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HURRICANE OTTO DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162016
400 AM EST WED NOV 23 2016

The satellite presentation of Otto has not changed much overnight,
as deep convection continues to burst near the estimated center
position in a small ragged CDO pattern.  The latest Dvorak estimates
are T4.0/65 kt from TAFB and SAB, and that will be the intensity
for this advisory.  An Air Force Reserve Hurricane Hunter aircraft
is already en route to investigate Otto later this morning.

Vertical shear, currently analyzed at 15-20 kt, should lessen a
little bit in the next 12 to 24 h, but given the ragged nature of
the system right now, only modest strengthening is expected before
landfall.  Weakening is then forecast through 48 hours while the
center moves across Central America.  Once Otto reaches the eastern
Pacific, gradual weakening is expected to continue due to increasing
shear and a drier atmospheric environment.  In fact, the 00Z GFS
and UKMET model runs both show the circulation of Otto dissipating
in 4-5 days, and the NHC forecast now shows a remnant low by the end
of the period.  The new NHC intensity forecast is close to the
SHIPS model through 72 hours and follows the weakening trend of the
global models after that time.

Otto is moving toward the west-northwest with an initial motion
estimate of 290/04, although it has been difficult to pinpoint the
center overnight.  The mid-level ridge currently centered north of
Otto will build westward and amplify during the forecast period.
As a result, Otto should turn westward and accelerate in the short
term, bringing the center to the coast in about 36 hours.  Later in
the period, a motion south of due west is indicated as the mid-level
ridge amplifies over the eastern Pacific.  The latest official
forecast is slightly north of and slower than the previous one
through landfall, and then has been adjusted southward and faster
late in the period.  The new NHC track is closest to the FSU
Superensemble through 72 hours and is near a blend of the ECMWF
and GFS after that time.

Based on the latest forecast, tropical storm watches have been
issued for portions of the Pacific coasts of Nicaragua and Costa
Rica.

FORECAST POSITIONS AND MAX WINDS

INIT  23/0900Z 10.9N  80.4W   65 KT  75 MPH
 12H  23/1800Z 11.1N  81.2W   65 KT  75 MPH
 24H  24/0600Z 11.2N  82.3W   70 KT  80 MPH
 36H  24/1800Z 11.3N  83.9W   65 KT  75 MPH...INLAND
 48H  25/0600Z 11.0N  86.0W   45 KT  50 MPH...OVER WATER
 72H  26/0600Z 10.0N  91.0W   40 KT  45 MPH
 96H  27/0600Z  9.5N  96.0W   35 KT  40 MPH
120H  28/0600Z 10.0N 100.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brennan

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