LANSING, Mich. — A strong ridge of high pressure will build over the Great Lakes this week, bringing several days of dangerous heat and humidity across Mid-Michigan.
Temperatures are expected to climb well into the 90s beginning Monday, with the hottest weather arriving Tuesday through Thursday. Combined with tropical humidity, it could feel as hot as 100 to 105 degrees during the afternoons.
Why It's Going to Get So Hot
A large dome of high pressure will settle over the Ohio Valley and Great Lakes this week. That will allow warm air several thousand feet above the ground to surge into Lower Michigan while trapping heat near the surface.
At the same time, dew points are expected to climb into the middle 70s, creating oppressive humidity. While the air temperature alone will be impressive, the combination of heat and moisture will make it feel considerably hotter.
Heat index values are expected to reach 100 to 105 degrees, with isolated locations potentially seeing values as high as 110 degrees during peak afternoon heating.
Because this is our first prolonged stretch of significant heat this summer, the National Weather Service's Heat Risk places much of Mid-Michigan in the Major to Extreme categories, meaning heat-related illnesses become much more likely for those spending extended time outdoors.
Heat Advisories and other heat alerts are expected to become necessary during the week.
7-Day Forecast
Sunday:
Mostly sunny with highs around 85 degrees. Comfortable compared to what's ahead, although humidity will slowly begin increasing. A few showers or thunderstorms may develop late Sunday night.
Monday:
High: 93° | Low: 73°
A few morning showers or thunderstorms are possible as a warm front moves through, especially north of I-96. Skies become mostly sunny during the afternoon with building heat and humidity.
Tuesday:
High: 96° | Low: 75°
Sunny, very hot and increasingly humid. Heat index values could climb above 100 degrees during the afternoon.
Wednesday:
High: 98° | Low: 74°
Likely the hottest day of the week. Afternoon temperatures could approach the upper 90s across Lansing and Jackson, with heat index values between 100 and 105 degrees.
Thursday:
High: 97° | Low: 73°
Another dangerously hot and humid day with plenty of sunshine. Continue limiting strenuous outdoor activity during the hottest part of the afternoon.
Friday:
High: 94° | Low: 70°
Still very warm, but the ridge begins to weaken. That may allow scattered thunderstorms to develop later in the day.
Saturday:
High: 90°
Temperatures ease slightly, but it remains warm and humid. A few showers will remain possible as the weather pattern gradually becomes more active.
Will We See Any Thunderstorms?
Aside from a few showers and thunderstorms Sunday night into Monday morning, much of the week looks dry.
The strong ridge of high pressure acts like a lid on the atmosphere, making it difficult for storms to develop despite the heat and humidity. By Friday into next weekend, that ridge may begin to weaken enough to allow a few disturbances to move through, increasing the chance for scattered showers and thunderstorms.
Heat Safety Tips
With several consecutive days of dangerous heat expected:
Drink plenty of water, even if you don't feel thirsty.
- Take frequent breaks if working outdoors.
- Limit strenuous outdoor activities during the afternoon.
- Never leave children or pets inside parked vehicles.
- Check on elderly neighbors, family members, and anyone without reliable air conditioning.
This will likely be the hottest stretch of weather we've experienced so far this year. If you're making outdoor plans, prepare for dangerous heat and stay weather aware throughout the week.
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