Just before 6am, the first Tornado Warning was issued for southern Mississippi County, AR, just west of Tipton County. This was the first sign (locally) that the squall line was capable of producing brief, "spin-up" tornadoes that sometimes occur in severe squalls, verifying forecasts from the previous day that the scenario was plausible.
5:55am A Tornado Warning has been issued until 6:45am for southern Mississippi Co, AR - just west of Tipton Co - for the potential for a brief spin-up tornado. We'll be watching it carefully as it heads towards Tipton. #ARwx pic.twitter.com/U5QgcLvvtD— MemphisWeather.net (@memphisweather1) October 21, 2019
About the same time, a Severe Thunderstorm Warning was issued for the western half of the metro, including western Shelby County. Over the next two hours, the line crossed the entire metro, then weakened considerably when it reached central Fayette County.
In those intervening hours, no less than four Tornado Warnings were issued in the metro - one in northern Tipton County, one in northern Shelby County, one in southeast Memphis, and one in central Fayette County. Radar showed low-level wind rotation in each, but the southern Shelby storm is the one most likely to have produced a tornado.
6:41am TORNADO WARNING for southeast Shelby Co until 7am. Rotation appearing near I-240 and Perkins moving NE onto the eastern loop and E Memphis. TAKE COVER! https://t.co/N6ylFzYIpx— MemphisWeather.net (@memphisweather1) October 21, 2019
Wind damage began near Memphis International Airport with trees and limbs down on the west side of the airport, windows blown out in the airport terminal, and damage just east of the airport. The storm's path east-northeast took it parallel to I-240 through Parkway Village, along SR 385 into Hickory Hill, and then into parts of west Germantown near Poplar and Poplar Pike. There were many reports trees down or uprooted, damage to structures (perhaps the worst of which was in the Cottonwood Apartments), and utility poles snapped with wires down. See our Twitter timeline for many reports and photos.
There was also radar evidence of a possible tornado in the form of a "debris ball" - a radar signature that indicates that debris is being lofted into the storm and detected by the radar beam.
— Richard Hoseney (@rhoseney) October 21, 2019
MLGW reported that over 43,000 customers (which amounts to more than 100,000 people) lost power during the storms. Scattered traffic light outages were spread across the city. The official peak wind gust at Memphis International Airport was 53 mph, but the storm intensified as it moved east of the airport and rotation in the storm tightened. As of this writing, we are unaware of any major injuries.
An official report from the National Weather Service indicates that the storm produced a preliminary EF-1 rated tornado with maximum wind of 105 mph. Radar evidence and storm damage supports the ground evidence of a tornado. These "QLCS (quasi-linear convective system) tornadoes" - or those that spin up in a squall line and last a short period of time - are very difficult to provide much warning lead time on and frequently are missed completely until after they have done their damage. Fortunately, they also tend to produce damage on the low end of the tornado scale, but that doesn't mean that if one affects you it was no big deal. It is for those affected.
Preliminary EF-1 Tornado damage around Cottonwood Apartment area in Memphis. pic.twitter.com/C1UcXRjwTF— NWS Memphis (@NWSMemphis) October 21, 2019
A word on "unexpected" storms
Inevitably after a storm that produces damage, we hear that the storm "hit without warning" or was "unexpected." It happened again this morning when MLGW issued a press release calling the storm unexpected.
I understand that there is damage control that must be done when 10% of your customer base loses power. I also understand that perhaps the storm packed more of a punch than what some may have been "expecting." But the presence of a squall line was not unexpected, nor was the timing, nor should have been the potential intensity.
The National Weather Service first mentioned the possibility of Monday's strong storms last Wednesday morning in their Hazardous Weather Outlook - a full five days in advance. By Saturday morning, they had increased their concern level:
.DAYS TWO THROUGH SEVEN...Sunday through Friday Strong to severe storms are possible on Monday as a cold front moves across the Mid-South. Damaging winds, large hail, and isolated tornadoes will be possible. In addition, heavy rainfall could lead to flash flooding.
On Sunday, areas along and east of the Mississippi River were included in a Slight Risk (level 2/5) for severe weather on Monday by the Storm Prediction Center. As high-resolution model data got within range of the event, we also posted detailed information Sunday afternoon that had the timing within an hour of the actual event and the mention of a line of storms with damaging wind as the chief concern and an isolated tornado possible. The confidence level was assigned "moderate to high."
By 3am, a Tornado Watch was issued and the line was evident on radar in AR with a history of producing well-publicized tornadoes in the Dallas area. Severe Thunderstorm Warnings were issued well in advance of the line. Tornado Warnings were issued as quickly as possible once rotational signatures became evident.
In my opinion, the squall line was not only NOT unexpected, it was well forecast - down to the hour nearly a day in advance. The potential impact was stated clearly and unequivocally. There is no way to know where and when a tornado will touch down more than minutes in advance. But the possibilities are enumerable and were communicated. Damaging wind was clearly identified as a hazard. It's time to tell it like it is... "a storm system that was well-forecast produced damage that was in line with the potential reasonable worst case scenario and we're doing everything we can to resolve the issues."
No one (in their right mind anyway) expects 43,000 customers to have power restored instantaneously. We just expect hard work towards executing a well-conceived, predefined contingency plan with strong communication on how that plan is evolving throughout the process. I happen to believe MLGW is executing that plan and appreciate the "Memphis grit" that the front line workers are displaying as they work to restore power. Let's not insult the weather community that did an exemplary job attempting to communicate the threat by calling it unexpected.
Erik Proseus
MWN Meteorologist
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