By Aaron Wilson, Ohio State University Extension
Hot and mostly dry conditions have continued across Ohio. As of July 20, Columbus has reached at least 90°F on 16 out of 20 days in the month, with many locations around the state recording at least double-digit days at that mark. Recent temperatures averaged 2 to 8 degrees F above normal, with the warmest conditions compared to average across northern Ohio.
Outside of locally heavy thunderstorms, widespread rainfall has been lacking. Only far northeastern counties, far northwestern Ohio, and isolated locations generally south of I-70 picked up more than 0.50 inch of rain this past week, with much of the state collecting less than 0.10 inch. With very little rain and intense evaporation rates (0.25 to 0.30 inch per day), soil moisture continues to dissipate across the region.
Much of northwest Ohio has now fallen below the tenth percentile for soil moisture in the top 1 meter (3.3 feet) of the surface. These dry conditions have led to the introduction of D1 – Moderate Drought conditions for two small areas in Ohio, including Williams, Defiance, Paulding, Van Wert, Hardin, Logan, and Champaign Counties (~3% of the state). Abnormally dry conditions are now reported for nearly 60% of Ohio, and an expansion of these conditions is likely given the continued hot, dry conditions. Remember, if you are seeing drought impacts in your area, consider submitting a report to the Drought Impact Reporter. For more information on recent climate conditions and impacts, check out the latest Hydro-Climate Assessment from the State Climate Office of Ohio.
We are not expecting any major weather systems over the next seven days, but scattered storms with locally heavy rain are possible. The best chance for rain is on Wednesday and Thursday. Humidity will be elevated, which should keep highs primarily in the mid-80s to low-90s and lows in the upper-60s to low-70s. Overall, we are only looking at 0.25 inch to 0.75 inch over the next 7 days, with the greatest totals over the far northeastern counties and along the Ohio River.
The latest NOAA/NWS/Climate Prediction Center outlook for the 8-14 day period (July 28-August 3) shows increased confidence in above average temperatures with no strong indications of above or below (read near-normal) precipitation (Figure 3). Normal highs during the period should be in the mid-80s, normal lows in the mid-60s, with 0.85-1.05” of rainfall per week. The 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Center shows the driest conditions likely remaining over the areas that have already dried out in northwest Ohio. This forecast suggests continued crop stress, with only isolated and intermittent relief.