NOAA’s Weather Prediction Center issued a level 3 out of 4 flash flooding risk for major cities in the Mid-Atlantic and Northeast, including Washington, D.C., Baltimore and Philadelphia.

After days of record-challenging heat, the Northeast is bracing for a dramatic weather shift as rounds of heavy rain threaten to unleash dangerous flash flooding across major cities and travel corridors.

Storms pummeled the Northeast on Thursday, with states of emergency declared for New York City and parts of New Jersey. Torrential rain and thunderstorms swept through the region, prompting flash flood alerts and causing widespread disruption to transport services.