HOLT, Fla., July 18, 2026—The chance for a tropical storm developing in the northern Gulf has increased with the latest National Hurricane Center outlook update.

The system, now labeled Invest 91, has a 40 percent chance of further development through the next seven days.

As of 1 p.m. CDT, winds remain light and showers and thunderstorms associated with the low are still unorganized.

Gradual development is possible and it could become a tropical depression as it moves slowly northward or north-northwestward during the next few days, according to the NHC.

According to the forecast from the National Weather Service in Mobile, the further south this system meanders, the greater the chance of a tropical system developing.

An Air Force Reserve reconnaissance mission is scheduled to investigate the system tomorrow, if needed, to look for closed, low-level circulation which could determine if the system is to become Tropical Storm Bertha.

Should it form, it would be the second tropical system of the 2026 hurricane season. Tropical Storm Arthur formed in the western Gulf in early June from leftover energy from Tropical Storm Cristina that formed in the eastern Pacific and crossed over Mexico as a low pressure area.

For now, Invest 91 has a medium formation chance through the next seven days.

National Hurricane Center forecast