Severe weather to trim heat from Midwest to Northeast
AccuWeather meteorologists say that a drastic drop in temperature is on the way for the northern tier of the U.S., but not before thunderstorms sweep through the area this week. The stormy weather will come with dangers.
The calendar may say that it's meteorological fall, but Mother Nature has said otherwise in recent days, with a surge of extreme heat across much of the northern United States. Now, AccuWeather meteorologists say that rounds of thunderstorms, some severe, will ease the heat, bringing fall-like conditions.
Much of the central Plains has been sweltering under prolonged heat for weeks, and the first days of September have been no exception.
On Sunday, temperatures in Minneapolis surged to 98 degrees Fahrenheit, setting a new daily high-temperature record. The historical average high temperature in early September is around 77 F. Meanwhile, highs on the first four days of September climbed above 90 F degrees in Omaha, Nebraska, averaging 7.5 F above the historical average.
AccuWeather forecasters say a potent storm, which will spark rounds of thunderstorms, may finally bring an end to the wave of exceptional heat across the northern tier.
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Temperatures in Chicago have been more than 8 degrees above the historical average for the start of September. The early-September hot spell officially became a heat wave on Tuesday when the high temperature reached the 90-degree mark for the third consecutive day. However, the temperatures will come crashing down following Wednesday's thunderstorms.
The wet weather in Chicago started first thing in the morning on Wednesday, with drenching downpours moving in around 4 a.m. CDT. The thunderstorms prompted flash flood warnings by the National Weather Service for the city and the southern and eastern suburbs and caused ground stops at Chicago's Midway and O'Hare airports.
As Wednesday progresses, another wave of drenching, and perhaps severe, thunderstorms are expected. This time, the storms will target locations to the east of Chicago.
Thunderstorms from central Michigan to western Tennessee, northern Mississippi and southern Arkansas will have the potential to turn severe into Wednesday evening, with the possibility of hail and damaging winds.
"These severe weather impacts may be more localized in nature, compared to heavy downpours," AccuWeather Senior Meteorologist Matt Benz added.
Temperature drop in store for the Midwest
Behind the severe weather, a drastic change in air mass will bring much-needed relief from the heat.
High temperatures in the 60s are predicted for cities like Minneapolis and Madison, Wisconsin, by Wednesday, and in the lower 70s for Chicago and Indianapolis, Indiana, by Thursday. The drop in temperature will be as much as 20-30 degrees below the peak heat from earlier in the week.
While temperatures are expected to trend upward late this week or over the weekend, they are not forecast to return to the extreme levels of earlier in the month. Instead, temperatures will be near, or even a few degrees below, historical averages for the second week of September.
Northeast heat relief to be delayed but not denied
The thunderstorms crossing the eastern U.S. through Wednesday will temporarily erase the heat across the northern Plains and much of the Great Lakes, but it won't be removed from the entire country. Instead, the heat will be squeezed eastward, making for another few hot days in the Northeast.
Residents of New York City have experienced a milder-than-average start to the month of September, but one particular milestone remains elusive: a high of 90 degrees Fahrenheit. In fact, the city managed to stay below 90 degrees for the entire month of August.
There were two instances this summer where the city had two-day stretches of 90-or-greater temperatures, both in July, but no official three-day heat waves have gone down in the books. It's possible that New York City will finally experience its first heat wave of the summer this week, ahead of the late-week wet weather.
A wet and humid end to the week is expected in the Northeast, thanks to the storm and a surge of heat and moisture up the Eastern Seaboard helping to fuel thunderstorms.
These potent thunderstorms crossing the area will make locally damaging winds Thursday and Thursday night possible from southern Canada to northern Virginia, including major cities such as Ottawa, Buffalo, New York, and Washington, D.C.
"The progression of the storms will slow late-week, allowing for thunderstorms to linger in the same areas for longer," explained Benz. As such, drenching downpours could target the same locations Thursday through Friday, heightening the risk of flash flooding.
Locations right along the Eastern Seaboard, like New York City, Philadelphia, and Washington, D.C., can expect the wet weather to wait until late Thursday night or Friday. In the meantime, temperatures are forecast to rise into the 90s. With high humidity factored in, AccuWeather RealFeel® Temperatures could climb to around 100 F.
AccuWeather forecasters say that while long-lived severe weather risks are not expected to linger past Friday, the wet weather may stick around. Round after round of wet weather is likely to target the Northeast, bringing more opportunities for rain and thunderstorms all the way through the weekend.
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