The storm's sweeping effects have included flooding and more than 20 tornadoes in the Southern Plains.
Nineteen million Americans are in the path of destruction again today after almost four dozen tornadoes ripped through six states this weekend leveling homes and tossing trees. Damage was reported in many areas, including the town of Mangum, but no deaths have been reported.
Video from CNN affiliate KOCO also showed a team of four firefighters pushing a boat containing four people against a current, up a driveway that had become a stream. In Kansas, winds from a massive tornado overturned a tractor trailer that was driving almost two miles away.
Roads were closed, and numerous high-water rescues were required.
And in Mangum, Oklahoma, we're seeing evidence of structural damage to homes.
The Oklahoma Department of Transportation shut down Interstate 40 in El Reno, about 25 miles west of Oklahoma City, because of high water.
To the northeast, in Stillwater, Oklahoma State University and Stillwater Public Schools both closed due to floodwaters Tuesday. "Many roads are impassable, with water rescues being performed from homes", the Weather Service tweeted early Tuesday morning.
Heavy snow melt from the north and significant spring rains have led to waves of flooding in Missouri.
A tornado that touched down early on Tuesday near Tulsa International Airport was among more than two dozen that have ripped through the region since Monday, according to the weather service.
Risk of severe storms Tuesday.
"These storms will maintain a risk of large hail, damaging winds, and isolated tornadoes through the night in some areas", the Storm Prediction Center said.
Serious river flooding - including along the already swollen Mississippi River - also is expected in the central United States as another 2 to 5 inches of rain are expected to fall over the region in the next few days. NWS added that this was only the second time on record in NWS Storm Prediction Center history that "every category of watch probabilities (torn, wind, hail) are greater than 95%".
Tuesday night into Wednesday, this storm system is forecast to lift northeast through the Plains into Minnesota, dragging a cool front through the Upper Midwest, which will generate heavy showers and storms through eastern Iowa, much of IL, and Wisconsin.