Polar air and a powerful winter storm put millions under winter alerts ...

CNN —

For millions of Americans across a large swath of the country, the holiday week is beginning with unrelenting below-freezing temperatures made even more miserable by heavy snow expected Tuesday and Wednesday in several central and northwestern states.

A developing ‘bomb cyclone’ has prompted alerts from Washington state to Maryland that cover over 50 million people, according to the National Weather Service, and that number is expected to grow over the coming days.

A ‘bomb cyclone’ is a term used by meteorologists to describe a rapidly strengthening storm. Specifically, it means a drop of 24 millibars (a term used to measure atmospheric pressure), in 24 hours. These storms frequently occur with winter nor’easters, but in this case, the bomb cyclone is expected to occur in the Plains. That’s because of the extreme temperature difference between the warm and moist air in advance of the storm and the extreme Arctic air mass moving in from Canada.

This weather phenomenon is expected to be the pressure equivalent of a category 2 hurricane as it reaches the Great Lakes, with the weather service now calling the strength of the low a “once-in-a-generation” event.

More than 40 million people are under wind chill alerts across much of the central and northwestern US, including in places slammed with blizzard conditions by a separate storm system last week. Parts of Alabama and Tennessee are also under a wind chill watch as the “feel like” temperatures are expected to plummet below zero.

On Tuesday, the sprawling weather system is delivering dangerously cold temperatures and snow to Montana, North Dakota, South Dakota and most of Minnesota, where high temperatures will remain below zero, according to forecasters at the NWS.

The air feels so cold, frostbite on exposed skin can occur in under 10 minutes in most of the impacted areas, and some isolated locations in under five minutes, forecasters warn.

“In addition to the brutally cold temperatures, dangerous wind chill values of 35 to 55 degrees below zero are possible into the end of the week across these areas,” the Weather Prediction Center said Monday.

Wind chill advisories are in place for Sioux, South Dakota, and Fargo, North Dakota, Tuesday, when the dangers of frostbite are settling in. Wind chill, which indicates what the wind feels like, will be as low as 40 degrees below zero, and in Wyoming on Wednesday night could hit a staggering 70 degrees below zero.

“Starting tonight, the worst of the arctic air mass will reach our area, bringing dangerous temperatures and wind chills. Slippery roads will continue with additional accumulating snow expected Tuesday afternoon through Wednesday morning,” the weather service office in Glasgow, Montana, said Monday evening.

Drastic temperature drops are coming. In Denver, for example, the temperature will be 50 degrees at noon on Wednesday but is expected to drop to 12 below by daybreak on Thursday. Similarly, New Yorkers will enjoy 60-degree weather on Friday in Manhattan and then see a temperature of 24 degrees as a high on Christmas Eve.

Snowfall has already begun in Seattle, which is under a winter storm warning Tuesday. The storm will move east into portions of Idaho Tuesday morning and then spread out across northern and central Montana later in the afternoon.

As the storm moves east this week, it stands to make holiday travel difficult, if not dangerous, in many places, with forecasters urging people to be prepared to make changes.

In Minnesota, the weather service in the Twin Cities implored residents to be cautious of the “potentially dangerous week of weather,” with the worst of the effects in the Midwest beginning Wednesday.

“The bottom line is travel will be very dangerous and could be LIFE-THREATENING later this week so be prepared to alter travel plans now!” the local weather service office said.

Many local governments in the affected areas have opened warming centers in an attempt to provide relief to those who need it.

Sioux Falls, South Dakota, was hit last week by a massive winter storm. The city is again under winter weather alerts Tuesday. Erin Woodiel/Argus Leader/USA Today

What’s ahead Christmas week

Overall, most of the US is expected to see abnormally cold temperatures this week. In fact, more than 80% of the country, excluding Hawaii and Alaska, are forecast to see below-freezing temperatures.

In Montana, Helena and Missoula are under winter storm warnings beginning Tuesday, and Billings is under a wind chill advisory through noon Friday.

The storm is also expected to intensify as it approaches the Midwest, where the greatest impacts are forecast. Snow will begin in the region Wednesday and last through much of the Christmas weekend.

In parts of central Minnesota, several inches of fluffy snow are expected Wednesday, followed by high winds, creating the potential for blizzard conditions. A blizzard is defined as having winds of at least 35 mph along with falling or blowing snow which reduces visibility to a quarter-mile or less, for at least three hours.

“By Thursday, wind gusts of 40-50 mph appear likely. With the fluffy snow in place, blizzard conditions are highly likely area wide, even in areas that typically aren’t favored for whiteout conditions,” the weather service said.

Kristin Jagodzinske sweeps the snow off the sidewalk in front of her shop in snowy downtown Poulsbo on Tuesday, Dec. 20, 2022. Meegan M. Reid/Kitsap Sun/USA Today Network

Chicago is forecast to be one of the hardest hit cities, where a winter storm watch is in effect starting Thursday night through Friday evening. With blizzard conditions likely, holiday travel could grind to a halt for many seeking to celebrate with family and loved ones.

The city could pick up 6 to 8 inches of snow from Thursday morning through late Friday night and when combined with 55 mph winds, the weather will bring travel to a stand still. The blizzard conditions could close O’Hare airport during the peak of the storm and will likely cause the cancellations of hundreds of flights in Chicago alone.

“Rapidly deteriorating conditions by late Thursday afternoon, with dangerous blizzard conditions appearing increasingly likely Thursday night into Friday,” said the weather service office in Chicago, home not only to one of the nation’s busiest airports but also long-distance train depots.

South bracing for unseasonably cold temps

Meanwhile, even southern cities unaccustomed to wintry conditions will get a brittle taste of it this holiday season, with Austin, Houston, Atlanta, and even Orlando at risk of seeing temperatures below freezing beginning midweek.

In Texas, the weather service made it a point to reassure residents this week’s unusually cold temperatures are not expected to affect the state as severely as last year’s brutal winter storms, when millions of people lost power during a weeklong extreme weather event in February 2021.

However, water pipes will be at risk of bursting, the weather service said. A wind chill watch for Amarillo, Texas, is in effect from Wednesday night through Friday afternoon.

“Outdoor pipes will be at risk due to well below freezing temps and windy conditions late this week,” the weather service in Fort Worth said. “Make sure to cover pipes and let faucets drip!”

Mississippi is urging residents to start bracing for what could be an extremely cold couple of days, the state’s emergency management agency said in a Facebook post Tuesday morning.

“Dangerous, cold temperatures are expected this week for most of the state. Start prepping NOW,” the post said. “Wrap pipes and keep a preparedness kit in your car with extra blankets. Remember the Four P’s of Winter Weather Preparedness. People, Pets, Pipes, and Plants!”

Much of the state is under a hard freeze watch, according to the weather service. Subfreezing temperatures are expected.

“A prolonged period of subfreezing temperatures may cause pipes to burst. Bitterly cold temperatures and wind chills will result in hypothermia and become life-threatening to those with prolonged exposure or without access to adequate warmth,” the weather service said.

In a post Monday, state emergency management officials reminded residents to seal windows and doors, insulate pipes and test smoke alarms.

More than half the US population awaits Christmas weekend under ...

CNN —

Nearly 177 million Americans – or more than half the US population – will await Christmas weekend under wind chill alerts as a major arctic blast plunges temperatures to dangerous levels in much of the country, according to the National Weather Service.

And the snowiest part is yet to come as the perilous winter storm barrels east across the nation.

A developing “bomb cyclone” is set to unload heavy snow and blizzard conditions especially in the Midwest on Thursday and Friday.

The cold air and storm are affecting nearly every state in some way: More than 200 million people coast-to-coast were under winter-weather alerts for snow or icy conditions Thursday evening, the weather service said.

Wind chill alerts are impacting people from the Canadian border to the Mexican border and from Washington state to Florida, with below-zero wind chills recorded as far south as Texas on Thursday morning and expected in the Southeast by Friday.

