000 WTNT44 KNHC 200832 TCDAT4 Potential Tropical Cyclone Four Discussion Number 3 NWS National Hurricane Center Miami FL AL042022 400 AM CDT Sat Aug 20 2022 We have a much better view of the low clouds on the western side of the disturbance in proxy-visible satellite imagery than we did last evening when they were obscured by high-level cirrus, and the low clouds' south-to-north motion just off the coast of Mexico suggests that the disturbance still does not have a closed surface circulation. However, a mid-level circulation remains evident and is the focus of a recent resurgence in deep convection. It is assumed that the maximum winds in the system are still 30 kt, but an Air Force Reserve reconnaissance flight scheduled for later this morning should give us a better idea of the disturbance's structure and intensity. The disturbance continues to move northwestward at 12 kt, and model guidance is in fairly good agreement that a steady northwestward or north-northwestward motion should continue for the next 24 hours or so. This trajectory should bring the system inland near or just south of the mouth of the Rio Grande late this afternoon or evening, which is the same scenario that has been indicated in previous advisories. There remains uncertainty if the disturbance will be able to develop a closed surface circulation--and become a tropical cyclone--before it reaches the coast later today. At best, the global models are resolving a well-defined vorticity maximum at about 5000 ft above the surface and perhaps a surface trough near the coast of Mexico, but none of them explicitly show the development of a well-defined surface circulation. As long as deep convection continues, however, it could spur the development of a surface center before reaching the coast. That said, the new NHC forecast now only shows the system reaching a peak intensity of 35 kt, which is still above all of the guidance. A remnant low position is provided at 36 hours for continuity, but it's more likely that the system will have dissipated by then--if it even forms at all. KEY MESSAGES: 1. Tropical storm conditions are expected across portions of northeastern Mexico and southern Texas this afternoon and evening, where a Tropical Storm Warning is in effect. 2. Rains from the disturbance may begin to affect the eastern coast of Mexico, from northern Veracruz across parts of Tamaulipas and Nuevo Leon, today. This rainfall may produce flash flooding. Heavy rain may also move to the far south Texas coast through Sunday morning, producing local flash, urban, and small stream flood impacts. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 22.8N 95.8W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 20/1800Z 24.4N 96.9W 35 KT 40 MPH...TROPICAL CYCLONE 24H 21/0600Z 26.3N 98.3W 30 KT 35 MPH...INLAND 36H 21/1800Z 27.5N 99.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 22/0600Z...DISSIPATED $$ Forecaster Berg