Thread by @JoshWeather

(THREAD) If you missed the FB Live, there were 3 very important clues that a tornado was imminent north of Birmingham last night. And @NWSBirmingham saw those clues, reacted quickly, and provided a world-class, lifesaving service to the people in the tornado's path...#alwx

First, there was a pocket of enhanced helicity over northeast Alabama...likely a remnant of the "wedge" front that had brought cooler air into north Georgia and NE Alabama. See that bullseye over Rome, GA? It extends back towards Birmingham. #alwx

Secondly, the reflectivity data showed this storm "tilt" - the overall line was clearly oriented from SW to NE, but just before the tornado formed, it assumed a more S to N orientation. This is often a clue that a QLCS/embedded supercell is about to produce a tornado. #alwx

Finally, the lightning! Lightning mapping showed a very intense, very rapid increase in lightning output as the storm approached I-65 north of Birmingham. This has been shown to be associated with increased rotation.

See for yourself here:

https://twitter.com/cschultzwx/status/1353930771032113153?s=20

#alwx

My friend @cschultzwx links a paper on this: Here's a vital excerpt: "...a consistent pattern of lightning jumps prior to intensification of the low-level mesocyclone either before tornadogenesis or during early intensification of strong-to-violent tornadoes was observed." #alwx

Read the full paper here, if you're into that kind of thing. Hint - if you're a broadcast meteorologist - be into that kind of thing. #alwx

journals.ametsoc.org/view/journals/… #alwx