“Life-threatening wind chills over the Great Plains (will) overspread the eastern half of the nation by Friday,” the Weather Prediction Center said – and wind chills below minus 50 degrees already have been reported in the past two days in parts of Montana, South Dakota and Wyoming.

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Some low temperature records were set Thursday morning in the West and South, and in some cases they dropped this week with record-breaking speed: Denver International Airport saw a 37-degree plunge over one hour Wednesday, preliminarily the biggest one-hour drop recorded there, according to the National Weather Service.

Snow, meanwhile, has been hitting parts of the West and is expected in the next two days across much of the country’s eastern half.

A major snowstorm is shaping up for the Midwest and Great Lakes especially – with widespread light to moderate snowfall – but with powerful winds that may make for impossible travel conditions.

“Heavy snowfall rates” of 1 to 2 inches per hour, “along with wind gusts of over 50 mph will result in near-zero visibility and considerable blowing and drifting of snow,” the prediction center said.

The storm is expected to become a “bomb cyclone” – a rapidly strengthening storm that drops a certain amount of pressure within 24 hours – Thursday evening into Friday, reaching the pressure equivalent of a Category 2 hurricane as it moves into the Great Lakes. This could be “a once in a generation type of event,” a forecaster in the weather service’s Buffalo office wrote Tuesday, after noting that kind of strengthening doesn’t often happen in the lower Great Lakes.

A blizzard warning will be in place at 7 a.m. Friday in Buffalo and surrounding communities, where one to three feet of snow and 70 mph wind gusts are likely, according to the National Weather Service.

“This is not going to be a typical storm,” Buffalo Mayor Byron Brown said Thursday. “In fact, this could be a life-threatening storm.”

About 2,400 flights have been canceled across the US Thursday, according to the flight tracking site FlightAware, snarling air travel amid the busy holiday season. And airlines have canceled more than 2,200 US flights scheduled for Friday.

In South Dakota, a 340-mile stretch of Interstate 90 was closed in both directions Thursday morning, from Rapid City to Sioux Falls, because of blizzard-like conditions, officials said. Near-zero visibility also led to many highway closures between Colorado and Wyoming on Wednesday.

Even Florida won’t be spared, with residents of the Sunshine State expected to see sudden temperature drops Friday. Some cities in the South – including Nashville and Memphis – are expected to see snow Thursday.

Flooding, meanwhile, is possible in parts of the Northeast, including Washington and Philadelphia, as rain hits the area Thursday before temperatures plummet overnight and bring a “flash freeze.”

President Joe Biden received a briefing on the weather Thursday morning at the White House, from the National Weather Service and Federal Emergency Management Agency. He encouraged Americans to heed the warnings of local officials and to stay safe in the face of the extreme cold.

“This is really a very serious weather alert here,” Biden said, adding that the White House has reached out to 26 governors in the affected regions.

Snow blankets buildings in Buffalo, New York, on Wednesday, December 28. Joed Viera/AFP/Getty Images National Guard troops check on Buffalo residents on December 28. Jeffrey T. Barnes/AP A traveler searches for luggage December 28 at a Southwest Airlines baggage holding area in Denver International Airport. More than 90% of Wednesday's US flight cancellations were Southwest flights, according to flight tracking website FlightAware. Southwest canceled more than 2,500 flights. Michael Ciaglo/Getty Images People help push a car out of snow in Buffalo on Tuesday, December 27. John Normile/Getty Images Niagara Falls in New York is partially frozen on December 27. Lokman Vural Elibol/Anadolu Agency/Getty Images Travelers at Baltimore/Washington International Airport deal with the impact of canceled flights on December 27. Michael McCoy/Reuters A gas station canopy lays on its side after high winds and heavy snow in Lackawanna, New York, on December 27. The historic winter storm dumped up to 4 feet of snow on the area. John Normile/Getty Images Hundreds of unclaimed suitcases sit near the Southwest Airlines baggage claim area in Tennessee's Nashville International Airport after the airline canceled thousands of flights on December 27. Seth Herald/AFP/Getty Images A street is blanketed by snow in downtown Buffalo on Monday, December 26. Gov. Kathy Hochul/Twitter/AP A person clears a snow-covered driveway in Buffalo on December 26. Faith Aktas/Anadolu Agency/Getty Images A man and a boy walk across the frozen Reflecting Pool towards the Lincoln Memorial in Washington, DC, on December 26. Jim Watson/AFP/Getty Images Firefighters carry rescue equipment as they respond to a fire on a snow-covered street in Buffalo on Sunday, December 25. Jalen Wright/The New York Times/Redux Snow blankets a neighborhood in Cheektowaga, New York, on Christmas Day. Western New York is drowning in thick "lake effect" snow -- which forms when cold air moves over the warm waters of the Great Lakes -- just one month after the region was slammed with a historic snowstorm. John Waller via AP A man tries to dig out his car after he got stuck in a snowdrift about a block from home in Buffalo on Saturday, December 24. Derek Gee/The Buffalo News via AP Icicles created by a sprinkler hang from an orange tree in Clermont, Florida, on December 24. Paul Hennessy/Anadolu Agency via Getty Images A young holiday traveler passes the time at Detroit Wayne County Metro Airport on December 24. Matthew Hatcher/Getty Images Pedestrians deal with the cold in Chicago on December 24. Pat Nabong/Chicago Sun-Times via AP Hoak's Restaurant in Hamburg, New York, is seen covered in ice from the spray of Lake Erie on December 24. Kevin Hoak via Reuters Nissan Stadium employees clear the field in Nashville before the an NFL football game on December 24. Mark Zaleski/AP Amanda Kelly cleans off snow and ice from her car in Columbus, Ohio, on Friday, December 23. Joseph Scheller/Columbus Dispatch/USA Today Network Cars drive in whiteout conditions in Orchard Park, New York, on December 23. Mark Mulville/The Buffalo News/AP Travelers sleep while lines of people pass through a security checkpoint at Denver International Airport. David Zalubowski/AP Snow-covered buildings are seen in Louisville, Kentucky. Leandro Lozada/AFP/Getty Images The waters of Lake Erie wash over the shoreline in Hamburg, New York, on December 23. John Normile/Getty Images Snow collects on a bison at the Longfield Farm in Goshen, Kentucky, on December 23. Michael Clevenger/Courier Journal/USA Today Network Volunteers welcome a homeless person to a shelter at Louisville's Broadbent Arena on December 23. Leandro Lozada/AFP/Getty Images Stones are removed from a road in Westport, Massachusetts, after a storm surge made landfall, flooding many coastal areas on December 23. Peter Pereira/The Standard-Times/AP The Louisville skyline is obscured by steam rising from the Ohio River on December 23. Matt Stone/The Louisville Courier/USA Today Network Antonio Smothers jump-starts his vehicle in Nashville on December 23. Seth Herald/AFP/Getty Images Rows of headstones at the North Dakota Veterans Cemetery are blanketed by drifting snow in Mandan on Thursday, December 22. Tom Stromme/The Bismarck Tribune/AP Migrants warm themselves by a fire next to the US-Mexico border fence on December 22 in El Paso, Texas. John Moore/Getty Images Robert Arnold puts chains onto the tires of his semitrailer while he waits for the eastbound lane of I-70 to reopen in Silverthorne, Colorado, on December 22. Jason Connolly/AFP/Getty Images A musician departs following a show on Broadway in Nashville on December 22. Seth Herald/AFP/Getty Images Brady Myers helps turn the Stewpot Community Services day shelter for the unhoused into an emergency overnight shelter in Jackson, Mississippi, on December 22. Barbara Gauntt/Clarion Ledger/USA Today Network Vehicles travel along Interstate 44 on December 22, in St. Louis. Jeff Roberson/AP A person walks through the snow on December 22 in downtown Minneapolis. Alex Kormann/Star Tribune/AP A clean car passes a snow-covered car in Des Moines, Iowa. Charlie Neibergall/AP Travelers walk in front of flight information screens at O'Hare International Airport in Chicago on December 22. Nam Y. Huh/AP Ice collects on a window in Oklahoma City on December 22. Bryan Terry/The Oklahoman/USA Today Network Bus riders wait at a sheltered stop in Chicago on December 22. Charles Rex Arbogast/AP An accident involving a semi-tractor-trailer blocks the eastbound lanes of Interstate 80 in West Des Moines on December 22. Bryon Houlgrave/The Des Moines Register/AP Kids shovel snow off a sidewalk and driveway in Minneapolis on December 22. Abbie Parr/AP Travelers arrive for their flights at O'Hare International Airport on December 22 in Chicago. Kamil Krzaczynski/AFP/Getty Images Mist rises above ice flows on the Yellowstone River on December 22 in Paradise Valley, Montana. William Campbell/Getty Images Students walk to school buses after early dismissal at a middle school in Wheeling, Illinois, on December 22. Nam Y. Huh/AP Miguel Salazar clears sidewalks in Denver on December 22. Hyoung Chang/Denver Post/Getty Images Travelers arrive at the Minneapolis-Saint Paul International Airport on December 21. Alex Kormann/Star Tribune/AP Salt is prepared to be loaded onto a truck at the Department of Public Works sanitation yard in Milwaukee on December 21. Mike De Sisti/Milwaukee Journal-Sentinel/AP Propane heaters sit next to pens at the City of Mission Animal Shelter in Mission, Texas, on December 21. Joel Martinez/The Monitor/AP Crews de-ice a Southwest Airlines plane before takeoff in Omaha, Nebraska, on December 21. Chris Machian/Omaha World-Herald/AP An Iowa Department of Transportation plow clears a road in Iowa City on December 21. Joseph Cress/Iowa City Press Citizen/AP Snow covers homes in Seattle on December 20. Daniel Kim/The Seattle Times/AP In pictures: Winter storm impacts the US Prev Next

