Three other storm systems are monitored in tropics.

A tropical system off the coast of Africa is likely to become a tropical depression by the middle of the week, the National Hurricane Center says.

It’s one of three systems — and a likely fourth — beside Hurricane Dorian that are being monitored in the tropics.

The large area of thunderstorms and showers is gradually becoming better organized, and conditions are conducive to development, the hurricane center said. It has an 80% chance of development in the next two days and a 90% chance of developing within the next 5 days, the hurricane center said.

The system is moving northwest.

A second system, disorganized showers and thunderstorms, is in the southeastern Gulf of Mexico and is associated with a broad area of low pressure. According to the hurricane center, “a tropical depression could form during the next few days while the low moves slowly westward across the south-central and southwestern Gulf of Mexico toward the coast of Mexico.”

According to the hurricane center, that system has a 60% chance of becoming a tropical cyclone over the next two days and a 70% chance of formation over the next five days.

A tropical cyclone is a storm system rotating around a center of low pressure. Tropical cyclones are classified by their wind speed from tropical depression to tropical storm to hurricane.

A third system several hundred miles southsoutheast of Bermuda has a 30% chance of becoming a tropical cyclone in the next two days and a 40% chance of formation over the next five days, the hurricane center said in its 2 p.m. update Monday.

“Gradual development of this system is possible during the next few days while the disturbance moves slowly northward or northnorthwestward,” the hurricane center said.

Additionally, a new tropical wave is forecast to emerge off Africa in the far eastern Atlantic by the end of the week. Gradual development of that system will be possible late this week or over the weekend, the hurricane center said.