Tens of millions of people from the Upper Midwest to the Ohio Valley are on alert as a multiday severe weather threat begins Wednesday, with forecasters warning of storms capable of producing tornadoes,

Given the increased severe threat, we have declared tomorrow a 13. You’ll want to be sure to stay weather aware and have ways to receive warning notifications. While some details remain uncertain, recent forecast guidance has provided clarity on the timing of a cold front that will arrive from the west and provide the lift necessary for storms to develop.