Why do heat domes bring oppressive temperatures?
Dangerously hot and humid conditions are choking nearly the entire eastern half of the United States this week, caused by a 'heat dome' that's parked over parts of the country.
Heat alerts were in effect Wednesday for around 150 million people. Temperatures over 95 degrees Fahrenheit were widespread across the Ohio Valley and through the East Coast. 'Extremely dangerous heat' is expected to persist through Thursday, according to the National Weather Service.
But what is a heat dome, and why does the phenomenon bring oppressive heat with it?
A heat dome occurs when a strong and persistent region of high pressure sits over land and traps hot air, like a lid on a pot.
Heat domes are usually affected by the behavior of the jet stream, a ribbon of fast-moving air high in the atmosphere that flows from west to east in the Northern Hemisphere and affects weather systems.
The jet stream is fueled by temperature differences between the colder polar region to the north and warmer air masses to the south. As the jet stream flows around the planet, it can ripple in places, creating troughs and ridges that often result in unusual weather patterns.
Certain ripples can, for instance, amplify cold snaps. Others can move hot air over land, blasting heat and intensifying humidity.
Heat domes can linger for days or weeks, fueling prolonged heat waves that can turn deadly. Heat-related illness and death can affect any person of any age, but children, people with pre-existing health conditions and the elderly are particularly susceptible when temperatures spike.
Climate change is also increasing the frequency, intensity and duration of heat waves around the world, studies have shown. The planet's 10 hottest years since 1850 have all occurred in the past decade, according to the National Oceanic and Atmospheric Administration.
Some relief is expected later this week across the Midwest and throughout the East Coast, but heat and humidity are expected to remain high in the coming days.
This article was originally published on NBCNews.com
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CNN
36 minutes ago
- CNN
The best firm mattress in 2025, tried and tested
The best firm mattresses we tested Best firm mattress: Birch Luxe Natural Best budget firm mattress: Plank by Brooklyn Bedding Firm Mattress When thinking about the best mattresses, it's easy to associate a dreamy night's rest with something plush and cloudlike. But not everyone enjoys sleeping on a mattress that's overly soft, and some might prefer something firmer. If that's you, know you're not alone. Sleeping on one of the best firm mattresses can be a therapeutic and relaxing experience for certain sleepers. They can provide support for back pain and improve alignment, and are often more comfortable for those who prefer sleeping on their backs or stomachs. To find the best firm mattress, a panel of staffers here at CNN Underscored spent more than a month sleeping on various mattresses that fall squarely in the 'firm' category. To give you an idea of how dedicated this search was, know that everyone who participated in this test tossed their old mattress in favor of these firm options. For some, it was a positive experience and, for others, not so much. Ultimately, we settled on two firm mattresses we'd recommend to anyone. Birch Luxe Natural Mattress The Birch Luxe Natural Mattress is firm yet forgiving, as it has a plush top layer that provides soft (but firm, of course) support. Our tester said it's the best mattress she's ever slept on and that it's incredibly supportive for various sleep styles and positions. Read our review Plank by Brooklyn Bedding Firm Mattress The Firm Mattress from Plank by Brooklyn Bedding is a firm sleeper's dream that our tester said perfectly threads the needle of being supportive and comfortable. It's also discounted often, making it one of the best value buys in our entire testing pool. Read our review The Birch Luxe Natural Mattress achieves the feat of being both soft and firm. We know how contradictory this sounds, but this was the main takeaway from associate testing writer Gareen Puglia after she spent over a month sleeping on it. It also helped her get some of the most comfortable nights of sleep she can remember getting. After a rather laborious setup process (the mattress is quite heavy), Puglia said she immediately plopped down on the bed and drifted off for a nap within minutes. This is despite the fact that the Birch Luxe was the firmest mattress she'd ever slept on. It was that comfortable. One of Puglia's favorite features of the Birch Luxe is how even it felt, no matter what position she slept in. She said she's one to switch from side to side throughout the night, and that there was never a time when she adjusted her position and couldn't immediately get comfortable again. She attributed this to the mattress's unique combination of being mostly firm yet with a soft, plush top. Puglia also said that she experienced some relief from back pain