Blistering heat wave to grip the East: See what major cities will sizzle
- Much of the U.S. is under extreme heat warnings or advisories while New York, Philadelphia and Washington could feel like 100 degrees or more.
- Heavy rain, flash flooding and severe weather are likely July 24 from the Central Plains and Midwest to the Great Lakes.
ARLINGTON, Va. − The unrelenting heat wave that has baked the Midwest for days was expanding to the east on July 24 and promised temperatures approaching 100 degrees in New York, Philadelphia and Washington, D.C., by July 25.
More than 130 million Americans were already under a heat warning, watch or advisory early on July 24 under a "heat dome" that has mixed a cocktail of high heat and humidity to push heat indices over 100 degrees in many areas. Heat indices measure how hot it actually feels when factoring for humidity.
"A late July heat wave will continue to expand eastward during the second half of the week with sultry conditions on tap from the Lower Mississippi Valley and Midwest to the Northeast and Mid-Atlantic," wrote Peter Mullinax, meteorologist at the National Weather Service's Weather Predicition Center.
Mullinax said record high temperatures are "likely to be challenged" in parts of the Northeast over the next two days, and all regions affected are also likely to see some record warm minimum temperatures broken.
Heat indices will generally top out somewhere from 100 to 105 from the Southern Plains, Midwest and Great Lakes on July 24 and the Northeast and Mid-Atlantic by July 25, Mullinax said. Localized heat indices could possibly approach 110.
Developments:
∎ Heavy rain, flash flooding and severe weather are likely July 24 from the Central Plains and Midwest to the Great Lakes.
∎ "Relatively tranquil" weather was expected across the West, but a fire weather threat was in effect for Northern California and parts of Nevada, Utah, Oregon, Idaho and Wyoming because of lightning.
All quiet on the hurricane front - for now
The hurricane season has gotten off to a slow start, but this doesn't mean the hurricane season will be less dangerous overall. The heart of the season is yet to come − and the 2025 season is still expected to have 13 to 19 named storms, with six to 10 of those will become hurricanes, according to the National Oceanic and Atmospheric Administration. The agency's website underscores the importance of being prepared regardless of the hurricane season forecast.
The official Atlantic hurricane season starts June 1 and ends Nov. 30. The agency's website shows that 97% of tropical cyclone activity occurs during this time, and August, September and October see the majority of storms that result in major damage in the United States.
− Janet Loehrke
Sheriff says officials slept as deadly flood surged in Texas
The sheriff and emergency management coordinator in Kerr County, Texas, were both asleep in the predawn hours of the Fourth of July when deadly flash floods overwhelmed the Guadalupe River, Sheriff Larry Leitha told CNN. Leitha, asked if he knew whether coordinator William "Dub" Thomas was working at the time, told CNN "I'm sure he was at home asleep at that time" and added that he was also asleep.
Thomas, also a deputy sheriff under Leitha, did not immediately respond to a request for comment from Paste BN.
The National Weather Service had begun issuing information July 3 warning that storms could cause "considerable flash and urban flash flooding." At 1:14 a.m. on July 4 the weather service upgraded the watch to a flash flood warning, and at 3:08 a.m. an alert using the term "disaster" was used.
At 4:23 a.m. a flash flood emergency was declared. A half hour later reports of rooftop rescues began coming in.
Leitha said the county's emergency operations center was not up and running from 1-3 a.m., when some of the worst flooding occurred.
Florida facing more heavy rainfall
While a stubborn high pressure system has fueled the heat dome in the Midwest, a low pressure system over the northeastern Gulf means much of Florida and portions of the northern Gulf Coast could see more heavy rainfall July 24. Parts of Florida have already seen multiple inches of rain in recent days, and a Melbourne recreation center's roof partially collapsed during a storm July 22.
The National Hurricane Center said in a July 24 advisory the area of low pressure is "currently producing a broad area of disorganized showers and thunderstorms." Forecasters said the system is expected to move generally westward across the north-central and northeastern portion of the Gulf over the next day or two where some slow development is possible. By the weekend, the system is expected to move inland, ending its chances for development.
− Gabe Hauari and Finch Walker
What causes a heat dome?
A heat dome occurs when a persistent region of high pressure traps heat over an area, according to William Gallus, professor of in meteorology with the Department of Geological and Atmospheric Sciences, Iowa State University.
"The heat dome can stretch over several states and linger for days to weeks, leaving the people, crops and animals below to suffer through stagnant, hot air that can feel like an oven," Gallus said in an article in The Conversation. Read more here.
− Janet Loehrke
Heat dome could linger for two weeks
The heat dome won't dissipate soon. Dangerous heat is expected across parts of the Central and Southeast through July, the weather service says. High temperatures will reach 100 degrees from Texas to western Tennessee almost every day for a week or two, AccuWeather said.
The Northeast was given a couple days reprieve: highs in the 80s and relatively low humidity. But the dome will spread across the region July 25, driving high temperatures deep into the 90s that will feel like more than 100 degrees as the humidity builds there.