000
WTNT42 KNHC 222035
TCDAT2

TROPICAL DEPRESSION SEVEN DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016
500 PM AST MON AUG 22 2016

The low pressure area located west-southwest of the Cabo Verde
Islands has developed a well-defined circulation and sufficient
organized convection to be considered a tropical depression.
Microwave imagery suggests that the system is likely still
consolidating, with two or more vorticity centers rotating around
a mean center.  The initial intensity is set to 30 kt in agreement
with a satellite intensity estimate from TAFB.

The initial motion is 275/16.  The cyclone is on the south side of
a deep-layer ridge over the eastern Atlantic, and as a result it
should move generally west-northwestward for the next 36-48 hours.
Beyond that time, the cyclone is forecast to turn northwestward
toward a weakness in the ridge over the central Atlantic.  The
track guidance is in good agreement with this scenario, and the
forecast track lies near the consensus models.

The depression is currently in an environment of light to moderate
easterly vertical shear.  This, combined with warm sea surface
temperatures, should allow strengthening. One possible negative
factor, however, is a tongue of African dust/dry air wrapping
around the west side of the circulation.  On that basis that the
dry air will not stop development, the intensity forecast calls for
steady strengthening through 72 hours.  After that time, arrested
development is likely due to the cyclone encountering moderate to
strong westerly vertical shear.


FORECAST POSITIONS AND MAX WINDS

INIT  22/2100Z 12.1N  29.0W   30 KT  35 MPH
 12H  23/0600Z 12.4N  31.4W   40 KT  45 MPH
 24H  23/1800Z 13.2N  34.4W   50 KT  60 MPH
 36H  24/0600Z 14.5N  37.2W   60 KT  70 MPH
 48H  24/1800Z 16.2N  39.9W   70 KT  80 MPH
 72H  25/1800Z 19.7N  44.8W   80 KT  90 MPH
 96H  26/1800Z 23.8N  50.1W   75 KT  85 MPH
120H  27/1800Z 26.8N  54.0W   75 KT  85 MPH

$$
Forecaster Beven/Roberts