A sprawling storm system crossing the U.S. on Friday overturned semitrucks on highways and fanned wildfires in Texas, Oklahoma, Missouri and Kansas.

Scientists said the storm's strength and potential for far-reaching impacts is notable, but its timing isn't unusual.

A multi-day tornado outbreak will begin today and last through the weekend in the Midwest, South and East. Strong, long-tracked tornadoes, widespread damaging winds, large hail and flash flooding are ...