Alert archive / Alabama / Tornado Warnings in 2021

Tornado Warning 76, NWS Birmingham, AL

May 4, 2021Shelby County, Alabama

NWS Birmingham, AL issued this tornado warning at May 4, 2021, 5:38 PM CDT for Shelby County, Alabama. It was in force for 12 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 4, 2021, 5:38 PM CDT (22:38 UTC)
Expired: May 4, 2021, 5:50 PM CDT
In force: 12 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Shelby County, AL

The radar

The Birmingham radar (KBMX), 5 km from the middle of the area, began a volume at 22:43 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.

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 10.6 hours before the alert went out and 5 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 2158 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 569 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 145 m²/s²
0-3 km storm-relative helicity: 195 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 7.3

Open this sounding in Storm Lab

The text

As transmitted.

635 
WFUS54 KBMX 042238
TORBMX
ALC117-042315-
/O.NEW.KBMX.TO.W.0076.210504T2238Z-210504T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Birmingham AL
538 PM CDT Tue May 4 2021

The National Weather Service in Birmingham has issued a

* Tornado Warning for...
  Southwestern Shelby County in central Alabama...

* Until 615 PM CDT.
    
* At 538 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near University Of Montevallo, or near Montevallo,
  moving east at 35 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Alabaster, Calera, Montevallo, Columbiana, University Of
  Montevallo, Shelby County Airport, American Village, Camp Branch,
  Alabaster Veterans Park, Bounds Lake and Dogwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3309 8695 3315 8696 3327 8664 3313 8657
TIME...MOT...LOC 2238Z 257DEG 31KT 3313 8692 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

17/KLAWS

1 follow-up statement

994 
WWUS54 KBMX 042250
SVSBMX

Severe Weather Statement
National Weather Service Birmingham AL
550 PM CDT Tue May 4 2021

ALC117-042259-
/O.CAN.KBMX.TO.W.0076.000000T0000Z-210504T2315Z/
Shelby AL-
550 PM CDT Tue May 4 2021

...THE TORNADO WARNING FOR SOUTHWESTERN SHELBY COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has weakened 
Therefore, the warning has been cancelled.  However gusty winds are 
still possible with this thunderstorm.

A Tornado Watch remains in effect until 1000 PM CDT for central
Alabama.

