Grab the jackets and cover the plants, a freeze warning will be in effect for the metro and most of southern Minnesota Thursday night into Friday morning.

Cold air rushing in from the north will send the mercury falling into the upper 20s and low 30s in the Twin Cities for the next two nights, prompting the National Weather Service to issue the warning for Thursday night and a freeze watch for Friday night into Saturday morning.

"Frost and freeze conditions will kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing," the weather service says.

The ominous warning officially is in effect from 3 a.m. to 9 a.m. Friday covers an area stretching from the Twin Cities west to Willmar to the South Dakota border then south to the Iowa border. To the east of the metro, the warning includes all or parts of St. Croix, Pierce, Pepin, Chippewa and Eau Claire counties in Wisconsin.

Many of the same areas could see subfreezing temperatures again Friday night to Saturday morning. The weather service has issued a freeze watch covering places such as Willmar, Redwood Falls, Fairmont, Albert Lea, Red Wing and Eau Claire, Wis.

Thermometers in the Twin Cities could flirt with record low readings Thursday and Friday nights. The coldest reading for May 7 was recorded in 1885 when the mercury fell to 27 degrees. For May 8 the record low is 28 degrees set in 1960, according to the NWS.

A low pressure system and a dip in the jet stream is dragging in the cold air leading to the sharp cool down after a 78-degree high last Friday.

"It's kind of a January pattern right now," said Caleb Grunzke, a meteorologist at the National Weather Service in Chanhassen. "It's like an Alberta clipper."

Cool conditions with abundant sunshine are expected to hang around the Twin Cities and much of Minnesota for another week before there is a switch to a warmer weather pattern, Grunzke said.

Tim Harlow • 612-673-7768