Posted Wednesday, September 22, 2021
Late September is not exactly one of those times of the year when we have to deal with severe weather. However, today will be a day where you will need to pay attention to the weather. We do have a fairly legitimate threat for severe storms headed our way for today.
Our area this morning is under a dry slot and this should provide quiet weather for most of the morning. A strong cold front draped across western Ohio this morning will slide east today. Low pressure near the front will deepen as it pivots north through the state and provide the energy for the development of thunderstorms this afternoon.
The NWS Storm Prediction Center has upgraded our area to “Slight Risk” or, level 2 on a scale of 1-5. While this might seem insignificant, it is a level of severe risk we normally don’t see at this time of the year.
Today’s risk for strong storms also includes an unusually elevated threat for isolated tornadoes. The SPC has increased the threat for tornadoes from 2-percent to 5-percent for most of our area.
A 5-percent risk sounds pretty low. But, it’s significantly higher than what we normally have for any day in the summer and it’s highly unusual for the latter end of September. Basically, the tornado threat on any normal day this time of the year is zero.
A 5-percent threat doesn’t sound like much and it’s no guarantee tornadoes will develop. It does deserve your attention, though.
ANY sunshine we might get this morning will only make the atmosphere more unstable ahead of the afternoon storms. Sun will not be our friend today.
As I mentioned earlier, the dry slot and calm weather conditions will be with us for the bulk of the morning and probably lunchtime. There can be a stray shower but we should generally stay dry during this period.
Primetime for severe weather in our area will set up after 1:00 PM this afternoon to around 6:00 PM. I wouldn’t be at all surprised that either a Severe Thunderstorm Watch or even a Tornado Watch is issued for parts or all of our area by this afternoon.
The image above might not look like much to worry about. The main reason for the elevated threat for tornadoes today is wind shear high overhead. Wind shear is air traveling at different speeds and different directions as you gain height. Wind shear can cause rotation at the surface and, that’s the factor that will be in place today.
- Pay close attention to the weather this afternoon
- Have a reliable way to get warnings and information
Showers and storms this afternoon and evening will also be capable of producing heavy rainfall and strong wind gusts. There can also be hail where strong updrafts occur.
TONIGHT AND THURSDAY
Showers and storms will push east of the area tonight. Much cooler air will flow behind the front and temperatures tomorrow will be cooler than normal. Daytime highs will struggle to reach 60° under a mix of clouds and sun. As a bonus the humid air will also be replaced by a much dryer air mass. Dew point in the upper-60s today will be replaced by dewpoints in the upper-40s by Thursday.
Updates will be posted here as changes occur or more information becomes available. I’ll also post updates on Twitter (@tuscwx) throughout the day. Be safe out there.