while sleeping on the Birch Luxe (which is understandable since firm mattresses are often better for those with symptoms of back pain). It took only three weeks of testing for Puglia to admit that she would have a hard time going back to her old mattress and that she'd become accustomed to the quality of rest she got with the Birch Luxe. That isn't to say Puglia didn't have a few nitpicks. First, when the mattress arrived, its box was moderately damaged (though, thankfully, the mattress was inside its own wrapping and unharmed). It was also extremely heavy. So much so that Puglia had to recruit the help of a few family members just to drag it inside. Its heavy weight was even more noticeable when it came time to unwrap and unfurl the mattress, which ended up being an awkward (and exhausting) experience. There were also two pillows taped to the bottom of the mattress that Puglia nearly missed during the setup process. This was a minor issue, though Puglia said she wished they had been attached to the top for better visibility. All told, the Birch Luxe Natural Mattress has been a revelation for Puglia. She reported a far better night's rest, along with the ability to fall asleep quicker at night, something that she rarely experienced with her old mattress. If you're on the hunt for a firm mattress but prefer a budget option, consider the Firm from the Brooklyn Bedding brand Plank. CNN Underscored's director of social, Stephanie Griffin, tested this mattress over several weeks and was amazed at how comfortable it was and how well it helped relieve some of her nagging back pain. But perhaps its best feature is how it's reversible, with one side being a 'Firm' side while the other is the 'Firmest.' This allows a level of versatility not often seen in the mattress market. Because you can usually find this on sale for around $1,000 (for the queen size), it's an excellent value buy for anyone shopping for a new mattress. According to Griffin, unboxing and setting up the mattress is a breeze. Hers showed up in a bit of a tattered box, but the mattress itself was in perfect condition as it was wrapped individually and vacuum sealed. The fact that it was vacuum sealed means it also immediately started to unfurl when Griffin removed the packaging. The entire process was smooth, though, as she had already set it on her bed frame before unwrapping it. After a few minutes, it was fully expanded. Griffin also reported no weird chemical smells or any design problems. After only a few weeks of sleeping on the Firm, Griffin noticed a marked improvement in her back pain, noting that aches in her upper back and stiffness in her neck had subsided considerably since she started sleeping on it. She also said her overall sleep quality improved as a result. If you want a quality firm mattress, yet don't want to spend too much more than $1,000, the Firm is an excellent option. It offers two firmness levels, is easy to set up and helped our tester achieve noticeably better sleep in just a few weeks. Testing a batch of mattresses isn't as glamorous as it sounds. The space needed to test even one mattress is more than many of CNN Underscored's NYC-based product reviewers can manage in an apartment. That's why we thought conducting a panel test on these firm mattresses was our best bet. After we chose the mattresses to test, each participant received a new firm mattress and did everything from delivery and setup to sleeping on it for several weeks. As the days and weeks passed, they considered a few specific things to determine if the mattress they had was worth purchasing. Here's everything we took note of during the testing process. Quality of delivery: How was the mattress delivered? Was the box in good shape or tattered? What condition was the mattress in? Ease of setup: Did the tester set the mattress up alone, or did they require help? Was it vacuum sealed upon arrival? What was the set-up process? Did they encounter any challenges or issues? Sleep quality: What was the experience like compared to other mattresses the tester had slept on? What did they think about the level of firmness? Did they notice any change in their sleep quality and in what ways? Value and cost-effectiveness: Is this a mattress they would want to spend their own money on? Is it worth the full sticker price, and why? Do they feel confident in recommending it as something to purchase? There are multiple levels of firmness If you prefer a firm mattress, know that there's more than just one firm option to select. Many brands offer choices like 'medium firm' or even 'luxury firm,' so it helps to dig further into a mattress's specific firmness levels to see what is best for you. According to Dr. Chelsie Rohrscheib, a neuroscientist and the head sleep researcher and consultant at the Wesper sleep clinic in New York City, a medium-firm mattress may be the best choice for anyone who experiences back pain. Rohrscheib said that medium-firm mattresses can help keep someone's spine in the correct alignment while sleeping and may even alleviate