The last couple of weeks have been marked by precipitation extremes across the Buckeye State. A stalled boundary and repeated showers and storms brought 3-7 inches of rain across portions of Clark and Madison counties on August 12th. Last week, tropical moisture combined with a small mid-level trough to drop 4.96 inches of rain in Reynoldsburg in Franklin County (Fig. 1). This was followed by the remnants of Tropical Storm Fred, which dumped 2-6 inches of rain across many of our eastern and southeastern counties (Fig. 1). Meanwhile, most of west received minimal rainfall this week, generally less than 0.50”. Conditions over portions of Butler, Preble, Darke, and Mercer counties are drying rapidly. During this two-week stretch, temperatures have averaged 2-4°F above normal (1991-2020), driven strongly by warm overnight lows due to increased humidity.
Hot and humid conditions will stick around all week. High pressure will slide off to the southeast of Ohio by Tuesday. Southerly flow around the high will pump warm, humid air into the region with highs expected in the low to mid 90s and overnight lows in the low 70s for Tuesday through Thursday. A cold front, slowly approaching the region could provide enough energy to create pop-up storms on Tuesday and Wednesday, with a little better chance of scattered showers and storms for Thursday through the weekend. Highs will remain close to 90 or so throughout the period. Overall, the Weather Prediction Center is calling for up to 0.50 inch of rainfall over the next 7 days across the south, and up to 1 inch across the north. Most of this is likely to fall late weekend into early next week. Isolated heavier totals will occur where stronger storms develop.
The Climate Prediction Center’s 6–10-day outlook for the period of August 29 – September 2 and the 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Center indicate above average temperatures are likely, with near to above average precipitation (Fig. 2). Climate averages for this period include a high temperature range of 80-85°F, a low temperature range of 60-65°F, and average rainfall of 0.60-0.75 inches.