Severe weather lowers heat from the Midwest to the Northeast

The calendar may say it’s fall, but Mother Nature has said otherwise in recent days, with sweltering temperatures across much of the northern United States. Now, meteorologists at AccuWeather say rounds of thunderstorms, some severe, will dampen the heat, resulting in sleet-like conditions.

Much of the Central Plains had been suffering from the sweltering heat for weeks, and the early days of September were no exception.

On Sunday, temperatures in Minneapolis soared to 98 degrees Fahrenheit, setting a new record for the daily high temperature. The average historical high temperature in early September is around 77 F. Meanwhile, highs in the first four days of September rose above 90 degrees Fahrenheit in Omaha, Nebraska, averaging 7.5 degrees Fahrenheit above the historical average.

AccuWeather meteorologists say the powerful storm, which will spark rounds of thunderstorms, may finally put an end to the exceptional heat wave across the northern tier.

Thunderstorms are expected through Tuesday evening from parts of the upper Midwest and western Great Lakes into northern Texas.

“The largest concentration of severe thunderstorms is expected across Minnesota and Wisconsin during the evening,” said Matt Benz, AccuWeather’s chief meteorologist. The same area will also have the highest risk for an isolated tornado or two.

Severe thunderstorms may separate more widely in the south, especially from Missouri to the Red River, which flows along the Oklahoma-Texas border. However, any thunderstorm can be capable of bringing heavy rain, flooding, hail and damaging wind gusts of 60-70 mph. The AccuWeather Local StormMax™ is also available for 80 mph winds.

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Farther east, temperatures in Chicago rose more than 7 degrees above the historical average for the beginning of September. The city is on track for another heat wave, which is defined as three consecutive days in which temperatures exceed 90 degrees, and it is expected to see a drop in temperatures after thunderstorms on Wednesday.

The core of the strongest storms on Wednesday is likely to be east of Chicago.

Thunderstorms from central Michigan to western Tennessee, northern Mississippi and southern Arkansas are likely to become more intense, with the potential for hail and damaging winds, according to AccuWeather meteorologist Brett Anderson.

“These extreme weather effects may be more local in nature, compared to heavy rain,” Benz said.

Behind the harsh weather, a drastic change in air mass will bring much-needed relief from the heat.

High temperatures are expected to reach the 60s in cities like Minneapolis and Madison, Wisconsin, by Wednesday, and the low 70s in Chicago and Indianapolis, Indiana, by Thursday. The drop in temperatures will be 20-30 degrees lower than the peak temperature recorded earlier in the week.

While temperatures are expected to rise later this week or over the weekend, they are not expected to return to the extreme levels seen earlier in the month. Instead, temperatures will be close to, or even a few degrees below, historical averages for the second week of September.

Thunderstorms crossing the eastern United States through Wednesday will temporarily remove heat across the northern plains and much of the Great Lakes, but not remove it from the entire country. Instead, the heat will press eastward, resulting in a few more hot days in the northeast.

New York City residents experienced a milder-than-average start to September, but one milestone was still out of reach: the 90-degree Fahrenheit temperature. 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 experienced temperatures of 90 degrees or more for two days, both in July, but no official three-day heat waves are on the books. New York City will likely finally experience its first heat wave of the summer this week, ahead of the humid weather late in the week.

The weekend is expected to be rainy and humid in the northeast, thanks to the storm and increased heat and humidity on the east coast helping to fuel thunderstorms.

These powerful thunderstorms crossing the region will produce locally damaging winds Thursday and Thursday nights from southern Canada into northern Virginia, including major cities such as Ottawa, Buffalo, New York and Washington, DC.

“The progression of the storms will slow towards the end of the week, allowing thunderstorms to persist in the same areas for a longer period,” Benz said. As such, heavy rains can target the same locations from Thursday to Friday, increasing the risk of flash floods.

Locations along the East Coast, such as New York City, Philadelphia and Washington, D.C., can expect wet weather to wait until late Thursday or Friday night. Meanwhile, temperatures are expected to climb into the 90s. With high humidity in mind, AccuWeather RealFeel can be used® Temperatures can rise to about 100 Fahrenheit.

AccuWeather meteorologists say that although long-term severe weather risks are not expected to persist beyond Friday, wet weather could persist. Wet weather is likely to target round after round in the northeast, providing more chances for rain and thunderstorms throughout the weekend.

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