A Heat Warning will go into effect for Fond du Lac County today, Monday, August 26, 2024 at 1:00 p.m. This warning will be in effect until 8:00 p.m. During this same time period, an Extreme Heat Warning will also be in effect for counties just west and south of us.

An extreme heat warning is in effect for all of southeastern Wisconsin on Tuesday, but cloud cover from storms moving in from the west could prevent some areas from reaching dangerous levels.

Sunday was 31 degrees Celsius with a heat index of 34 degrees Celsius. Monday the temperature will be even higher with maximums around 36 degrees Celsius and a heat index of over 38 degrees Celsius.

The heat is a result of what we call a ridge in the atmosphere, or a big bump in the jet stream that extends north. Imagine looking at a map of the United States and the jet stream is a huge highway running from west to east. Typically the jet stream has little bumps and dips as it runs through the middle of the country, but a ridge would cause the highway to dip down into the southwestern states and then turn north all the way into Canada before coming back over the New York area. The jet stream often helps separate air masses with warmer air to the south and cooler air to the north, so with the jet stream now so far north of us, it causes the warm, moist air that would normally be along the southern Gulf states to extend all the way north to the Canada-US border.

These ridges, as they are called, also tend to have warm air in the air, which prevents the formation of storms that you often associate with warm, humid days. That is, until the western portion of this ridge merges with the jet stream, allowing cooler air to return to the area. This looks to happen on Tuesday, at some point when we could see an area of ​​strong to severe storms pass through. On Monday, that area of ​​storms will be in the South Dakota region and move into Minnesota overnight. There, they are expecting some severe weather later Monday and into Monday night.

As of Monday morning, the models disagree on tomorrow’s storm placement, as one model predicts two rounds of storms moving through the area. One around mid-morning and another in the evening. Another model predicts that storms will largely escape us to the north. As always, stay tuned to KFIZ.com and KFIZ Facebook for updates on any warnings that may accompany these storms.

After the storms pass, temperatures will return to normal on Wednesday, with daytime temperatures dropping to around 27 degrees Celsius.