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Tropical Depression NINE-E


Tropical Depression Nine-E Discussion Number   2
NWS National Hurricane Center Miami FL       EP092018
800 PM PDT Thu Jul 26 2018

It has been difficult to identify the center of the depression on
visible imagery since this afternoon, and microwave imagery from the
SSMI and GMI instruments between 2300 and 0000 UTC suggest that the
low-level circulation of the depression has not become any better
organized. The initial intensity has been held at 30 kt, but Dvorak
intensity estimates from TAFB and SAB suggest that this could be
generous. Based on an analysis from UW-CIMSS, 20-25 kt of
northwesterly shear is currently affecting the depression, and SHIPS
diagnostics from the GFS and ECMWF indicate that the shear will
increase over the next 24 hours. None of the intensity guidance
brings the cyclone above minimal tropical storm strength, and the
dynamical models all indicate that it will degenerate into a trough
of low pressure early next week. The intensity forecast therefore
keeps the cyclone as a depression through 96 h, and now shows
dissipation by day 5. Given the high shear and disorganized nature
of the depression, it is very possible that dissipation will occur
sooner than currently forecast.

Due to the uncertainty associated with the initial position of the
depression, the initial motion is fairly uncertain but is estimated
to be 265/13 kt. Little change has been made to the NHC forecast,
and the depression is still forecast to continue moving generally
westward for the next several days, steered by a low- to mid-level
ridge to the north. The models are in good agreement on the track of
the depression through dissipation, and the NHC forecast is near the
center of the guidance envelope.


INIT  27/0300Z 10.8N 136.8W   30 KT  35 MPH
 12H  27/1200Z 10.7N 138.4W   30 KT  35 MPH
 24H  28/0000Z 10.6N 140.5W   30 KT  35 MPH
 36H  28/1200Z 10.6N 142.7W   30 KT  35 MPH
 48H  29/0000Z 10.7N 145.0W   30 KT  35 MPH
 72H  30/0000Z 11.6N 149.7W   30 KT  35 MPH
 96H  31/0000Z 12.5N 155.5W   30 KT  35 MPH
120H  01/0000Z...DISSIPATED

Forecaster Zelinsky