Clear skies and an east breeze are setting up a mostly sunny Labor Day in St. Louis, with temperatures climbing from the mid-60s early Monday to around 89 degrees this afternoon. The relatively cooler, drier air will be brief, with hotter weather building Tuesday and Wednesday before thunderstorms move in late Wednesday.
The National Weather Service expects east winds of 5 to 8 mph Monday and no rain during the day. Skies will stay mostly clear Monday night, with temperatures dropping to about 62 degrees across the city and nearby communities.
Heat Builds Quickly Tuesday
Tuesday will bring mostly sunny skies and a high near 96 degrees as winds turn southeast at just 2 to 6 mph. Wednesday looks hotter still, with a forecast high near 99 and a small chance of afternoon showers or thunderstorms.
The forecast discussion says humidity should remain slower to return than during the region’s previous heat wave, keeping heat index values closer to the actual air temperature for much of Tuesday. By Wednesday afternoon, however, heat index readings could reach roughly 100 to 105 degrees, and forecasters are watching whether conditions warrant a heat advisory; none is posted at this time.
Storm Chances Rise Wednesday Night
The best chance for rain arrives Wednesday evening into Thursday morning, when the chance of precipitation rises to 80%. Showers and thunderstorms are expected to continue into Thursday morning before tapering off around midday, with partly sunny skies and a cooler high near 84 degrees afterward.
The National Weather Service says a few storms Wednesday afternoon and evening could become strong to severe, although the overall threat remains low. Residents planning outdoor activities should keep alerts on hand, especially Wednesday night, when storms may bring lightning, downpours and gusty winds.
Weekend Heat Returns
Friday should turn mostly sunny and warm with a high near 88 degrees. The weekend stays hot, with highs around 92 Saturday and 91 Sunday, plus a 30% chance of showers and thunderstorms Saturday and a slight storm chance Sunday morning.
