Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 40, NWS Birmingham, AL

July 22, 2021Jefferson County, Alabama

NWS Birmingham, AL issued this flash flood warning at Jul 22, 2021, 5:21 PM CDT for Jefferson County, Alabama. It was in force for 62 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: Jul 22, 2021, 5:21 PM CDT (22:21 UTC)
Expired: Jul 22, 2021, 6:23 PM CDT
In force: 62 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Flood severity: None

County Jefferson County, AL

The radar

The Birmingham radar (KBMX), 37 km from the middle of the area, began a volume at 22:25 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, 10.4 hours before the alert went out and 36 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: 824 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 776 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 27 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

108 
WGUS54 KBMX 222221
FFWBMX
ALC073-230045-
/O.NEW.KBMX.FF.W.0040.210722T2221Z-210723T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Birmingham AL
521 PM CDT Thu Jul 22 2021

The National Weather Service in Birmingham has issued a

* Flash Flood Warning for...
  East Central Jefferson County in central Alabama...

* Until 745 PM CDT.

* At 521 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts up to 1 inch are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Birmingham, Homewood, Mountain Brook, Irondale, Fairfield, U.A.B. 
  Campus, Five Points South, Regions Field, B.j.c.c., Legion Field, 
  Kingston, Birmingham Southern College, Birmingham Fairgounds, 
  Vulcan Park, Highland Park Golf Course, Birmingham Zoo and 
  Rickwood Field.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3355 8683 3355 8677 3352 8670 3348 8673
      3347 8677 3347 8683 3347 8689 3348 8691

FLASH FLOOD...RADAR INDICATED

$$

40/Sizemore

1 follow-up statement

933 
WGUS74 KBMX 222323
FFSBMX

Flash Flood Statement
National Weather Service Birmingham AL
623 PM CDT Thu Jul 22 2021

ALC073-222333-
/O.CAN.KBMX.FF.W.0040.000000T0000Z-210723T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson AL-
623 PM CDT Thu Jul 22 2021

...FLASH FLOOD WARNING IS CANCELLED FOR EAST CENTRAL JEFFERSON 
COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose an 
immediate threat. Please continue to heed remaining road closures.

LAT...LON 3355 8683 3355 8677 3352 8670 3348 8673
      3347 8677 3347 8683 3347 8689 3348 8691

$$

40/Sizemore

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 4:42 PM CDT	Areal Flood Advisory	BMX	Jefferson	39 min
Jul 22, 6:06 PM CDT	Special Weather Statement	BMX	Chilton	24 min
Jul 22, 6:22 PM CDT	Areal Flood Advisory	BMX	Tuscaloosa	113 min
Jul 22, 6:48 PM CDT	Special Weather Statement	BMX	Marengo	27 min

Nearby

Flash Flood Warnings in Alabama, 2021 Every flash flood 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.