Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 34, NWS Huntsville, AL

August 19, 2021Franklin County, Alabama

NWS Huntsville, AL issued this flash flood warning at Aug 19, 2021, 5:51 PM CDT for Franklin 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
Aug 19, 2021, 5:51 PM CDT (22:51 UTC)
Expired
Aug 19, 2021, 8:00 PM CDT
In force
2 hr
Issued by
NWS Huntsville, AL
Area
Storm-based polygon
Flood severity
None

County Franklin County, AL

The radar

The Columbus AFB radar (KGWX), 76 km from the middle of the area, began a volume at 22:55 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, 10.9 hours before the alert went out and 173 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 2021-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2206 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 2021-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
2206 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
517 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

989 
WGUS54 KHUN 192251
FFWHUN
ALC059-200100-
/O.NEW.KHUN.FF.W.0034.210819T2251Z-210820T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Huntsville AL
551 PM CDT Thu Aug 19 2021

The National Weather Service in Huntsville has issued a

* Flash Flood Warning for...
  Franklin AL County in northwestern Alabama...

* Until 800 PM CDT.

* At 551 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. 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...
  Russellville, Red Bay, Littleville, Belgreen, Vina, Hodges, Little 
  Bear Creek Reservoir, Dempsey, Cedar Creek Reservoir, Rockwood, 
  Duketon, Isbell, Atwood, Halltown, Pleasant Site, Pogo, Tharptown, 
  Newburg and western Bankhead National Forest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3458 8814 3457 8754 3441 8755 3441 8774
      3431 8774 3432 8817

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

RSB
2 follow-up statements
258 
WGUS74 KHUN 200016
FFSHUN

Flash Flood Statement
National Weather Service Huntsville AL
716 PM CDT Thu Aug 19 2021

ALC059-200100-
/O.CON.KHUN.FF.W.0034.000000T0000Z-210820T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin AL AL-
716 PM CDT Thu Aug 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING 
FOR FRANKLIN AL COUNTY IN NORTHWESTERN ALABAMA...

At 716 PM CDT, Doppler radar indicated showers that produced heavy 
rain across much of Franklin County have moved east of the area. 
However runoff from the recent rainfall continues a flash flooding 
threat. 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...
  Russellville, Red Bay, Littleville, Belgreen, Vina, Hodges, Little 
  Bear Creek Reservoir, Dempsey, Cedar Creek Reservoir, Rockwood, 
  Duketon, Isbell, Atwood, Halltown, Pleasant Site, Pogo, Tharptown, 
  Newburg and western Bankhead National Forest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3458 8814 3457 8754 3441 8755 3441 8774
      3431 8774 3432 8817

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

RSB
488 
WGUS74 KHUN 200057
FFSHUN

Flash Flood Statement
National Weather Service Huntsville AL
757 PM CDT Thu Aug 19 2021

ALC059-200107-
/O.EXP.KHUN.FF.W.0034.000000T0000Z-210820T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin AL AL-
757 PM CDT Thu Aug 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 PM CDT THIS EVENING FOR 
FRANKLIN AL COUNTY IN NORTHWESTERN ALABAMA...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 3458 8814 3457 8754 3441 8755 3441 8774
      3431 8774 3432 8817

$$

RSB

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 7:39 PM CDTSevere Thunderstorm WarningHUNMadison36 min
Aug 19, 8:17 AM CDTSpecial Weather StatementHUNMorgan43 min
Aug 19, 9:04 AM CDTSpecial Weather StatementHUNCullman, Morgan41 min
Aug 19, 9:47 AM CDTFlash Flood WarningHUNCullman3 hr
Aug 19, 10:32 AM CDTSpecial Weather StatementHUNMarshall43 min
Aug 19, 11:05 AM CDTSpecial Weather StatementHUNDeKalb55 min
Aug 19, 11:58 AM CDTSpecial Weather StatementHUNDeKalb32 min
Aug 19, 1:06 PM CDTAreal Flood WarningHUNCullman39 min
Aug 19, 2:22 PM CDTSpecial Weather StatementHUNFranklin38 min
Aug 19, 2:49 PM CDTSpecial Weather StatementHUNFranklin41 min
Aug 19, 4:45 PM CDTFlash Flood Warning EmergencyHUNFranklin3 hr
Aug 19, 6:18 PM CDTSpecial Weather StatementHUNMadison27 min
Aug 19, 6:45 PM CDTSpecial Weather StatementHUNMadison45 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.