(AP) — As hot and humid conditions prevail from the Ohio Valley to the Northeast today, thunderstorms are forecast to fire near a cool front from parts of Nebraska and Kansas to western and northern New York state.

Some of the storms can be locally severe in the afternoon with strong winds, hail and flash flooding.

A mosaic of drenching thunderstorms will exist from eastern Texas to the Carolinas, West Virginia and western Virginia. The most concentrated downpours will be from eastern Texas to Louisiana, where a tropical rainstorm that was over the Gulf of Mexico on Thursday will move to the north.

Farther west, a prevailing moist southerly breeze that represents the North American monsoon will continue over the Southwest states with thunderstorms.

The rest of the West will be dry and mainly sunny.

In the tropics, a system expected to become a tropical storm later today will go ashore in Nicaragua between Friday and Saturday before emerging into the Pacific Ocean. There are no current serious threats to the U.S. mainland, although tropical wave activity is starting to pick up a bit across the Atlantic.