A high based squall line, exhibiting little to no lightning, roared southeast through southern middle Tennessee during the late afternoon and early evening. The initial gust front was likely responsible for the highest wind gusts and observed damage.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS HUN wrote it up.
A high based squall line, exhibiting little to no lightning, roared southeast through southern middle Tennessee during the late afternoon and early evening. The initial gust front was likely responsible for the highest wind gusts and observed damage. Widespread measured wind gusts of 40-55 mph were observed. Estimated gusts of 60 mph likely occurred as well given the number of trees being knocked down in the area. However, no official wind measurements of 58 mph or higher were recorded.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Huntsville, AL wrote its last area forecast discussion before the first event at May 6, 5:12 PM CST, 16 minutes earlier.
Area Forecast Discussion National Weather Service Huntsville AL 612 PM CDT Thu May 6 2021 .UPDATE... For 00Z TAFS. && .NEAR TERM...(Tonight) Issued at 248 PM CDT Thu May 6 2021 Temperatures have climbed into the upper 60s to lower 70s in most locations except in portions of southern middle Tennessee. A surface low is moving east into Ohio with a trailing cold front extending southwest from this feature into extreme southeastern Missouri and the northeastern tip of Arkansas. Some strong to severe thunderstorms have developed within a line ahead of this cold front. This line of shower and thunderstorm activity is moving quickly southeast towards the Jonesboro community in northeastern Arkansas. Based on current movement, this still looks to push into locations near the AL/TN/MS borders between 5 and 6 PM roughly. It appears at least right around 5 to 7 PM, there may be steep enough lapse rates, shear, moisture between 850 mb and 500 mb, and around 500 J/KG MUCAPE for strong thunderstorms capable of producing winds gusts to 55 mph and small hail. An isolated threat of large hail and damaging winds still looks possible, especially in northwestern Alabama, where instability will be highest before it wanes in the evening with the loss of daytime heating. Models continue to show much drier air aloft pushing into the area between 9 PM and midnight. This should shutoff precipitation from west to east during that timeframe. Left isolated showers/thunderstorms chances in through 11 PM in the east and towards Cullman county. Confidence lowers concerning whether the isolated severe threat can hold on east of I-65 past 8 or 9 PM, but can't rule it out entirely. Not expecting much rain with this, since the line will be moving very quickly through the area and may be weakening substantially as it approaches the I-65 corridor. .SHORT TERM...(Friday through Saturday) Issued at 248 PM CDT Thu May 6 2021 Clear skies should return during the early morning hours. Believe winds will stay up enough overnight to keep fog from forming. The exception might be in areas sheltered from winds in northwest Alabama where winds will be lighter around daybreak on Friday. Another cool night in store with lows dropping back into the lower to mid 40s behind the front towards daybreak. Another cool day in store on Friday, despite abundant sunshine. Highs still look to only climb into the mid 60s in many areas and to around 70s degrees west of the I-65 corridor. Westerly flow kicks in as the surface high over the area quickly begins shifting eastward Friday night. Fairly decent warm air advection should allow dewpoints to climb and lows to only drop into the mid upper 40s/lower 50s west of the I-65 corridor and cloud cover should help keep temperatures warmer there as well. Further east, this should setup quite a gradient in temperatures, due to drier air trapped in valley areas and clear skies much of the night. Lows there will likely drop into the lower to mid 40s. Expect a weak warm front to exit from central Missouri into southern Tennessee Saturday morning. This warm front extends east from a storm system developing over the midwestern states. At this point northern Alabama still looks to be in a very dry and stable airmass overall. Models show some light precipitation moving across our southern middle Tennessee counties Saturday afternoon, but as stated earlier this should be all light rain showers at best. No thunderstorms are expected at this time. Should be a bit warmer with highs reaching the lower 70s in most locations. Most guidance continues to push this warm front further north Saturday night into Sunday morning. This should make for an even warmer night on Saturday night with lows only dropping into the mid to upper 50s in most locations. .LONG TERM...(Saturday night through Wednesday) Issued at 248 PM CDT Thu May 6 2021 This warm front also appears to be re-enforced by a secondary warm front via a strong low level jet that develops ahead of the cold front approaching from the west over eastern Kansas and western Missouri. This low level jet will provide for at least breezy conditions on Sunday, despite cloud cover. For now, went with highs in the lower 80s, but this may be too low, given strong warm air advection and 925 mb temperatures, despite abundant cloud cover. Expect sustained winds of around 15 mph with gusts to 30 mph possible. The front is slow to move east and models continue to hold off any precipitation in Alabama until Sunday night into Monday. Models show some drier air and a drop to isolated scattered pop Monday night before shower and thunderstorm chances increase again as the front moves northward again after stalling in southern Alabama. Looking at some fairly heavy rainfall signals with this system and high PWAT values. So a good 1 to 2 inches currently in forecast may be a bit underdone. As the front waffles through the area Tuesday into the middle part of next week, we could start to see some flooding issues and stronger storms develop again. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 612 PM CDT Thu May 6 2021 Line of severe storms will move through the area, impacting KHSV/KMSL through 01z and producing gusty winds up to 35 kts. Thereafter, the sky will gradually clear by 03-04z, resulting in VFR conditions through the end of the period. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && NEAR TERM...KTW SHORT TERM...KTW LONG TERM...KTW AVIATION...AMP.24 For more information please visit our website at weather.gov/huntsville.
