ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM

Hurricane Otis Discussion Number  25
NWS National Hurricane Center Miami FL       EP152017
200 PM PDT Sun Sep 17 2017

Otis continues to surprise us.  Satellite images indicate that the
eye has become more distinct during the past few hours, and the
deep convection is wrapping around that center.  The cyclone is
currently undergoing rapid intensification, and the initial
intensity is increased significantly to 90 kt based on a blend of
the latest satellite estimates.  This makes Otis a category 2
hurricane on the Saffir-Simpson Hurricane Wind Scale.  Even though
Otis is a powerful cyclone, recent ASCAT data confirms that the
wind field of the system is extremely compact.

Some additional strengthening is likely during the next 12 hours
or so while the hurricane remains in an environment of low wind
shear and over 27 deg C waters.  After that time, however, lower
SSTs, drier air, and an increase in wind shear should cause
rapid weakening.  Even though Otis will be moving over warmer waters
by the end of the forecast period, the models continue to show Otis
decaying due to unfavorable atmospheric conditions.  The cyclone is
still forecast to become a remnant low by day 4 based on the global
models, but this is a low confidence prediction at this time.

The hurricane continues to move slowly northward at 4 kt.  A
slow north to north-northwest motion is expected during the next
24 to 36 hours while Otis moves on the west side of a weak mid-level
ridge.  Thereafter, a faster west and west-southwest motion is
expected when the weakening cyclone becomes more influenced by the
low-level tradewind flow.  This track forecast is not too different
from the previous one, and it lies close to the various consensus
aids.

FORECAST POSITIONS AND MAX WINDS

INIT  17/2100Z 17.0N 127.3W   90 KT 105 MPH
 12H  18/0600Z 17.7N 127.4W  110 KT 125 MPH
 24H  18/1800Z 18.6N 127.6W   90 KT 105 MPH
 36H  19/0600Z 19.0N 128.0W   70 KT  80 MPH
 48H  19/1800Z 18.8N 128.6W   50 KT  60 MPH
 72H  20/1800Z 17.7N 130.7W   35 KT  40 MPH
 96H  21/1800Z 16.4N 133.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  22/1800Z 15.0N 136.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

NNNN