Timing this evening's strong wind and severe storm threat

 Winds are already gusting near 35-40 mph as of 1PM this afternoon. A WIND ADVISORY and RED FLAG WARNING run through tonight for all of Northern Illinois for the wind gust potential to reach 45 mph or greater even before our storms arrive this evening. Avoid any burning, as fires will rapidly spread in these conditions!

 

The wave of precipitation approaching the Mississippi river in Missouri right now is just the precursor to the storms expected later this evening/tonight. The line of cumulus clouds beginning to form in Oklahoma will be the focus for our line of storms later tonight. One thing we will need to keep a close watch of is our dew points. This will be one of the determining factors for how long storms will be able to maintain their strength after sunset. A drier slot of air approaching ahead of these storms may act as a weakening mechanism.

 

Either way, our storms will arrive between 8-9PM for our Western communities, producing potentially severe wind gusts upwards of 60 mph or more. Storms will not need much to tap into the stronger winds aloft, hence the higher risk for damaging winds locally compared to other hazards.

The storms will be approaching the I-39 corridor likely between 10-11PM, but will be in a gradually weakening phase. How much they weaken before arriving will likely depend on how much of an influence that dry pocket of air has on the storms.

Things will be winding down for the Western half of the Stateline by 12-1AM before storms clear the Eastern half of the Stateline by 2AM. Storms will only last in any given location for an hour or two at most.

Locally, our overall risk for strong to severe storms has gone up since Thursday night's outlook. Most of the Stateline is now under a Level 3/5 Enhanced risk for severe weather, while most of Southern Wisconsin is under a Level 2/5 Slight risk. Our highest threats will be the damaging winds, both within and outside of thunderstorms, while the tornado and hail threats are on the lower side. Occasionally you will see a tornado spin up in such a line of storms, known as a QLCS tornado. These are typically shorter-lived than traditional supercell tornadoes. Movement of these storms will be to the Northeast at around 50-60 mph, so be sure to heed any warnings that come in!

 

That said, have multiple ways to receive warnings, including a method to wake you up if you will otherwise be sleeping late this evening. Updates will follow on www.mystateline.com/weather as we receive them. Stay weather aware this evening and tonight!