LAT...LON 3309 8695 3315 8696 3327 8664 3313 8657
TIME...MOT...LOC 2248Z 257DEG 31KT 3315 8680 

$$

17/KLAWS

The office that day

Everything else NWS Birmingham, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
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, 7:29 PM CDT	Areal Flood Advisory	BMX	Chambers, Lee, Macon, Tallapoosa	2 hr
May 3, 7:40 PM CDT	Severe Thunderstorm Warning	BMX	Elmore, Macon, Montgomery	47 min
May 3, 7:46 PM CDT	Special Weather Statement	BMX	Chilton	44 min
May 3, 8:30 PM CDT	Special Weather Statement	BMX	Lee, Macon	45 min
May 3, 8:36 PM CDT	Special Weather Statement	BMX	Chilton	39 min
May 3, 8:51 PM CDT	Areal Flood Advisory	BMX	Bibb, Chilton, Perry	3 hr
May 3, 8:59 PM CDT	Special Weather Statement	BMX	Russell	46 min
May 3, 9:31 PM CDT	Special Weather Statement	BMX	Shelby	59 min
May 4, 7:27 AM CDT	Special Weather Statement	BMX	Marion	48 min
May 4, 7:57 AM CDT	Special Weather Statement	BMX	Lamar, Marion	48 min
May 4, 9:07 AM CDT	Severe Thunderstorm Warning	BMX	Winston	38 min
May 4, 10:26 AM CDT	Severe Thunderstorm Warning	BMX	Blount	23 min
May 4, 10:59 AM CDT	Special Weather Statement	BMX	Walker	31 min
May 4, 11:00 AM CDT	Areal Flood Advisory	BMX	Fayette, Lamar, Walker	3 hr
May 4, 11:06 AM CDT	Areal Flood Advisory	BMX	Blount, Calhoun, Cherokee, Etowah, St. Clair	3 hr
May 4, 11:12 AM CDT	Tornado Warning	BMX	Fayette, Tuscaloosa	21 min
May 4, 11:25 AM CDT	Severe Thunderstorm Warning	BMX	Jefferson, Walker	50 min
May 4, 11:45 AM CDT	Areal Flood Advisory	BMX	Jefferson	2 hr
May 4, 11:49 AM CDT	Severe Thunderstorm Warning	BMX	Blount, Jefferson, St. Clair	26 min
May 4, 12:03 PM CDT	Flash Flood Warning	BMX	Blount, Etowah, St. Clair	117 min
May 4, 12:10 PM CDT	Flash Flood Warning	BMX	Jefferson	7 hr
May 4, 12:14 PM CDT	Severe Thunderstorm Warning	BMX	Calhoun, St. Clair, Talladega	46 min
May 4, 12:17 PM CDT	Severe Thunderstorm Warning	BMX	Jefferson, St. Clair, Shelby	28 min
May 4, 12:35 PM CDT	Flash Flood Warning	BMX	Calhoun, Etowah, St. Clair, Talladega	3 hr
May 4, 12:56 PM CDT	Severe Thunderstorm Warning	BMX	Calhoun, Cherokee, Cleburne, Talladega	64 min
May 4, 1:15 PM CDT	Severe Thunderstorm Warning	BMX	Jefferson, Shelby	30 min
May 4, 1:25 PM CDT	Tornado Warning	BMX	Cleburne	24 min
May 4, 1:39 PM CDT	Flash Flood Warning	BMX	Jefferson, St. Clair, Shelby	5 hr
May 4, 2:07 PM CDT	Areal Flood Warning	BMX	Blount, Calhoun, Cherokee, Etowah, St. Clair	6 hr
May 4, 2:54 PM CDT	Areal Flood Advisory	BMX	Clay, Cleburne, Randolph, Shelby, Talladega	3 hr
May 4, 3:50 PM CDT	Severe Thunderstorm Warning	BMX	Sumter	55 min
May 4, 4:01 PM CDT	Flash Flood Warning	BMX	Shelby, Talladega	3 hr
May 4, 4:05 PM CDT	Flash Flood Warning	BMX	Bibb, Tuscaloosa	3 hr
May 4, 4:13 PM CDT	Severe Thunderstorm Warning	BMX	Tuscaloosa	29 min
May 4, 4:20 PM CDT	Severe Thunderstorm Warning	BMX	Greene	55 min
May 4, 4:30 PM CDT	Severe Thunderstorm Warning	BMX	Hale, Marengo	63 min
May 4, 4:45 PM CDT	Special Weather Statement	BMX	Walker, Winston	30 min
May 4, 5:00 PM CDT	Severe Thunderstorm Warning	BMX	Bibb, Chilton, Dallas, Perry	75 min
May 4, 5:17 PM CDT	Flash Flood Warning EmergencyCatastrophic damage threat	BMX	Jefferson, Shelby	3 hr
May 4, 5:29 PM CDT	Severe Thunderstorm Warning	BMX	Autauga, Chilton, Lowndes	76 min
May 4, 5:30 PM CDT	Tornado Warning	BMX	Chilton, Perry	30 min
May 4, 5:54 PM CDT	Severe Thunderstorm Warning	BMX	Coosa	50 min
May 4, 5:59 PM CDT	Severe Thunderstorm Warning	BMX	Elmore	61 min
May 4, 6:07 PM CDT	Severe Thunderstorm Warning	BMX	Montgomery	68 min
May 4, 6:19 PM CDT	Severe Thunderstorm Warning	BMX	Tallapoosa	56 min
May 4, 6:24 PM CDT	Tornado Warning	BMX	Elmore, Montgomery	13 min
May 4, 6:37 PM CDT	Severe Thunderstorm Warning	BMX	Bullock, Macon, Pike	83 min
May 4, 6:41 PM CDT	Severe Thunderstorm Warning	BMX	Chambers, Lee	61 min
May 4, 6:48 PM CDT	River Flood Warning	BMX	Bibb, Jefferson, Shelby	22 hr

Nearby

Tornado Warnings in Alabama, 2021 Every tornado warning in 2021 Tornadoes 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.