Severe thunderstorms likely today with elevated tornado threat

Yesterday's atmosphere managed to produce some pretty powerful storms in Mid Michigan. Over 2,500 customers are without power in Saginaw County after a severe warned storm moved through. Most of the Thumb got a good soaking from that storm, too. A great deal of the state wound up seeing some thunder last night, and I'm hoping that the conditions in the forecast for today equate to an even better coverage of rain than yesterday's. Unfortunately this rain may also come with a fairly decent chance for severe hazards, including tornadoes.

These graphics represent something known as "updraft helicity". What the model does is first predict that a thunderstorm will form over a given area. It then predicts how much "spin" the storm's updraft will have, and the momentum of that spin. The stronger the values, the more rotation it predicts. The swaths you see appear in dark green and yellow represent the paths of storms predicted to form this afternoon. The HRRR model is calling for some pretty strong rotation to be associated with these storms. Last night's NAM4KM run also predicts strong rotation in some of the storms expected to form.

It goes without saying that the more rotation is present in a storm, the higher the likelihood of severe hazards. At this point, the SPC has designated most of eastern lower Michigan for a 2% tornado risk, and a 15% damaging wind/hail risk.

I'm actually thinking the chances of severe weather today should be pretty good. Unlike the previous systems we've seen come through the state, this one has some power - to the tune of 40-50kts of bulk shear. That means that wind speeds will increase by 40-50kts between the surface and the tops of the thunderstorms. Timing is also on our side this time, and capping appears as though it's going to erode by the early afternoon while CAPE levels rise to around 2000j/kg or more. The setup has also seemed to fall right in line with and in some cases even outperform what the models have predicted thus far.

As much as I don't like the idea of anyone getting hit by a tornado, I'm of the opinion that any storms we get that don't carry some severe risks wouldn't be able to offset the drought at this point. We need some more powerful storms that carry very heavy rains to reinvigorate the earth in our area. A few days of storms like this, once a week or so for the next couple months, is a great prescription for a drought recovery. If any tornadoes do strike, I'm hoping they'll be over open country, in front of someone with a camera.