Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 32, NWS Huntsville, AL

August 19, 2021Cullman County, Alabama

NWS Huntsville, AL issued this flash flood warning at Aug 19, 2021, 9:47 AM CDT for Cullman County, Alabama. It was in force for 3 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, 9:47 AM CDT (14:47 UTC)
Expired
Aug 19, 2021, 1:06 PM CDT
In force
3 hr
Issued by
NWS Huntsville, AL
Area
Storm-based polygon
Flood severity
None

County Cullman County, AL

The radar

The Northeast Alabama radar (KHTX), 95 km from the middle of the area, began a volume at 14:51 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, 2.8 hours before the alert went out and 116 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.

598 
WGUS54 KHUN 191447
FFWHUN
ALC043-191745-
/O.NEW.KHUN.FF.W.0032.210819T1447Z-210819T1745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Huntsville has issued a

* Flash Flood Warning for...
  Northern Cullman County in north central Alabama...

* Until 1245 PM CDT.

* At 947 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen in northwest Cullman County. The expected rainfall 
  rate is 1 to 3 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...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...
  Cullman, Good Hope, Holly Pond, Baldwin, Vinemont, Baileyton, West 
  Point, Phelan, Walter, Logan, Battleground, Jones Chapel and Joppa.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3410 8665 3411 8711 3431 8711 3430 8649
      3429 8646 3425 8650 3425 8652 3423 8652
      3422 8654 3420 8655

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

$$
2 follow-up statements
827 
WGUS54 KHUN 191718
FFWHUN
ALC043-191845-
/O.EXT.KHUN.FF.W.0032.000000T0000Z-210819T1845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Huntsville AL
1218 PM CDT Thu Aug 19 2021

The National Weather Service in Huntsville has extended the

* Flash Flood Warning for...
  Northwestern Cullman County in north central Alabama...

* Until 145 PM CDT.

* At 1218 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 5 inches of rain 
  have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. Additional rainfall amounts of 1 to 2 inches are 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...
  Cullman, Baldwin, Vinemont, West Point, Jones Chapel, Logan and 
  Battleground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3411 8691 3411 8711 3427 8711 3428 8711
      3429 8711 3430 8711 3431 8711 3430 8683
      3428 8684 3425 8685 3419 8687

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

$$
213 
WGUS74 KHUN 191806
FFSHUN

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

ALC043-191816-
/O.CAN.KHUN.FF.W.0032.000000T0000Z-210819T1845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cullman AL-
106 PM CDT Thu Aug 19 2021

...FLASH FLOOD WARNING FOR NORTHWESTERN CULLMAN COUNTY HAS BEEN 
REPLACED WITH A FLOOD WARNING...

Heavy rainfall has diminished, thus the threat of flash flooding has 
ended. However, areal flooding resulting from the earlier 3 to 5 
inch rainfall can be expected for another hour or so.

LAT...LON 3411 8691 3411 8711 3427 8711 3428 8711
      3429 8711 3430 8711 3431 8711 3430 8683
      3428 8684 3425 8685 3419 8687

$$

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, 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, 5:51 PM CDTFlash Flood WarningHUNFranklin2 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.