Tropical Storm Nadine Forecast Discussion Number 3

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WTNT45 KNHC 092031

Tropical Storm Nadine Discussion Number   3
NWS National Hurricane Center Miami FL       AL152018
500 PM AST Tue Oct 09 2018

Nadine is a sheared tropical cyclone this afternoon with the center
partially exposed on the southwestern side of an increasing area of
convection. Dvorak estimates are unchanged since earlier, so the
initial wind speed remains 35 kt. The shear is forecast to remain
low enough to support strengthening during the next day or so, along
with sufficiently warm waters.  However, Nadine should encounter a
large upper trough after that time, which should cause weakening to
begin on Thursday. Later on, cooler SSTs and strong shear are
expected to cause Nadine to degenerate into a trough of low pressure
by the weekend. Model guidance is in fair agreement on this
scenario, and the new NHC prediction is close to the previous one
and the model consensus.

Satellite imagery today shows that Nadine has turned rightward and
is moving 300/7.  A northwestward track should begin overnight and
continue for the next few days due to steering from a mid-level
ridge near the Cabo Verde Islands.  A westward turn is expected
beyond day 3 as Nadine becomes a shallow system and dissipates.  The
track forecast isn't super confident because it is somewhat
dependent on the intensity. For example, a stronger cyclone like the
GFS shows would have the potential to move more toward the north-
northwest as it attempts to remain a vertically coherent system.
Since Nadine isn't expected to get very strong, the official
forecast will stay near or just south of the model consensus, which
results in no significant change to the previous track forecast.


INIT  09/2100Z 10.9N  30.6W   35 KT  40 MPH
 12H  10/0600Z 11.6N  31.5W   40 KT  45 MPH
 24H  10/1800Z 12.6N  32.5W   45 KT  50 MPH
 36H  11/0600Z 13.7N  33.4W   40 KT  45 MPH
 48H  11/1800Z 15.0N  34.7W   35 KT  40 MPH
 72H  12/1800Z 17.0N  37.5W   25 KT  30 MPH
 96H  13/1800Z...DISSIPATED

Forecaster Blake