AccuWeather.com
Another round of intense heat is forecast to strengthen over the Rockies, Plains, Midwest and parts of the East this week, posing significant health risks and potentially straining power grids across the Central states.
Although this heat wave is not expected to be as intense or long-lasting as the “Fourth of July Furnace” that scorched parts of the Eastern states during the first week of the month, it will still be dangerous enough that residents should take it seriously.
Northern portions of the Plains and the Midwest will experience higher actual temperatures with this heat dome than at the start of the month.
“From a weather statistics standpoint, dew point temperatures will, on average, be 5-8 degrees Fahrenheit lower in the Midwest and Northeast with this heat dome compared to early July,” AccuWeather Senior Meteorologist Alex Sosnowski said. “Some sensitive individuals may notice, and the slightly less humid air may allow temperatures to fall off a bit more at night compared to the early days in July. But, if you are laboring away in the heat or spending time outdoors as recreation, it will still be hot and feel humid.”
The dew point is the saturation temperature of the air. The higher the number, the more humid the air is. With the air mass this week, dew points will generally be in the 60s to near 70, compared to dew points well into the 70s to near 80 earlier this month.
Under the belly of the heat dome in the central United States, peak heat will occur on Tuesday before shifting eastward.
“AccuWeather RealFeel® Temperatures are expected to reach 105-115 degrees Fahrenheit across many areas from the Plains to the Great Lakes early this week. The worst of the heat dome will be focused across this region before it shifts eastward,” AccuWeather Meteorologist Breanna Grill said.
RealFeel Temperatures take into account the actual temperature, humidity, sky conditions and wind.
Across the central U.S., the heat dome’s impacts will be particularly significant for agriculture. Under the high-pressure heat dome, rainfall will be suppressed, and the region will get little or no rainfall, which will lead to an expansion of the drought.
Heat expands eastward midweek
By Wednesday, the heat dome will gradually migrate eastward, spreading dry, hot weather from the Plains and Great Lakes into the Northeast and mid-Atlantic region.
By Tuesday afternoon, AccuWeather RealFeel® Temperatures are expected to soar to the upper 90s F throughout the Central states.
Some zones will even experience RealFeel® Temperatures surpassing the 100-degree mark on Tuesday, particularly in southern Minnesota, central Iowa and central Missouri, eastward through portions of the Ohio Valley.
“It is recommended that residents, who are able, remain indoors during peak heating hours, early this week. If you have to be outside, consider taking numerous breaks, utilizing shaded areas, wearing light-colored clothing and staying hydrated,” explained AccuWeather Meteorologist Brandon Buckingham.
Even though this round of heat will not last as long as the early-July heat dome, the pattern will still raise the risk of heat exhaustion, heatstroke and heat-related deaths across the Central and Eastern states.
In New York City, high temperatures will peak around the upper 90s F on Wednesday, approaching the daily record, and will be roughly 10-15 degrees above the historical average for mid-July. Meanwhile, AccuWeather RealFeel® Temperatures will exceed 100 F during the afternoon on Wednesday.
Temperatures Wednesday afternoon in Philadelphia will peak even higher, with a forecast high of 100 F, while RealFeel® Temperatures will rise to near 105 F across the City of Brotherly Love.
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Along with the heat and moderate to high humidity will be a hazy appearance to the air and even the sun appearing to be filtered at times. “Much of haze will be due to high-level smoke produced by fires north and west of Lake Superior,” AccuWeather Meteorologist Brandon Buckingham said.
“A more direct weather effect of the smoke may be to shave a few degrees off of high temperatures,” Sosnowski said. “From a health standpoint, enough smoke could filter down to low levels of the atmosphere to lead to dangers for those with respiratory ailments.”
As the week progresses, high temperatures in the Northeast will fall a few degrees from the 90s F into the 80s F, which will be welcome by many sick of the hot weather. Dew points are also projected to decline a bit, dipping into the 40s and 50s, resulting in an added layer of relief.
As the week comes to a close, the north-to-south breakdown of the heat dome will promote impactful thunderstorms from the Great Lakes into the Northeast coast.
Rounds of thunderstorms, some of which can produce locally gusty winds and intense downpours, will spread from Wisconsin to the mid-Atlantic states.
This weekend, a northward surge of tropical Gulf moisture will push into the Southeast. This pattern will persist into the upcoming week, becoming a factor to watch with tropical activity potentially brewing in the Gulf.
Contributions to this story were made by Forecasting Intern Noah Bodner.
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