Storm clouds swept across the Miami Valley Saturday afternoon and evening. 2 News Viewers caught some photos showcasing the rising air, gusty wind, and heavy rainfall. A few people snapped a photo of the wall cloud that prompted the Tornado Warning in Preble County shortly after 5 p.m.
7:47 p.m.: The severe threat has diminished. Scattered thunderstorms will continue through midnight with spotty showers overnight. A few thunderstorms are possible into Sunday morning. There will be some dry time with pop up showers and storms possible in the afternoon.
5:45 p.m.: The Tornado Warnings have expired. Scattered thunderstorms remain possible this evening, with damaging winds as the main threat. There is also the potential for heavy rain and localized flooding.
5:20 p.m.: A Tornado Warning is in effect until 5:45 for Montgomery and Preble Counties.
3:30 p.m. Update: Right now the stronger thunderstorms are southeast of the Miami Valley and will not track into the area. However, breaking clouds will add to instability this evening. Scattered thunderstorms have developed and will continue into the region. With increasing instability, these thunderstorms have the potential to be severe. The main threat is still damaging wind gusts.
12:07 p.m. Update: Storms are beginning to develop southwest of the Miami Valley. These storms will strengthen as they begin to track into the Miami Valley. We will see scattered shower with possible thunderstorm development mostly south of I-70 for now. I still think the greatest risk of severe weather will be after 2 p.m.
9:45 a.m. Update: The storm prediction center has upgraded the southwest portion of the Miami Valley to a slight risk of severe weather. This includes western Clark County, Greene County, Warren County, and Clinton County.
Thunderstorms will develop along the Ohio Valley around 2 p.m. These thunderstorms will track northeast into the Miami Valley.
The risk of severe weather will be between 4 p.m. and 10 p.m. Starting in Butler and Warren County and ending in Logan County. Storms will be scattered meaning there will be off and on rain into the evening. Thunderstorms will weaken once the sun goes down. Scattered showers will continue into Sunday morning.
Damaging wind will be the primary threat. The tornado threat cannot be ruled out. There is a low risk of large hail. With periods of heavy rainfall, flash flooding is also a concern.
Moisture, rising air, wind shear, and lift are the key ingredients for tornado development.
We have a lot of low-level moisture. The dew point will be near 70 with afternoon highs staying in the mid to upper 70s. The lower the difference is between these two numbers, the lower the cloud base will be. Lower cloud bases make it easier for tornadoes to develop.
The cloud base alone will not lead to a tornado. Additionally, you need a lot of rising air to create a thunderstorm updraft. Rising air happens when air at the surface can quickly become saturated and remain warmer than the rest of the air in the atmosphere. Meteorologists monitor Convective Available Potential Energy or CAPE. The CAPE is will be moderate to strong this evening.
A strong updraft does not immediately result in a tornado. The updraft needs to rotate. This happens when the wind at the surface is blowing a different direction than the wind higher up in the atmosphere. The wind at the surface is out of the east southeast this morning. Upper-level winds are out of the SW. This is not a dramatic change and will lower our tornado risk. We will see the wind speed increase at higher heights of the atmosphere. When the wind is slower at the surface and increases with height this can create horizontal tubes of rotating air. If the rising air interacts with this tube of rotating air it can cause it to become a vertical rotating column of air. This will lead to a strong thunderstorm with the potential to produce a tornado.
Additionally, the warm front will create an additional boost to help create rising air and initiate thunderstorms.
Overall the tornado risk is very low today. The area we see the most of all of these ingredients is east of the Miami Valley. portions of Champaign, Clark, Greene, and Clinton county have a 2% risk of a tornado. This is very low, but means a tornado can’t be ruled out of the forecast.
Scattered showers are tracking across the Miami Valley this morning. It will be muggy and mild with temperatures around 70 degrees.
This afternoon around 2 p.m. Thunderstorms will develop along the Ohio Valley and track NNE across the Miami Valley.
Severe weather is possible 2 p.m. – 8 p.m. The main risk will be high wind gusts resulting in tree damage and power outages. Additionally, localized flooding will be possible.
TODAY: Cloudy and humid with showers and a few thunderstorms, rain could be heavy in the afternoon. High 78
TONIGHT: Muggy with showers and a few thunderstorms. Low 67
SUNDAY: Mostly cloudy with a chance of a shower or thunderstorm. High near 80
The chance of showers and thunderstorms will continue Sunday. Finally, some cooler and less humid air moves in our direction around the middle of next week.