The National Weather Service has issued a severe thunderstorm watch effective until 2 p.m. for the Ann Arbor area as well as other parts of southeast Michigan.

The weather service said storms capable of producing hail up to an inch in diameter, wind gusts to 80 mph and dangerous lightning are possible. Such storms sometimes produce tornadoes.

The threat of severe weather accompanies a forecast for a day of scorching heat and high humidity when the heat index could climb to 100 degrees or higher. The high temperature for today is expected to be 90 to 94.

Conditions won’t improve much on Tuesday, when the weather service predicts a high of 87 to 91. Relief will arrive Wednesday when the expected high is 76 to 80

A watch means conditions are favorable for storms to form, and the weather service said people should be on the lookout for threatening weather today. Such storms sometimes produce tornadoes.

Just before 10 a.m., radar showed light rain moving into the Ann Arbor area, with heavier storms off to the southwest and northwest.

For updated conditions and forecasts throughout the day, check AnnArbor.com’s weather page.