St. Louis is waking up to a cloudy, muggy Saturday with temperatures hovering near 66°F and light winds. It will warm into the mid 80s this afternoon, but the bigger story is what is lining up for Sunday: a much wetter, stormier setup that has officials warning about heavy rain, strong to severe thunderstorms, and the potential for flash flooding across the metro.
What To Expect Sunday
Showers and thunderstorms are likely Sunday, June 21, and forecasters say widespread heavy rainfall is on the table for much of the region. Many neighborhoods could see 1 to 3 inches of rain, with locally higher amounts where storms repeatedly track over the same areas. That kind of soaking could trigger flash flooding along creeks, in low lying spots, and at roadway underpasses. There is also a risk of damaging wind gusts, large hail, and a few isolated tornadoes, according to the National Weather Service.
Timing And Winds
Storms may start to develop overnight Saturday and then fire back up Sunday morning, with several rounds possible into late Sunday night. Expect south winds Sunday around 6 to 15 mph with gusts up to about 28 mph, shifting to the west Sunday night at 8 to 13 mph with gusts near 22 mph. Stronger storms could briefly knock out power in spots. Heavy downpours will likely cut visibility and slow traffic, so if you have to drive Sunday, plan for extra time on the roads.
Travel And Safety Tips
If you are banking on outdoor plans Sunday, you may want to bump them up to Saturday or keep a backup plan handy. Secure loose outdoor furniture, and double check sump pumps and drains ahead of the rain. Do not try to drive through standing water, since just a few inches can stall or even float a vehicle, and steer clear of low underpasses during the heaviest rain. Keep your phone charged so you can receive weather alerts, and follow local emergency guidance if flooding begins to develop in your area.
Looking Ahead
Most of the active weather should ease by Monday, June 22, as a front slides east, with highs in the upper 70s, a bit below normal for this time of year. A drier, cooler stretch is expected from Tuesday through the end of the week, which should feel like a welcome break after a stormy weekend.
We reported on similar flooding concerns in May; you can revisit how streets stayed under flood watch during previous rounds of heavy rain for neighborhood level examples and commute impacts.
