Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 43, NWS Birmingham, AL

July 27, 2021Shelby County, Alabama

NWS Birmingham, AL issued this flash flood warning at Jul 27, 2021, 3:32 PM CDT for Shelby County, Alabama. It was in force for 3 hr. 2 reports 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
Jul 27, 2021, 3:32 PM CDT (20:32 UTC)
Expired
Jul 27, 2021, 6:08 PM CDT
In force
3 hr
Issued by
NWS Birmingham, AL
Area
Storm-based polygon
Flood severity
None

County Shelby County, AL

The radar

The Birmingham radar (KBMX), 13 km from the middle of the area, began a volume at 20:32 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

TimeReportWhereRemark
Jul 27, 3:37 PM CDTFLASH FLOODAlabaster, ALSIGNIFICANT FLOODING IN SEVERAL SPOTS AROUND ALABASTER. WATER WAS OVER BRIDGES AND ROADWAYS WERE IMPASSABLE.
Jul 27, 3:37 PM CDTFLASH FLOODAlabaster, ALSIGNIFICANT FLOODING IN SEVERAL SPOTS AROUND ALABASTER. WATER WAS OVER BRIDGES AND ROADWAYS WERE IMPASSABLE INCLUDING HWY 119, HWY 31, 1ST ST W, 8TH ST SW, AND OLD SIMMSVILLE RD.

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, 8.5 hours before the alert went out and 12 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-pSkew-T log-p diagram, Birmingham, AL at 12:00Z on 2021-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1546 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2021-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1546 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
923 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
-17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

907 
WGUS54 KBMX 272032
FFWBMX
ALC117-272330-
/O.NEW.KBMX.FF.W.0043.210727T2032Z-210727T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Birmingham AL
332 PM CDT Tue Jul 27 2021

The National Weather Service in Birmingham has issued a

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

* Until 630 PM CDT.

* At 332 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Across parts of the warning 
  area, as much as 2 and 3 inches of rain have fallen onto already 
  wet ground, with additional heavy rain expected to continue. 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...
  Hoover, Alabaster, Pelham, Helena, Calera, Montevallo, Indian 
  Springs Village, Wilton, Maylene, Shelby County Airport, American 
  Village, University Of Montevallo, Oak Mountain Amphitheater, 
  Riverchase, Oak Mountain State Park, Siluria, Alabaster Veterans 
  Park, Saginaw, Saddle Lake Farms and Camp Branch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3337 8679 3334 8675 3332 8674 3329 8670
      3319 8669 3317 8673 3307 8679 3307 8688
      3312 8694 3327 8694 3328 8693 3329 8693
      3331 8690 3333 8689 3333 8688 3333 8683
      3336 8683 3336 8681 3337 8680

FLASH FLOOD...RADAR INDICATED

$$

89^GSatterwhite
3 follow-up statements
483 
WGUS74 KBMX 272037
FFSBMX

Flash Flood Statement
National Weather Service Birmingham AL
337 PM CDT Tue Jul 27 2021

ALC117-272330-
/O.CON.KBMX.FF.W.0043.000000T0000Z-210727T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Shelby AL-
337 PM CDT Tue Jul 27 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM CDT THIS 
EVENING FOR SOUTHWESTERN SHELBY COUNTY...

At 337 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 3 inches of rain have 
fallen across parts of the warning area, with heavy rain expected to 
continue over the next hour, or so. Flash flooding is already 
occurring.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Hoover, Alabaster, Pelham, Helena, Calera, Montevallo, Indian 
  Springs Village, Wilton, Maylene, Shelby County Airport, American 
  Village, University Of Montevallo, Oak Mountain Amphitheater, 
  Riverchase, Oak Mountain State Park, Siluria, Alabaster Veterans 
  Park, Saginaw, Saddle Lake Farms and Camp Branch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3337 8679 3334 8675 3332 8674 3329 8670
      3319 8669 3317 8673 3307 8679 3307 8688
      3312 8694 3327 8694 3328 8693 3329 8693
      3331 8690 3333 8689 3333 8688 3333 8683
      3336 8683 3336 8681 3337 8680

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

89^GSatterwhite
410 
WGUS74 KBMX 272211
FFSBMX

Flash Flood Statement
National Weather Service Birmingham AL
511 PM CDT Tue Jul 27 2021

ALC117-272330-
/O.CON.KBMX.FF.W.0043.000000T0000Z-210727T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Shelby AL-
511 PM CDT Tue Jul 27 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM CDT THIS 
EVENING FOR SOUTHWESTERN SHELBY COUNTY...

