Here’s what hit Houston yesterday

The National Weather Service will make final decisions on the weather phenomenon that moved through Houston yesterday, but my best guess this morning is that we had a “Derecho”, pronounced Deh-RAY-cho (Spanish for “right”) .

Let me explain. By definition, a Derecho creates straight-line wind damage that extends more than 240 miles and includes wind gusts of at least 58 mph or greater for most of its length. If you look at yesterday’s severe storm reports, you will see a long line of “blue dots” or severe wind reports.

There were 130 wind reports (you can imagine how many were NOT reported) and you can see them all over the site. And if, geographically, the reports of the system that moved started in Austin and moved through New Orleans, then that definition of “240-mile band of damaging winds” was met. And the definition of a 58 mph wind gust was easily found from Austin to New Orleans, where Lakefront Airport recorded an 82 mph wind gust. In fact, most wind gusts in Houston easily ranged from 70 to 90 mph.

Additionally, Derechos are linked to “bow echoes,” a Ted Fujita term about tornadoes, necessarily formed by strong winds that strike the surface and unfold like pancake batter. You can see on yesterday’s Stormtracker2 radar that the arc echoes were absolutely visible. I drew a blue line to illustrate:

Climatologically, May is the most common month for derechos to form and our part of Texas statistically experiences a derecho every two to four years:

If you are interested in meteorology, you can learn more about derechos from the National Weather Service. Was this actually a derecho? I think so and I can tell you that in my career, I have never experienced one until yesterday. Like I always say, if you plan long enough for Houston, you’ll see it all.

Bottom line: I hope you and your family are safe and my heart goes out to those who have lost loved ones. Please have a safe weekend.

Franc

Send me comments and questions