N.J. weather: Severe thunderstorm watch issued in 10 counties. Up to 70 mph winds possible.

With heavy rain in the forecast and wind gusts of up to 70 mph possible, the National Weather Service has issued a severe thunderstorm watch for 10 counties in central and southern New Jersey.

The watch took effect at 12:45 p.m. and runs until 7 p.m. Wednesday, covering the counties of Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Mercer, Monmouth, Ocean and Salem.

Isolated thunderstorms and rain showers are expected in parts of New Jersey starting Wednesday afternoon and might last though the evening as a warm front pushes across the state.

Forecasters expect the rain to move offshore Wednesday night.

However, New Jersey faces another threat of severe thunderstorms Thursday afternoon and Thursday evening, when a strong cold front is expected to clash with hot and humid air.

Temperatures on Thursday are expected to rise into the upper 80s to low 90s, providing extra fuel for the thunderstorms that develop.

In addition to gusty winds, forecasters say flash flooding, frequent lightning and small hail stones are possible.

They also say isolated tornadoes or waterspouts can’t be ruled out on Thursday because of the high level of wind shear expected in the atmosphere.

Wind shear, the change of wind speed and direction at different heights in the atmosphere, is a key ingredient in the formation of tornadoes.

Current weather radar