By Doug Schneider
Mid-Ohio was one of those events where I felt like I make a pretty good forecast overall, but when I look at the numbers for verification, it doesn't look very good.
A big reason for that is how we verify precipitation. In forecasting, rain only counts if you can measure it to the closest hundredth of an inch. Sometimes you'll feel some raindrops, but it won't be enough to measure 0.01 inches. In that case, it is considered a trace (T), and it is counted the same as if it didn't rain.
A big reason for that is how we verify precipitation. In forecasting, rain only counts if you can measure it to the closest hundredth of an inch. Sometimes you'll feel some raindrops, but it won't be enough to measure 0.01 inches. In that case, it is considered a trace (T), and it is counted the same as if it didn't rain.
Friday at Mid-Ohio ended up being a very wet day at the track, with some of the late afternoon sessions being canceled. That worked out well for my forecast, as I had been targeting Friday as the wettest day from my initial forecast post on Monday. I don't know how much rain fell at the track, as there is no weather station there, but it looked like quite a bit from the pictures I saw on Twitter. However, at the Mansfield Regional Airport about 10.5 miles northeast (which I'm using as my data source for verification), there was only a trace of rain recorded that day. Since I know for certain that rain fell at the track, I'm counting it as a "hit". There turned out to be a good amount of sunshine in the morning before the rain arrived, so temperatures ended up being several degrees warmer than forecast on Friday.
For Saturday, my initial forecast may have been the most accurate one. Through the week, the chance of rain was looking higher with each day, since there would be a front lying east to west across central Ohio, with a low pressure center tracking east along the front. There were numerous showers and thunderstorms around the area, but luckily for those at the track (and unluckily for us meteorologists), they didn't directly hit Mid-Ohio. I was watching storms on radar most of the day, and at least twice, the storms completely fell apart within 10 miles of the track. It was like there was a force field around Mid-Ohio, deflecting all the rain.
For Saturday, my initial forecast may have been the most accurate one. Through the week, the chance of rain was looking higher with each day, since there would be a front lying east to west across central Ohio, with a low pressure center tracking east along the front. There were numerous showers and thunderstorms around the area, but luckily for those at the track (and unluckily for us meteorologists), they didn't directly hit Mid-Ohio. I was watching storms on radar most of the day, and at least twice, the storms completely fell apart within 10 miles of the track. It was like there was a force field around Mid-Ohio, deflecting all the rain.
 |  |  |
Our friend Shay Hazen (@SHAYZEN) reported feeling "about a dozen" raindrops at the track on Saturday. So while it did rain at the track, such a small amount of rain is likely not enough to measure 0.01 inches, so I have to be honest and call it a trace. That means my 70% chance of rain that I forecast on Saturday morning was technically a bust, even though 70% was probably quite representative of the actual coverage of storms that day.
I had been advertising a dry day on Sunday, and that worked out. There were some isolated showers north and east of the track on Sunday, coming within 20 miles or so of the track.
To summarize with gifs:
Rain forecast on Friday - nailed it:
I had been advertising a dry day on Sunday, and that worked out. There were some isolated showers north and east of the track on Sunday, coming within 20 miles or so of the track.
To summarize with gifs:
Rain forecast on Friday - nailed it:
A magical force field keeps Mid-Ohio dry on Saturday:
Me tweeting about approaching storms, only to watch them dissipate a few miles away:
So close, but came up short:
