Get ready, North Carolina: Temperatures will soar here too later this week

The Triangle will see high temperatures that are about 10 degrees hotter than normal this weekend, as the region grapples with the effects of a heat dome that will affect much of the country.

Forecasters at the Raleigh office of the National Weather Service expect the Triangle to experience “increasingly oppressive heat” toward the end of the week and over the weekend, even though the region is near the southern edge of the heat dome.

By Friday, high temperatures could reach the mid 90s, they say.

Saturday and Sunday, temperatures could reach the upper 90s, the NWS said. That would challenge record highs for both days, according to NWS data.

And it may feel even hotter. The weekend’s highest heat indexes are expected to be as high as 105 degrees Fahrenheit, the NWS said. Heat index is a measurement that combines air temperature and humidity to gauge the “feels like” temperature.

The weekend will come with an increased risk of heat illness, forecasters warned. People working outdoors can especially be at risk.

Symptoms of heat exhaustion include heavy sweating, dizziness and nausea, according to the N.C. Department of Health and Human Services. It is also associated with a fast, weak pulse.

Heat exhaustion can quickly advance into heat stroke, which is associated with losing consciousness; a fast, strong pulse; and hot, dry skin. If someone is suffering from heat stroke, call 911 right away, health officials said.

“Think about your neighbors. Check on your elderly, your disabled neighbor or somebody who might be at risk. Check and make sure they’re OK,” said Ashley Ward, the director of Duke University’s Heat Policy Innovation Hub.

This heat wave is particularly risky, Ward added, because it is coming at the beginning of summer, when people are still acclimating to hotter temperatures.

The NWS agrees, with a Tuesday morning forecast saying, “These unusually hot conditions for this time of year will increase the risk of heat-related illness, especially for those without access to air conditioning.”

What’s a heat dome?

Heat domes are high pressure systems that trap warm air in place. The systems can prevent clouds from forming, and the high pressure systems push storms and colder winds around their edges.

That means the sun is able to keep warming an area over an extended period of time, without a way for the hot air to escape. When hot air rises under a heat dome, the high pressure system pushes it back down, returning it to the surface.

In June and July 2021, a record-breaking heat dome in the Pacific Northwest caused more than 650 deaths across Canada and the United States.

How can I stay safe?

Avoiding exposure to high heat is a key part of staying safe, Ward said.

That means trying to stay inside when temperatures are high over the weekend if possible, Ward said. And if you do need to work outside, do it early in the morning before the sun starts heating things up or in the evening as temperatures are cooling off.

In addition to avoiding the hottest parts of the day, outdoor workers are typically advised to take frequent breaks in cool or shady places, drink more water and have a buddy system to check on coworkers.

“Everyone is vulnerable to heat. You can be a person in good shape and good health and still succumb to heat exposure,” Ward said.

Other ways to bring the body temperature down, Ward said, include:

• Taking a cool shower for about 10 minutes.

• Dipping your arms above your elbows into a sink full of cool water for 5 to 7 minutes.

• Dipping your feet into cool water above your ankles for 5 to 7 minutes.

• Walking around a mall, store or similar public space that is air conditioned.

Dousing a cloth in cool water and wiping down your arms, neck and head and then sitting in front of a fan is also helpful, Ward said, basically mimicking the cooling effects of sweating.

“There are ways to protect yourself using cool water in your home and using fans that can help reduce the heat stress on your body,” Ward said.

What will the heat risk be?

Forecasters expect that heat risk will start to increase on Friday and elevate over the weekend, according to a new tool from the National Weather Service.

The HeatRisk tool evaluates forecasts to see how much higher temperatures are expected to be than normal, whether people have likely had a chance to adjust to the heat and whether high temperatures are expected to last into the nighttime. It also looks at whether temperatures are expected to reach levels the Centers for Disease Control and Prevention say threaten human health.

In Raleigh, Friday is expected to reach a “moderate” risk level, characterized by the color orange. That means people who are sensitive to heat are at risk, particularly those who don’t have access to enough water or to a place with cool temperatures.

Then, Saturday, the risk increases to the “major” level, which is shown by red on the map. That will affect anyone who lacks access to enough water or to somewhere that is cool, the warning system says. It will have impacts in some health systems, in industries where people work outside and on some infrastructure, the warning system says.

That risk is expected to continue through Sunday, though, some isolated areas around the Triangle are expected to reach extreme levels, particularly in northern Raleigh and eastern Durham. That means anyone who doesn’t have cooling or enough water will be impacted, according to the risk map.

What role do overnight temperatures play?

The NWS is forecasting that low temperatures for Saturday and Sunday will be in the 70s. Overnight low temperatures are important during heat waves, Ward said.

If temperatures aren’t low enough, people’s bodies aren’t able to fully relax in the evening. Heart rates will remain elevated, potentially causing decreased blood flow to the kidneys, Ward said.

People who have diabetes, heart disease or high blood pressure are particularly at risk, Ward said. Those impacts are most significant if overnight temperatures remain above 75 degrees, just above what forecasters are predicting this weekend.

For many people, air conditioning during a heat wave is too expensive. It is tempting in those cases to focus on cooling a living area, Ward said, even though that isn’t the choice that will provide the most safety.

“If you can’t afford to cool your entire house,” Ward said, “prioritize cooling your bedroom so that you can get that reprieve overnight.”

Does climate change factor in?

The 2021 Pacific Northwest heat dome would have been “virtually impossible” without climate change caused by humans’ burning of fossil fuels, found an international panel of 21 scientists.

But climate change is having an impact on heat waves locally, too.

In Raleigh, the season in which heat waves occur expanded by 64 days between 1961 and 2021, according to the National Oceanic and Atmospheric Administration. Scientists typically see a “heat wave” as a period where temperatures are abnormally hot for two or more days.

Climate change is also making heat waves more common here, with about five additional heat waves a year occurring in 2021, according to NOAA. And when they happen, they are lasting about 1.7 days longer.

“Unusually hot days and heat wave events are a natural part of day-to-day variation in weather. As the Earth’s climate warms, however, hotter-than-usual days and nights are becoming more common ... and heat waves are expected to become more frequent and intense,” the EPA said on its website.

How frequent is heat illness in NC?

There were 406 emergency department visits related to heat illness between May 1 and June 1, according to the N.C. Department of Health and Human Services’ heat-related illness surveillance reports.

The most frequent diagnosis has been heat exhaustion, with 104 cases.

Emergency room visits increased during the weeks of May 19 and May 26, with 118 and 111 cases, respectively.

This story was produced with financial support from the Hartfield Foundation and Green South Foundation, in partnership with Journalism Funding Partners, as part of an independent journalism fellowship program. The N&O maintains full editorial control of the work. If you would like to help support local journalism, please consider signing up for a digital subscription, which you can do here.