778 
 WTNT44 KNHC 280231
 TCDAT4
  
 TROPICAL STORM DON DISCUSSION NUMBER   2
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042011
 1000 PM CDT WED JUL 27 2011
  
 THE CLOUD PATTERN HAS NOT CHANGED SIGNIFICANTLY DURING THE PAST
 SEVERAL HOURS WITH THE EXCEPTION OF THE UPPER-LEVEL OUTFLOW THAT IS
 EXPANDING IN THE WESTERN PORTION OF THE CYCLONE. DEEP CONVECTION
 NEAR THE CENTER HAS DIMINISHED BUT THERE IS A CYCLONICALLY
 CURVED CONVECTIVE BAND TO THE SOUTH. T-NUMBERS HAVE NOT CHANGED AND
 THE INITIAL INTENSITY IS KEPT AT 35 KNOTS. ANOTHER RECONNAISSANCE
 PLANE IS SCHEDULED TO CHECK THE CYCLONE AT DAYBREAK.
  
 DON IS MOVING OVER WARM WATERS AND THE SHIPS GUIDANCE AS WELL AS
 MOST OF THE GLOBAL MODELS INDICATE THAT THE SHEAR IS LIKELY TO
 REMAIN RELATIVELY LOW...ALLOWING FOR SOME INTENSIFICATION.
 HOWEVER...NONE OF THE INTENSITY MODELS SHOW SIGNIFICANT
 STRENGTHENING. IT SHOULD BE NOTED THAT THE 48-HR OFFICIAL INTENSITY
 FORECAST OF 55 KT IS BEFORE LANDFALL...AND DON COULD GAIN SOME
 ADDITIONAL STRENGTH AS IT APPROACHES THE COAST.
  
 THE CYCLONE IS MOVING TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT
 10 KNOTS. THE RIDGE OVER THE SOUTHERN UNITED STATES CONTROLLING THE
 CURRENT MOTION OF DON IS EXPECTED TO PERSIST OR EVEN BUILD WESTWARD
 A LITTLE. THEREFORE...NO SIGNIFICANT CHANGE IN THE STEERING PATTERN
 IS ANTICIPATED...AND DON SHOULD CONTINUE TO MOVE ON THE SAME
 GENERAL WEST-NORTHWEST OR NORTHWEST TRACK TOWARD THE TEXAS COAST.
 THE TRACK GUIDANCE IS NOT IN QUITE AS GOOD AGREEMENT AS ONE WOULD
 LIKE TO SEE...HOWEVER.  SOME MODELS LIKE THE GFDL AND GFDN BRING
 THE CYCLONE ON A MORE NORTHWESTERLY TRACK WHILE OTHERS...LIKE THE
 ECMWF...INDICATE A MORE WESTERLY MOTION. THE OFFICIAL FORECAST IS
 BASICALLY IN THE MIDDLE OF THE TWO OPTIONS.
  
 GIVEN THE CURRENT FORECAST TRACK AND UNCERTAINTIES... A TROPICAL
 STORM WATCH IS BEING ISSUED FOR A LARGE PORTION OF TEXAS COAST AT
 THIS TIME. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  28/0300Z 22.8N  88.1W   35 KT  40 MPH
  12H  28/1200Z 23.6N  89.5W   40 KT  45 MPH
  24H  29/0000Z 25.0N  91.5W   45 KT  50 MPH
  36H  29/1200Z 26.2N  93.6W   50 KT  60 MPH
  48H  30/0000Z 27.5N  96.0W   55 KT  65 MPH
  72H  31/0000Z 29.5N 100.0W   25 KT  30 MPH...INLAND
  96H  01/0000Z...DISSIPATED
  
 $$
 FORECASTER AVILA
  
 

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