Editor’s Note: For the latest updates on the Memorial Day weekend storms, our coverage has been moved here.
(CNN) – The National Weather Service has issued a tornado watch for parts of three states, calling it a “particularly dangerous situation,” a rare designation indicating the possibility of unusually strong storms.
The tornado watch covers parts of north Texas, much of central Oklahoma and south-central Kansas. It will expire at 11:00 p.m. CT.
The watch predicts several tornadoes – likely a few intense tornadoes – over an area that includes cities such as Wichita, Kansas and Oklahoma City, Oklahoma, according to the Storm Prediction Center.
This is a special type of tornado watch issued only when there is an unusually high level of confidence in the potential for multiple tornadoes of at least EF2 and long duration in the area, according to the National Weather Service.
Another tornado watch was added in parts of Kansas until 1 a.m., affecting half a million people, according to the Storm Prediction Center. More than 4.5 million Americans were under tornado watch as of Saturday evening.
Supercell thunderstorms that initiate in the watch area will also be capable of producing extremely large hail up to the size of a grapefruit and damaging wind gusts of up to 80 mph.
An EF4 tornado — the third such violent tornado this year — killed at least four people Tuesday in Greenfield, Iowa, and left parts of the town in ruins. Stronger tornadoes – at least EF2 strength – are possible Saturday in parts of the Plains and Sunday in parts of the Midwest.
Some tornadoes on Saturday could be particularly violent and exceed EF4 strength, the Storm Prediction Center warned Friday.
Supercell thunderstorms that began brewing Saturday could be capable of producing a few tornadoes, scattering large hail up to the size of a softball and damaging wind gusts of up to 70 mph, according to the Storm Prediction Center .
Dangerous storms are expected the rumble comes alive in the evening in parts of western Nebraska, Kansas and Oklahoma. Storms will gain strength and strength in the evening and overnight and move eastward into the Mississippi Valley.
A Level 4 of 5 severe thunderstorm risk is in place Saturday for much of Kansas and Oklahoma, including Oklahoma City, Tulsa and Wichita, and far western Missouri.
“Severe tornadoes, extreme hail and corridors of wind damage” are most likely in this area, according to the SPC, but could extend beyond. Everywhere from Texas to Nebraska to the Mississippi Valley, storms could occur, bringing strong wind gusts, hail and tornadoes.
Severe thunderstorms will continue over parts of the Mississippi Valley through Sunday morning before gradually losing strength. But a new series of devastating storms is expected to arrive soon after.
Thunderstorms will develop over parts of the Midwest Sunday afternoon and develop farther south and east through the evening and overnight. Powerful storms could potentially extend from the Great Lakes to the South Sunday evening.
Damaging wind gusts and hail will be the main dangers of any severe thunderstorms Sunday, but some could produce tornadoes. Right now, the greatest tornado threat is in parts of the Midwest, especially in the afternoon and evening.
Travel hubs in Chicago, Indianapolis, St. Louis and Nashville could face devastating storms, leading to flight delays or cancellations.
Thunderstorm activity will likely continue into Memorial Day Monday and could disrupt outdoor plans and travel across much of the East. Some of these storms could become severe, but it is not yet known how serious the threat will be.
Even in the absence of damaging wind gusts, hail or tornadoes, lightning poses a serious threat to any outdoor projects like picnics, pool parties or trips to the beach.
Meanwhile, dangerous storms and scorching heat continue to affect large areas of the United States this Memorial Day weekend and could disrupt outdoor plans and travel.
A near-record number of people will travel this weekend in what could be the busiest period in nearly two decades, according to AAA.
Travelers will face a dangerous and disruptive severe thunderstorm lasting several days, accompanied by damaging winds, dangerous hail and strong tornadoes. It is expected to spread this weekend to parts of the central, southern and eastern United States.
The bad weather was relentless in May, but reached an even more frenzied pace this week. Nearly 850 reports of wind damage and at least 80 reports of tornadoes have occurred in the United States since Sunday.
As severe storms batter inland areas this weekend, some coastal areas will face a different threat. A generous helping of summer heat is on the menu as many head to the beach to celebrate the unofficial start of summer.
It’s already been record-breaking temperatures in parts of the South this month, particularly in South Texas and South Florida, the type of extreme heat made more likely by human-caused climate change.
The record-breaking heat will extend through the weekend and jeopardize daily high temperature records from Texas to the Southeast as air temperatures climb into the 90s.
Houston, New Orleans, Miami, Mobile, Alabama, Tampa, Florida, and Charleston, South Carolina, are just a few cities along the Gulf and Southeast Atlantic coasts where one will feel more like July and late May until Memorial Day.
The heat index, which measures how the body actually feels, could approach triple digits in the southern United States, increasing health risks from the deadliest weather threat.
For those exposed to heat, it is important to stay hydrated and be alert for signs of heat exhaustion or heat stroke.
Heat index values have climbed as high as 100 this week in South Texas and could climb higher into very dangerous territory through Monday. The heat index is expected to peak between 110 and 120 degrees in South Texas, including Corpus Christi and Laredo, according to the National Weather Service.
