Tracking a hot and humid Fourth of July and scattered storms on Monday

Max heat index values on Sunday will be in the mid 90s.
Published: Jul. 4, 2021 at 4:22 AM CDT
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MADISON, Wis. (WMTV) - Happy Fourth of July! Independence Day is going to live up to its reputation of being the hottest holiday of the year. Make sure to take heat precautions if you are going to spend a lot of time outside Sunday afternoon: stay hydrated, wear sunscreen, and find the shade or cool off in the A/C from time to time. We’ll add scattered rain showers and storms to the heat and humidity on Monday.

Forecast Heat Index Values Sunday 4PM
Forecast Heat Index Values Sunday 4PM(WMTV NBC15)

Sunday morning is mild and a little muggy. Temperatures are generally in the 60s and will quickly jump into the 70s. Sunday morning is also mostly clear, and no rain is expected. No major weather problems will impact travelers across southern Wisconsin Sunday morning.

There will be no shortage of sunshine, heat, or humidity Sunday afternoon. Highs will be near 90 degrees. The elevated humidity levels will add a few degrees to the actual air temperature. Max heat index values, or feels like temperatures, will be in the mid 90s. Borderline dangerous heat will be possible in spots Sunday afternoon. The UV index Sunday afternoon will be very high. Once again, smoke from the wildfires in Canada will cause a hazy sky on Sunday. The highest concentrations of smoke will be in the mid to upper levels of the atmosphere, so the air quality should not be impacted across south central Wisconsin. However, the WI DNR has issued an Air Quality Alert for the Lake Michigan shoreline due to elevated ozone levels.

Sunday's Fair & Festival Forecast
Sunday's Fair & Festival Forecast(WMTV NBC15)

The weather looks great for Fireworks Sunday evening. It’s going to be warm and muggy. Temperatures will be dropping in the upper 70s by 10 p.m. The sky will be mostly clear to partly cloudy. Scattered rain showers and storms will fire up along a cold front Sunday evening across northern Wisconsin and central Minnesota. This rain activity will drop south overnight but won’t reach southern Wisconsin until well after midnight. There are still some question marks on far south these rain showers and storms will make it. Places northwest of Madison will have the best chance of rain Sunday night into Monday morning. Sunday night will be warm. Lows will be in the lower to mid 70s.

Firework Forecast - Sunday
Firework Forecast - Sunday(WMTV NBC15)

Monday will be another hot and humid day. Highs on Monday will once again be in the upper 80s to near 90 degrees with max heat index values in the mid 90s. A slow-moving cold front will drop into the area on Monday be the focal point for scattered rain showers and storms. Monday will be far from a washout. The best chance of rain will be Monday afternoon and evening. There are still some question marks on how widespread the rain and thunderstorm activity will be. If storms develop, there will be the potential for a strong storm, or two, that could produce gusty winds, small hail, brief heavy rain, and lightning. The rain and storm activity will drop from northwest to southeast across the area Monday afternoon and evening.

Next Big Weather Maker - A cold front will bring in scattered rain showers and storms Monday...
Next Big Weather Maker - A cold front will bring in scattered rain showers and storms Monday afternoon and evening.(WMTV NBC15)

The chance of rain and storms will increase Tuesday into Wednesday as storm system rides along the cold front and impacts the region. Right now, the forecast models are trending towards a more northerly track with this storm system so the heaviest rain could develop across central Wisconsin. Where the heaviest develop will depend on the exact track this storm system takes. Widespread rainfall totals Sunday through Wednesday will be between 0.5 - 1.5″. The heat and humidity will stick around on Tuesday. Highs on Tuesday will be in the upper 80s. Wednesday will be much cooler. Highs on Wednesday will only be in the lower 70s.

Thursday will be a mostly sunny and pleasant day. Expect highs in the mid to upper 70s. The best part about Thursday will be the comfortable humidity levels.

Our rain and storms chances will start to ramp up again towards the end of the workweek and into next weekend. Highs Friday and Saturday of next week will be in the upper 70s to near 80 degrees.

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