What’s ahead for the bomb cyclone

• Snow was falling early Thursday afternoon from Oklahoma to Michigan.

• Snow and high winds are expected to make for terrible travel conditions from eastern Montana and the northern Plains into the Midwest and upstate New York.

• Blizzard warnings – meaning snow and wind of 35 mph will frequently reduce visibility to less than a quarter of a mile for at least three hours – were in effect Thursday morning in some of those areas, including just southwest of Minneapolis, just south and east of Chicago, and western and northern Michigan.

• Major cities including Minneapolis, Chicago, Kansas City, St. Louis, Indianapolis, Cleveland, Columbus and Detroit are under winter storm warnings.

More on the extreme cold

• Wind chill warnings, watches and advisories were in effect for more than 30 states from Washington to Florida on Thursday.

• The arctic front will push south into the Gulf of Mexico and sweep off the Eastern Seaboard by late Friday, bringing cold into the Deep South.

• Thursday’s daytime temperatures may stay below zero in the northern Plains and get barely above that in the central Plains.

• Areas further south – Texas and the Gulf Coast – will see temperatures in the single digits and teens Thursday evening, the Storm Prediction Center said.

• Officials in several southern states are warning residents to take precautions. Alabama warned Thursday and Friday would likely feature “the coldest December airmass to hit the state since 1989,” the state’s emergency management agency said. Friday’s lows in that state were expected to range from the single digits in the north to the low 20s by the Gulf of Mexico.

• Louisiana Gov. John Bel Edwards asked residents Thursday to check on friends and family members that might have a hard time with the frigid temperatures. Lows Friday and Saturday were expected to be in the teens and 20s there.

• Two locations in Wyoming set records early Thursday for the lowest temperatures ever recorded at a particular location, regardless of the date on the calendar. Those new records are minus 41 degrees in Casper, and minus 29 in Riverton.

• Other locations in the West and South set record lows Thursday for temperatures on any December 22. They included several places in Montana (including minus 34 degrees in Boseman and minus 20 in East Cut Bank); Greybull, Wyoming, (minus 26); East Rapid City, South Dakota, (minus 18); Ketchikan Airport, Arkansas, (3); and three places in Washington state, including minus 20 degrees in Pullman.

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50 million under winter weather warnings as arctic cold moves in ...

A three-day ice accumulation that could exceed a half inch exists over parts of central Texas and Arkansas.

In the Dallas-Fort Worth area, a winter storm warning was put in place until 6 a.m. Wednesday.

Wind chill warnings and advisories have been issued from Oregon to Wisconsin.

DENVER – Fifty million Americans were under winter weather watches and advisories Monday amid warnings of a "prolonged and potentially significant icing event" affecting at least 15 states.

A swath of the nation from Texas to Ohio and Tennessee was bracing for days of treacherous travel conditions as an arctic cold front swept down into the southern Plains and Mid-South, the National Weather Service said. Freezing rain totals could become significant across parts of central Texas, southwest Oklahoma and central Arkansas, the weather service said.

"The interaction of an arctic air mass and moisture will set the stage for an expansive area of dangerous travel conditions early in the week," weather service meteorologist Craig Snell said. "Sleet and freezing rain accumulations are likely to create widespread hazardous travel conditions for several days in a row."

Icy developments:

A three-day ice accumulation could exceed a half inch over parts of central Texas and Arkansas. Parts of Tennessee could see more than a quarter inch of ice.

In addition to the potentially hazardous travel conditions, scattered tree damage and power outages are possible, the weather service warned.

In Maine, where temperatures are expected to dip as low as minus 14 degrees this week, thousands of residents will begin receiving energy-cost-relief payments of $450.

Monday's forecast calls for heavy rain and flooding in large parts of the Hawaiian islands.

BITTER COLD TARGETS NATION'S MIDSECTION: Texas, Gulf Coast states could see tornadoes: Updates

Icy conditions snarl travel, flight issues affect Texas

More than 1,100 flights, according to flight tracking site FlightAware, were canceled Monday as icy weather hit the U.S. Flight delays also mounted as more than 5,400 flights in or out of the U.S. were delayed.

Most of the delays and cancellations are affecting Dallas Love Field and Dallas-Fort Worth International airports in Texas.

A large portion of Texas, including the Dallas-Fort Worth area, is under a winter storm warning until Wednesday. The weather service warned of treacherous road conditions and told travelers to be cautious while driving.

"Dangerous travel conditions are expected during this time, with icy bridges/overpasses and surface streets," the weather service said Monday.

Denver ties record for cold: 'It's brutal out there'

In Denver, the overnight low hit minus 10, tying the record set in 1985, according to the National Weather Service, which warned of wind chills down to minus 19 degrees at Denver International Airport on Monday, and minus 23 on the state's eastern plains.

"It's really brutal out there," said Andrew Karras, a Denver city park ranger.

Like his colleagues, Karras was checking on unhoused people who had declined to move into emergency shelter. As estimated 2,000 people live unsheltered in Denver. While camping in city parks is illegal, rangers suspend enforcement in cold weather and instead focus on helping unhoused people with hats, gloves, blankets, snacks and handwarmers.

"We're handing out a lot of handwarmers right now. It sounds like a bit of a Band-Aid, but they can help keep people's fingers from freezing," Karras said. "We don't want anyone to die from the cold. That's the most important thing right now."

WHAT DO I DO IF MY FLIGHT IS CANCELED?'Your multitasking skills need to come through'

Heavy snow in West, Great Lakes

Heavy snow was forecast over parts of the western Colorado mountains. Travel could be difficult at times for some of the highest mountain passes. Farther east, lake effect snow is likely downwind of the Great Lakes early this week. The heaviest amounts of over 6 inches are possible off Lake Superior and Lake Erie.

Snow was stretching lower than usual in the mountains of Southern California, and snow was falling Monday on Interstate 5 in Grapevine. The weather service said traffic was being escorted over the freeway because of hazardous conditions.

The low snow levels will likely cause travel problems Monday on Highway 14 and other major thoroughfares in parts of Los Angeles and Ventura counties, the weather service said.

