Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 30, NWS Huntsville, AL

August 13, 2021Lawrence County, Limestone County, Morgan County, Alabama

NWS Huntsville, AL issued this flash flood warning at Aug 13, 2021, 5:38 PM CDT for Lawrence County, Limestone County, Morgan 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 13, 2021, 5:38 PM CDT (22:38 UTC)
Expired
Aug 13, 2021, 8:00 PM CDT
In force
2 hr
Issued by
NWS Huntsville, AL
Area
Storm-based polygon
Flood severity
None

Counties Lawrence County, AL, Limestone County, AL, Morgan County, AL

The radar

The Northeast Alabama radar (KHTX), 95 km from the middle of the area, began a volume at 22:41 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, 10.6 hours before the alert went out and 166 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 2021-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 157 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2021-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 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
157 J/kg
Mixed-layer CIN
-100 J/kg
Mixed-layer LCL
1006 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

898 
WGUS54 KHUN 132238
FFWHUN
ALC079-083-103-140100-
/O.NEW.KHUN.FF.W.0030.210813T2238Z-210814T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Huntsville AL
538 PM CDT Fri Aug 13 2021

The National Weather Service in Huntsville has issued a

* Flash Flood Warning for...
  South Central Limestone County in north central Alabama...
  Western Morgan County in north central Alabama...
  East Central Lawrence County in northwestern Alabama...

* Until 800 PM CDT.

* At 538 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. The expected rainfall rate is 1 to 3 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...
  Decatur, Athens, Hartselle, Priceville, Trinity, Falkville, 
  Tanner, Basham, Caddo, Neel and Ripley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3473 8713 3476 8712 3477 8713 3477 8692
      3439 8691 3441 8715

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-3 INCHES IN 1 HOUR

$$

RSB
2 follow-up statements
965 
WGUS74 KHUN 140012
FFSHUN

Flash Flood Statement
National Weather Service Huntsville AL
712 PM CDT Fri Aug 13 2021

ALC079-083-103-140100-
/O.CON.KHUN.FF.W.0030.000000T0000Z-210814T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lawrence AL-Limestone AL-Morgan AL-
712 PM CDT Fri Aug 13 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING 
FOR SOUTH CENTRAL LIMESTONE, WESTERN MORGAN AND EAST CENTRAL 
LAWRENCE COUNTIES...

At 712 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 3 inches of rain have 
fallen. Additional rainfall amounts of one inch is 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...
Decatur, Athens, Hartselle, Priceville, Trinity, Falkville, Tanner, 
Basham, Caddo, Neel and Ripley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3473 8713 3476 8712 3477 8713 3477 8692
      3439 8691 3441 8715

FLASH FLOOD...RADAR INDICATED

$$

RSB
746 
WGUS74 KHUN 140052
FFSHUN

Flash Flood Statement
National Weather Service Huntsville AL
752 PM CDT Fri Aug 13 2021

ALC079-083-103-140102-
/O.EXP.KHUN.FF.W.0030.000000T0000Z-210814T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lawrence AL-Limestone AL-Morgan AL-
752 PM CDT Fri Aug 13 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 PM CDT THIS EVENING FOR 
SOUTH CENTRAL LIMESTONE, WESTERN MORGAN AND EAST CENTRAL LAWRENCE 
COUNTIES...

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

LAT...LON 3473 8713 3476 8712 3477 8713 3477 8692
      3439 8691 3441 8715

$$

RSB

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 12:05 PM CDTSpecial Weather StatementHUNDeKalb40 min
Aug 13, 12:52 PM CDTSpecial Weather StatementHUNDeKalb38 min
Aug 13, 3:23 PM CDTSpecial Weather StatementHUNMadison37 min
Aug 13, 4:35 PM CDTSpecial Weather StatementHUNLauderdale25 min
Aug 13, 4:39 PM CDTSpecial Weather StatementHUNLimestone36 min
Aug 13, 5:01 PM CDTFlash Flood WarningHUNColbert, Lauderdale119 min
Aug 13, 5:12 PM CDTSpecial Weather StatementHUNMorgan48 min
Aug 13, 5:18 PM CDTSpecial Weather StatementHUNFranklin42 min
Aug 13, 5:44 PM CDTSpecial Weather StatementHUNCullman46 min
Aug 13, 5:57 PM CDTSpecial Weather StatementHUNLimestone63 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.