MIDLOTHIAN, Texas — The National Weather Service of Fort Worth said its network of seven unique weather radars helped detect Monday's EF-1 tornado near River Oaks.
“What's nice about (CASA radars) is that they are cheaper, but they are also higher resolution and they scan much faster,” Ted Ryan, NWS Fort Worth’s science and operations officer, said.
CASA radars are located in seven North Texas cities: Addison, Arlington (UTA), Cleburne, Denton (UNT), Fort Worth, Mesquite and Midlothian.
“We're the only pilot in the country right now for this type of actual network,” Ryan said. There are plans to put an eighth CASA radar in Collin County, he added.
D-FW’s network of CASA radars has been in place for roughly the last four years, and they’re funded through a collaborative grant between the National Science Foundation and local entities across the Metroplex, Ryan said.
“We use the traditional weather radar to kind of give us that lead time to see when things are getting more favorable for tornadoes, but we use that CASA radar to actually see that it's occurring and see exactly where it's occurring,” Ryan said.
Here’s how it all works: The National Weather Service radars can reliably see roughly 150 miles away in a straight line, according to Ryan. Meanwhile, the Earth is curved.
“The problem is, as you go out 100 or 150 miles, the beam is actually 10,000-20,000 feet above the ground,” Ryan said.
So, it’s hard to get a clear view of what’s actually happening closer to the ground.
The solution? These CASA radars.
“Because it's only going about 15 to 20 miles, the beam just doesn't have time to get that far off the surface,” Ryan said. So, the CASA radar network tends to look a lot lower in the sky.”
This network of lower-looking cameras helped detect a tornado in Tarrant County this week.
“What was unique about Monday was that the spin-up process or the tornado developed from a process from the ground up. So that's why the CASA radar network was able to detect it, whereas the traditional radar network was not,” Ryan said.
WFAA asked Ryan if crews would’ve been able to see the EF-1 tornado near River Oaks if it hadn’t been for the CASA radars.
"Most likely not. There probably would not have been a tornado warning issued for the River Oaks tornado,” Ryan said. “It would have been one of these very brief and very shallow tornado processes that just weren't detected by the traditional methods.”