WHAT IS LAKE EFFECT SNOW?Here's how it happens and how much snow it can bring with it

Cold front will sweep east, but NYC remains free of snow

Periods of light snow are possible throughout the interior Northeast and Mid-Atlantic as a cold front pushes through by Tuesday. The region then faces several days of temperatures well below average, with some plummeting up to 50 degrees between Thursday and Saturday. Washington, D.C., will see a low of 15 degrees on Saturday; Philadelphia will drop to 10 degrees and Boston has minus 6 degrees to look forward to this weekend.

The cold front is not expected to bring any snow to New York City, which hardly feels like a winter wonderland these days. The city has yet to get any measurable snowfall this winter, defined as at least one-tenth of an inch accumulating on the ground. Never before had New York gone so late in the winter without snow, and a second record is within its grasp.

The current 327 consecutive days without snow are just five short of the longest such stretch, which concluded in mid-December 2020, and there are no flurries in the forecast for the week, according to National Weather Service meteorologist James Tomasini.

“Storm tracks and cold air have been remaining to the north and west of the area,” he said.

TEMPTED TO JOKE ABOUT GLOBAL WARMING IN BITTER COLD?Here's what experts say about that

Dallas-Fort Worth storm warning lasts into Wednesday

In the Dallas-Fort Worth area, a winter storm warning was put in place until 6 a.m. Wednesday. The weather service said mixed precipitation, primarily in the form of freezing rain and/or sleet, was expected. "Significant impacts" to travel may begin as early as Monday afternoon and continue through at least Tuesday night, the weather service said. Elevated surfaces such as bridges and overpasses will be the first to become icy, slick and hazardous as temperatures hover around or below freezing.

The weather service's office in Fort Worth said it had received several reports of traffic accidents by 6 a.m. Monday and repeatedly urged drivers to slow down, particularly on bridges and overpasses, which are prone to black ice.

Farther south in San Antonio, driving conditions were expected to resemble those of the Metroplex later in the day.

"Those in the most impacted areas should consider completing last minute travel plans before midday today," the weather service office in San Antonio said. "Icy road conditions may deteriorate rapidly this afternoon."

WHAT IS WIND CHILL? Understanding the wind chill index and how it's calculated

Bitter cold blasts Midwest, Northwest

The cold air responsible for the icy forecast in the Mid-South also brought a frigid start to the workweek throughout the central U.S. and into some Western states, the weather service said. Temperatures were 20 to 30 degrees below average in some areas facing single-digit high temperatures from the central High Plains to the Upper Midwest on Monday.

"Gusty winds will also create dangerous wind chills, as low as 55 below zero in the northern Plains this morning," the weather service said.

Wind chill warnings and advisories have been issued from Oregon to Wisconsin.

Nearly every state to be impacted by a 'once in a generation' winter ...

CNN —

A major winter storm and cold blast will impact nearly every state and bring what the National Weather Service is calling a “once in a generation type event” that will cripple travel on some of the busiest travel days of the year.

The strengthening storm will bring more than a foot of snow and possible blizzard conditions to the Midwest, as the weather service warns of “life-threatening” wind chills for millions.

More than 90 million people are under winter weather alerts and more than 87 million are under wind chill alerts. The alerts stretch across 37 states, dipping as far south as the Texas/Mexico border.

The number of people under winter alerts and wind chill alerts has grown to over 100 million people, or roughly a third of the US population, according to the National Weather Service.

The cold will stick around for Christmas weekend, making this the coldest Christmas in roughly 40 years for portions of the Plains and Midwest.

LIVE UPDATES ON THE WINTER STORM FOR THURSDAY

Storm timeline:

Wednesday: The storm will strengthen over the Northern Plains through the day as heavy snow falls across much of the Rockies, the Northern Plains and into the Midwest. Slick roads will lead to travel headaches and airport delays through places like Minneapolis, Omaha and Rapid City.

This system will bring 5 to 9 inches of light fluffy snow across the region, with “the highest amounts just north and west of the Twin Cities,” said the weather service office in Twin Cities. While snow will steadily fall across the region, the high winds won’t kick in until Thursday.

Denver will go from a high of 47 on Wednesday to a low of minus 14 on Thursday morning. That would be the city’s coldest day in 32 years, according to the weather service.

Temperatures in the Denver metro area will drop drastically once the front passes in the next couple of hours.

By sunrise, the temperature is expected to be around 10 degrees below zero and gusty north winds will create a wind chill of around minus 25. The high-temperature tomorrow will likely not make it above zero degrees.

A wind chill warning is in effect as well as a winter weather advisory. Several inches of snow will also make for difficult travel late this afternoon through early Thursday.

Thursday: Thursday will be the most difficult day for travel. The storm will be hitting the Midwest extremely hard with heavy snow and strong winds. Western Minnesota will face not only blizzard conditions, but potentially deadly wind chills Thursday and Friday.

“Whiteout conditions are expected during that time with travel becoming very difficult or impossible,” said the weather service. “This event could be life-threatening if you are stranded with wind chills in the 30 below to 45 below zero range.”

Chicago could also face blizzard conditions with winds gusting as high as 50 mph, with 2 to 4 inches of snow forecast.

“Overall, concern continues to increase in the quick development of dangerous conditions Thursday afternoon with potentially significant impacts to the evening peak travel window,” warned the weather service office in Chicago.

Snowfall early Wednesday in Glasgow, Montana. Angel Enriquez

Additionally, strong winds may knock out power lines in the Midwest, especially in areas where heavy snow fell last week and is already weighing down tree branches. This will leave millions finding a way to stay warm as temperatures plummet to well below freezing.

Snow could fall as far south as Jackson, Mississippi, Memphis and Nashville in Tennessee and even Birmingham, Alabama, on Thursday. Little to no accumulation is expected for most of the southern cities, however, Nashville could pick up about an inch of snow.

In anticipation of what will be a week of travel nightmares, United, American, Delta, Southwest and Jet Blue have issued travel waivers for dozens of airports across the country from the South to the Northeast, because in addition to snow covering roadways, low visibility could make air travel dangerous.

At least 1,000 flights had been canceled across the US, according to the flight tracking site Flightaware on Wednesday evening.

Chicago’s O’Hare International Airport leads the way, followed by Denver International and Chicago’s Midway International.

Cancellations at those airports could have a wider impact because they are busy hubs where travelers often change planes in order to reach other destinations. Thursday is expected to be the busiest pre-Christmas day for travel.

Friday: The storm is expected to become a “bomb cyclone” Thursday evening into Friday. A bomb cyclone is when a storm rapidly intensifies – and drops 24 millibars (a term used to measure atmospheric pressure) in 24 hours.

The storm is expected to reach the pressure equivalent of a Category 3 hurricane as it reaches the Great Lakes, with the weather service describing the strength of the low a “once-in-a-generation” event.

“This is a case in which snow totals may not tell the whole story. Even small snow amounts, when combined with very strong wind gusts and plummeting temperatures, can cause poor visibility and slick spots on roads. The sudden arrival of these conditions can increase the danger,” the weather service explained.

The storm will be over the Great Lakes on Friday and continuing to produce heavy snow across much of the Midwest. Portions of Michigan could pick up more than a foot of snow by Friday, making travel impossible at times.

Blizzard warnings are in effect for parts of the Dakotas, Montana, Minnesota, Iowa, Indiana and Michigan – where travel conditions will become difficult to impossible as the storm peaks Thursday into Friday. Major cities like Chicago, Kansas City, St Louis, Twin Cities and Detroit are under winter storm warnings for heavy snow and near blizzard conditions.

Heavy rain will also blanket much of the I-95 corridor, adding to the travel troubles and lengthy airport delays.

Even in places where the snow has ended, strong winds will continue to blow 30 to 40 mph across much of the Midwest and into the Northeast.

Friday night into Saturday morning, New England will get a quick shot of snow and windy conditions.

Travelers check in at Minneapolis' St. Paul Airport, Wednesday, December 21, 2022. Abbie Parr/AP

Life-threatening cold

Places that will escape the snow, won’t escape the cold. Areas from eastern Montana through the Dakotas will experience the coldest air beginning Thursday morning. Temperatures will be running 40 degrees below normal for these places. The combination of cold temperatures and windy conditions will send wind chills as low as 50 degrees below zero.

