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What caused those high winds this evening?

Today’s heat and humidity led to some storms this evening that caused quite the stir! I have a downed oak tree that thankfully fell away from the road. It was in bad shape, but it’s withstood a lot of wind in its day. Others of you have some roof damage, downed trees, and other wind-blown damages of various degrees.

Thankfully, the storms moved through rather fast and didn’t linger. I was in Tractor Supply when the storm hit Crossville and it got a little loud. The automatic doors got stuck on “open” and so I had a real good view of the storm! ha

While it was very humid here at the surface, there was actually quite a bit of dry air aloft. That should have kept us dry today but the heat and humidity overcame that hindrance. The rain chance for today was 10%, but it should have been more on the lines of 50%. I have more to say about this dry air beneath the diagram below.

The storms that did manage to fire off this evening created very strong winds along their gust fronts. I hope the diagram below helps explain what I’m talking about. As the rain falls from a storm, it sends out a rush of cooler air known as a gust front. You feel that cool rush of air before a storm and some even claim the air “smells like rain.” That cooler air creates a “baby cold front” (gust front) that creates new clouds and then new storms, if conditions are right. That’s what we saw this evening. One storm would form and then send out a very windy gust front that would then kick off a new storm and repeat all over again.

MWN Blog: July 2012

To make matters worse for us today, the dry air aloft caused some of the rain that was falling from the storm to evaporate above us. Evaporation is a cooling process and cooler air is heavy. That creates a situation where the heavier, cooler air above us gets so heavy that it dramatically falls to the ground, causing very gusty winds. Sometimes winds created in this way can exceed 100 mph. From what I’ve seen, the winds with our storms were probably in the 60 -70 mph range.

Storms fired off so quickly that the NWS was not able to issue any warnings. That’s why your weather radios didn’t go off and why you didn’t get alerts on your phone.

A cold front will pass through here tomorrow evening and it could kick off some more storms. As with any summer storm, any storm that develops will be capable of gusty winds, cloud-to-ground lightning, and very heavy rainfall.

Behind this cold front, a much drier airmass will move in, giving us a very nice week for weather.

You all take care and enjoy the evening.

4 thoughts on “What caused those high winds this evening?

  1. Sorry for those that had damage! We were happy because those gusts finally brought down a Frisbee that’s been stuck on our roof for several weeks!!

    1. Always a silver lining! lol

  2. Mark, thanks for taking time to explain what was behind the sudden weather we experienced yesterday afternoon. The diagram helps. In my lifetime I remember many such days and was always puzzled that there was no warning or forecast showing the possibility. My wife and I feel blessed to have you and what you share to help us understand. Thank you.

    1. You are more than welcome, Harlan! I’m blessed to have those of you to follow. Without you all, I would have no reason to do what I love to do!

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