WASHINGTON (Reuters) - The central United States will see temperatures well below normal next week as a low pressure system pulls in colder Canadian air, the National Weather Service said on Thursday.
Temperatures could fall up to 20 Fahrenheit (11 Celsius) degrees below normal by Wednesday in Kansas and Oklahoma, states that are more used to heat waves in the middle of July than cold snaps, said Dan Petersen, a meteorologist with the National Weather Service.
"The basic idea (is) of a large area of below-normal temperatures and some very impressive anomalies for the central and southern Plains," he said.
The cold front is being generated by a low pressure system in the upper atmosphere that is expected to intensify, pulling in cold air from over Canada, Petersen said.
Temperatures will begin to fall on Sunday in the northern Great Plains. The cold snap will reach into the Ohio Valley and Oklahoma on Wednesday, with lows in the 50s F (10-15 C), he said.
The system will begin to move to the northeast and temperatures will become normal by the weekend, Petersen said.
The cold snap is not a summer version of the "polar vortex" that put much of the United States in a deep freeze during the winter. "That's a wintertime phenomenon," Petersen said.
Reporting by Ian Simpson