Rapid City will feel like 45 degrees below zero on Thursday morning. By Friday morning, Chicago’s wind chill will bottom out at 30 degrees below zero.

“The dangerously cold wind chills could cause frostbite on exposed skin in as little as 5 minutes,” warned the weather service office in Bismarck.

Even the South will be dangerously cold. Nashville and Atlanta’s wind chill will drop to minus 11 on Saturday morning and Birmingham will feel like minus 5.

Georgia Gov. Brian Kemp on Wednesday declared a state of emergency due to the upcoming “historic low temperatures” across the state, with near zero or negative digit wind chills by midday on Friday.

Greg Behrens, of Des Moines, Iowa, tries to stay warm as he makes his way on a snow-covered sidewalk, Wednesday, December 21, 2022, in Des Moines, Iowa. Charlie Neibergall/AP

The declaration will help “ensure that essential supplies, especially propane can be delivered for both commercial and residential needs,” the governor told reporters.

“Communities across the state are about to see temperatures that they haven’t experienced in a decade or more,” Kemp said.

The state will be pretreating roads and bridges in anticipation of the inclement weather and officials urged residents to avoid travel if possible.

Kentucky Gov. Andy Beshear also declared a state of emergency, with wind gusts expected to reach 40 to 50 mph on Friday and minus 10 to minus 26 degrees wind chills expected on Saturday. Beshear asked residents to stay off roads and to have a backup heat source.

Jackson and Birmingham will both spend more than 80 hours below freezing between Friday and Monday. Houston could sit below freezing for 46 hours between Thursday and Saturday.

The cold temperatures will stay through Christmas weekend, before finally moderating next week.

Aya Elamroussi Jennifer Gray
Aya Elamroussi
Jennifer Gray

Severe weather for East Coast: 2 dead, more than 1M without power

Update: Thousands still without power Tuesday after severe storms batter the East Coast.

Severe thunderstorms across the eastern United States turned deadly Monday, killing at least two people and cutting power to more than 1.1 million customers as damaging winds and large hail battered the region.

Destructive weather conditions were widespread with tornado watches and warnings issued across 10 states from Tennessee to New York. Toppled trees and power lines were seen falling into roads and some homes in multiple states.

“This does look to be one of the most impactful severe weather events across the Mid-Atlantic that we have had in some time,” National Weather Service meteorologist Chris Strong said during a Facebook live briefing.

The Washington, D.C., area is being hit by thunderstorms, turbulent rainfall, and gusty winds affecting the area as part of a severe weather outbreak with a rare Level 4 out of 5 ranking, according to the National Weather Service and the Washington Post's Capital Weather Gang.

The district was one of many areas along the East Coast under a tornado watch Monday afternoon through 9 p.m. It's part of a wicked weather system that had a large chunk of the East Coast in its crosshairs Monday in a summer of relentless heat and pounding storms.

The weather service said more than 29.5 million people were under a tornado watch Monday afternoon.

By Monday night, more than 2,600 U.S. flights had been canceled and nearly 7,900 delayed, according to flight tracking website FlightAware. And over one million Americans are without power, according to the website PowerOutage.us.

"A severe weather outbreak is expected across parts of the eastern U.S. today with widespread and locally destructive damaging winds and tornadoes as the greatest threats, especially across the southern/central Appalachians and Mid-Atlantic States," according to the weather service.

At least 2 people killed amid severe weather

Severe thunderstorms killed at least two people Monday.

A 15-year-old boy died after a tree fell on him as he got out of the car after he arrived at his grandparent's house in Anderson, South Carolina, according to the Anderson County Office of the Coroner.

In Florence, Alabama, police said a 28-year-old man died after he was struck by lightning, WAAY-TV reported.

Power outages; flights delayed due to East Coast storm

Electricity is out for more than one million Americans in nine states affected by the storms, according to the website PowerOutage.US.

In North Carolina, 211,746 customers lost electricity by Monday evening. The same goes for 131,644 customers in Pennsylvania; 77,311 customers in Georgia; and 85,652 customers in Maryland who were without power late Monday.

More than 2,600 planes have also been canceled and thousands more have been delayed, according to FlightAware.

"The FAA is re-routing aircraft around the storms heading to the East Coast as much as possible," said the Federal Aviation Administration on Monday afternoon.

'Widespread damaging winds'

From Atlanta to Philadelphia, more than 80 million people were at risk for dangerous winds, flash flooding and isolated tornadoes, forecasters said.

"Robust southwesterly winds will transport abundant moisture up the Eastern Seaboard, providing the potential for a washout in some interior sections of the Northeast as thunderstorms produce impressive downpours," AccuWeather Meteorologist La Troy Thornton said.

Thunderstorms were already triggering localized torrential downpours and disrupting travel in parts of the central Appalachians and the Northeast on Monday morning, AccuWeather said.

NOAA's Storm Prediction Center issued a moderate risk warning for severe storms across parts of the mid-Atlantic, including Baltimore and Washington, and warned of "widespread damaging winds." AccuWeather said it has been at least five years since the prediction center issued that threat level for the area.

What is the timeline for the storms?

The showers and thunderstorms that were dotting the Midwest, South and East early Monday were expected to intensify by early afternoon and roll through the evening, weather.com said. The outlet warned of destructive straight-line winds that could topple trees and spark power outages, hail, flash flooding and tornadoes.

Other cities that could be thrashed by the intense system, according to AccuWeather: Pittsburgh; Cleveland; Cincinnati; Baltimore; Charleston, West Virginia; Knoxville, Tennessee; Huntsville, Alabama; and Raleigh, North Carolina.

The turbulent weather could plague much of the East the rest of the week as well, forecasters said.

"The pattern this week will feature frequent showers and thunderstorms, typically every other day or so, across much of the East," AccuWeather Senior Meteorologist Alex Sosnowski said. "Even though it may not rain as much or as often as it did in July, conditions may again pose daily challenges for outdoor plans and travel."

And while the DC-area storm may not become a derecho − the equivalent of an inland hurricane − it could have some "derecho-like impacts," the Washington Post's Capital Weather Gang said.

How hot is it?:6.5 billion people endured climate-change-driven heat in July, report says

Will the extreme heat return in the mid-Atlantic?

The good news − for now − is that the stormy, wet weather should keep at bay the intense heat that engulfed the mid-Atlantic and part of the Northeast in July, forecasters said.

August temperatures have been 3-6 degrees below the historical average from Washington, D.C., to Boston so far, AccuWeather said, but forecasters warned the heat could make a comeback.

"Heat can build during the middle to late part of August in the Northeast and mid-Atlantic as many kids return to school. This can be accompanied by high humidity and a risk for thunderstorm activity," AccuWeather Meteorologist Brandon Buckingham said.

But heat still has the South in its grips

"Dangerously hot daytime temperatures" were expected across the South on Monday and Tuesday, according to the National Weather Service. The record highs would persist from the Desert Southwest into Texas and extend eastward along the Gulf Coast into parts of the Southeast and Florida, the weather service said.

Everything you need to know about heat:From the heat index to a heat dome to an excessive heat warning

Highs could hit the upper 90s to the lower 100s with a heat index − what the temperature feels like when relative humidity is combined with the air temperature − of 105 to 115 degrees in those areas, according to the weather service. The hot temperatures, dry ground conditions, low humidity, and gusty winds would elevate the wildfire risk in the Four Corners states into Texas, the weather service said.

Contributing: Associated Press

Heat wave across US: Arizona county brings in coolers to store bodies

Tens of millions of Americans were under heat notices Thursday − and major metropolitan areas were set to hit temperatures not seen in years − as the crushing heat felt in the West and South began to engulf parts of the Midwest and Northeast.

