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HURRICANE OTTO DISCUSSION NUMBER  14
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162016
400 AM EST THU NOV 24 2016

Otto continues to produce an area of deep convection over the
center, but it is difficult to tell if there have been any
structural changes to the cyclone without microwave or aircraft data
overnight. Dvorak estimates at 06Z were T4.5/77 kt from SAB and
T4.0/65 kt from TAFB, with the 06Z UW-CIMSS ADT estimate at 72 kt.
The initial intensity is held at 75 kt for this advisory based on
the higher satellite estimates and continuity. An Air Force Reserve
Hurricane Hunter aircraft will investigate Otto later this morning.

There is an opportunity for some additional strengthening before
Otto makes landfall in about 12 hours. After landfall, quick
weakening is expected while the center moves across Central America,
and Otto is expected to emerge into the eastern Pacific by 24 h as a
tropical storm. Gradual weakening is forecast after that time, due
to moderate to strong vertical shear, and this weakening trend is
also shown in most of the global model guidance. The new NHC
intensity forecast is similar to the previous one and near the low
end of the TC intensity guidance late in the period. This forecast
ends up closest to the FSU Superensemble by day 5, and shows Otto as
a remnant low at that time.

The initial motion estimate is 270/07, as Otto is under the steering
influence of a mid-level ridge centered over Cuba and the Bahamas.
As as mid/upper-level trough lifts out of the Gulf of Mexico, the
ridge will build westward and amplify during the next 3-4 days. This
pattern should result in an increase in forward speed and a motion
somewhat south of due west for the next 72 hours. By the end of the
period, Otto or its remnant low should turn west-northwestward as it
rounds the western side of the weakening ridge. While there is
general agreement on this scenario, there remains some spread in the
track guidance. In particular, the latest ECMWF solution has shifted
north and is slower than the rest of the guidance, especially
compared to the GFS, which is faster and farther south. The new NHC
track forecast is largely an update of the previous one but trends a
little faster following the latest consensus. This track is close to
the ECMWF/GFS blend at days 3 through 5.

FORECAST POSITIONS AND MAX WINDS

INIT  24/0900Z 11.2N  82.9W   75 KT  85 MPH
 12H  24/1800Z 11.1N  83.9W   75 KT  85 MPH...INLAND
 24H  25/0600Z 10.6N  86.2W   50 KT  60 MPH...OVER WATER
 36H  25/1800Z 10.2N  88.4W   45 KT  50 MPH
 48H  26/0600Z  9.8N  90.9W   40 KT  45 MPH
 72H  27/0600Z  9.5N  96.5W   40 KT  45 MPH
 96H  28/0600Z 10.0N 101.5W   35 KT  40 MPH
120H  29/0600Z 11.5N 104.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brennan

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