Alert archive / Alabama / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 152, NWS Birmingham, AL

October 4, 2021Bibb County, Shelby County, Alabama

NWS Birmingham, AL issued this severe thunderstorm warning at Oct 4, 2021, 5:47 PM CDT for Bibb County, Shelby County, Alabama. It was in force for 43 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: Oct 4, 2021, 5:47 PM CDT (22:47 UTC)
Expired: Oct 4, 2021, 6:30 PM CDT
In force: 43 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Bibb County, AL, Shelby County, AL

The radar

The Birmingham radar (KBMX), 19 km from the middle of the area, began a volume at 22:50 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.

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 10.8 hours before the alert went out and 17 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: 565 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 616 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 69 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

514 
WUUS54 KBMX 042247
SVRBMX
ALC007-117-042330-
/O.NEW.KBMX.SV.W.0152.211004T2247Z-211004T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Birmingham AL
547 PM CDT Mon Oct 4 2021

The National Weather Service in Birmingham has issued a

* Severe Thunderstorm Warning for...
  Southwestern Shelby County in central Alabama...
  Northeastern Bibb County in central Alabama...

* Until 630 PM CDT.

* At 547 PM CDT, a severe thunderstorm was located near Ashby, or 8
  miles northeast of Centreville, moving northeast at 20 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Alabaster, Helena, Ashby and Marvel. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3325 8703 3325 8698 3327 8697 3327 8695
      3328 8693 3330 8693 3331 8690 3333 8689
      3333 8687 3324 8686 3301 8692 3304 8712
TIME...MOT...LOC 2247Z 211DEG 17KT 3305 8701 

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

$$

75 Linhares

1 follow-up statement

049 
WWUS54 KBMX 042320
SVSBMX

Severe Weather Statement
National Weather Service Birmingham AL
620 PM CDT Mon Oct 4 2021

ALC007-117-042330-
/O.EXP.KBMX.SV.W.0152.000000T0000Z-211004T2330Z/
Shelby AL-Bibb AL-
620 PM CDT Mon Oct 4 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN SHELBY AND
NORTHEASTERN BIBB COUNTIES WILL EXPIRE AT 630 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 3325 8703 3325 8698 3327 8697 3327 8695
      3328 8693 3330 8693 3331 8690 3333 8689
      3333 8687 3324 8686 3301 8692 3304 8712
TIME...MOT...LOC 2320Z 211DEG 17KT 3318 8692 

$$

25/Owen

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 3, 8:04 PM CDT	Areal Flood Advisory	BMX	Fayette, Walker	116 min
Oct 3, 9:05 PM CDT	Flash Flood Warning	BMX	Fayette, Jefferson, Marion, Walker	3 hr
Oct 3, 10:59 PM CDT	Areal Flood Advisory	BMX	Jefferson	3 hr
Oct 4, 12:53 AM CDT	Areal Flood Advisory	BMX	Jefferson, St. Clair, Shelby	3 hr
Oct 4, 1:23 AM CDT	Dense Fog Advisory	BMX	Blount, Fayette, Lamar, Marion, Pickens, Tuscaloosa and 2 more	8 hr
Oct 4, 3:11 AM CDT	Flash Flood Watch	BMX	Autauga, Barbour, Bibb, Blount, Bullock, Calhoun and 30 more	3 days
Oct 4, 9:37 AM CDT	Areal Flood Advisory	BMX	Lee	3 hr
Oct 4, 11:51 AM CDT	Areal Flood Advisory	BMX	Russell	3 hr
Oct 4, 12:20 PM CDT	Flash Flood Warning	BMX	Lee, Russell	3 hr
Oct 4, 12:44 PM CDT	Areal Flood Advisory	BMX	Lowndes, Montgomery	3 hr
Oct 4, 1:33 PM CDT	Flash Flood Warning	BMX	Montgomery	87 min
Oct 4, 3:12 PM CDT	Special Weather Statement	BMX	Coosa	33 min
Oct 4, 3:21 PM CDT	Flash Flood Warning	BMX	Lee, Russell	3 hr
Oct 4, 3:28 PM CDT	Flash Flood Warning	BMX	Lowndes, Montgomery	3 hr
Oct 4, 4:40 PM CDT	Areal Flood Advisory	BMX	Chilton, Coosa	3 hr
Oct 4, 4:56 PM CDT	Flash Flood Warning	BMX	Chilton	3 hr
Oct 4, 5:09 PM CDT	Special Weather Statement	BMX	Bibb	36 min
Oct 4, 5:09 PM CDT	Special Weather Statement	BMX	Shelby	36 min
Oct 4, 5:16 PM CDT	Severe Thunderstorm Warning	BMX	Bibb	29 min
Oct 4, 5:22 PM CDT	Special Weather Statement	BMX	Shelby	23 min
Oct 4, 5:43 PM CDT	Severe Thunderstorm Warning	BMX	Shelby	47 min
Oct 4, 6:02 PM CDT	Special Weather Statement	BMX	Shelby	28 min
Oct 4, 6:17 PM CDT	Special Weather Statement	BMX	Jefferson	28 min
Oct 4, 6:34 PM CDT	Special Weather Statement	BMX	Jefferson	26 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.