A "dangerous" heat wave will settle over cities including Washington, D.C., Philadelphia and Boston from Thursday through at least Saturday, the National Weather Service said. Temperatures could creep up toward triple digits, and the "oppressive humidity" will make it feel more like 105 degrees. Nighttime lows will be 10 to 15 degrees hotter than usual.

The situation was bleak in Phoenix, where the Maricopa County medical examiner's office was over capacity Thursday amid a growing number of heat-related deaths, forcing officials to bring in coolers for the first time since an early pandemic wave.

The widespread coverage of intense heat this week, from Phoenix and Houston to cities such as Chicago to the East Coast, makes it the "most widespread heat" this summer, according to AccuWeather chief meteorologist Jonathan Porter.

"This week seems to us to be probably the hottest week of the summer if you spatially average that across the country," Porter told USA TODAY on Thursday.

The air was thick and sticky with humidity in the Washington, D.C., region Thursday morning. The nation's capital could see 100 degrees for the first time in seven years, and the city declared a hot weather emergency. Baltimore, too, is poised to hit 100 for the first time in years, AccuWeather reported.

Arizona county brings in coolers to store bodies amid heat deaths

A relentless heat wave pummeling Arizona has brought with it a wave of heat-related deaths. The Maricopa County Medical Examiner’s Office was at 106% capacity Thursday, prompted the county to bring in coolers for the first time since the peak of the COVID-19 pandemic in 2020.

“Maricopa County has brought in 10 refrigerated coolers to increase capacity at our Medical Examiner's Office. We have not yet had to utilize them,” Jessie Caraveo, a spokesperson for Maricopa County, told the Arizona Republic, part of the USA TODAY Network.

According to Caraveo, a surge in deaths is normally seen during this time of year. But with a historic heatwave scorching, this year may be worse than normal. On Wednesday, a weekly heat report from Maricopa County confirmed seven new heat-associated deaths since last week; increasing the number of such deaths to 25 so far this year, with hundreds of other deaths under investigation.

-Fernando Cervantes Jr., Arizona Republic

Where are Americans under heat warnings?

Over 41 million Americans were under excessive heat warnings as of Thursday morning, including most of Illinois and other parts of the Midwest. Phoenix residents and parts of Southern California were also under warnings.

Much of the Midwest, from the Twin Cities to the whole state of Ohio, were under a heat advisory that covered nearly 129 million people. Also impacted: parts of Texas, Oklahoma and Tennessee.

Heat advisories were in place in the Northeast as well, stretching from parts of Virginia up through Massachusetts. The New York City region and parts of northeastern New Jersey will see heat indices from 103-106 degrees Thursday and Friday, the weather service said.

The weather service in Twin Cities, Minnesota, said heat indices were expected in near or hit above 100 with serious humidity. People should wear light, loose-fitting clothing, stay hydrated, avoid strenuous activity outdoors and try to stay in air-conditioned areas, the weather service said.

'GLOBAL BOILING HAS ARRIVED':July temps to smash records, maybe 120,000-year-old ones

Heat isn't done with the Southwest yet

Record-breaking heat will remain a concern across the Southwestern and Central U.S. through the end of the week, the National Weather Service said.

"Widespread heat advisories are in effect through Friday evening as dangerous heat indices of 105 F to 110+ F are expected" in areas of the Central Plains, Upper Mississippi Valley, Ohio Valley, and Midwest, the weather service said.

In Phoenix on Wednesday night, the temperature fell below 90 degrees at Sky Harbor airport for the first time since the morning of July 9, the weather service there said. Still, dangerous conditions were predicted to last through at least Saturday with highs from 110-116.

El Paso reached 100 for the 41st consecutive day on Wednesday, 18 days more than the previous record, the weather service there said.

Biden announces actions to protect workers in extreme heat

President Joe Biden will meet with mayors of cities experiencing some of the most extreme heat this summer – Phoenix and San Antonio – to discuss how heat is impacting their cities, the White House announced Thursday.

The White House also said Biden has instructed the Department of Labor to issue a "hazard alert," which will "reaffirm that workers have heat-related protections under federal law."

The Department of Labor will give employers information on how to protect workers during inclement heat and inform workers of their rights, as well as enhance enforcement for any heat-safety violations, the White House said.

New York City opens over 500 cooling centers

Officials in New York City announced residents could beat the heat by visiting one of hundreds of cooling centers being opened around the five boroughs. The city's website lists over 500 air-conditioned public facilities, including some designated for older residents and some that will accept pets.

The city activates the network of cooling centers whenever it is under a heat advisory by the National Weather Service with a heat index of at least 95 degrees for two consecutive days or 100 for any period, according to the city's heat plan.

“Heat kills more New Yorkers every year than any other kind of extreme weather event," Mayor Eric Adams said at a news conference Thursday.

Adams said the heat index will hit 105 on Thursday and be between 105 and 108 in the city on Friday, and New Yorkers should call 311 to find out where to go for a respite from the heat.

What is a heat wave?

"It's not the heat, it's the humidity." That's a partly valid phrase you may have heard in the summer, but it's actually both, the weather service said. The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature, according to the weather service.

A heat wave is a period of unusually hot weather that typically lasts two or more days, according to the National Oceanic and Atmospheric Administration. To be considered a heat wave, the temperatures have to be outside the historical averages for a given area.

A couple of 95 degree summer days in Maine, for example, might be considered a heat wave, but a couple of 95 degree summer days in Death Valley would be pretty unremarkable, the weather service said.

EVERYTHING YOU NEED TO KNOW ABOUT HEAT:From the heat index to a heat dome to an excessive heat warning

− Doyle Rice, USA TODAY

When will this heat wave end?

The question on many Americans' minds as they slog through day after day of extreme heat is: When will this be over? It depends on where you are, according to Porter, the AccuWeather chief meteorologist.

The same weather conditions that have caused the heat dome to stretch on in the South and Southwest, an area of high pressure in the atmosphere that produces sinking air currents, is expanding into the Midwest and Northeast, but the prognosis differs by location.

It will be "brief but impactful" in Midwest cities such as Chicago and those in the Northeast, Porter said. That's because the jet stream – narrow bands of wind high in the atmosphere sometimes called "rivers of air" – will dip as we go into the weekend, bringing thunderstorms and scaling back the heat. The peak of the wave in the majority of those regions will be Friday, Porter said.

As the heat wave has expanded to the east, it's loosened its grip on some parts of the Southwest, but only slightly. Phoenix has seen a slight reprieve. Thunderstorms have helped drop temperatures a bit, which will last into the weekend.

In Houston, Porter said the heat is expected to build once again and a heat wave will likely start Sunday and last through about Aug. 8. Temperatures will hover around 100 and there will be plenty of humidity leading to a "dangerous heat situation once again."

How to stay safe in a heat wave

Heat is the cause of the most weather-related deaths in the United States every year. Porter calls it a "silent killer."

The most at-risk populations are the very young, the elderly and people with certain underlying conditions or who take medications that make them less able to regulate body temperature, Porter said. People experiencing homelessness are also at extreme risk. He said kids playing sports or people who work outdoors are at special risk if they don't realize the dangers.

"As a heat wave goes on longer and longer, that accumulates greater heat stress on people's bodies and increases the risk for heat-related illnesses and heat-related stroke," he said.

The National Weather Service in Los Angeles gave residents in different environments tips for staying safe:

Severe weather 'outbreak' to impact 25 million people in southern US

A massive storm system moving into the Pacific Northwest on Sunday is predicted to bring severe weather ranging from strong winds and rain to a few tornadoes in the South, meteorologists warn, as weary travelers return home from their Thanksgiving weekend.

About 25 million people in the south-central region of the United States will be affected by severe thunderstorms later Tuesday, according to AccuWeather. The system will likely impact portions of northeastern Texas, northwestern Louisiana, and central and eastern Arkansas first.

The National Weather Service warned of “severe storms with a threat for strong tornadoes, wind damage, and some hail will be possible Tuesday” in the Mississippi Valley.

“A significant severe-weather event appears likely across parts of this region,” the weather service said on Twitter.

