David Epstein: Severe weather is in the forecast. Here’s what to expect.

The greatest threat from the storms comes Tuesday from about 2 p.m. through 8 or 9 p.m.

–Jim Davis / The Boston Globe, File

The humid air you experienced Tuesday morning is part of a one-day affair, lasting just long enough to bring in some thunderstorms and showers. A cold front will approach the coastline Tuesday afternoon, and ahead of it showers and thunderstorms will develop.

Meteorologists look at a bunch of different indices, which help us understand the atmosphere, when forecasting possible thunderstorms. The indices help predict not only the type of storms, but whether or not hail or tornadoes will be involved.

Most of the instability will be west of Interstate 495, and then farther south. Here’s a look at where the greatest chance of severe weather will occur and where the National Weather Service has the highest risk.


That said, the indices are not perfect, and we know that there will be enough humidity in the air along with this approaching cold front. Some of the storms could reach strong to severe levels, even where the indices are not as high.

The chance for hail, strong winds, and tornadoes is highest in northeast Pennsylvania, the Hudson Valley, and western New England.

I don’t think we’re going to have widespread severe issues in the Boston area, but many of us will see heavy rain and thunder. Some storms could be accompanied by strong, gusty winds and even some small hail.

The greatest threat from the storms comes Tuesday from about 2 p.m. through 8 or 9 p.m., and from the northwest toward the southeast.

The GIF below shows the storms’ progression as forecast by one of the models. A reminder: These radar predictions are not very accurate, and they just give us an idea of the movement and strength of the storms.