Sprawling Storm Turns Deadly with Tornadoes, Flooding, Downburst Winds

Signals Summary: Climate change is increasing unusual jet stream patterns, and when the jet stream dips, creating a sharp trough, you get extreme upward motions of air that can cause severe thunderstorms or even tornados.

Article Excerpt: At least eight people in four states died on Friday and Saturday as a well-advertised spring-like storm system plowed from the Southern Plains into the Southeast. A tornado confirmed on radar by the National Weather Service in Birmingham killed three people on Saturday afternoon in two locations near Carrollton in west central Alabama, weather.com reported.

Late Friday night, an elderly couple died when a manufactured home was demolished by a tornado near Haughton in northwest Louisiana, just east of Shreveport. The twister was rated as a high-end EF2 by the NWS office in Shreveport, with top winds of 135 mph and a path length of 40 miles.

Both tornadoes were spawned by an intense squall line that formed in Texas and eastern Oklahoma on Friday afternoon and was still progressing, albeit in a weakened state, over Georgia and the Carolinas on Saturday night.

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The strong winds were coupled with mild air and extreme values of moisture for midwinter, with some of the highest values of precipitable water on record for the month of January.

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Juiced by the unusually moist airmass, the storm system dumped heavy rains within the squall line as well as along a broad swath to the north of the surface low, from Oklahoma to Michigan. Nearly 5 inches of rain had fallen near Lake Texoma as of Saturday morning, according to CoCoRaHS observations for Texas and Oklahoma.