ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM Tropical Storm Lorena Discussion Number 6 NWS National Hurricane Center Miami FL EP152019 400 PM CDT Wed Sep 18 2019 Visible satellite imagery has continued to show an improvement in banding around the center of Lorena this afternoon. Bands now wrap completely around the center, but there have been no recent microwave images to see if an eye has developed. The increase in organization has led to higher objective satellite intensity from UW/CIMSS, and a blend of the SAB and ADT estimates yields an initial intensity of 60 kt. Additional strengthening is likely, and Lorena is forecast to become a hurricane tonight while it moves over warm water with low shear conditions. The storm is predicted to move very close to or over the southwestern coast of Mexico later tonight and early Thursday, and the remainder of the intensity forecast will depend on how much land interaction occurs and the eventual structure of the storm afterward. If Lorena moves to the right of the official forecast, more significant weakening is likely and the storm would struggle to re-strengthen later in the period. The new NHC track forecast shows slightly less interaction of the core of the cyclone with land, and assumes Lorena will be able to continue strengthening while the shear remains low and it moves over very warm waters southeast of the Baja California peninsula. Lorena is moving northwestward or 320/11 kt. The track guidance remains about the same as before, with the ECMWF taking the center inland over southwestern Mexico while most of the remainder of the guidance keeps it just offshore. The NHC forecast is slightly west of the previous advisory through 24 hours, but continues to show the center passing very close to southwestern Mexico. After that time, a narrow mid-level ridge is forecast to build to the north of Lorena, and this should lead to a west-northwestward motion with Lorena passing near or just south of the southern tip of the Baja Peninsula. The NHC track forecast is in best agreement with the HFIP corrected consensus. Due the potential for land interaction within the next 12-24 hours, there is greater than usual uncertainty in both the track and intensity forecast for Lorena through day 5. Key Messages: 1. Lorena is forecast to become a hurricane and move dangerously close to the coast of southwestern Mexico tonight and Thursday. A hurricane warning is in effect and preparations to protect life in property should be rushed to completion. 2. Lorena is forecast to cause heavy rain over portions of the Mexican states of Guerrero, Michoacan, Colima, and Jalisco during the next few days. This rainfall may produce life-threatening flash flooding and mudslides. 3. Lorena could threaten the southern portion of the Baja California peninsula as a hurricane this weekend, but the forecast is more uncertain due to the potential for land interaction tonight and Thursday. Residents should ensure that their hurricane plan is in place as watches may be required tonight or Thursday. FORECAST POSITIONS AND MAX WINDS INIT 18/2100Z 17.9N 104.4W 60 KT 70 MPH 12H 19/0600Z 19.2N 105.3W 70 KT 80 MPH 24H 19/1800Z 20.1N 106.2W 70 KT 80 MPH 36H 20/0600Z 20.7N 107.2W 75 KT 85 MPH 48H 20/1800Z 21.2N 108.3W 80 KT 90 MPH 72H 21/1800Z 22.5N 110.8W 85 KT 100 MPH 96H 22/1800Z 24.5N 113.0W 60 KT 70 MPH 120H 23/1800Z 26.6N 115.0W 40 KT 45 MPH $$ Forecaster Brown NNNN