[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

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
 WWWW
This weather bulletin was brought to you by:
www.nashvilleweather.net