Wednesday is a 9 First Warning Weather Alert Day due to the potential at strong and severe thunderstorms across the Tri-State.
A strong low-pressure system will move into the Great Lakes region over the next 48 hours, placing the Tri-State in an area for severe weather. Because of this, the Storm Prediction Center has placed an Enhanced Risk (Level 3 of 5) for severe weather Wednesday in our area.
These storms will develop along and ahead of a cold front which will sweep through the Tri-State, driving the storms into our area. Let's break down the impacts we need to look for and the timing of the threat itself.
9 FIRST WARNING: The Entire Tri-State is in an Enhanced Risk (Level 3 of 5) for severe weather Wednesday. The main threat is damaging wind gusts of 60+ mph, but tornadoes & hail cannot be ruled out. This looks like an afternoon event at this point #WCPO @WCPO #CincyWX #OHwx pic.twitter.com/S3Qk7QGgw8
— Brandon Spinner WCPO (@wxSpinner89) April 4, 2023
STORM IMPACTS
As these storms come into the Tri-State on Wednesday they will bring the potential of all severe weather hazards; Damaging wind gusts, tornadoes, and large hail. Severe wind gusts of 60-70 mph will be our primary threat with these storms as the line/wave rolls through. Tornadoes will also be possible, especially low-end "spin-up" tornadoes. These are likely to be embedded within the line of thunderstorms that roll through and would be hidden within the storms themselves. We may have a few strong singular super cells ahead of the main line, and if that is the case our threat for tornadoes would be a little bit higher. Large hail of 1 inch in diameter, or greater, is possible, but it is the lowest threat of the bunch.
There will be the potential for some flooding, but because the speed of these storms we are not expecting widespread flooding. Rain totals should stay between 0.25" to 0.75" for most communities, but we may see some localized heavier totals. The localized stronger storms will bring potential for 1 to 2 inches which would increase the flooding potential.
TIMELINE:
Storms will be possible off and on through the morning and midday Wednesday, but the best threat for severe weather will be during the mid to late afternoon. The isolated storms midday are likely between 12 p.m. and 3 p.m. Our severe weather window will open up around 4 p.m. and should close around 10 p.m. as the front passes through.
While supercell storms are possible early, the storms will likely move through the Tri-State as a quasi-linear convective system (QLCS) also called a "Squall line." This is why we will have more of a damaging wind threat.
Areas to look for on radar will be "bowing" segments.
WHAT WE NEED TO WATCH:
When we forecast severe storms we look for many ingredients. Like baking a cake, you need the correct ingredients for things to come together. While there are many variables that can impact or inhibit storm development, there are four main factors we look for. I use the acronym of S.L.I.M. This covers Shear, Lift, Instability, & Moisture. Shear is a measure of the spin in the atmosphere, which you need for storms to turn and strengthen. Lift is what helps these storms develop with an upward motion to push the storms higher in the atmosphere. Instability measures the energy in the atmosphere for storms to feed off of. The higher those levels get, the stronger storms are able to become. Lastly, Moisture. You can’t have storms without moisture, but the higher the levels, the better the threat for strong storms & tornadoes.
Shear values look to be there, at least for areas to the west of the I-75 corridor, so there isn't much question there. The next on the list, lift, should be there with storms already developing and a cold front being a source of lift as well. From there, we look to instability.
This is the ingredient that we lacked during last Friday's event and we will have much more for this threat. Values of 1,000+ are more likely to increase and develop severe weather, and once again you see that the highest values are to the west of I-75. These numbers may be lower depending on how much rain we see during the day. If we have more rainfall, that is likely to suppress these values, which could limit storm development.
Another question we have had is whether or not we have enough moisture available for the storms. Dewpoints of 65°F and greater are usually the target for severe storm potential. Right now, the sweet spot again is to the west of I-75. However, we will still have enough moisture out east for storms to be severe.
The graphic below is a product that shows the likely path of where the strongest rotations will move through. Again, this is just a projection, but it still shows that storms will be strong/severe as they move in.
As always, make sure to stay weather alert Wednesday. We will have coverage for you on-air when needed, but you can also stream coverage on your WCPO mobile app as well as on our streaming app on your Roku, Amazon Fire, and Apple TV devices. Keep checking in for the latest updates as we get closer and closer.
