060 WTPZ45 KNHC 251434 TCDEP5 Tropical Storm Rosa Discussion Number 2 NWS National Hurricane Center Miami FL EP202018 900 AM MDT Tue Sep 25 2018 The cloud pattern of the tropical cyclone has become better organized, with developing convective banding features. Dvorak intensity estimates are 35 kt and 45 kt from SAB and TAFB, respectively, and the current intensity estimate is set at 40 kt. Thus the system is being upgraded to a tropical storm. Conditions favor continued strengthening, with Rosa likely to remain in an environment of warm waters, low shear, and a very moist mid-level air mass for the next several days. The official intensity forecast is a little higher than the previous one, but below some of the objective guidance. By late in the forecast period, a gradual weakening trend should commence as the system begins to move over slightly cooler waters. The storm is moving west-northwestward, or 285/8 kt. A mid-level ridge is forecast by the global models to remain in place to the north of Rosa through the middle part of the forecast period. This would likely maintain a generally west-northwestward motion for the next 72 hours or so. By days 4-5, the ridge is predicted to weaken which should result in a gradual turn toward the northwest and north-northwest. The official track forecast is similar to that from the previous advisory and is close to the corrected dynamical model consensus, HCCA. FORECAST POSITIONS AND MAX WINDS INIT 25/1500Z 14.7N 108.0W 40 KT 45 MPH 12H 26/0000Z 15.2N 109.1W 50 KT 60 MPH 24H 26/1200Z 15.8N 110.6W 60 KT 70 MPH 36H 27/0000Z 16.1N 112.1W 70 KT 80 MPH 48H 27/1200Z 16.4N 113.7W 80 KT 90 MPH 72H 28/1200Z 17.1N 116.7W 95 KT 110 MPH 96H 29/1200Z 18.8N 118.9W 90 KT 105 MPH 120H 30/1200Z 21.0N 120.0W 85 KT 100 MPH $$ Forecaster Pasch