At 511 PM CDT, Areas of flash flooding have been reported by the 
public and law enforcement. Radar estimates totals of two to four 
inches. Heavy rainfall has ended across the warning area, though 
instances of light rain may occur. Flood waters are expected to 
gradually recede over the coming hours.

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, Montevallo, Indian 
  Springs Village, Wilton, Maylene, Shelby County Airport, American 
  Village, University Of Montevallo, Oak Mountain Amphitheater, 
  Riverchase, Oak Mountain State Park, Siluria, Alabaster Veterans 
  Park, Saginaw, Saddle Lake Farms and Camp Branch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3337 8679 3334 8675 3332 8674 3329 8670
      3319 8669 3317 8673 3307 8679 3307 8688
      3312 8694 3327 8694 3328 8693 3329 8693
      3331 8690 3333 8689 3333 8688 3333 8683
      3336 8683 3336 8681 3337 8680

FLASH FLOOD...OBSERVED

$$

89^GSatterwhite
387 
WGUS74 KBMX 272308
FFSBMX

Flash Flood Statement
National Weather Service Birmingham AL
608 PM CDT Tue Jul 27 2021

ALC117-272318-
/O.CAN.KBMX.FF.W.0043.000000T0000Z-210727T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Shelby AL-
608 PM CDT Tue Jul 27 2021

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

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

LAT...LON 3337 8679 3334 8675 3332 8674 3329 8670
      3319 8669 3317 8673 3307 8679 3307 8688
      3312 8694 3327 8694 3328 8693 3329 8693
      3331 8690 3333 8689 3333 8688 3333 8683
      3336 8683 3336 8681 3337 8680

$$

89^GSatterwhite

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 26, 8:51 PM CDTAreal Flood AdvisoryBMXPickens100 min
Jul 26, 10:05 PM CDTSpecial Weather StatementBMXRussell40 min
Jul 27, 4:04 AM CDTHeat AdvisoryBMXAutauga, Barbour, Bibb, Blount, Bullock, Calhoun and 33 more6 days
Jul 27, 12:30 PM CDTSpecial Weather StatementBMXMontgomery45 min
Jul 27, 12:37 PM CDTSpecial Weather StatementBMXTallapoosa38 min
Jul 27, 1:25 PM CDTSpecial Weather StatementBMXTallapoosa35 min
Jul 27, 1:52 PM CDTSpecial Weather StatementBMXCoosa38 min
Jul 27, 2:33 PM CDTAreal Flood AdvisoryBMXShelby117 min
Jul 27, 2:39 PM CDTAreal Flood AdvisoryBMXJefferson, Shelby111 min
Jul 27, 2:47 PM CDTAreal Flood AdvisoryBMXClay3 hr
Jul 27, 3:06 PM CDTAreal Flood AdvisoryBMXShelby3 hr
Jul 27, 3:19 PM CDTAreal Flood AdvisoryBMXCalhoun, Cleburne, Talladega3 hr
Jul 27, 3:48 PM CDTAreal Flood AdvisoryBMXJefferson2 hr
Jul 27, 4:58 PM CDTAreal Flood AdvisoryBMXBibb2 hr
Jul 27, 5:22 PM CDTAreal Flood AdvisoryBMXEtowah2 hr
Jul 27, 5:26 PM CDTAreal Flood AdvisoryBMXFayette, Tuscaloosa2 hr
Jul 27, 6:02 PM CDTSpecial Weather StatementBMXDallas43 min

Nearby

Flash Flood Warnings in Alabama, 2021Every 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.