- There were 130 wind reports from Thursday evening’s storm in Houston, indicating the presence of a derecho.
- Bow echoes, which are associated with strong winds hitting the surface and then fanning out, were visible on the radar.
- May is the most common month for derechos to form, and the Houston area experiences them every two to four years.
The National Weather Service will make the final determination, but Houston weather icon Frank Billingsley suspects the weather phenomenon that roared through downtown Houston and its north and northwestern suburbs Thursday evening, killing at least 7 people, might have been a derecho.
IMAGES: Daylight illuminates just how severe the storm that hit Houston was
Billingsley, Chief Meteorologist for Houston NBC affiliate KPRC 2, has been forecasting in Houston for nearly 30 years. His weather expertise includes the San Jacinto River floods of 1994, Tropical Storm Allison, Hurricane Ike, and the 2017 devastating Category 4 Hurricane Harvey.
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 along most of its length. If you look at severe storm reports across Texas yesterday, they show a long line of blue dots, which represent high wind reports.
The storms that slammed into Houston killed four people, blew out windows of downtown high rises, and shut off power to more than 900,000 customers.
The National Weather Service Storm Prediction Center notched 130 wind reports during the event. If, geographically, the reports connected to the storm system that started in Austin and traveled through New Orleans are confirmed, the “240-mile swath of damaging winds” definition for a derecho was met. The wind gust definition of 58 mph was met in several cities from Austin to New Orleans, where Lakefront Airport recorded a wind gust of 82 mph. Most wind gusts across the Houston area were between 70 mph and 90 mph.
In addition, derechos are tied to bow echoes, which is a term from Ted Fujita of tornado fame, necessarily formed by strong winds that hit the surface and fan out like pancake batter. Below are several radar images captured by KPRC’s Storm Tracker 2 Radar showing visible bow echoes. Billingsley highlighted them with the blue lines below.
Climatologically, May is the most common month for derechos to form and, statistically, southeast Texas experiences a derecho every two to four years.
“Was this, in fact, a derecho? I think so,” said Billingsley. “I can tell you that in my career, I have never actually been through one until yesterday. As I always say, if you forecast in Houston long enough, you’ll see it all.”
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