MADISON, Wis. -

The chance of severe weather will be hanging around southern Wisconsin throughout the weekend.

News 3 meteorologist Gary Cannalte said temperatures and humidity will increase as the weekend gets underway leading to heat index readings climbing into the 90s at times.

Those who are susceptible to the heat will be more vulnerable to its effects, especially if they are without air conditioning, or the ability to get to a cooler location. The elderly, the very young, and those in poor physical condition or on certain medications are most at risk from the effects of the hot and humid weather.

Thunderstorms are in the forecast through the weekend and into Monday of next week. Because of the high humidity, any thunderstorm is capable of producing heavy rainfall. For areas that already have saturated soils, or near creeks and rivers that already have high water levels due to recent rains, localized flooding may develop quickly if a heavy thunderstorm is occurring, or nearby. Urban areas where water has to flow into sewers are also locations that can experience flash flooding if heavy rain occurs in a short period of time.

There also is some threat for severe weather from Saturday through Monday. Severe thunderstorms should develop in Iowa and Minnesota Saturday afternoon, and may reach western Wisconsin later Saturday afternoon or Saturday evening before weakening a little. These storms should move east of Wisconsin Sunday morning, but more severe thunderstorms may develop near an approaching storm system and cold front in Minnesota Sunday afternoon, and move into Wisconsin Sunday night.

As the storm and cold front move through Wisconsin on Monday, a few additional severe thunderstorms may be possible. Hail and high winds are the main severe weather threats. If a cluster or extended line of thunderstorms develops, a greater threat for damaging straight-line winds may occur; at this time, that might be a little more likely on Sunday night or Monday afternoon.

The tornado threat appears to be somewhat low at this time, but where thunderstorms initially develop, the tornado threat may a little higher. In Wisconsin, that might be a little more likely on Monday.

There is a chance for showers and thunderstorms at the time of the "Rhythms and Booms" fireworks display set for 9:30 p.m. Saturday. However, it's impossible to say for certain whether it will be raining or dry at a particular location at a given time. The mathematical chances for rain are around 40 percent, with the better chances for rain later Saturday night. It's best to plan for the worst and hope for the best.

Follow Channel3000.com, the News 3 Weather App, and WISC-TV for the latest updates on the weekend weather.