This weekend’s severe weather outbreak across the eastern United States claimed nine lives and caused damage from the Deep South to New England. The extent of the severe weather on Saturday, April 13, wasn’t quite as bad as forecasters had initially feared given the extremely favorable dynamics across parts of Louisiana and Mississippi. However, several storms did manage to take advantage of the environment and produce destructive tornadoes. Two of those tornadoes touched down within a few miles of a weather radar in Mississippi, giving us an incredible view of how quickly an intense tornado can develop.
A squall line with embedded supercells moved through northeastern Mississippi late in the evening on Saturday. One such supercell produced a duo of violent tornadoes as it passed through Monroe County, Mississippi, which is home KGWX, a weather radar located about 28 miles north of Columbus Air Force Base.
The tornado that killed at least one person and nearly wiped out northeastern Mississippi’s weather radar developed so fast that there was almost no time for folks along the tornado’s initial path to react to the warning. Rotation on the storm began to tighten up at 11:05 PM. Forecasters issued a warning at 11:06 PM. The tornado touched down and had already kicked debris high into the air by 11:07 PM. It happened in a flash—a scary situation that highlights the danger of fast-moving severe thunderstorms in a favorable environment.
That first tornado—rated an EF-2 by the National Weather Service in Memphis, Tennessee—dissipated about two miles to the west of the radar after it wrapped itself in stable air that choked off the circulation. The supercell regrouped quickly—so fast, in fact, that the new tornado touched down just one mile to the east of the radar while the other tornado was still weakening to the west of the radar. For a couple of minutes, there were tornadoes on either side of the radar. Eventually, the easternmost tornado became the thunderstorm’s dominant feature and continued to produce at least EF-1 damage as it continued north through Monroe County and away from the radar site.
Tornadoes happen fast. Only 58 percent of all tornadoes that touched down in the United States in 2017 developed within a tornado warning. Most of those unwarned tornadoes were weak and small, sometimes unfolding so quickly that they can touch down and dissipate between radar sweeps, going undetected until damage reports come in after the fact. What we saw in northeastern Mississippi was a case where a tornado developed so quickly that forecasters were barely able to get the warning out before debris started showing up on radar.
Saturday’s storms are a stark reminder that folks under threat for severe weather need to react quickly when dangerous conditions are in the forecast. It’s a good idea to stay ahead of severe thunderstorms even before a warning is issued. If there’s a severe thunderstorm headed your way and you know there’s an elevated risk of tornadoes for you area, it’s good to ride out the storm in your safe spot—basement, closet, wherever is safest—just in case the storm produces a tornado faster than meteorologists can issue a warning. It’s smart to stay proactive when severe weather is on the way instead of waiting for it to show up at your doorstep.
As for the weather radar itself, it’s doing just fine. The latest brush adds to an ever-growing list of NOAA weather radars coming within a hair of getting destroyed by the weather they’re tracking. The most recent case of a storm destroying a radar occurred in September 2017 when Hurricane Maria made landfall in Puerto Rico. The radar was down for nine months while crews removed the old radar site and replaced it with new equipment.