ZCZC MIATCDEP1 ALL
TTAA00 KNHC DDHHMM

Hurricane Sergio Discussion Number  19
NWS National Hurricane Center Miami FL       EP212018
800 PM PDT Wed Oct 03 2018

Sergio is quite the sight tonight over the eastern Pacific with a
large central dense overcast and mesovortices observed within the
well-defined eye.  Subjective estimates from TAFB and SAB both
support a slightly higher initial wind speed of 115 kt on this
advisory, which is a good compromise between lower microwave
estimates but higher ADT values.  Notably, Sergio is the record most
8th category 4 hurricane of the 2018 eastern Pacific season-
breaking the old record of 7 set in 2015. Reliable records in the
eastern Pacific for major hurricanes go back to 1971.

Further strengthening is possible during the next day or so while
the shear is forecast to remain low and the water is quite warm.
After that time, a combination of cooling waters and higher shear
should generally cause Sergio to weaken.  This will probably be an
unsteady process, however, since eyewall cycles are also likely over
the next few days.  Overall, the hurricane should be on a weakening
trend, and that is the NHC forecast, very similar to the previous
one, and a bit higher than the model consensus.

Sergio is moving northwest or 315/8.  This motion should gradually
bend toward the west over the next day or two as the steering flow
changes from a ridge near Mexico to a building ridge to the
northwest of the hurricane.  Sergio could turn to the northwest
early next week as the hurricane comes under the influence of
a deepening trough over the far eastern Pacific and southwestern
United States. The model guidance is in excellent agreement during
the next few days, and no significant changes were required to the
previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 13.8N 118.3W  115 KT 130 MPH
 12H  04/1200Z 14.6N 119.1W  120 KT 140 MPH
 24H  05/0000Z 15.5N 120.4W  120 KT 140 MPH
 36H  05/1200Z 15.9N 121.5W  110 KT 125 MPH
 48H  06/0000Z 15.9N 122.8W  100 KT 115 MPH
 72H  07/0000Z 15.6N 125.4W   90 KT 105 MPH
 96H  08/0000Z 15.8N 128.0W   80 KT  90 MPH
120H  09/0000Z 17.0N 129.0W   75 KT  85 MPH

$$
Forecaster Blake

NNNN