Johnson County and the wider Kansas City metro area are preparing for a major heat wave that will settle over the region later this week.
Beginning Wednesday, daily temperature highs are expected to reach triple digits for nearly a week straight.
Good afternoon, periods of hot and humid conditions are expected this week. However, it's looking more likely we could see a few storm systems impact the region each morning, which could cut into temperatures. Regardless, stay safe in the hot and humid conditions this week! pic.twitter.com/aay53bV1Ws
— NWS Kansas City (@NWSKansasCity) July 24, 2023
The hottest days will come at the end of the week
Things will start to warm up noticeably Tuesday, with anticipated highs in the upper 90s, possibly hitting 100.
Jared Leighton, a lead forecaster for the National Weather Service’s Kansas City field office, said thunderstorms at times this week could cool things off a bit but days without rain and storms will suffer the most “oppressive” heat of the week, with highs potentially reaching 105 degrees by Friday or Saturday.
“The moisture that we have in the (Kansas City) area generally keeps the temperatures around 90 to 95 degrees,” he said. “So it takes a pretty rare circumstance — either a very anomalously high-pressure system or not a lot of moisture in the area — which sometimes that can happen when we’re in a really bad drought.”
This heat wave is linked to high temps further west
Leighton said what the KC metro will experience this week is partly attributable to a summer phenomenon typically seen in the U.S. Southwest, called the “four corners high.”
That results in high temperatures caused by high pressure in the “four corners” area around Arizona, New Mexico, Colorado and Utah that usually occurs towards the middle and end of July.
The American Southwest is suffering through a prolonged and historic heat wave, with daily high temperatures in Phoenix, Arizona, topping 110 degrees for at least 24 straight days, with no expected abatement in sight.
Leighton said the “four corners” high phenomenon and the blistering temperatures that come with it can sometimes move east and impact the Midwest.
Effects could prove most pronounced in local heat islands — developed areas with more buildings and impermeable surfaces that have less shade and green space, where temperatures can be up to 20 degrees hotter than surrounding areas.
The daily low temperatures also matter
While the high temperatures during the daytime may raise eyebrows, Leighton said there may still be even more serious heat impacts for those who aren’t able to find cool places at night.
This is because low temperatures will still settle to between 80 and 85 degrees most nights this week — which will still be uncomfortable for those who don’t have access to cooling shelters and air-conditioned businesses outside of regular business hours.
“One thing that people really need to be aware of is that the overnight lows are not going to recover very much,” he said. “If the low is at 80 (degrees), it’s probably only 80 degrees for like an hour or two in the morning. Most of the night is still going to be around 85 to 87 degrees.”
Johnson County has 17 cooling centers
- The Johnson County Library system’s 14 library branches will operate as cooling centers during regular library hours.
- Both branches of the Olathe Public Library also serve as cooling centers, in addition to the Spring Hill Civic Center at 401 N. Madison St.
- Johnson Countians — especially those who work outside — are encouraged to take caution against the heat by staying hydrated and wearing loose clothing.
Such heat is not unprecedented but is part of a larger trend
The hottest summers on record in Kansas history remain two extremely hot and dry summers in the midst of the Dust Bowl — 1934 and 1936.
Historic data collected by Kansas State University shows that temperatures in both those years spiked to near 120 degrees at times, with Olathe experiencing at least 40 days of 100-degree highs in both years.
Still, such prolonged heat waves with daily temperatures in the triple digits could become more regular with a changing climate.
Local group Climate Action KC predicts that by the year 2100, the average number of days in which temperatures exceed 105 degrees will increase from 0.7 to 21.9.
Scientists say this June around the globe was the hottest June ever recorded, in terms of average temperatures, and July is on pace to be even hotter.
The National Oceanic and Atmospheric Administration says there have been more than 2,000 local daily high temperature records set around the U.S. in the past 30 days.
Go deeper: Find a full list of cooling centers in the Kansas City metro area here.
