Seventies to Storms…Severe?

It took awhile, but we finally started warming up this afternoon on very strong southerly winds. There is a slight east component to the wind so lake areas are a bit cooler, but most areas will hit the seventies today. Friday will be another warm and windy day with partly sunny skies. The wind will be more southwesterly tomorrow so everyone should get well into the 70s. Nice way to finish of April.

With the good comes the potential bad. A cold front will be making its way into Wisconsin late in the day on Friday. That cold front will run into the warmer and semi-moist air kicking off thunderstorms. Some of these storms may be severe, especially in western Wisconsin. The timing of the storms still looks to be overnight in our area and that will help keep our chances for severe weather here a little lower than the rest of the state.

Here is the latest from the Storm Prediction Center. They have the whole state in slight risk.

There are a lot of elements to figuring out severe weather chances. I’m going to show you our in-house computer model with some of the important ingredients of severe weather. All of  the following graphics are for the late evening Friday night. First, let’s take a look at the dew point. The more moisture available, the better the instability.

Our RPM model shows the dew points reaching the low 60s. This is not incredibly moist, but would be enough for severe storms if all other elements came together. Next, let’s take a look at the lifted index. This is a measure of  the buoyancy of the atmosphere.

The lifted index is forecast to be around -2. When the lifted index gets lower than -5, we really get interested. Next up is CAPE. CAPE stands for convective available potential energy. Without getting overly technical, it is another measurement of the buoyancy of the atmosphere. The higher the number, the better the chance of severe storms.

I believe the CAPE is a little overdone due to the dew points being slightly higher than I expect. Finally, the surface map.

Even with some favorable conditions, the RPM model is not overly impressed about getting severe weather in our area. Make sure you stay tuned tonight and Friday for the latest on WISN-12. We will be keeping a close eye on the potential storms. Thanks for reading.

Mark

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2 Responses

  1. Nice explanation on the blog. Maybe someday you will give a high level tutorial on skew-Ts. LOL

  2. I like the pretty colors used in the different parts of the model. Wish I could run my own in house model on my HP laptop at home, but one I don’t have the training in meterology, and two I don’t have the software. I am glad we are at the time of the year where we are talking about thunderstorms instead of thundersnow.

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