ALERT DAY - Tracking dangerous heat and a line of severe storms Tuesday

There is an ENHANCED threat of severe weather on Tuesday.
Published: Aug. 10, 2021 at 12:14 PM CDT|Updated: Aug. 10, 2021 at 4:37 PM CDT
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MADISON, Wis. (WMTV) - Tuesday is a FIRST ALERT WEATHER DAY due to the potential for dangerous heat and severe weather. Heat index values Tuesday afternoon could be as high as 105 degrees.

The focus will turn away from the heat and towards the threat of severe weather late Tuesday afternoon. A line or broken line of strong to severe storms will impact the area Tuesday evening.

The National Weather Service has reported windspeeds over 50 mph in Potosi and that some building damage has been reported. There also have been reports of powerlines downed in Platteville.


First Alert Weather Day - Tuesday
First Alert Weather Day - Tuesday(WMTV NBC15)

A HEAT ADVISORY will be in effect for much of the area from noon to 7 p.m. Tuesday. High temperatures Tuesday afternoon will be near 90 degrees. With a dew point temperature in the low to mid 70s, the higher humidity levels are going to make it feel oppressive outside and add a few degrees to the actual air temperature. Max heat index values will range from 100 - 105 degrees.

Heat Advisory until Tuesday 7PM
Heat Advisory until Tuesday 7PM(WMTV NBC15)

With dangerous heat expected, try to limit the time you spend outside. If you have to spend time outside, make sure to take heat precautions: drink plenty of water and take breaks in the shade or A/C. It is also important to know the signs and symptoms of heat stress and heat stroke.

Heat Safety - Know the signs and symptoms of heat exhaustion and heat stroke
Heat Safety - Know the signs and symptoms of heat exhaustion and heat stroke(WMTV NBC15)

There is an ENAHNCED threat of severe weather across southern Wisconsin Tuesday evening. An ENHANCED threat is 3 out of 5 on the severe scale, so this is a medium threat of severe weather. Even though all types of severe weather will be possible, the main threat with this line of strong to severe storms that is expected to develop will be damaging wind gusts. There is a medium to high threat of damaging wind gusts. It looks like the ingredients could come together for significant severe weather Tuesday, so some of the storms could be stronger than the average severe storms. The strongest storms that develop could produce 70 plus mph wind gusts. If wind gusts this strong develop, widespread tree damage and power outages will be possible. The strongest storms could also produce large hail. The tornado threat will likely remain low, but not zero. There could be the potential for quick spin-up tornadoes on the leading edge of this line of storms.

Severe Weather Threats - Tuesday
Severe Weather Threats - Tuesday(WMTV NBC15)

Thunderstorms will start to develop across the western half of the area between 4 p.m. and 6 p.m. Tuesday evening. These storms could quickly reach severe limits. The storms will likely form into a line or broken line as they move east across the area this evening. These storms move east southeast across the area quickly this evening, which is one reason why the threat of widespread flash flooding and flooding will likely remain low. This line of storms will likely impact Madison between 6 p.m. and 8 p.m. The strongest storms will likely be exiting southern Wisconsin by 10 p.m. this evening.

HI-RES Future Radar - Tuesday 7PM
HI-RES Future Radar - Tuesday 7PM(WMTV NBC15)

There will be a chance of more rain and storms late Tuesday night into Wednesday morning. However, there are still some question marks on if more rain and storms will redevelop. Overall, Tuesday night is going to be warm and muggy. Low temperatures Tuesday night will be in the upper 60s to near 70 degrees.

Wednesday will be another FIRST ALERT WEATHER DAY due to the potential for dangerous heat and severe weather. With highs near 90 degrees and dew point temperatures in the lower to mid 70s, max heat index values could top 100 degrees Wednesday afternoon.

Temperature Vs Heat Index Forecast - Wednesday
Temperature Vs Heat Index Forecast - Wednesday(WMTV NBC15)

Another round of rain showers and storms will fire up along a cold front late Wednesday afternoon through Wednesday evening. With all the heat and humidity around, there will be the potential for strong to severe storms. Much of southern Wisconsin will be under a SLIGHT threat of severe weather on Wednesday. The main threats on Wednesday will likely be damaging wind gusts and large hail. The tornado threat is low, but not zero.

Severe Weather Threat Maps - Wednesday
Severe Weather Threat Maps - Wednesday(WMTV NBC15)

The heat, humidity and the threat of rain showers and storms will continue into Thursday. Highs on Thursday will be in the upper 80s to near 90 degrees. A cold front will slide through the area Thursday or Thursday night. This front will bring in a chance of rain showers and storms and knock the heat and humidity out of southern Wisconsin.

This cold front will set us up for a very comfortable end of the workweek and weekend. Highs on Friday, Saturday and Sunday will only be near 80 degrees, which is much more seasonable for this time of year. Plus, this weekend looks dry with a lot of sunshine.

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