A complex of thunderstorms dropped southeast from Tennessee. Outflow from these thunderstorms produced new strong to severe thunderstorms over north Alabama during the mid to late morning hours.
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 complex of thunderstorms dropped southeast from Tennessee. Outflow from these thunderstorms produced new strong to severe thunderstorms over north Alabama during the mid to late morning hours. There were several reports of wind damage, including a measured wind gust of 58 mph at the Huntsville International Airport. An EF-0 tornado produced a short track of damage in Higdon. Rainfall of 1 to 3 inches fell in a very short period of time producing brief flash flooding as well on the north side of the Quad Cities.
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 4, 4:59 AM CST, 1 hour 5 minutes earlier.
Area Forecast Discussion National Weather Service Huntsville AL 559 AM CDT Tue May 4 2021 .UPDATE... For 12Z TAFS. && .NEAR TERM...(Today) Issued at 232 AM CDT Tue May 4 2021 This morning, an ongoing storm complex in Arkansas is pushing into Tennessee, as of this writing at 2 AM. Additionally, a secondary MCS tracking through southwestern AR into TX is starting to merge with the more severe line to the northeast. As a result, we expect a large MCS to track trough the MS Valley into the Southeast this morning. Timing the current line of storms has it approaching NW Alabama around 5 AM, but southwesterly forward-propagating Corfidi vectors and mean flow increase heading into the morning hours, so we expect the most severe portion of the line to track northeast of the TN Valley. A severe thunderstorm watch has been issued to our northwest, and we do not expect expansion into our area. While we cannot rule out a stray strong to severe storm this morning with this line, forecast soundings indicate a capping inversion just above the surface, keeping this line of storms elevated. A capping inversion was observed in the 06z OHX sounding, and this is not expected to erode this morning ahead of this first line of storms. Behind this storm complex, a surface low pressure system and attendant cold front approach the TN Valley from the Southern Plains. We expect daytime heating to allow for surface-based convection in the late morning, and ample instability for convection to capitalize on. While there is still the potential for severe storms this afternoon, an additional scenario is coming into play, which keeps most severe convection at least south of the TN river, if not south of the TN Valley altogether. The second line of storms this afternoon and evening is mostly likely to be severe along and south of where the morning line of storms decays and sets up a differential heating boundary. With deterministic and ensemble guidance supporting a more southerly track of the surface low, there is decreasing confidence that the severe potential with the second line of storms will extend northward into the TN Valley. This afternoon is a time to be vigilant with mesoscale analysis to determine whether we will see mostly rain with a few thunderstorms, or a severe line of storms capable of widespread damaging winds, hail, and tornadoes. Heavy rainfall will be a threat, regardless, and localized flash flooding will be possible with multiple rounds of showers and storms. .SHORT TERM...(Tonight through Thursday) Issued at 232 AM CDT Tue May 4 2021 As the second line of storms pushes east of the TN Valley this evening, lingering rainfall will be possible overnight. Additional shower development is possible ahead of the approaching cold front, but these are not expected to bloom into thunderstorms, much less strong to severe convection. Increasing cold air advection will drop overnight temperatures tonight near daily averages in the mid to upper 50s. Surface high pressure over the Mid-Mississippi Valley and zonal flow aloft will create a pleasant forecast for mid week, with highs in the low 70s and mostly clear skies. .LONG TERM...(Thursday night through Monday) Issued at 232 AM CDT Tue May 4 2021 On Thursday night, a shortwave trough will push through the Ohio Valley and sweep a weak cold front through the region. While isolated showers are possible in TN, this is unlikely, so stayed with a dry forecast for late this week. Reinforcing weak CAA will keep highs on Friday in the upper 60s to low 70s, but then warm into the upper 70s on Saturday. As this shortwave trough lifts into the Northeast, zonal flow is reestablished. Several impulses traverse the zonal flow late this weekend into early next week, bringing additional chances for multiple rounds of showers and storms. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 600 AM CDT Tue May 4 2021 Scattered to numerous showers and storms will overspread the region with MVFR decks this morning ahead of an approaching line of storms. Occasional gusts up to 30-40 kts are possible, and some of these storms may be severe with hail, damaging winds, and heavy rainfall. After a brief break late this morning into the early afternoon, a second round of strong to severe storms will be possible. Today is a day where many amendments and convective airport weather warnings will be issued. Expect IFR or LIFR conditions in any thunderstorms. Behind the second line of storms, IFR ceilings may develop late tonight into early tomorrow morning. Showers may linger overnight, but confidence was too low to include at this time. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && NEAR TERM...30 SHORT TERM...30 LONG TERM...30 AVIATION...30 For more information please visit our website at weather.gov/huntsville.
