A cold front will team up with warm, humid air as it tracks eastward, setting the stage for intense storms to spread from the Plains on Tuesday to the East Coast by Thursday.

Severe weather struck Minnesota on Monday, with more than a dozen reported tornadoes in the state. The storms also brought strong wind, intense rain and hail larger than baseballs to the region.

It was only a matter of time before a long-lived heat wave would develop in the Midwest and Northeast. This one could last from late this week into early next week.

While the heat and humidity of summer have already arrived for some, the new season's arrival officially comes with the solstice Friday evening. Here's a look at how the forecast is shaping up for July through September.

Storm chasers captured spellbinding video of a large tornado that stayed on the ground for nearly an hour near Dickens and North Platte, Nebraska, on Monday evening. Watch how the twister seemed to shape-shift as it tore across wide open landscapes.