Hazardous Weather Outlook National Weather Service Huntsville AL 153 PM CDT Thu May 6 2021 ALZ001>010-016-TNZ076-096-097-071100- Lauderdale-Colbert-Franklin AL-Lawrence-Limestone-Madison-Morgan- Marshall-Jackson-DeKalb-Cullman-Moore-Lincoln-Franklin TN- 153 PM CDT Thu May 6 2021 This Hazardous Weather Outlook is for north central Alabama, northeast Alabama, northwest Alabama and southern middle Tennessee. .DAY ONE...This afternoon and tonight. Scattered thunderstorms will move southeast into the area from 4 pm through 8 pm. A few of these could be strong with small hail and wind gusts up to 50 mph. An isolated severe thunderstorm is also possible with higher gusts and larger hail, but this risk is low. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. A few thunderstorms are possible Sunday through Wednesday. .SPOTTER INFORMATION STATEMENT... Formal activation of storm spotters and emergency management personnel is not anticipated at this time. However, timely reports of hail and high winds will be greatly appreciated. Please relay any information about observed severe weather to the NWS while following all local, state, and CDC guidelines.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
551 PM CDT THU MAY 6 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0520 PM TSTM WND DMG 6 WNW UNDERWOOD-PETERSV 34.90N 87.79W
05/06/2021 LAUDERDALE AL PUBLIC
LARGE LIMBS BLOCKING THE INTERSECTION OF
COUNTY ROAD 6 AND COUNTY ROAD 15.
&&
BCCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
552 PM CDT THU MAY 6 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0536 PM TSTM WND DMG 1 NE TUSCUMBIA 34.73N 87.70W
05/06/2021 COLBERT AL PUBLIC
TREE DOWN ON A HOUSE ON CAVE STREET IN
TUSCUMBIA. TIME ESTIMATED FROM RADAR.
&&
BCCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
559 PM CDT THU MAY 6 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0524 PM TSTM WND DMG 4 WNW UNDERWOOD-PETERSV 34.90N 87.75W
05/06/2021 LAUDERDALE AL BROADCAST MEDIA
TREES DOWN ON COUNTY ROAD 281. TIME
ESTIMATED FROM RADAR.
&&
BCCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
611 PM CDT THU MAY 6 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0604 PM TSTM WND DMG 6 ESE ROGERSVILLE 34.80N 87.19W
05/06/2021 LIMESTONE AL PUBLIC
TREE DOWN ALONG US HWY 72 NEAR CLEMENTS.
&&
BCCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
617 PM CDT THU MAY 6 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0608 PM TSTM WND DMG 7 SW ELKMONT 34.86N 87.05W
05/06/2021 LIMESTONE AL PUBLIC
TREE DOWN AT THE INTERSECTION OF ELK RIVER
MILLS RD AND TILLMAN MILL RD. TIME ESTIMATED
FROM RADAR.
&&
BCCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
619 PM CDT THU MAY 6 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0535 PM TSTM WND DMG 1 NNW FLORENCE 34.84N 87.67W
05/06/2021 LAUDERDALE AL BROADCAST MEDIA
SHINGLES OFF A HOUSE NEAR THE INTERSECTION
OF HELTON DR. AND COX CREEK PKWY. TIME
ESTIMATED FROM RADAR.
&&
BCCThe Northeast Alabama radar (KHTX), 48 km away, was scanning. The volume nearest the first event began at 23:27 UTC.
3 thunderstorm wind. Local standard time, as filed.
Portions of a metal roof was peeled off of a home in Park City.
Trees were knocked down near Park City. Time estimated by radar.
Trees were knocked down throughout the city of Winchester. Time estimated by radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Tennessee in 2021Every state in 2021This day in weather historyWarnings in Tennessee, May 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 958310, 958311, 958312.