USA National Forecast

Heat Wave to Remain Locked in the Midwest and Great Lakes This Week

By Jonathan Belles

July 07 2020 05:00 AM EDT

weather.com

Midwest, Plains Heating Back Up After a Taste of Fall

At a Glance

  • A double team of high pressure systems will bring dangerous heat this week.
  • Highs in the 90s are expected in many Midwest and Great Lakes cities.
  • A few record warm temperature records could be set.
  • Hot conditions will also build from the Southwest into the Plains.

An extended heat wave is expected to bring highs in the 90s to parts of the Midwest and Great Lakes this week. Dangerously hot temperatures are also forecast to develop from the Southwest into the Plains.

A broad ridge of high pressure and a jet stream that will remain well to the north will allow heat to spread across large sections of the Plains, Midwest, Northeast and Rockies.

This pattern will be supported by two domes of high pressure – one over the East and a second, stronger dome over the Southwest – that will cause air to sink and warm over their respective regions. The domes will also bring warmer air northward on their western and northern sides and diminish rain chances.

The hottest temperatures compared to average will be focused around the Great Lakes through later this week with the easternmost dome of high pressure. This area will have temperatures 10 to 20 degrees above average at times throughout the week ahead, including Chicago, Detroit and Buffalo, New York.

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Current Temperatures

Highs in the 90s will be widespread in the Midwest, Great Lakes and interior Northeast this week.

Modest humidity values could add a couple of degrees to the numbers below to get a slightly higher heat index.

The added humidity could become more problematic toward the middle of the upcoming week, especially during the overnight hours. Overnight lows will be kept up by the humidity.

This means overnight temperatures may not dip below the low to mid 70s in many spots from the southern Great Lakes to the Northeast, which could set daily record warm lows in a few spots.

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Forecast Highs and Departures from Average

Some cities could approach records for their most 90-degree days in a row.

Detroit could see nine consecutive 90-degree days from this past Thursday through this coming Friday. That is just two days short of their record streak of 11 days in a row set in 1953

Buffalo, New York, could tie its record of seven days in a row with 90-degree heat on Thursday. Monday marked the fourth consecutive day the western New York city reached the lower 90s.

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A second, stronger area of high pressure will also amplify temperatures in the Southwest and Plains this week.

Highs will climb well into the upper 90s and lower 100s in the Central and Southern Plains.

Parts of the Desert Southwest, including Phoenix, will see highs 110 degrees or hotter on multiple days through Sunday.

This heat isn't going anywhere fast.

NOAA's Climate Prediction Center says the greatest chance of hotter than average temperatures next week is in the Southwest and parts of adjacent Central and Southern Plains.

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Extended Temperature Outlook

Another twist to this forecast is that the building dome of high pressure will also cut off any moist flow from Mexico through mid-month if the forecast plays out.

This means that the already-delayed Southwest monsoon, which typically brings increased thunderstorms to the Desert Southwest, could be delayed even further.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.