Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 38, NWS Birmingham, AL

July 19, 2021Jefferson County, Shelby County, Alabama

NWS Birmingham, AL issued this flash flood warning at Jul 19, 2021, 6:27 PM CDT for Jefferson County, Shelby County, Alabama. It was in force for 3 hr. 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 19, 2021, 6:27 PM CDT (23:27 UTC)
Expired: Jul 19, 2021, 9:00 PM CDT
In force: 3 hr
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Flood severity: None

Counties Jefferson County, AL, Shelby County, AL

The radar

The Birmingham radar (KBMX), 37 km from the middle of the area, began a volume at 23:30 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

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 11.5 hours before the alert went out and 243 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: 73 J/kg
Mixed-layer CIN: -76 J/kg
Mixed-layer LCL: 779 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 51 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

583 
WGUS54 KBMX 192327
FFWBMX
ALC073-117-200200-
/O.NEW.KBMX.FF.W.0038.210719T2327Z-210720T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Birmingham AL
627 PM CDT Mon Jul 19 2021

The National Weather Service in Birmingham has issued a

* Flash Flood Warning for...
  Southwestern Jefferson County in central Alabama...
  West Central Shelby County in central Alabama...

* Until 900 PM CDT.

* At 627 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has fallen. Additional rainfall amounts of 1 to 2 inches 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...
  Southwestern Birmingham, Hoover, Alabaster, Bessemer, Pelham, 
  Helena, Hueytown, Indian Springs Village, Lake View, North Johns, 
  Splash Adventure, Ross Bridge, Hoover Metropolitan Stadium, Bluff 
  Park, Patton Creek, Riverchase, Riverchase Galleria, Oak Mountain 
  Amphitheater, Promenade Tannehill and Bent Brook Golf Club.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3338 8723 3340 8723 3340 8725 3342 8725
      3342 8727 3343 8715 3340 8674 3322 8685
      3323 8697 3323 8703 3325 8703 3325 8707
      3328 8707 3329 8709 3329 8713 3330 8713
      3331 8715 3334 8718 3334 8719 3336 8720

FLASH FLOOD...RADAR INDICATED

$$

86/Martin

1 follow-up statement

886 
WGUS74 KBMX 200153
FFSBMX

Flash Flood Statement
National Weather Service Birmingham AL
853 PM CDT Mon Jul 19 2021

ALC073-117-200203-
/O.EXP.KBMX.FF.W.0038.000000T0000Z-210720T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson AL-Shelby AL-
853 PM CDT Mon Jul 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 9 PM CDT THIS EVENING FOR 
SOUTHWESTERN JEFFERSON AND WEST CENTRAL SHELBY COUNTIES...

The heavy rain has ended but light rain will continue for the next 
couple hours. Some minor flooding may persist in low lying areas, 
and a couple creeks remain out of their banks. Please continue to 
heed remaining road closures.

LAT...LON 3338 8723 3340 8723 3340 8725 3342 8725
      3342 8727 3343 8715 3340 8674 3322 8685
      3323 8697 3323 8703 3325 8703 3325 8707
      3328 8707 3329 8709 3329 8713 3330 8713
      3331 8715 3334 8718 3334 8719 3336 8720

$$

32/Davis

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 7:25 PM CDT	Areal Flood Advisory	BMX	Talladega	2 hr
Jul 18, 7:30 PM CDT	Areal Flood Advisory	BMX	Jefferson	2 hr
Jul 18, 9:00 PM CDT	Areal Flood Advisory	BMX	Etowah	3 hr
Jul 19, 5:15 AM CDT	Special Weather Statement	BMX	Sumter	60 min
Jul 19, 6:00 AM CDT	Areal Flood Advisory	BMX	Bibb, Jefferson, Shelby	3 hr
Jul 19, 1:58 PM CDT	Areal Flood Advisory	BMX	Blount	107 min
Jul 19, 4:55 PM CDT	Flash Flood Warning	BMX	Jefferson	4 hr
Jul 19, 5:56 PM CDT	Areal Flood Advisory	BMX	St. Clair, Shelby, Talladega	2 hr

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.