Alert archive / Alabama / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 141, NWS Birmingham, AL

August 11, 2021St. Clair County, Alabama

NWS Birmingham, AL issued this severe thunderstorm warning at Aug 11, 2021, 1:05 PM CDT for St. Clair County, Alabama. It was in force for 25 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: Aug 11, 2021, 1:05 PM CDT (18:05 UTC)
Expired: Aug 11, 2021, 1:30 PM CDT
In force: 25 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County St. Clair County, AL

The radar

The Birmingham radar (KBMX), 61 km from the middle of the area, began a volume at 18:09 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, 6.1 hours before the alert went out and 61 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: 1557 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 940 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -29 m²/s²
0-3 km storm-relative helicity: -15 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

731 
WUUS54 KBMX 111805
SVRBMX
ALC115-111830-
/O.NEW.KBMX.SV.W.0141.210811T1805Z-210811T1830Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Birmingham AL
105 PM CDT Wed Aug 11 2021

The National Weather Service in Birmingham has issued a

* Severe Thunderstorm Warning for...
  West central St. Clair County in central Alabama...

* Until 130 PM CDT.

* At 104 PM CDT, a severe thunderstorm was located over Bald Rock, or
  near Odenville, moving northeast at 10 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Moody, Springville, Odenville, Margaret, Bald Rock, Branchville,
  Wattsville and Chula Vista.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3355 8641 3361 8650 3374 8642 3367 8624
TIME...MOT...LOC 1804Z 220DEG 9KT 3361 8640 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

61

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 8:17 PM CDT	Special Weather Statement	BMX	Coosa	28 min
Aug 10, 8:44 PM CDT	Special Weather Statement	BMX	Coosa	31 min
Aug 11, 12:10 PM CDT	Areal Flood Advisory	BMX	Jefferson	110 min
Aug 11, 12:40 PM CDT	Special Weather Statement	BMX	Shelby	35 min
Aug 11, 12:53 PM CDT	Special Weather Statement	BMX	St. Clair	37 min
Aug 11, 1:15 PM CDT	Special Weather Statement	BMX	Jefferson	30 min
Aug 11, 1:23 PM CDT	Special Weather Statement	BMX	Shelby	37 min
Aug 11, 1:28 PM CDT	Special Weather Statement	BMX	St. Clair	32 min
Aug 11, 1:46 PM CDT	Special Weather Statement	BMX	Jefferson	29 min
Aug 11, 1:49 PM CDT	Special Weather Statement	BMX	Bibb, Shelby	26 min
Aug 11, 2:05 PM CDT	Special Weather Statement	BMX	Tuscaloosa, Walker	25 min
Aug 11, 2:27 PM CDT	Special Weather Statement	BMX	Tuscaloosa	48 min
Aug 11, 2:34 PM CDT	Special Weather Statement	BMX	Calhoun	26 min
Aug 11, 2:44 PM CDT	Special Weather Statement	BMX	Tallapoosa	31 min
Aug 11, 2:58 PM CDT	Special Weather Statement	BMX	Calhoun	32 min
Aug 11, 3:02 PM CDT	Special Weather Statement	BMX	Fayette	43 min
Aug 11, 3:22 PM CDT	Areal Flood Advisory	BMX	Calhoun	105 min
Aug 11, 3:28 PM CDT	Special Weather Statement	BMX	Cherokee	32 min
Aug 11, 3:41 PM CDT	Special Weather Statement	BMX	Fayette, Lamar, Marion, Pickens, Winston	49 min
Aug 11, 3:52 PM CDT	Special Weather Statement	BMX	DeKalb	23 min
Aug 11, 4:38 PM CDT	Special Weather Statement	BMX	Greene	37 min
Aug 11, 5:19 PM CDT	Areal Flood Advisory	BMX	Greene, Sumter	3 hr
Aug 11, 6:18 PM CDT	Special Weather Statement	BMX	Pike	27 min
Aug 11, 6:25 PM CDT	Severe Thunderstorm Warning	BMX	Pike	20 min
Aug 11, 6:30 PM CDT	Severe Thunderstorm Warning	BMX	Montgomery	30 min

Nearby

Severe Thunderstorm Warnings in Alabama, 2021 Every severe thunderstorm warning 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.