(CNN) Tropical storm Melissa has formed in the eastern Atlantic, the U.S. National Hurricane Center in Miami said Saturday.
It has winds of 40 mph, but poses no immediate threat to land.
In the eastern Pacific, a tropical depression was upgraded to Tropical Storm Juliette but remained nearly 500 miles off the coast of central Mexico on Saturday afternoon.
Atlantic Tropical Storm Karen faded into a tropical depression and was likely to dissipate soon, with winds of 35 mph about 495 miles east of the Leeward Islands.
Meanwhile, floodwaters from Hurricane Lorenzo were receding Saturday after rains caused mudslides and floods that killed at least five people and drove tens of thousands from their homes in eastern Mexico.
Rivers in Mexico had swollen 21 feet above usual levels. Officials said it might take weeks for all flooding to subside.
Lorenzo hit Mexico's Gulf coast on Friday and quickly faded into a potent rainstorm as it moved over the lush, ravine-cut mountains of east-central Mexico, dumping more than 13 inches of rain in some areas in less than a day.
In hard-hit parts of Veracruz state, streets remained flooded by weather that ripped roofs off some 2,000 homes and swept cars away. In Alamo, a burst pipeline released oil into the Buenavista River and damaging nearby pastures, police said. At least two children were sickened by the fumes.
Residents in the oil city of Poza Rica fled their homes as the water rose.