932 WTPZ41 KNHC 040236 TCDEP1 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