ST. LOUIS — Rounds of rain are moving into the region, bringing a heightened risk of flash flooding and severe storms—particularly for areas southeast of St. Louis. While rainfall will ease slightly over the weekend, the risk for flooding will linger, and cold air pushing in by early next week could bring overnight freezes and even a few flakes of snow.

The rain is already spreading northward this morning, and it will continue through the afternoon and evening in waves. Flash flooding is likely, especially in flood-prone areas along and south of I-70. Creeks, culverts, and low-lying roads are at high risk of flooding, and drivers should be alert to the potential for water-covered roads. The Missouri Department of Transportation is warning that 141 may flood at I-44 this weekend.

In addition to flooding, southeast Missouri and far southern Illinois face a Level 3 (out of 5) risk for severe storms late Friday afternoon and evening. Areas south of Farmington, Missouri, and southeast of the Kaskaskia River in Illinois are most at risk. Large hail and damaging winds are the primary threats, with a brief tornado window between 5 p.m. and 8 p.m. in the far southeastern counties. While the St. Louis metro is not expected to see severe storms, scattered hail and flooding are possible.

The rain will continue into the weekend but should lighten up Saturday and Sunday. As colder air moves in, a few areas may see a mix of rain and wet snow early Sunday. No accumulation is expected.

Smaller rivers in the region, particularly in southeast Missouri and southern Illinois, are forecast to rise significantly. The Meramec River at Valley Park is expected to crest at major flood stage—15 to 16 feet above flood stage by Tuesday, with Eureka nearing 19 feet above flood stage. Dardenne Creek in St. Charles County is also expected to flood.

Looking ahead, temperatures will drop sharply early next week, with a freeze possible Monday and Tuesday mornings.

Forecast Timeline:

  • Today (Friday): Heavy rain in waves with flash flooding likely, especially south of I-70.
  • Late Friday Afternoon/Evening: Level 3 severe storm risk in far southeast Missouri and Illinois—hail, wind, and possible tornadoes.
  • Saturday–Sunday: Lighter rain continues; a rain/snow mix possible Sunday morning.
  • Monday–Tuesday: Freezing temperatures likely overnight; take precautions for sensitive plants.
  • River Flooding: Smaller rivers in southeast Missouri and southern Illinois may reach moderate to major flood stage by early next week.