTERWARDS...GLOBAL MODELS SUGGEST THAT THE
TROUGH WILL WEAKEN AND THE UPPER-TROPOSPHERIC FLOW NEAR THE STORM
WILL BECOME MORE ANTICYCLONIC.  BASED ON THIS SCENARIO...THE
OFFICIAL FORECAST SHOWS RE-INTENSIFICATION LATE IN THE FORECAST
PERIOD.  THIS IS CONSISTENT WITH THE LGEM AND SOME OF THE OTHER
NUMERICAL MODELS.

IT HAS BEEN A CHALLENGE TO TRACK THE CENTER BUT A ROUGH ESTIMATE OF
THE INITIAL MOTION IS 280/11.  THE TRACK FORECAST REASONING IS
ESSENTIALLY UNCHANGED FROM THE PREVIOUS PACKAGE.  A GRADUAL TURN
TOWARD THE WEST-NORTHWEST IS EXPECTED AS OPHELIA MOVES AROUND THE
SOUTHERN PERIPHERY OF A SUBTROPICAL HIGH PRESSURE SYSTEM.  LATER IN
THE PERIOD...A TURN TOWARD THE NORTHWEST IS ANTICIPATED AS THE
TROPICAL CYCLONE NEARS THE SOUTHWEST SIDE OF THE HIGH.  THE
OFFICIAL FORECAST IS A LITTLE NORTH OF THE PREVIOUS ONE...BUT ON
THE SOUTHERN SIDE OF THE GUIDANCE SUITE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/1500Z 13.6N  47.6W   55 KT  65 MPH
 12H  23/0000Z 14.0N  49.8W   55 KT  65 MPH
 24H  23/1200Z 15.0N  52.3W   50 KT  60 MPH
 36H  24/0000Z 16.2N  54.4W   50 KT  60 MPH
 48H  24/1200Z 17.4N  56.5W   45 KT  50 MPH
 72H  25/1200Z 20.5N  60.5W   45 KT  50 MPH
 96H  26/1200Z 22.5N  63.0W   50 KT  60 MPH
120H  27/1200Z 25.5N  65.5W   55 KT  65 MPH
 
$$
FORECASTER PASCH