000
WTNT45 KNHC 172101
TCDAT5

Tropical Storm Don Discussion Number   1
NWS National Hurricane Center Miami FL       AL052017
500 PM AST Mon Jul 17 2017

An Air Force Reserve reconnaissance aircraft investigating the area
of low pressure located east-southeast of the Windward Islands has
found a small, but well-defined surface circulation and a small
area of tropical-storm-force winds over the eastern semicircle of
the circulation.  The associated convection is not particularly
well organized, but there is a curved band located to the north
of the center and a couple of bursts have formed closer to the
small circulation center this afternoon. Based on these data,
advisories are being initiated on a tropical storm, the fourth of
the 2017 Atlantic hurricane season. Don is currently within a
low shear environment and over warm water, so some strengthening is
possible tonight and Tuesday. Once the system enters the eastern
Caribbean Sea, strong upper-level westerly winds and strong
low-level easterly flow are likely to cause the small circulation to
open up into a trough.  As a result, dissipation is forecast within
72 hours.

Don is moving westward or 275/15 kt. The tropical storm is forecast
to move quickly westward within the strong trade-wide flow for the
next few days.  The NHC track is along the southern edge of the
guidance envelope, closest to the HFIP corrected consensus
prediction.


FORECAST POSITIONS AND MAX WINDS

INIT  17/2100Z 11.2N  52.6W   35 KT  40 MPH
 12H  18/0600Z 11.5N  55.5W   40 KT  45 MPH
 24H  18/1800Z 11.8N  58.9W   40 KT  45 MPH
 36H  19/0600Z 12.0N  62.8W   40 KT  45 MPH
 48H  19/1800Z 12.2N  67.0W   40 KT  45 MPH
 72H  20/1800Z...DISSIPATED

$$
Forecaster Brown