Weekend Storms, A Derecho, And The 4th Of July.July 2nd, 2012 at 8:40 am by Jeremy Wheeler under Weather
What a wild weekend it was. We had several sets of storms that did damage across the region. Especially the huge windstorm on Friday night which was a special storm called a derecho. So this has folks asking…Why are we seeing such strong storms recently? Well one part of that is of course the heat and humidity. We get hot/humid conditions every Summer, but it has been a little hotter and more humid than usual. Another big piece of the strong storms are some upper level pockets of cooler air. These are basically ripples of energy in the upper levels of the atmosphere which you can think of as pockets of energy:
- Upper Level Cool Pockets (light blue)
Notice too that the jetstream has been dipping down into our region. This is something that I talked about late last week in previous blogs. This setup created severe storms that were able to pull down some of the upper level winds and push them to the surface. So Friday was a good example of that. We had a derecho event that was pretty scary around here and very damaging up towards Washington D.C. This particular storm started out over northern Indiana over 650 miles away:
- Derecho Friday Night
A derecho is a special type of storm. It is a large windstorm that lasts for over 240 miles, and has to have severe winds of over 58mph along its path. Here is a great link from the Storm Prediction Center about Derechos. The storm moved at an average speed of 65mph, and at times moved over 70mph. The individual wind gusts can be over 100mph. So it is basically like being in a hurricane for about 1-5 minutes. The word derecho is Spanish and means straight. This due to the large area of straight-lined winds involved. I was up posting on facebook about the storm when all of the sudden my power went out. Without A.C. the house got really hot, really quick. So that was a rough night of sleep to say the least. It’s nothing compared to the local folks that didn’t even have power restored through the heat this weekend. I’ve actually been in a derecho before in Mississippi. That event was one of the most memorable weather events ever. Numerous car windows were broken, and there were huge road signs blown down.
- Today’s Weather Map