After summer-like heat through mid-week last week, a strong cold front ushered fall-like weather into the Ohio Valley, bringing the first reports of patchy frost to low-lying valleys Friday morning. Overall, the month of September has been above average, with temperatures running 1-3°F above the long-term mean (1991-2020). September tends to be a drier month, even more so for much of northern, southern, and west central Ohio this year (Figure 1). On the other hand, wet conditions have prevailed in the Cincinnati region, across the northern Miami Valley, and much of central Ohio, with precipitation running 125-200% of normal in those areas. For the latest up-to-date conditions, seasonal outlooks, and monthly climate summaries, please visit the State Climate Office of Ohio.
A lot of moving pieces to talk about in the forecast. First, a low-pressure system nearly stationary in southern Ontario is producing lake-effect rain showers and storms across far northeastern counties of Ohio. Rainfall totals have already exceeded 3 inches in spots this past weekend, and this pattern is likely to continue through Wednesday with locally heavy rain (Figure 2). A few scattered afternoon showers are also possible across northern counties in Ohio, with a decreasing chance as you move toward southern counties. Strong high pressure will take control of the weather for Thursday and Friday with tranquil conditions expected. Then, all eyes turn toward the eventual landfall of Hurricane Ian, situated just south of Cuba on Monday afternoon. Current trajectories have the storm reaching Major status by Wednesday morning with winds exceeding 115 mph, with a likely landfall as a weaker storm in the Florida Panhandle early Friday morning. Latest model guidance suggests that moisture from this system could rapidly move into southern and eastern Ohio in the Sunday-Monday timeframe. This may bring gusty winds and heavy downpours to parts of the state, so the situation should be monitored for changes throughout the upcoming week.
Temperatures will remain about ten degrees below average for much of the week, with highs ranging from the upper 50s to mid 60s (north to south) and overnight lows mainly in the 40s. A few cooler spots might see upper 30s on Thursday and Friday mornings, with a slight chance of patchy frost. Temperatures will moderate into the 60s and 70s this weekend ahead of what’s left of Ian. The Weather Prediction Center is forecasting 1-3 inches of precipitation along Lake Erie in northeast Ohio, 0.75-1.5 inches across southern Ohio with the remnants of Ian, and lighter amounts across west central and northwest Ohio this week (Figure 2).
The Climate Prediction Center’s 6–10-day outlook for the period of October 2 - 6, 2022 and the 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Center show near to near to above average temperatures and near to below average precipitation are expected (Figure 3). Climate averages include a high-temperature range of 70-74°F, a low-temperature range of 48-52°F, and average weekly total precipitation of 0.65-0.90 inches.