Official Discussion issued by the National Hurricane Center
(AL012024) DATA RELEASED: 6/18/2024 10:00:00 PM UTC
Copy of official data Potential Tropical Cyclone One Discussion Number 6 NWS National Hurricane Center Miami FL AL012024 1000 PM CDT Tue Jun 18 2024 Satellite images show little change with the low during the past several hours. Air Force Reserve dropsonde data indicate that the strongest winds remain hundreds of miles north of the center, with a large area of lighter winds in the circulation center. While there has been some increase in convection near the estimated center, the system still doesn't meet the requirements of a tropical cyclone. The official designation of a named storm or not is almost academic at this point, with almost all of the significant hazards well north of the center. The system has turned northwestward tonight at about 6 kt. A mid-level ridge over the eastern United States is forecast to build southwestward, forcing the disturbance to turn westward and accelerate toward the coast of Mexico overnight and on Wednesday. Guidance has trended southward since the last advisory, and the official track forecast is nudged that way. Global models continue to suggest that the circulation will gradually consolidate over the next 24 hours, and transition to a tropical storm is shown then. Only modest intensification is forecast before the center reaches land due to the continued broad nature of the circulation. Little change was made to the previous wind speed forecast. Regardless of the exact track of the low, this system will have a large area of heavy rains, moderate coastal flooding and tropical-storm-force winds well north of the center. Importantly, the official wind speed probabilities are likely underestimating the chances of tropical-storm-force winds along the Texas coast because of the unusually large and asymmetric area of strong winds on the northern side of the circulation. Key Messages: 1. Users are reminded not to focus on the exact forecast track of this system. The disturbance is very large with rainfall, coastal flooding, and wind impacts likely to occur far from the center along the coasts of Texas and northeastern Mexico. 2. Rainfall associated with Potential Tropical Cyclone One will impact large regions of Central America, north across northeastern Mexico and into South Texas. This rainfall will likely produce considerable flash and urban flooding along with new and renewed river flooding. Life-threatening flooding and mudslides are likely in areas of higher terrain across the Mexican states of Coahuila and Nuevo Leon, including the city of Monterrey. 3. Moderate coastal flooding is likely along much of the Texas Coast through midweek. 4. Tropical storm conditions are expected to begin overnight or on Wednesday along portions of the Texas coast south of San Luis Pass and along portions of the coast of northeastern Mexico within the Tropical Storm Warning area. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 22.5N 93.0W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 19/1200Z 22.7N 94.4W 40 KT 45 MPH...POTENTIAL TROP CYCLONE 24H 20/0000Z 22.8N 96.3W 40 KT 45 MPH...TROPICAL CYCLONE 36H 20/1200Z 22.9N 98.5W 35 KT 40 MPH...INLAND 48H 21/0000Z 23.0N 100.5W 20 KT 25 MPH...INLAND 60H 21/1200Z...DISSIPATED $$ Forecaster Blake |