certain pressures on their back. A quality mattress won't be cheap Almost all mattresses that fall into the 'good' or 'quality' category carry a price tag that's not exactly inexpensive. But that's all right. This is something you'll be sleeping on a few hundred times per year, so it's important to consider the cost per use instead of the overall price. For instance, if you spend $2,000 on a mattress and sleep on it an average of 300 times per year for 10 years (that's 3,000 nights), your cost per use comes out to about 0.66 cents per night. And that could be on the higher end if you own the mattress longer than 10 years (which is likely for high-quality mattresses) and sleep at home more than 300 nights per year. All this is to say, don't fret about spending on a mattress. This is one of the few luxuries where spending more for something is totally reasonable. You should take your sleep seriously, as it has a major impact on many aspects of your life. And good sleep starts with sleeping on a good mattress. Pay attention to warranties and guarantees Most mattresses come with some version of a multi-night trial period. Some might be in the one-month or 30-day range, while others are longer at 100 days or more. It's smart to take advantage of these trial periods, especially considering the money you'll be spending on a mattress. Similarly, ensure that all warranties and guarantees are adequate before purchasing. A mattress should come with a multi-year warranty (some even have five- or 10-year warranties), as well as a guarantee (likely tied to the trial period mentioned above). Don't be shy to exercise the warranty or guarantee if you're not 100% satisfied with a mattress. Nectar Premier Memory Foam Mattress The Nectar Premier is a firm memory foam mattress that's great for stomach or back sleepers. It's technically 'medium-firm' but our tester reported it feeling a bit firmer than they were used our review This mattress from Nectar is a middle of the road firm mattress that does offer a few unique features others in our product pool don't. First, it's made of memory foam but only allows for some contouring of the body due to how firm the foam is. Our tester reported that they didn't sink into it like they normally do with memory foam mattresses and that it felt far firmer than any mattress they'd slept on before. It's also a solid option for stomach sleepers and can help align the spine when sleeping in that position (same goes for those who sleep on their backs). Another feature our tester appreciated was its cooling top cover that helped limit overheating in the middle of the night. Avocado Green Pillow-Top Mattress In addition to being a quality firm mattress, our tester found the Avocado Green Pillow-Top Mattress excelled at helping her stay cool through the night. She noted that the mattress seemed to get more comfortable over time as it adapted to her body our review If you're shopping for a firm mattress that's also an organic mattress, consider the Avocado Green Pillow-Top. Though it's not 100% organic, it does have several third-party certifications that confirm it's free of chemicals such as formaldehyde, and it's also free of any polyurethane foams. It's also quite expensive at roughly $2,100 for a queen mattress. This won't fall into the budget-friendly category, but if you're green-conscious, sleep on your back and prefer a firm mattress, this is a good option. Nectar Classic Hybrid Mattress The Nectar Classic Hybrid is an extremely firm mattress that's only for die-hards. Our tester found it far too firm for his liking, even while sleeping on his back, and it actually increased his back pain over the testing our review If you're on the hunt for one of the firmest mattresses you can buy, perhaps the Nectar Classic Hybrid is what you seek. Our tester, outdoors, sustainable living and pets editor Kai Burkhardt, said that he had a very hard time getting comfortable while sleeping on this mattress because of how rigid and firm it was. He even tried sleeping solely on his back, and it ended up increasing his back pain instead of alleviating it. That's not to say this isn't a solid choice for anyone who prefers a firm mattress. Just know that this sits squarely at the furthest end of the firm spectrum. It's affordable price makes it an attractive option too. Awara Natural Luxury Hybrid Mattress The Natural Luxury Hybrid from Awara is a firm yet springy mattress that offers good edge support and is best for those who sleep on their backs. It also tends to be on sale for around $900 for a queen size, which is great our review Although CNN Underscored home and gifts editor Amina Lake Patel wasn't the target user of this Awara mattress (she's a side sleeper who prefers a more plush mattress), she admitted that it's likely a great option for back sleepers who prefer something firm. She also appreciated how springy it was to sit on and that it provided solid edge support. However, that springy feature didn't equate to increased comfort, and since Patel sleeps entirely on her