Sunday morning in St. Louis is starting off calm and comfortable, with clear skies, temperatures already in the upper 60s, and an afternoon high near 80°F expected. East winds remain light before turning southeasterly later in the day, so it is a good window to enjoy the warm, dry weather while it hangs around.
Monday Severe Threat
Showers and a few thunderstorms could slip in late tonight into Monday morning, but the main concern is Monday afternoon and evening, April 27, 2026, when storms may strengthen into strong to severe territory. According to NWS St. Louis, potential hazards on Monday include very large hail, damaging winds and tornadoes, with some tornadoes possibly strong, along with locally heavy rain that could trigger brief flooding. Forecast details call for winds gusting into the 30s and a high near 84°F, so anyone with outdoor plans later Monday should be ready to change course quickly.
Where The Threat Could Be Worst
Forecasters expect the highest severe-weather probabilities along and south of I-70, although the warm sector could bring much of the metro into play if storms reorganize. Supercells are possible early in the event before storms grow into lines, which heightens both tornado and damaging wind concerns and boosts the risk of quick, heavy downpours in any training storms. We flagged this system in an earlier preview; see our April 24 update for more background on the setup.
What To Do Now
Now is the time to charge your phone, identify a reliable shelter spot in your home (an interior room or basement), and make sure everyone in the household knows where to go if warnings are issued on Monday. If you have outdoor events scheduled for Monday afternoon or evening, consider moving them or locking in a solid indoor backup, since flash flooding and damaging winds can make travel hazardous. Keep local alerts enabled and check the National Weather Service for watches and warnings before heading out.
After Monday night, a secondary front is expected to bring in cooler, drier air. Highs should slip back to the upper 60s by midweek with mostly dry conditions, offering the region a short break from the severe-weather threat. Plan on highs running below average by Wednesday, April 29, 2026.
