000 WTPZ41 KNHC 190847 TCDEP1 Hurricane Fernanda Discussion Number 30 NWS National Hurricane Center Miami FL EP062017 200 AM PDT Wed Jul 19 2017 Fernanda's convective cloud pattern has continued to wither, and has been accompanied by a general warming of the cloud tops. The eye is no longer evident in infrared imagery and a 0640Z AMSU overpass indicated that the eye had become open in the southern semicircle. Intensity estimates are a consensus T4.5/77 kt from TAFB and SAB, along with a recent CIRA-AMSU estimate of 82 kt. A blend of these values supports lowering the advisory intensity to 80 kt. The initial motion estimate remains 310/08 kt. Fernanda is forecast to move northwestward today and turn toward the west-northwest by tonight or Thursday. A continuation of that general motion is expected through the end of the forecast period due to a strong subtropical ridge remaining entrenched to the north and northeast of the Hawaiian Islands. The new NHC forecast track is almost on top of the previous advisory track, and lies close to the HFIP Corrected Consensus (HCCA) and TVCN consensus models. Fernanda is expected to steadily weaken throughout the forecast period. The first 36-48 hours of weakening will primarily be due to the cyclone moving over sub-25C SSTs. Following that will be a sharp increase in southwesterly vertical wind shear to 25-30 kt, causing Fernanda to degenerate into a post-tropical cyclone by 72 hours. The official intensity forecast follows the downward trend of the previous advisory and is similar to the ICON and IVCN consensus models. FORECAST POSITIONS AND MAX WINDS INIT 19/0900Z 17.0N 135.0W 80 KT 90 MPH 12H 19/1800Z 17.5N 135.9W 70 KT 80 MPH 24H 20/0600Z 18.1N 137.2W 60 KT 70 MPH 36H 20/1800Z 18.6N 138.8W 50 KT 60 MPH 48H 21/0600Z 19.1N 140.6W 40 KT 45 MPH 72H 22/0600Z 20.1N 143.9W 35 KT 40 MPH...POST-TROPICAL 96H 23/0600Z 21.1N 147.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 24/0600Z 22.0N 152.1W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Stewart