Alert archive / Alabama / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 128
The Storm Prediction Center issued this severe thunderstorm watch at May 3, 2021, 11:47 AM CDT for 52 counties in Alabama; 19 counties in Mississippi. It was in force for 10 hr.
The area
The outline as issued.
The facts
- Issued
- May 3, 2021, 11:47 AM CDT (16:47 UTC)
- Expired
- May 3, 2021, 10:00 PM CDT
- In force
- 10 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 55 kt
All 71 counties
Autauga County, AL, Barbour County, AL, Bibb County, AL, Blount County, AL, Bullock County, AL, Butler County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Cleburne County, AL, Coffee County, AL, Conecuh County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Etowah County, AL, Fayette County, AL, Geneva County, AL, Greene County, AL, Hale County, AL, Henry County, AL, Houston County, AL, Jefferson County, AL, Lamar County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Attala County, MS, Choctaw County, MS, Clarke County, MS, Clay County, MS, Jasper County, MS, Kemper County, MS, Lauderdale County, MS, Leake County, MS, Lowndes County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Scott County, MS, Smith County, MS, Wayne County, MS, Webster County, MS, Winston County, MS
The radar
The Birmingham radar (KBMX), 42 km from the middle of the area, began a volume at 16:50 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
- 10%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 3, 1:42 PM CDT | Severe Thunderstorm Warning | TAE | Coffee | 63 min |
| May 3, 1:47 PM CDT | Severe Thunderstorm Warning | JAN | Lowndes | 28 min |
| May 3, 1:57 PM CDT | Tornado Warning | MOB | Covington, Crenshaw | 48 min |
| May 3, 2:00 PM CDT | Severe Thunderstorm Warning | JAN | Lowndes | 45 min |
| May 3, 2:24 PM CDT | Severe Thunderstorm Warning | BMX | Pickens | 66 min |
| May 3, 6:26 PM CDT | Severe Thunderstorm Warning | BMX | Autauga, Elmore, Montgomery | 49 min |
| May 3, 6:34 PM CDT | Severe Thunderstorm Warning | BMX | Chambers, Lee | 41 min |
| May 3, 7:02 PM CDT | Severe Thunderstorm Warning | BMX | Elmore, Montgomery | 43 min |
| May 3, 7:13 PM CDT | Severe Thunderstorm Warning | BMX | Bibb, Chilton, Perry | 32 min |
| May 3, 7:25 PM CDT | Flash Flood Warning | BMX | Autauga, Elmore, Macon, Montgomery | 5 hr |
| May 3, 7:40 PM CDT | Severe Thunderstorm Warning | BMX | Elmore, Macon, Montgomery | 47 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 12:00Z, 4.8 hours before the alert went out and 43 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
- 1106 J/kg
- Mixed-layer CIN
- -20 J/kg
- Mixed-layer LCL
- 552 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 313 m²/s²
- 0-3 km storm-relative helicity
- 363 m²/s²
- Significant tornado parameter
- 1.7
- Supercell composite
- 11.4
The text
As transmitted.
794 WWUS20 KWNS 031646 SEL8 SPC WW 031646 ALZ000-MSZ000-040100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 128 NWS Storm Prediction Center Norman OK 1150 AM CDT Mon May 3 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Alabama Eastern Mississippi * Effective this Monday morning and evening from 1150 AM until 800 PM CDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Scattered thunderstorms are expected to be focused in two corridors of confluence across east-central to central Alabama and farther south in southern Alabama. Damaging winds and large hail are the primary threats. The severe thunderstorm watch area is approximately along and 105 statute miles east and west of a line from 50 miles northwest of Birmingham AL to 40 miles south southeast of Evergreen AL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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 127... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27025. ...Grams
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 2, 11:45 PM CDT | Mesoscale Discussion | SPC | Colbert, Franklin, Marion | 2 hr |
| May 3, 9:29 AM CDT | Tornado Watch | SPC | Bullock, Chambers, Clay, Cleburne, Coosa, Elmore and 6 more | 5 hr |
| May 3, 10:38 AM CDT | Mesoscale Discussion | SPC | Butler, Clarke, Conecuh, Covington, Crenshaw, Dallas and 7 more | 97 min |
| May 3, 4:00 PM CDT | Mesoscale Discussion | SPC | Autauga, Barbour, Bibb, Bullock, Butler, Calhoun and 38 more | 90 min |
| May 3, 1:56 AM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, DeSoto, Marshall, Tippah | 3 hr |
Nearby
Severe Thunderstorm Watches in Alabama, 2021Severe Thunderstorm Watches in Mississippi, 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.