Alert archive / Alabama / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 67
The Storm Prediction Center issued this severe thunderstorm watch at Mar 28, 2021, 5:10 AM CDT for 18 counties in Alabama; 17 counties in Georgia. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 28, 2021, 5:10 AM CDT (10:10 UTC)
- Expired
- Mar 28, 2021, 10:00 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 55 kt
All 35 counties
Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Clay County, AL, Cleburne County, AL, Etowah County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Pickens County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Dade County, GA, Dawson County, GA, Fannin County, GA, Floyd County, GA, Gilmer County, GA, Gordon County, GA, Lumpkin County, GA, Murray County, GA, Pickens County, GA, Polk County, GA, Union County, GA, Walker County, GA, Whitfield County, GA
The radar
The Northeast Alabama radar (KHTX), 96 km from the middle of the area, began a volume at 10:11 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 50%
Warnings issued inside it
8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 28, 6:13 AM CDT | Severe Thunderstorm Warning | BMX | Blount, Jefferson, Walker | 62 min |
| Mar 28, 6:50 AM CDT | Severe Thunderstorm Warning | FFC | Chattooga, Floyd, Walker | 25 min |
| Mar 28, 7:13 AM CDT | Severe Thunderstorm Warning | BMX | Jefferson, St. Clair, Shelby | 32 min |
| Mar 28, 7:37 AM CDT | Severe Thunderstorm Warning | BMX | Calhoun, St. Clair, Talladega | 38 min |
| Mar 28, 7:50 AM CDT | Severe Thunderstorm Warning | BMX | Shelby | 40 min |
| Mar 28, 8:05 AM CDT | Severe Thunderstorm Warning | FFC | Bartow, Floyd, Gordon | 40 min |
| Mar 28, 8:14 AM CDT | Severe Thunderstorm Warning | FFC | Bartow, Floyd, Polk | 31 min |
| Mar 28, 8:17 AM CDT | Severe Thunderstorm Warning | FFC | Fannin, Gilmer, Lumpkin, Towns, Union | 28 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Birmingham, AL (KBMX), launched 00:00Z, 10.2 hours before the alert went out and 112 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 643 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 1359 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 126 m²/s²
- 0-3 km storm-relative helicity
- 152 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 3.7
The text
As transmitted.
739 WWUS20 KWNS 281007 SEL7 SPC WW 281007 ALZ000-GAZ000-281500- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 67 NWS Storm Prediction Center Norman OK 610 AM EDT Sun Mar 28 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of North-central/Northeast Alabama Northern Georgia * Effective this Sunday morning from 610 AM until 1100 AM EDT. * Primary threats include... Isolated damaging wind gusts to 65 mph possible A tornado or two possible SUMMARY...A broken cluster of storms will continue eastward through the pre-dawn/early morning hours across north-central/northeast Alabama into northwest/far northern Georgia. Isolated damaging winds are the primary concern, but a brief tornado embedded within the convective line cannot be ruled out. The severe thunderstorm watch area is approximately along and 30 statute miles north and south of a line from 20 miles north northwest of Tuscaloosa AL to 75 miles east northeast of Rome GA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 65...WW 66... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 24030. ...Guyer
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 27, 10:45 PM CDT | Mesoscale Discussion | SPC | Colbert, Franklin, Lauderdale, Lawrence, Limestone, Madison and 3 more | 90 min |
| Mar 27, 11:27 PM CDT | Tornado Watch | SPC | Blount, Colbert, Cullman, DeKalb, Fayette, Franklin and 11 more | 8 hr |
| Mar 28, 1:25 AM CDT | Mesoscale Discussion | SPC | Jackson | 2 hr |
| Mar 28, 1:57 AM CDT | Mesoscale Discussion | SPC | Blount, Colbert, Cullman, DeKalb, Etowah, Fayette and 11 more | 93 min |
| Mar 28, 4:56 AM CDT | Mesoscale Discussion | SPC | Blount, Cullman, DeKalb, Etowah, Marshall, Walker | 94 min |
| Mar 28, 7:29 AM CDT | Mesoscale Discussion | SPC | Calhoun, Cleburne, Talladega | 91 min |
| Mar 28, 9:14 AM CDT | Mesoscale Discussion | SPC | Autauga, Chambers, Chilton, Clay, Coosa, Dallas and 6 more | 61 min |
| Mar 28, 11:38 AM CDT | Mesoscale Discussion | SPC | Baldwin, Bibb, Bleckley, Burke, Butts, Columbia and 34 more | 3 hr |
| Mar 28, 4:51 PM CDT | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 46 more | 54 min |
| Mar 28, 2:07 AM CDT | Severe Thunderstorm Watch | SPC | Cherokee, Clay, Graham, Macon, Swain | 6 hr |
| Mar 28, 2:24 PM CDT | Severe Thunderstorm Watch | SPC | Beaufort, Bertie, Camden, Chowan, Craven, Cumberland and 26 more | 4 hr |
| Mar 28, 3:53 PM CDT | Mesoscale Discussion | SPC | Beaufort, Bertie, Camden, Chowan, Craven, Currituck and 13 more | 67 min |
Nearby
Severe Thunderstorm Watches in Alabama, 2021Severe Thunderstorm Watches in Georgia, 2021Every severe thunderstorm watch in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.