side, she reported some hip pain and discomfort after only a few weeks with this mattress. She also wasn't a fan of the delivery and setup process, as the mattress showed up at her apartment in a damaged box, and the entire thing was far too heavy for her to hoist up the multiple flights of stairs to her residence. Puffy 12-Inch Lux Hybrid Mattress Puffy's Lux Hybrid mattress is ideal for those who prefer firm mattresses and who sleep on their backs. If you're a side sleeper, you may want to look elsewhere. Read our review The Lux Hybrid from Puffy does a few things extremely well, according to CNN Underscored senior testing editor, Rick Stella. It looks and feels like a premium mattress, is firm enough to satiate those who like sleeping on their back and is middle of the pack in terms of price. That's why Stella thinks it's a great choice for anyone who experiences some back pain or who just prefer sleeping on something more firm. It also excels at keeping sleepers cool, something Stella mentioned was noticeable throughout his multi-week testing period with the mattress. He said he tends to sleep warm but never felt like he overheated at all. Sleep Number ClimateCool Premium Smart Bed The ClimateCool Premium Smart bed from Sleep Number is about as luxury a sleeping experience as you can get, offering adjustable firmness levels, dual cooling zones and an optional flexible base. It also costs over $4, our review It's hard to fully recommend Sleep Number's ClimateCool Premium Smart Bed, but one thing about it is certain: It lives up to its name of being a 'premium' bed. CNN Underscored associate testing writer Joe Bloss couldn't deny how nice it was to sleep on this mattress and said that being able to adjust the firmness and temperature of the mattress on either side of the bed puts it in a class of its own. But it's also extremely expensive, which makes it difficult to truly assess its value. Put simply, if you have the budget, this is probably the best mattress you can buy because of its versatility to satisfy almost any kind of sleeper. Outdoors, sustainable living and pets editor Kai Burkhardt tested the Nectar Classic Hybrid Mattress. Associate testing writer Joe Bloss tested the Sleep Number ClimateCool Premium Smart Bed. Home and gifts editor Amina Lake Patel tested the Awara Natural Luxury Hybrid Mattress. Director of social Stephanie Griffin tested the Plank Firm. Associate testing writer Gareen Puglia tested the Birch Luxe Natural Mattress. Senior testing editor Rick Stella tested the Puffy Lux Hybrid Mattress. Contributing writer Jamie Ueda tested the Avocado Green Pillow-Top Mattress as well as the Nectar Premier Memory Foam Mattress. For this article, we consulted the following expert for insights about the best mattresses for back pain. Dr. Chelsie Rohrscheib, sleep expert, neuroscientist and head sleep researcher and consultant at the Wesper sleep clinic in New York City The following FAQs were answered by sleep expert Dr. Chelsie Rohrscheib. Are firm mattresses good for a bad back? Are firm mattresses good for a bad back? 'A firm mattress can support spinal alignment, which may relieve back pain,' said Rohrscheib. 'However, if the mattress is too firm, it can create pressure points and worsen discomfort, especially in the hips and shoulders. The key is finding the right balance of support and cushioning.' Is it better to sleep on a firm or a soft mattress? Is it better to sleep on a firm or a soft mattress? 'It depends on your body type and sleep position,' Rohrscheib said. 'Back and stomach sleepers usually benefit from a medium-firm mattress for proper support. Side sleepers often need a softer to medium mattress to cushion the shoulders and hips. The goal is to maintain spinal alignment while minimizing pressure.' Can a firm mattress help joint pain? Can a firm mattress help joint pain? 'A medium-firm mattress can help joint and back pain by promoting proper spinal alignment and reducing strain on pressure points,' said Rohrscheib. 'But if the mattress is too firm, it may increase joint pain, especially for side sleepers or those with arthritis.' CNN Underscored editors thoroughly test all the products we cover and provide full transparency about how we test them. We have an experienced team of writers and editors with several years of testing experience who ensure each article is carefully edited and products are properly vetted. We talk to top experts when it makes sense to ensure we are testing each product accurately and speaking about the pros and cons of each item. For this guide, the CNN Underscored editorial team took on the task of testing seven different mattresses for more than a month. The testing panel consists of members of Underscored's in-house testing team, as well as its lifestyle and deals team. A standardized rubric was created so each mattress was judged similarly and the experience of each panel member's month with their new mattress was shared with senior testing editor, Rick Stella.
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