Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 59, NWS Birmingham, AL

October 5, 2021Shelby County, Alabama

NWS Birmingham, AL issued this flash flood warning at Oct 5, 2021, 6:25 AM CDT for Shelby County, Alabama. It was in force for 2 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: Oct 5, 2021, 6:25 AM CDT (11:25 UTC)
Expired: Oct 5, 2021, 8:31 AM CDT
In force: 2 hr
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Flood severity: None

County Shelby County, AL

The radar

The Birmingham radar (KBMX), 22 km from the middle of the area, began a volume at 11:25 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

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 11.4 hours before the alert went out and 209 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: 126 J/kg
Mixed-layer CIN: -112 J/kg
Mixed-layer LCL: 846 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: -22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

396 
WGUS54 KBMX 051125
FFWBMX
ALC117-051430-
/O.NEW.KBMX.FF.W.0059.211005T1125Z-211005T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Birmingham AL
625 AM CDT Tue Oct 5 2021

The National Weather Service in Birmingham has issued a

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

* Until 930 AM CDT.

* At 625 AM CDT, local law enforcement reported thunderstorms 
  producing heavy rain across the warned area. Between 2 and 2.5 
  inches of rain have fallen. The expected rainfall rate is 1.5 to 2 
  inches in 1 hour. Additional rainfall amounts of 1 to 3 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Law enforcement reported.

  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...
  Hoover, Alabaster, Pelham, Helena, Calera, Chelsea, Montevallo, 
  Columbiana, Wilsonville, Indian Springs Village, Oak Mountain 
  State Park, Oak Mountain Amphitheater, Shelby County Airport, 
  Riverchase, Meadowbrook, Inverness, Highland Lakes, Fowler Lake, 
  Maylene and Mount Laurel.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3350 8658 3316 8651 3310 8685 3327 8697
      3328 8693 3330 8693 3333 8688 3333 8683
      3336 8683 3337 8678 3339 8678 3340 8675
      3342 8675 3342 8672 3343 8672 3343 8670
      3345 8669 3345 8667 3347 8667 3347 8660

FLASH FLOOD...OBSERVED
EXPECTED RAINFALL...1.5-2 INCHES IN 1 HOUR

$$

05

1 follow-up statement

363 
WGUS74 KBMX 051331
FFSBMX

Flash Flood Statement
National Weather Service Birmingham AL
831 AM CDT Tue Oct 5 2021

ALC117-051341-
/O.CAN.KBMX.FF.W.0059.000000T0000Z-211005T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Shelby AL-
831 AM CDT Tue Oct 5 2021

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL SHELBY COUNTY...

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

A Flash Flood Watch remains in effect until 100 AM CDT Thursday for 
a portion of central Alabama.

LAT...LON 3350 8658 3316 8651 3310 8685 3327 8697
      3328 8693 3330 8693 3333 8688 3333 8683
      3336 8683 3337 8678 3339 8678 3340 8675
      3342 8675 3342 8672 3343 8672 3343 8670
      3345 8669 3345 8667 3347 8667 3347 8660

$$

05

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 4, 11:46 PM CDT	Areal Flood Advisory	BMX	Chambers, Lee	3 hr
Oct 5, 12:38 AM CDT	Flash Flood Warning	BMX	Chambers, Lee	3 hr
Oct 5, 3:27 AM CDT	Areal Flood Advisory	BMX	Barbour, Bullock, Lee, Macon, Pike, Russell	3 hr
Oct 5, 5:23 AM CDT	Flash Flood Warning	BMX	Chambers, Lee	5 hr
Oct 5, 5:27 AM CDT	Areal Flood Advisory	BMX	Jefferson, Shelby	3 hr
Oct 5, 7:53 AM CDT	Areal Flood Advisory	BMX	Bibb, Hale, Tuscaloosa	3 hr
Oct 5, 3:49 PM CDT	Areal Flood Advisory	BMX	Marion	116 min
Oct 5, 4:09 PM CDT	Areal Flood Advisory	BMX	Tuscaloosa	3 hr
Oct 5, 5:25 PM CDT	Special Weather Statement	BMX	Lamar	35 min
Oct 5, 6:43 PM CDT	Areal Flood Advisory	BMX	Jefferson, Shelby	6 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.