A weak low pressure system developed over the eastern Gulf of Mexico on Wednesday. The system was designated as Invest 91L by the National Hurricane Center. At 2:00 p.m. EDT on Wednesday the center of Invest 91L was located at latitude 26.4°N and longitude 85.9°W which put it about 275 miles (445 km) west of Naples, Florida. The low pressure system was nearly stationary. The maximum sustained wind speed was 25 m.p.h. (40 km/h) and there were wind gusts to 35 m.p.h. (55 km/h). The minimum surface pressure was 1009 mb.

A weak low pressure system developed over the eastern Gulf of Mexico on Wednesday and the system was designated as Invest 91L. The circulation around Invest 91L was not well organized. There was a broad counterclockwise rotation around the center of the low pressure system. At least one smaller center of rotation, that might have formed in a cluster of thunderstorms that dissipated on Tuesday night, was visible in the eastern side of the broader rotation. There were bands of showers and thunderstorms in the eastern and northern sides of the low pressure system. Bands in the western and southern parts of the system consisted primarily of lower clouds.

Invest 91L will be in an environment only marginally favorable for development of a tropical cyclone during the next 24 hours. The surface low pressure system will be over water where the Sea Surface Temperatures are near 27˚C. It will be under the eastern side of an upper level trough over the northeastern Gulf of Mexico. The upper level trough will produce southwesterly winds that will blow across the top of Invest 91L. Those winds will cause wind shear and the wind shear will inhibit the development of the surface low pressure system. There is also drier air over the northern Gulf of Mexico. The drier air will inhibit the formation of thunderstorms in the northern and western parts of Invest 91L. The National Hurricane Center is indicating that the probability is 20% that Invest 91L develops into a tropical cyclone during the next 48 hours. A reconnaissance plane is tentatively scheduled to investigate the system on Thursday afternoon, if necessary.

Invest 91L will continued to be under the eastern side of the upper level trough over the eastern Gulf of Mexico during the next 24 hours. The steering winds are weak under the upper level trough. So, Invest 91L could move with the upper level trough. The upper level trough is forecast to move slowly toward the east. Invest 91L could move slowly toward the southeast. If Invest 91L develops into a tropical cyclone with taller thunderstorms, then the winds in the middle troposphere could steer it more toward the north. Bands in the eastern side of the low pressure system are likely to bring locally heavy rain to parts of central and south Florida.