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Tropical Storm OTIS


Tropical Storm Otis Discussion Number  28
NWS National Hurricane Center Miami FL       EP152017
800 AM PDT Mon Sep 18 2017

Otis is weakening at a remarkable rate.  Only 12 hours ago, the
cyclone had an eye, but now most of the deep convection has
dissipated entirely. The cloud pattern now only supports an
intensity of about 45 kt, but Dvorak intensity estimates are
constrained to higher values by the rules of the technique.  Given
the small size of Otis, it seems possible that this is a rare case
where the intensity is dropping faster than the Dvorak
technique allows.  The initial intensity has been lowered to 60 kt,
but it is possible that Otis is even weaker than this.  Continued
rapid weakening is expected, and most of the dynamical models show
Otis becoming a remnant low within about 36 h.  The GFS and ECMWF
maintain a weak surface low for another couple days after that, but
suggest it will dissipate entirely shortly after 96 h.

Otis has continued to move northward over the past 6 hours, but
it appears to be slowing down.  As the circulation becomes shallower
over the next 12 to 24 hours, Otis will be increasingly steered by
the low-level northeasterly flow associated with a ridge over the
central Pacific.  This should cause the cyclone to make a sharp turn
toward the southwest later today or early tomorrow morning.  Little
change has been made to the track forecast, which is close to an
average of the HCCA and TVCX consensus aids.


INIT  18/1500Z 19.0N 127.4W   60 KT  70 MPH
 12H  19/0000Z 19.4N 127.6W   40 KT  45 MPH
 24H  19/1200Z 19.3N 128.1W   30 KT  35 MPH
 36H  20/0000Z 18.7N 128.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  20/1200Z 17.8N 130.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  21/1200Z 16.0N 132.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  22/1200Z 14.5N 135.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  23/1200Z...DISSIPATED

Forecaster Zelinsky