THANKSGIVING WEATHER: Heavy rain to blanket much of the southern U.S. on holiday weekend

How does climate change affect you?: Subscribe to the weekly Climate Point newsletter

The storm was expected to complicate Thanksgiving and Black Friday plans as heavy and steady rain already blanketed parts of Texas, Louisiana, and Arkansas Thursday afternoon. But there were no reports of significant travel delays during the holiday weekend.

Less than 70 flights within, into, or out of the U.S. were canceled on Saturday, according to flightaware.com.

"It's a pretty strong storm system that’s pretty typical this time of year," National Weather Service meteorologist Gregg Gallina told USA TODAY.

A severe weather "outbreak" is expected late Tuesday along the Mississippi River which will bring an "enhanced risk" and supercells, Gallina added.

The storm will shift across the mid-Mississippi Valley into the Northeast Sunday, according to the weather service.

The same storm is poised to trigger high winds in the Midwest to the Northeast. The system is forecast to form Tuesday morning and will move across Kansas with snow expected in the North as it enters the Great Lakes region Wednesday, Gallina said.

Due to the colder air, snow and freeze-up in certain regions of the Midwest and Northeast may cause substantial travel delays, according to AccuWeather.

The risks of the dayslong storm on Tuesday are possible power outages and property damage due to strong wind gusts, according to AccuWeather. Wind gust is 50 to 70 mph, with the possibility of reaching up to 75 mph.

The potent system also brought snow to eastern New Mexico and western Texas, lingering through Saturday morning, according to the weather service. With a strong cold front, a storm moving into the Pacific Northwest will bring heavy snow to the Cascade Range and northern Rocky Mountains Sunday and Monday.

Contributing: Claire Thornton, USA TODAY

Major storm to bring feet of snow, heavy rain and possible tornadoes ...

CNN —

An atmospheric river event, bringing ample amounts of moisture to the West this weekend, will gradually move across the country and bring hazardous weather to millions.

The blockbuster storm will begin in the West with heavy snow, gusty winds, and coastal flooding, then move eastward, threatening potential blizzard conditions in the Midwest and tornadoes in the South.

Winter weather alerts are in place for more than 10 million people across nearly a dozen states from California to Minnesota Sunday.

Snow could top out at 1 to 2 feet in the Rockies, and 3 to 5 feet in the Sierras by the end of the weekend. Heavy rain will also be notable in the West, particularly in California, where flooding concerns exist through Sunday.

An atmospheric river is a plume of moisture which streams in off the Pacific Ocean. Similar to a fire hose, it shoots moisture into one area for an extended period of time, resulting in very heavy rain or snow.

Most coastal communities will pick up 1 to 3 inches of rain through the weekend, and some areas of northern and central California could receive 3 to 5 inches of rain in total. Coastal erosion and flooded roadways will be the main concerns.

“Additional heavy rains may result in isolated runoff issues, especially across recent burn scars,” the Weather Prediction Center said.

Wind advisories and high wind warnings are also in places across several western states as gusts of 45 to 55 mph are possible.

This same storm system is forecast to track into the Rockies by Monday morning, bringing with it heavy mountain snow, before heading into the eastern half of the country.

“As the system moves into the Plains early next week, a springlike storm system develops,” Chad Myers, CNN Meteorologist said. “Significant severe weather will occur in the warm air across the South and a major snow and ice event will happen in the western Great Lakes and northern Plains.”

Potential blizzard conditions for the Plains and Midwest

For the northern Plains and Midwest, the threat for blizzard conditions is increasing, as significant snow, strong winds, ice and freezing rain will all be possible early next week from Colorado through Wisconsin.

CNN Weather

“A winter storm is expected to impact the Northern Plains Monday night through Thursday,” the National Weather Service office in Bismarck, North Dakota said. “Difficult travel conditions are expected Monday night through Wednesday night from heavy snow, reduced visibility, and drifting snow.”

Heavy snow and strong winds will be the main concerns, but freezing rain and ice are also possible.

If winds are at least 35 mph and visibility is less than one quarter of a mile for at least three hours, it could result in a full-blown blizzard across the region.

Widespread snow accumulations across the northern Plains and Midwest will be 4 to 8 inches, and some locations could pick up in excess of one foot through Friday of next week.

“While some uncertainty persists, confidence is increasing that strong winds and significant snows will produce hazardous impacts across much of the Central/Northern Plains and into the Upper Midwest,” the prediction center said.

Slick roadways and near-whiteout conditions will make travel very difficult if not impossible at times for some of these areas. Power outages will also be possible due to very strong winds.

Severe storms for the South next week

The threat for severe storms is also increasing across the southern Plains and Gulf Coast region including tornadoes, large hail, and damaging winds.

“While tornadoes in December are relatively uncommon when compared to the springtime, they are often more likely across portions of the Southeast and Lower Mississippi Valley, where there is often a secondary peak in the fall and winter,” Matthew Elliott, a meteorologist at the Storm Prediction Center, told CNN.

CNN Weather

The severe storm potential begins Monday night across Oklahoma and northern Texas, gradually spreading into Arkansas, Louisiana, and Mississippi on Tuesday.

Severe storms will likely continue Tuesday overnight across the Gulf Coast region. Nocturnal tornadoes are more dangerous because many people are asleep and unaware they need to be seeking a safe location.

While the greater tornado threat exists during the day, there is still the possibility for a few rotating storms through the evening hours.

By Wednesday, the greatest threat exists for an area from New Orleans to Panama City, Florida.

“The details regarding the areas most at risk from tornadoes will become clearer as the event approaches and smaller-scale trends become more evident,” Elliott said.

Because the forecast can change it is important to pay attention to developments in the coming days.

Thursday forecast: Severe weather for 40M; 3 die in Oklahoma ...

Three people are dead after tornadoes struck Oklahoma and about 40 million Americans are at risk of severe weather Thursday, forecasters say, marking the second consecutive day tornado and storm watches will be in effect for the central U.S.

A tornado watch was issued Thursday afternoon for portions of the upper Midwest, including the Chicago metro area. A tornado watch means weather conditions are favorable for tornadoes to form.

The Plains region has been the focal point for extreme weather throughout the week. Wednesday night, a severe storm spawned tornadoes in central Oklahoma, which also led to several injuries in addition to the deaths.

For some in the central U.S. who aren't threatened by Thursday's severe weather , the risk remains for flooding, fast-developing wildfires and even heavy snow.

In the East and South, residents will enjoy unseasonably warm temperatures. Flooding will be a concern in the East, red flag warnings will remain in the West, and precipitation should continue in the North.

America's 10 most endangered rivers 2023:See which waterways are most at-risk

Here's what to know about the national weather forecast for Thursday:

3 dead in Oklahoma after tornado

The small town of Cole, Oklahoma – home to about 600 people – was hit hard by a tornado, McClain County Deputy Sheriff Scott Gibbon told NBC's "Today."

Officials responded to multiple homes with people trapped inside, he said. One person died on the scene, and another died of a "heart-related issue" while being transported to a hospital, he said.

A third person who was injured by the tornado has also died, authorities said, but it was not clear where the person was injured.

While Oklahomans are to some degree used to tornadoes, the devastation "never gets easier," he said. "This has been one of the most significant tornadoes that we've received in that area."

Video:See what tornadoes in Cole and other storms look like across Oklahoma

Severe storms, tornadoes possible from Wisconsin to Texas

There is a slight risk for severe weather from the southern portion of the Plains to the Mississippi Valley through Thursday night, according to the National Weather Service.

A tornado watch was issued Thursday afternoon for much of northern Illinois, southern Wisconsin and portions of eastern Iowa. The watch in Illinois includes the Chicago metro area.

The possibility of severe thunderstorms, which can include hail, downpours and tornadoes, stretches from southern Wisconsin through central Texas, according to AccuWeather.

Areas where severe weather is most likely Thursday include:

Southern Missouri

Most of Illinois

Nearly all of Arkansas, including Little Rock

Eastern Oklahoma

Western Louisiana

Northeast and central Texas, including Dallas; Severe thunderstorms could approach Houston by late Thursday night.

