577 WTPZ41 KNHC 030847 TCDEP1 Hurricane Sergio Discussion Number 16 NWS National Hurricane Center Miami FL EP212018 200 AM PDT Wed Oct 03 2018 There has been little change to the overall organization of the hurricane overnight. Recent microwave data continue to show that the eyewall is open to the northwest and that there is some northeast to southwest displacement of the low- and mid-level centers due to northeasterly shear. A blend of the various objective and subjective satellite intensity estimates yields an initial intensity of 100 kt. The global models suggest that the shear currently affecting Sergio will decrease over the next 24 to 36 hours, which should allow for strengthening. The NHC intensity forecast calls for Sergio to reach peak intensity in about 36 hours, and it is near the upper-end of the intensity guidance. After that time, slightly cooler waters and the entrainment of drier mid-level air are forecast to cause gradual weakening, but Sergio is expected to remain a hurricane through the entire forecast period. Sergio is moving west-northwestward or 300 degrees at 10 kt. The western portion of a mid-level ridge to the north of Sergio is expected to weaken during the next day or so, which should cause the hurricane to move northwestward at a slightly slower forward speed. By the weekend, another ridge is predicted to build to the northwest of Sergio, and this should force the hurricane to turn westward. The track guidance is in good agreement through 48 hours, but there is increasing cross-track spread thereafter. The updated NHC forecast is near the middle of the guidance envelope for the first two days, but lies between the more northern GFS solution and the consensus aids thereafter. FORECAST POSITIONS AND MAX WINDS INIT 03/0900Z 12.3N 116.7W 100 KT 115 MPH 12H 03/1800Z 13.0N 117.8W 105 KT 120 MPH 24H 04/0600Z 14.0N 119.0W 110 KT 125 MPH 36H 04/1800Z 15.0N 120.3W 115 KT 130 MPH 48H 05/0600Z 15.8N 121.5W 110 KT 125 MPH 72H 06/0600Z 16.3N 124.0W 95 KT 110 MPH 96H 07/0600Z 16.3N 127.0W 90 KT 105 MPH 120H 08/0600Z 16.8N 130.0W 85 KT 100 MPH $$ Forecaster Brown