ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Hurricane Genevieve Discussion Number 8 NWS National Hurricane Center Miami FL EP122020 300 AM MDT Tue Aug 18 2020 Genevieve continues to rapidly intensify this morning. A recent GMI microwave overpass shows a well-defined eye and eyewall present, and the eye is becoming much better defined in conventional infrared imagery. Various objective and subjective satellite intensity estimates were averaging about 90 kt at 06Z, and recent objective raw T-numbers from the CIMSS ADT technique have increased to between 100-115 kt. Based on these data, the initial intensity is raised to 100 kt, making Genevieve a major category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. The initial motion is now northwestward or 310/15 kt. The hurricane is on the southwest side of a deep-layer ridge, and the global models forecast this feature to persist for the next several days. This should cause Genevieve to continue a northwestward motion during the forecast period with some decrease in forward speed. On the forecast track, the center of the hurricane should move parallel to, but offshore of, the southwestern coast of Mexico and the Baja California peninsula. The track model guidance remains tightly clustered, and the new forecast track is a little to the east of, and slightly slower than, the previous forecast. Environmental conditions appear favorable for continued rapid intensification during the next 24 h or so, with the only alternate possibility being that the intensification is interrupted by an eyewall replacement cycle. By 36-48 h, the center will be over decreasing sea surface temperatures and oceanic heat content, and during that time, Genevieve should start weakening. By the end of the forecast period, the cyclone is forecast to be over sea surface temperatures of 21-22C, which should cause rapid weakening. The new intensity forecast goes above the guidance in calling for a peak intensity of 125 kt in 24 h, and it would not be a surprise if Genevieve became stronger than that. After the peak, the new forecast shows steady to rapid weakening, and by 120 hours the system is expected to degenerate into a convection-free post-tropical cyclone. The forecast track and wind radii require a Tropical Storm Warning for the southern portion of the Baja California Peninsula at this time. Key Messages: 1. There is an increasing risk of tropical-storm-force winds over the southern portion of the Baja California peninsula beginning Wednesday afternoon and continuing into Thursday as Genevieve passes near or southwest of the southern tip of Baja California, and a Tropical Storm Warning is now in effect for a portion of this area. 2. Large swells generated by Genevieve are affecting portions of the coast of southern Mexico and will spread northward along the coast of Mexico to the Baja California peninsula by Wednesday. FORECAST POSITIONS AND MAX WINDS INIT 18/0900Z 17.4N 107.1W 100 KT 115 MPH 12H 18/1800Z 18.5N 108.7W 115 KT 130 MPH 24H 19/0600Z 19.7N 110.0W 125 KT 145 MPH 36H 19/1800Z 20.9N 111.0W 120 KT 140 MPH 48H 20/0600Z 21.9N 111.9W 110 KT 125 MPH 60H 20/1800Z 23.0N 113.0W 95 KT 110 MPH 72H 21/0600Z 23.9N 114.4W 80 KT 90 MPH 96H 22/0600Z 26.0N 117.5W 55 KT 65 MPH 120H 23/0600Z 28.5N 121.0W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Beven NNNN