"Severe winds, hail, isolated tornadoes and scattered incidents of flash flooding are possible across this region through Thursday evening into Friday morning," the NWS said.

A deadly, devastating year for tornadoes

With at least 66 people killed by tornadoes so far in 2023, according to the Storm Prediction Center, it's been an unusually deadly year for these violent storms.

A March 31 storm produced tornadoes that killed at least 32 people from Arkansas to Delaware, and days later a tornado left five dead in Missouri.

At least 26 died in Mississippi and Alabama when tornadoes during a late-March storm carved a path of destruction through the Deep South.

A deadly year:Historic number of tornadoes have left a path of death and destruction in 2023. Is climate change to blame?

Flash floods possible in eastern Texas, Louisiana

Along with the areas at risk of severe weather in the central U.S., flash flooding is possible beginning Thursday night in:

Eastern Texas

Louisiana

Arkansas

Northwest Mississippi

Western Tennessee

Southeast Arkansas

Western Kentucky

Southern Illinois

Southern Indiana

"Localized flash flooding is also a possibility from Thursday night to Friday night in urban areas and in poor drainage locations," AccuWeather said.

Red flag warnings issued in Southwest, Midwest

Red flag warnings were issued in nine states Thursday morning, including an area of the country not typically at risk for fires.

New Mexico and its surrounding areas have been on red flag warnings throughout the week, but good news may be coming soon: Thursday is the last day "critical" fire weather conditions are expected in the region, according to the NWS.

"Behind the dryline across the Southern High Plains, strong winds and dry/hot weather continue to pose a critical fire weather risk as forecast by the (Storm Prediction Center), across much of New Mexico and the Texas/Oklahoma Panhandles and adjacent regions of Colorado and southwest Kansas and western Oklahoma," the NWS said.

"Red flag warnings are posted for much of this area, any fires could rapidly spread given this dry high wind environment."

A red flag warning was also issued for large parts of Ohio, Indiana, Kentucky and Tennessee.

What's a red flag warning?

A red flag warning means warm temperatures, very low humidity levels and stronger winds are expected to combine to produce an increased risk of fire danger, according to the NWS.

The NWS reminds Americans to never leave a fire unattended, to extinguish all outdoor fires properly and to not throw cigarettes or matches out of a moving vehicle.

"If you are allowed to burn in your area, all burn barrels must be covered with a weighted metal cover, with holes no larger than 3/4 of an inch," the NWS advises.

Red flag warning map

Heavy snow in North Dakota, Minnesota

There's potential for heavy snowfall across northern North Dakota and Minnesota, as well as in parts of Minnesota and Washington state, beginning Thursday morning into the afternoon, as the NWS issued a winter storm watch through Friday morning.

"Rain and snow will be the initial precipitation type on Thursday before changing over to primarily snow Thursday night," the NWS said. "Snow that accumulates will be heavy and wet."

Winter storm map

East Coast heats up

The roller coaster of temperatures will continue in the East, as the region went from having warm weather to a "major cooldown" in less than a week. Temperatures have been on the rise in the Southeast and now the heat is extending north, with parts of Virginia expected to reach 90 degrees Thursday.

Here are some of the forecast highs in the East:

Washington, D.C.: 87

Charlottesville, Virginia: 91

New York: 68

Philadelphia: 78

Charlotte: 86

Atlanta: 84

US weather watches and warnings

National weather radar

Follow Jordan Mendoza on Twitter: @jordan_mendoza5.

Texas heatwave spreads: 110M under heat warnings, advisories ...

Along with the dismal air quality across the upper Midwest, the main weather story across the nation Wednesday was the deadly, record-breaking heat wave scorching the south-central U.S. over the past couple of weeks, killing at least 14 people. Temperatures Wednesday were forecast to approach or surpass 100 degrees from New Mexico to Mississippi.

“These are unprecedented temperatures,” Webb County, Texas, medical examiner Corine Stern said this week. Eleven people have died in Webb County, Stern said. Two others died in Texas while hiking in extreme heat at Big Bend National Park. One person died last week in Louisiana.

And as of late Wednesday, more than 110 million Americans were under some level of heat alert from the National Weather Service. As of Wednesday evening, the alerts span thousands of miles, from California to Florida.

“There may be more danger than a typical heat event, due to the longevity of near-record or record high nighttime lows and elevated heat index readings,” the National Weather Service said.

Meanwhile, much of the upper Midwest continued to face smoke-filled skies Wednesday. The Environmental Protection Agency’s AirNow.gov site showed Detroit in the “hazardous” range and warned that “everyone should stay indoors and reduce activity levels.”

This followed a smoky Tuesday: Chicago and Detroit had the worst air-quality in the world on Tuesday as smoke from Canadian wildfires drifted across the upper Midwest.

Most of the upper Midwest will remain under an air-quality advisory through Wednesday, and as the smoke moves east, air quality is expected to reach unhealthy levels in parts of western and central New York and eastern Lake Ontario, Gov. Kathy Hochul warned.

Here's a look at Wednesday's forecast.

Brutal Texas heat wave set to reach Central Plains and Mississippi Valley

The heat wave will be "life-threatening" to those working or spending time outdoors Wednesday, the weather service warned, because of the extreme humidity.

The heat index, which is how hot it feels with humidity factored in, will be in the 110 to 120 degree range across the eastern third of Texas, along the Central Gulf Coast and north through the Lower Mississippi Valley and Lower Tennessee Valley, the weather service said.

That includes the major metro areas Dallas-Fort Worth; San Antonio; New Orleans; Little Rock, Arkansas; Jackson, Mississippi; Memphis and Nashville, Tennessee; and Montgomery Alabama.

"Take this dangerous heat seriously," said Weather.com meteorologist Jon Erdman. "Avoid any prolonged, unnecessary outdoor activity, especially in the hottest part of the day. Check on the elderly and anyone else who may be living without air conditioning."

What is an excessive heat warning?

An excessive heat warning is issued by the weather service within 12 hours of the onset of extremely dangerous heat.

The general rule of thumb for such a warning is when the maximum heat index temperature is expected to be 105 degrees or higher for at least two days and nighttime air temperatures will not drop below 75 degrees. But these criteria vary across the country, especially for areas not used to extreme heat.

That's important because if you don't take precautions immediately when conditions are extreme, you may become seriously ill or even die, the weather service warned.

An excessive heat warning means some people can be seriously vulnerable to heat if precautions are not taken. Studies in Canada, Europe and the U.S. have indicated that mortality begins to increase exponentially as the heat increases or stays above a heat index of 104 degrees.

What is a heat advisory?

Just like an excessive heat warning, the weather service issues a heat advisory within 12 hours of the arrival of extremely dangerous heat conditions.

A heat advisory is issued when the maximum heat index temperature is expected to be 100 degrees or higher for at least two days and nighttime air temperatures will not drop below 75 degrees. These criteria also vary across the country, especially for areas not used to dangerous heat.

US heat index map

Heat, wildfires a concern in parts of California

After a relatively cool couple of weeks across much of California, summer has kicked off with an increasingly hot weather pattern for the interior valleys of California set to start Thursday and continue into the weekend.

In Southern California, wildfire season has begun in Riverside County.

A brush fire called the Juniper Fire has spread 50 acres, burning homes and leading to evacuations Tuesday afternoon in Perris, about 75 miles east of Los Angeles.

Southern California wildfire map

Canadian wildfires deteriorate air quality in Midwest

Poor air quality is set to continue in the Midwest, Great Lakes and Upper Mississippi Valley thanks to Canadian wildfires, according to the weather service. Detroit is under an air quality advisory through Wednesday night.

Chicago and Detroit ranked as the two cities with the worst quality, according to IQAir’s Air Quality Index, switching back and forth between the "unhealthy" and "very unhealthy" categories through Tuesday.

US air quality map

US weather warnings and watches

National weather radar

Contributing: The Associated Press