Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 44, NWS Birmingham, AL

August 10, 2021Jefferson County, Alabama

NWS Birmingham, AL issued this flash flood warning at Aug 10, 2021, 3:47 PM CDT for Jefferson County, Alabama. It was in force for 2 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 10, 2021, 3:47 PM CDT (20:47 UTC)
Expired: Aug 10, 2021, 6:16 PM CDT
In force: 2 hr
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Flood severity: None

County Jefferson County, AL

The radar

The Birmingham radar (KBMX), 48 km from the middle of the area, began a volume at 20:48 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.

What was reported inside it

Time	Report	Where	Remark
Aug 10, 4:00 PM CDT	FLASH FLOOD	1 Ese Ketona Lakes, AL	A FEW ROADS WERE FLOODED IN TARRANT AND WERE IMPASSABLE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 8.8 hours before the alert went out and 47 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: 1809 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 908 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: -25 m²/s²
0-3 km storm-relative helicity: -36 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

721 
WGUS54 KBMX 102047
FFWBMX
ALC073-110000-
/O.NEW.KBMX.FF.W.0044.210810T2047Z-210811T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Birmingham AL
347 PM CDT Tue Aug 10 2021

The National Weather Service in Birmingham has issued a

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

* Until 700 PM CDT.

* At 347 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across 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...
  Northeastern Birmingham, Gardendale, Irondale, Fultondale, Center 
  Point, Pinson, Tarrant, Ketona Lakes, Birmingham Airport, 
  Danville, New Castle and Ruffner Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3355 8679 3368 8679 3367 8667 3364 8667
      3353 8671

FLASH FLOOD...RADAR INDICATED

$$

32/Davis

1 follow-up statement

119 
WGUS74 KBMX 102316
FFSBMX

Flash Flood Statement
National Weather Service Birmingham AL
616 PM CDT Tue Aug 10 2021

ALC073-102326-
/O.CAN.KBMX.FF.W.0044.000000T0000Z-210811T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson AL-
616 PM CDT Tue Aug 10 2021

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

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3355 8679 3368 8679 3367 8667 3364 8667
      3353 8671

$$

32/Davis

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 4:31 AM CDT	Heat Advisory	BMX	Autauga, Barbour, Bibb, Blount, Bullock, Calhoun and 28 more	38 hr
Aug 10, 1:21 PM CDT	Special Weather Statement	BMX	Lee	24 min
Aug 10, 2:08 PM CDT	Special Weather Statement	BMX	Russell	37 min
Aug 10, 2:39 PM CDT	Special Weather Statement	BMX	Chambers	36 min
Aug 10, 2:40 PM CDT	Special Weather Statement	BMX	Macon	35 min
Aug 10, 3:19 PM CDT	Special Weather Statement	BMX	Jefferson	26 min
Aug 10, 3:30 PM CDT	Areal Flood Advisory	BMX	Jefferson	2 hr
Aug 10, 3:50 PM CDT	Special Weather Statement	BMX	Bullock	40 min
Aug 10, 3:59 PM CDT	Special Weather Statement	BMX	Jefferson	31 min
Aug 10, 4:19 PM CDT	Special Weather Statement	BMX	Blount	26 min
Aug 10, 4:32 PM CDT	Special Weather Statement	BMX	Jefferson	28 min
Aug 10, 4:35 PM CDT	Special Weather Statement	BMX	Pike	40 min
Aug 10, 4:46 PM CDT	Special Weather Statement	BMX	Blount	29 min
Aug 10, 5:23 PM CDT	Areal Flood Advisory	BMX	Montgomery	98 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.