A weather system over the southwestern Gulf of Mexico was designated as Potential Tropical Cyclone Four on Friday afternoon and Tropical Storm Warnings were issued for portions of the coasts of Texas and Mexico. At 5:00 p.m. EDT on Friday the center of Potential Tropical Cyclone Four was located at latitude 20.7°N and longitude 94.5°W which put it about 400 miles (640 km) south-southeast of the Mouth of the Rio Grande River. Potential Tropical Cyclone Four was moving toward the northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1009 mb.

A Tropical Cyclone Warning was issued for the portion of the coast from Port Mansfield, Texas to Boca de Catan, Mexico.

A weather system over the southwestern Gulf of Mexico exhibited more organization on Friday. However, observations from a U.S. Air Force Reserve Hurricane Hunter plane on Friday afternoon indicated that there was not a well defined center of low level circulation in the weather system. The National Hurricane Center designated the system as Potential Tropical Cyclone Four in order to issue a Tropical Storm Warning for the coast of South Texas. The government of Mexico also issued a Tropical Storm Warning for the northern coast of Mexico.

More thunderstorms developed in Potential Tropical Cyclone Four on Friday afternoon. Some of the thunderstorms in the eastern half of the circulation appeared to be organizing into bands. The thunderstorms in Potential Tropical Cyclone Four began to generate upper level divergence that pumped mass away from the weather system.

Potential Tropical Cyclone Four will move through an environment favorable for intensification during the next 18 hours. Potential Tropical Cyclone Four will move over water where the Sea Surface Temperatures are 30˚C. It will move under an upper level ridge over the southwestern Gulf of Mexico. The upper level winds are weak in that region and there will be little vertical wind shear. Potential Tropical Cyclone Four is likely to intensify during the next 18 hours. A well defined low level center of circulation will have to develop in order for the system to become a tropical storm.

Potential Tropical Cyclone Four will move around the southwestern part of a subtropical high pressure system that extends over the Gulf of Mexico. The high pressure system will steer Potential Tropical Cyclone Four toward the northwest during the next 24 hours. On its anticipated track Potential Tropical Cyclone Four will make landfall south of Brownsville, Texas during Saturday night. It will bring locally heavy rain and gusty winds to South Texas and northern Mexico. Locally heavy rain could cause flash floods in some locations.