At least 68 million people were under severe weather warnings on Memorial Day, as storms turned toward the Northeast after claiming the lives of at least 19 people and leaving half a million homes and businesses without power across the central United States.

Heavy storms will move across Arkansas and Tennessee and into the Ohio Valley before heading north up to the East Coast, through the Carolinas, Pennsylvania and New York. Heavy rain, winds of more than 60mph and hail more than 2in across are expected, with some tornadoes possible, NBC meteorologist Michelle Grossman said in a report early Monday.

Flash flooding alerts were in place for 9 million people, mostly in Tennessee, Kentucky and southern Indiana.

Severe weather stretched up to Colorado, where a rancher and 34 of his cattle were killed in a lightning strike near the town of Rand, 80 miles northwest of Denver, the Jackson County coroner said. Mike Morgan, 51, was feeding cattle from a trailer when the bolt struck open pasture — the rest of the 100 head of cattle were unharmed, police said.

The PowerOutage.us website, which tracks energy connections, said there were well over 500,000 customers without power as of 5:30 a.m. in affected areas, including 200,000 in Kentucky, representing nearly 10% of the state’s 2.3 million total power connections. Missouri and West Virginia both had more than 72,000 lost connections, the site said.

Some emergency phones lines had been damaged and were not operational, Kentucky State Police said, according to NBC affiliate WNKY of Bowling Green, Kentucky.

Monday’s weather warnings come after a torrid night across southern states and in the Great Plains. Eight people were reported dead in Arkansas; seven in Texas; two in Oklahoma, and two in Kentucky. The deaths were caused by weather-related incidents including falling trees.

Tornadoes were confirmed across the region — images from the town of Valley View, Texas, about 55 miles north of Fort Worth, showed that homes and vehicles had been obliterated. Weather watchers posted pictures from Missouri and Kentucky showing huge, ominous funnel clouds as well as golf ball-sized hailstones.

The NWS will send at least two teams to survey the damage across Kentucky, a process it said would take several days. A state of emergency was declared in at least five countries in Kentucky and across parts of Arkansas.

While a cold front makes its way north, extreme heat warnings are in place for southern and central Texas, where temperatures could rise to more than 100 degrees on Monday, possibly breaking daily records.

The National Weather Service said in a forecast that the heat index — a measure of how hot it feels — could reach a potentially dangerous 120 degrees in the Lone Star State. Similarly hot weather is forecast for Key West, Florida, and surrounding areas.

The Associated Press contributed.