New Yorkers will struggle through intense heat throughout the day Tuesday, along with thunderstorms in the afternoon that pose the risk of dangerous flash flooding.

Heavy rains have the potential to grind New York City to a halt if waters force subway lines to shutter. Streets can become inundated after a downpour, and there’s the risk of transport snarls on commuter lines like the Metro-North trains. That was the case two years ago when torrential showers pelted the metropolitan area.