A widespread, intense heat wave has spread from the Midwest into the East and will continue through the Fourth of July weekend, accompanied by both oppressive humidity and sharp highs that flirt with some all-time records in some Mid-Atlantic states.
Before the Fourth of July, more than 165 million Americans in the Midwest and East were at risk of either “severe” or “extreme” heat-related health problems, according to the National Weather Service’s HeatRisk pilot product.
Triple-digit heat indices are expected for many, and for some, daytime low temperatures will not fall below the mid-80s, providing no relief overnight.
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(CARDS: US 10-Day Forecast: Highs and Lows)
Heat Alerts
The NWS has issued multiple heat warnings and advisories for the eastern half of the country this week, which are outlined in the map below.
Alerts continue to extend from the Central Plains to the Midwest, South and Northeast.
A heat warning means that dangerous heat is either occurring now or is imminent. Heat advisories are issued for heat that is less unusual but can still be dangerous.
(CURRENT US MAPS: Temperature | Heat index | Dew point)
Northeast attractions
For much of the Northeast, this heat wave will last through at least part of the holiday weekend.
Parts of the I-95 corridor from southern New England to Virginia could reach triple-digit highs every day through Saturday.
The club’s first centenary visit since 2012 has already taken place in New York.
Life-threatening heat readings will rise above 100 degrees in many areas and likely top 110 degrees in the hottest parts of the mid-Atlantic states.
Overnight lows may struggle to fall below 80 degrees or not even fall below 80 degrees in central Philadelphia, Baltimore, New York City, Boston and Washington, D.C., providing little relief during the night, another life-threatening factor during heat waves.
(CARDS: US 10-Day Forecast: Highs and Lows)
Records may be broken
In Philadelphia and Washington, the maximum temperature could approach historical records – in both cases it is 106 degrees. This heat wave may also be accompanied by record-long streaks of temperatures above 100 degrees in every city (3 in a row in Philadelphia, 4 in a row in Washington, DC).
Temperatures reached 100 degrees in New York City’s Central Park on Thursday, their first triple-digit high in nearly 14 years (July 18, 2012).
New York, Philadelphia and Washington, D.C. may also be flirting with all-time record low temperatures (84 in New York and D.C., 83 in Philadelphia), most recently set during a heatwave in late July 2011.
Hundreds of daily record highs and warm lows will also fade into the background this weekend in the Northeast.
Central USA: Highlights
Heat increased across the Plains and Midwest over the weekend and will continue in the Great Lakes region through Friday.
Parts of the Upper Midwest will see colder temperatures by this weekend, although that’s relative considering it’s only in the 80s and not the 90s.
When factoring in the heat index, many residents in the Central Plains and mid-Mississippi Valley will feel temperatures in the triple digits, making conditions downright dangerous for long-term exposure. This includes places like Omaha, St. Louis and Kansas City.
South
While the South is used to hot summers, the heat that has arrived is both constant and oppressive.
Temperatures reached the 90s across much of the region last weekend, and the heat wave continued throughout this week. Temperatures could even top 100 degrees in some places across both the Southern Plains and the Southeast from Virginia to the Carolinas, where daily record highs are most likely.
Add to that the humidity in the South, and the heat index will exceed 100 from Texas to the Carolinas.
How long will the heat last?
The heat has eased a bit across much of the Midwest, and highs in the 90s may be limited to the Ohio Valley area.
There will also be some relief in parts of New England and the Inland Northeast by Sunday.
A little more heat could move into the mid-Atlantic states by next Monday or Tuesday as the heat dome responsible for this heat wave could shift westward, bringing much of the above-average heat back to parts of the Plains and West.
(MORE: 5 things you need to know to stay safe during the heat)
Some records have fallen
One record has already been set in the entire history of the competition.
Tuesday’s low temperature in La Crosse, Wisconsin was just 81 degrees, tying it with four other warmest lows on record for the city, dating back to 1872. The last time this happened was on July 4, 2012.
Other record low temperatures for that date were set Tuesday in Rockford, Illinois (77); Louisville, Kentucky (79); and Topeka, Kansas (79).
Temperatures dropped to just 81 degrees in Dallas on Monday, setting the previous daily record set just two years ago.
Numerous warm low records were broken Tuesday. In Louisville, Kentucky, temperatures dropped to just 79 degrees. Record low temperatures for the day also fell in South Bend, Indiana, Holland, Michigan, Jackson, Kentucky, Dubuque, Iowa and Battle Creek, Michigan.
Wednesday in Roanoke, Va. (102); Cleveland, Ohio (97); Washington-Dulles (97); Syracuse, New York (96); Montpelier, Vermont (92); and Caribou, Maine (90).
Daily low temperature records were recorded at Chicago-O’Hare (80); Madison, WI (79); Flint, Michigan (78); Buffalo, New York (75); and Fort Wayne, Indiana (74), among several others.
More than 20 record highs were recorded Thursday. Some of the most famous: Newark (104), Philadelphia (103), Washington, DC (102), Boston (101), Atlantic City (103), Wilmington (101), New York’s Central Park (100).
Be sure to check back here as we continue to update the forecast and keep a close eye on the holiday weekend. For a more detailed forecast for the Fourth of July, see our latest forecast article here.