***Severe Thunderstorm Watch from 7/28/2021 7:22 PM to 7/29/2021 2:00 AM CDT for Kenosha County, WI, Racine County, WI, Washington County, WI, Ozaukee County, WI, Milwaukee County, WI, Sheboygan County, WI, Fond du Lac County, WI, Walworth County, WI, Dodge County, WI, Waukesha County, WI, Jefferson County, WI.***
There is high confidence that strong to severe storms will move across Wisconsin late Wednesday into early Thursday. Here is the current thinking regarding storms (written at 2:30 pm Wednesday afternoon).
The Storm Prediction Center has issued a Moderate Risk for severe weather across much of Wisconsin, including most of SE Wisconsin. This is a level 4/5 risk, which is fairly rare for our area. The last time a Moderate Risk was issued was the August 2020 derecho. Part of Kenosha and most of Walworth counties are in a level 3/5 risk area, where there is just a slightly lower chance for severe storms.
Storms will develop this evening, between 6 and 8 pm, to our northwest, and then storms will quickly move southeast. The current thinking is storms arrive in SE Wisconsin starting around 9-10 pm, and continue to move through into early Thursday morning, ending by 3 am. IF these storms congeal into one line, they may be able to move faster than current model guidance suggests. Stay with us through this evening into tonight for updates.
You can see in the above model graphics, there is still some disagreement as to whether these storms form into one singular line, or if there are clusters of storms. Either way, these storms are expected to be strong, with the main concern still being widespread damaging winds. Winds speeds of 70-80 mph or stronger are possible tonight! These winds could cause damage to trees, powerlines, and even structures.
There is a low-end risk for a few tornadoes. Sometimes we see tornadoes spin up along the edge of a line of storms. They can form quickly, leaving short lead times for warnings. They can also be rain-wrapped, so visual confirmation can be a challenge. Also, a few storms may produce quarter-size hail. As far as rainfall, a widespread 1-2" of rain is likely, but some areas could see pockets of heavier rain. Any flood threat is low, as the ground is very dry and area waterways are running lower than normal.
Tonight will be a night to be indoors, not outdoors. Camping tents and RV's will not provide safe shelter. Boats will not be a safe place to be. People need to be indoors in a sturdy structure. Do not wait until storms are moving in to take action. Plan ahead for this event. Outdoor plans can be resumed on Thursday.
It is a good idea to bring in outdoor objects and furniture. Also, charge up devices and cell phones in case of power outages. Make sure you have fresh batteries in your weather radio.
Here is a quick reminder on the difference between a watch and a warning.
Have multiple ways to get warnings. Have a device that will alert you if a warning is issued late at night, after you have gone to bed. A weather radio will alert you to a Severe Thunderstorm Warning, or a Tornado Warning. As of now, Wireless Emergency Alerts on your cell phone will only alert you for a Tornado Warning. Do not rely on sirens to wake you in the middle of the night, they are only designed to alert people who are outdoors. TMJ4 will be updating our platforms on air and online throughout the night. Stay weather aware and stay safe!