Alert archive / Alabama / Flash Flood Warnings in 2021

Flash Flood Warning 37, NWS Huntsville, AL

September 18, 2021Limestone County, Alabama

NWS Huntsville, AL issued this flash flood warning at Sep 18, 2021, 3:51 PM CDT for Limestone County, Alabama. It was in force for 3 hr. 3 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
Sep 18, 2021, 3:51 PM CDT (20:51 UTC)
Expired
Sep 18, 2021, 6:53 PM CDT
In force
3 hr
Issued by
NWS Huntsville, AL
Area
Storm-based polygon
Flood severity
None

County Limestone County, AL

The radar

The Northeast Alabama radar (KHTX), 78 km from the middle of the area, began a volume at 20:54 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
Sep 18, 4:03 PM CDTFLASH FLOODArdmore, ALOCCUPANTS OF VEHICLE RESCUED FROM FLOODED DITCH AT PARK AVE IN ARDMORE.
Sep 18, 5:16 PM CDTFLASH FLOOD4 Sw Ardmore, ALMULTIPLE VEHICLES SUBMERGED IN THE FLOOD WATERS BETWEEN ARDMORE AND ELKMONT.
Sep 18, 5:35 PM CDTFLASH FLOOD3 W Ardmore, ALBARNES ROAD WASHED OUT IN ARDMORE.

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

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 8.9 hours before the alert went out and 144 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, Nashville Metro, TN at 12:00Z on 2021-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1085 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, Nashville Metro, TN at 12:00Z on 2021-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
1085 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
648 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
51 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

830 
WGUS54 KHUN 182051
FFWHUN
ALC083-190000-
/O.NEW.KHUN.FF.W.0037.210918T2051Z-210919T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Huntsville AL
351 PM CDT Sat Sep 18 2021

The National Weather Service in Huntsville has issued a

* Flash Flood Warning for...
  Northeastern Limestone County in north central Alabama...

* Until 700 PM CDT.

* At 351 PM CDT, emergency management reported thunderstorms 
  producing heavy rain across the warned area. Flash flooding is 
  already occurring.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Emergency management 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...
  Athens, Ardmore, Elkmont, Lester, Cartwright, Holland Gin, 
  Leggtown, Cairo and Mt Rozell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3478 8679 3479 8716 3500 8716 3499 8678

FLASH FLOOD...OBSERVED

$$

25
2 follow-up statements
907 
WGUS74 KHUN 182116
FFSHUN

Flash Flood Statement
National Weather Service Huntsville AL
416 PM CDT Sat Sep 18 2021

ALC083-190000-
/O.CON.KHUN.FF.W.0037.000000T0000Z-210919T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Limestone AL-
416 PM CDT Sat Sep 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS EVENING 
FOR NORTHEASTERN LIMESTONE COUNTY...

At 416 PM CDT, emergency management reported 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 already occurring across the Ardmore area.

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

SOURCE...Emergency management reported multiple roads have become
         impassible and a car was swept off of a road in Ardmore.

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

Some locations that will experience flash flooding include...
  Athens, Ardmore, Elkmont, Lester, Cartwright, Holland Gin, 
  Leggtown, Cairo and Mt Rozell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3478 8679 3479 8716 3500 8716 3499 8678

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

25
112 
WGUS74 KHUN 182353
FFSHUN

Flash Flood Statement
National Weather Service Huntsville AL
653 PM CDT Sat Sep 18 2021

ALC083-190003-
/O.CAN.KHUN.FF.W.0037.000000T0000Z-210919T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Limestone AL-
653 PM CDT Sat Sep 18 2021

...FLASH FLOOD WARNING FOR NORTHEASTERN LIMESTONE COUNTY HAS BEEN 
REPLACED WITH A FLOOD WARNING...

The heavy rain has ended. Please continue to heed remaining road 
closures.

A Flash Flood Watch remains in effect until 700 PM CDT Sunday for 
portions of Alabama and southern middle Tennessee.

LAT...LON 3478 8679 3479 8716 3500 8716 3499 8678

$$

25

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 17, 7:59 PM CDTAreal Flood WarningHUNLauderdale116 min
Sep 18, 2:24 AM CDTFlash Flood WatchHUNColbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more65 hr
Sep 18, 5:11 PM CDTFlash Flood WarningHUNLimestone, Morgan3 hr
Sep 18, 6:53 PM CDTAreal Flood WarningHUNLimestone, Morgan6 hr

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.