Alert archive / Alabama / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 132, NWS Birmingham, AL

June 21, 2020Calhoun County, Etowah County, St. Clair County, Alabama

NWS Birmingham, AL issued this severe thunderstorm warning at Jun 21, 2020, 1:28 PM CDT for Calhoun County, Etowah County, St. Clair County, Alabama. It was in force for 17 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jun 21, 2020, 1:28 PM CDT (18:28 UTC)
Expired: Jun 21, 2020, 1:45 PM CDT
In force: 17 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Calhoun County, AL, Etowah County, AL, St. Clair County, AL

The radar

The Birmingham radar (KBMX), 100 km from the middle of the area, began a volume at 18:47 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, 6.5 hours before the alert went out and 100 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: 394 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 1353 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Birmingham, AL wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 21, 1:00 PM CDT, 28 minutes earlier.

Area forecast discussion, Jun 21, 1:00 PM CDT, 28 minutes before

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Hazardous weather outlook, Jun 21, 3:38 AM CDT, 9 hours 50 minutes before

Hazardous Weather Outlook
National Weather Service Birmingham AL
338 AM CDT Sun Jun 21 2020

ALZ011>015-017>050-221145-
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-Cherokee-
Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-Talladega-
Clay-Randolph-Sumter-Greene-Hale-Perry-Bibb-Chilton-Coosa-Tallapoosa-
Chambers-Marengo-Dallas-Autauga-Lowndes-Elmore-Montgomery-Macon-
Bullock-Lee-Russell-Pike-Barbour-
338 AM CDT Sun Jun 21 2020

This Hazardous Weather Outlook is for the counties served by the
National Weather Service office in Birmingham.

.DAY ONE...Outlook through Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management is not
expected at this time.

In the hours before

Special weather statement, Jun 21, 12:34 PM CDT, 54 minutes before

Special Weather Statement
National Weather Service Birmingham AL
1234 PM CDT Sun Jun 21 2020

ALZ014-211800-
Winston AL-
1234 PM CDT Sun Jun 21 2020

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN WINSTON COUNTY UNTIL 100
PM CDT...

At 1234 PM CDT, Doppler radar was tracking a strong thunderstorm near
Corinth Rec Area, or near Arley, moving northeast at 25 mph.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Arley, Addison, Nesmith, Helicon, Inmanfield, Sardis, Corinth Rec
Area, Falls City, Smith Lake, Houston, Mill Branch, Hullett Branch,
Winston County Airport, Cane Creek, Bull Branch, Yellow Creek,
Rockhouse Creek, Addison Town Hall, Panther Branch and Upshaw.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3410 8711 3403 8727 3418 8739 3430 8723
      3430 8711
TIME...MOT...LOC 1734Z 235DEG 24KT 3415 8726

05

Special weather statement, Jun 21, 12:49 PM CDT, 39 minutes before

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Special weather statement, Jun 21, 1:12 PM CDT, 16 minutes before

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Special weather statement, Jun 21, 1:13 PM CDT, 15 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 12:34 PM CDT	Special Weather Statement	BMX	Winston	26 min
Jun 21, 12:49 PM CDT	Special Weather Statement	BMX	St. Clair	26 min
Jun 21, 1:12 PM CDT	Special Weather Statement	BMX	Calhoun, St. Clair	48 min
Jun 21, 1:13 PM CDT	Special Weather Statement	BMX	Walker	32 min
Jun 21, 1:34 PM CDT	Special Weather Statement	BMX	Walker	26 min
Jun 21, 1:58 PM CDT	Special Weather Statement	BMX	Calhoun	47 min
Jun 21, 2:06 PM CDT	Special Weather Statement	BMX	Blount	39 min
Jun 21, 2:28 PM CDT	Special Weather Statement	BMX	Blount	47 min
Jun 21, 2:31 PM CDT	Special Weather Statement	BMX	Jefferson	44 min
Jun 21, 2:39 PM CDT	Special Weather Statement	BMX	Cleburne, Talladega	51 min
Jun 21, 2:54 PM CDT	Special Weather Statement	BMX	St. Clair	51 min
Jun 21, 2:56 PM CDT	Special Weather Statement	BMX	Clay	34 min
Jun 21, 3:14 PM CDT	Special Weather Statement	BMX	Randolph	46 min
Jun 21, 3:18 PM CDT	Special Weather Statement	BMX	Pickens	27 min
Jun 21, 3:29 PM CDT	Special Weather Statement	BMX	Walker	31 min
Jun 21, 4:02 PM CDT	Special Weather Statement	BMX	Walker	43 min
Jun 21, 4:19 PM CDT	Severe Thunderstorm Warning	BMX	Walker	28 min
Jun 21, 4:26 PM CDT	Special Weather Statement	BMX	Tallapoosa	34 min
Jun 21, 4:31 PM CDT	Severe Thunderstorm Warning	BMX	Tallapoosa	44 min
Jun 21, 4:39 PM CDT	Special Weather Statement	BMX	Jefferson	51 min
Jun 21, 4:56 PM CDT	Special Weather Statement	BMX	Chambers	49 min
Jun 21, 5:22 PM CDT	Special Weather Statement	BMX	Lee	38 min
Jun 21, 6:10 PM CDT	Special Weather Statement	BMX	Talladega	35 min
Jun 21, 6:45 PM CDT	Special Weather Statement	BMX	Talladega	45 min

Nearby

Severe Thunderstorm Warnings in Alabama, 2020 Every severe thunderstorm warning in 2020

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.