Hazardous Weather Outlook National Weather Service Huntsville AL 341 AM CDT Tue May 4 2021 ALZ001>010-016-TNZ076-096-097-050000- Lauderdale-Colbert-Franklin AL-Lawrence-Limestone-Madison-Morgan- Marshall-Jackson-DeKalb-Cullman-Moore-Lincoln-Franklin TN- 341 AM CDT Tue May 4 2021 This Hazardous Weather Outlook is for north central Alabama, northeast Alabama, northwest Alabama and southern middle Tennessee. .DAY ONE...Today. Two rounds of thunderstorms are expected today. The first will occur this morning, with gusty winds and small hail the most likely hazards. A severe thunderstorm with damaging wind or large hail remains possible. A greater risk of strong to severe thunderstorms exists this afternoon into the evening hours. Large hail, damaging winds, and heavy rainfall will be the greatest threats. A tornado or two is also possible. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. The probability for widespread hazardous weather is low. A few thunderstorms are possible Sunday into Monday. .SPOTTER INFORMATION STATEMENT... Activation of storm spotters and emergency management personnel is possible, especially this afternoon and evening. Please relay any information about observed severe weather to the NWS while following all local, state, and CDC guidelines.
The Birmingham radar (KBMX), 100 km away, was scanning. The volume nearest the first event began at 12:02 UTC.
14 thunderstorm wind, 3 flash flood, 1 tornado. Local standard time, as filed.
A tree was knocked down at the intersection of CR 291 and CR 292.
Up to 5 power poles were knocked down along with trees at this location.
A tree was knocked down at 2045 CR 222.
Measured at the Huntsville International Airport.
Up to eight trees were knocked down in the county from southwest to northeast.
A tree was knocked down on Sparkman Road near First Baptist Church in Hartselle.
A tree was knocked down. Time estimated by radar.
Trees were knocked down across Highway 79 at CR 21 south of Skyline.
Trees and power lines were knocked down at CR 107 at CR 241. Time estimated by radar.
Up to eight trees were knocked down in the county from southwest to northeast.
A tree was knocked down on CR 318. Time estimated by radar.
A tree was uprooted damaging a fence and shed. Social media report through broadcast media. Time estimated by radar.
A tree was knocked down in Flat Rock.
The Jackson County Emergency Management Agency surveyed a short tornado track in Higdon. The tornado touched down briefly west of County Road 320. A few trees were uprooted as the tornado moved east-southeast along County Road 320. A house on this road also sustained minor roof damage and a carport was destroyed. The tornado lifted just west of Highway 71.
Trees and power lines were knocked down blocking a roadway.
Flash flooding on Columbus Street in Albertville. At least 6 inches of water over the roadway. Report relayed via social media.
Intersection of Highway 75 and Highway 35 in Rainsville has between 1 and 1.5 feet of water covering the roadway.
Portions of 6 city streets were under water, with around 3 feet of water over the roads at one point.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alabama in 2021Every state in 2021This day in weather historyThe tornado archive for Alabama, 2021Warnings in Alabama, 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: 958365, 958366, 958367, 958368, 958378, 958369, 958371, 958372, 958373, 958379, 958374, 958375, 958376, 958561, 958377, 959723, 959724, 959725.