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Severe Weather Threat Returns to Illinois on Saturday, Oct. 18

Strategic Insights

— 1 min read

Rain and thunderstorms are forecasted to return to Illinois on Saturday, Oct. 18, with the severe weather threat expected to materialize later in the day. The Storm Prediction Center has issued a slight risk of severe weather for the southern portion of Illinois, with a marginal risk for the rest of the state. The severe weather threat is expected to be most pronounced between 12-6 PM, with Southeast Missouri and southwest Illinois facing the highest chance of seeing severe weather due to favorable environmental parameters.

Key Takeaways:

  • The severe weather threat is expected to congeal into a line of storms that will move across the region, with instability greatest between 12-6 PM.
  • Southeast Missouri and southwest Illinois have the highest chance of seeing severe weather, with a low threat still present.
  • The line of storms may initially take the form of supercells with large hail, but they are expected to quickly form into a line with a threat for damaging winds as they move southeast.
  • A tornado or two is possible, but there is currently no projected tornado threat with this system for the St. Louis metro region.
  • The severe wind risk is the largest threat, with a 15% severe wind risk reaching into St. Clair and Monroe County just south of the metro region.
  • The event is more likely to be a heavy rainmaker, with total rainfall projected to be in the 1.6-inch range for the event, and locally heavier rainfall amounts where training occurs.
  • The rain is expected to help alleviate the severe to extreme drought conditions in the region, with many locations potentially seeing over 1" of rain.

Statistics:

  • 2 out of 5 risk (slight risk) for the southern portion of Illinois according to the Storm Prediction Center's Day 2 outlook.
  • 1 out of 5 risk (marginal risk) for the rest of the Illinois region according to the Storm Prediction Center's Day 2 outlook.
  • 15% severe wind risk reaching into St. Clair and Monroe County just south of the metro region.
  • 5% severe wind risk for the rest of the area.
  • 2% tornado risk remaining just south of the St. Louis metro region.
  • 5% tornado risk entering the far southern tip of the state, south of Marion and Carbondale.

Sources:

  • the Jacksonville Journal-Courier (Jacksonville, Ill.)
  • www.myjournalcourier.com
  • Tribune Content Agency, LLC.

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