000 WTNT44 KNHC 130431 TCDAT4 Tropical Storm Nicholas Special Discussion Number 4 NWS National Hurricane Center Miami FL AL142021 1130 PM CDT Sun Sep 12 2021 The center of Nicholas has re-formed about 150 n mi to the north-northwest of the previous feature we were tracking, as confirmed by aircraft reconnaissance and Brownsville radar, and this large change necessitates a special advisory. The initial wind speed is set to 45 kt, a blend of the reduced 56-kt flight level winds and 45-50 kt SFMR values recently found by the plane. Because of the re-formation, the track forecast has been accelerated to indicate a landfall about 12 hours sooner than the last advisory. The intensity forecast is about 5 kt stronger in the short term, but actually ends up near the same intensity at landfall as the last advisory because of less time over water. The track forecast is blended with the previous one after landfall, and the intensity forecast is lower after landfall because it is farther inland. No changes to the watches or warnings are required at this time. Key Messages: 1. Periods of heavy rainfall are expected to impact portions of the Texas and Louisiana coasts through the middle of the week. Significant rainfall amounts are possible, potentially resulting in areas of considerable flash and urban flooding, especially in highly urbanized metropolitan areas. Isolated minor to moderate river flooding is also expected. 2. There is the danger of life-threatening storm surge inundation along the coast of Texas from Port Aransas to San Luis Pass. Residents in these areas should follow any advice given by local officials. 3. Nicholas is forecast to approach the middle Texas coast as a strong tropical storm on Monday, and could be near hurricane intensity if it moves to the right of the forecast track and remains over water longer. Tropical storm conditions are expected along portions of the middle Texas coast beginning Monday, with hurricane conditions possible from Port Aransas to Freeport late Monday and Monday night. 4. Tropical storm conditions are expected along portions of the northeastern coast of Mexico and the coast of south Texas beginning Monday morning. FORECAST POSITIONS AND MAX WINDS INIT 13/0430Z 24.8N 96.3W 45 KT 50 MPH 12H 13/1200Z 26.0N 96.7W 50 KT 60 MPH 24H 14/0000Z 28.0N 96.6W 55 KT 65 MPH 36H 14/1200Z 29.4N 96.3W 45 KT 50 MPH...INLAND 48H 15/0000Z 30.2N 95.6W 35 KT 40 MPH...INLAND 60H 15/1200Z 30.8N 94.9W 30 KT 35 MPH...INLAND 72H 16/0000Z 31.3N 94.2W 25 KT 30 MPH...INLAND 96H 17/0000Z 31.7N 92.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 18/0000Z...DISSIPATED $$ Forecaster Blake