Parts of Oklahoma, Kansas, Arkansas and Missouri were under tornado watches into Sunday morning.
A tornado watch is in effect until 3 a.m. Central Time for much of eastern Oklahoma, according to the National Weather Service. Northwest Arkansas and southwest Missouri were also under tornado watches into the morning, and the threat shifts east on Sunday to parts of Arkansas, eastern Missouri Illinois, and other areas.
Repeated heavy rain in the Plains could also cause flooding throughout the weekend.
Nineteen tornadoes were reported as of 10:00 p.m. CT, the Weather Channel reported, including six in Oklahoma, six in Minnesota, five in Texas, and one each in Kansas, Nebraska and Wyoming. Very large hail was also seen around Texas Saturday afternoon, including tennis ball-sized hail east of Happy, Texas, just after 2:30 p.m. local time.
The warning followed a relatively quiet night for most of the region, Michael Palmer, the Weather Channel's lead forecaster, said.
In contrast, the Eastern Seaboard looked set for a balmy if not outright steamy weekend, with temperatures hitting highs in the 80s and even the low 90s in some southern states.
The summer-like weather would be interrupted for some, with isolated thunderstorms likely soaking some of the warmer areas in the afternoon and evening, Palmer added.