Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 70, NWS Memphis, TN

July 11, 2021Shelby County, Tennessee

NWS Memphis, TN issued this flash flood warning at Jul 11, 2021, 3:12 AM CDT for Shelby County, Tennessee. It was in force for 3 hr. 1 report 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 11, 2021, 3:12 AM CDT (08:12 UTC)
Expired
Jul 11, 2021, 6:15 AM CDT
In force
3 hr
Issued by
NWS Memphis, TN
Area
Storm-based polygon
Flood severity
None

County Shelby County, TN

The radar

The Memphis radar (KNQA), 23 km from the middle of the area, began a volume at 08:12 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 11, 4:30 AM CDTFLASH FLOOD1 Ne Midtown Memphis, TNROAD FLOODING AND A TREE DOWN AT HIGHWAY 64 AND AIRLINES BVLD. TDOT AND SHERIFF ON SITE.

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

The nearest sounding before it

Little Rock, AR (KLZK), launched 00:00Z, 8.2 hours before the alert went out and 37 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, Little Rock, AR at 00:00Z on 2021-07-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1010 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, Little Rock, AR at 00:00Z on 2021-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 106 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
1010 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
1462 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
106 m²/s²
0-3 km storm-relative helicity
115 m²/s²
Significant tornado parameter
0.2
Supercell composite
4.9

Open this sounding in Storm Lab

The text

As transmitted.

139 
WGUS54 KMEG 110812
FFWMEG
TNC157-111115-
/O.NEW.KMEG.FF.W.0070.210711T0812Z-210711T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Memphis TN
312 AM CDT Sun Jul 11 2021

The National Weather Service in Memphis has issued a

* Flash Flood Warning for...
  Central Shelby County in western Tennessee...

* Until 615 AM CDT.

* At 312 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. Additional rainfall amounts up to 1 inch 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...
  Bartlett, Collierville, Germantown, Millington, Cordova, Memphis, 
  Lakeland, Arlington, Ellendale, Frayser, Midtown Memphis, Downtown 
  Memphis, Elmore Park, Raleigh, Spring Lake, White Station, Lucy, 
  Woodstock, Brunswick and Lenow.

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 3515 9008 3529 9002 3530 8965 3523 8968
      3511 8971 3506 9011 3512 9009 3512 9008
      3513 9007 3514 9007 3514 9006 3515 9007

FLASH FLOOD...RADAR INDICATED

$$
2 follow-up statements
566 
WGUS74 KMEG 110909
FFSMEG

Flash Flood Statement
National Weather Service Memphis TN
409 AM CDT Sun Jul 11 2021

TNC157-111115-
/O.CON.KMEG.FF.W.0070.000000T0000Z-210711T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Shelby TN-
409 AM CDT Sun Jul 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 AM CDT THIS 
MORNING FOR CENTRAL SHELBY COUNTY...

At 409 AM CDT, heavy rain from thunderstorms has moved east of the 
warned area, but runoff from earlier rainfall will continue to pose 
a threat. Between 2 and 4 inches of rain have fallen. Additional 
rainfall amounts up to 1 inch 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...
  Bartlett, Collierville, Germantown, Millington, Cordova, Memphis, 
  Lakeland, Arlington, Ellendale, Frayser, Midtown Memphis, Downtown 
  Memphis, Elmore Park, Raleigh, Spring Lake, White Station, Lucy, 
  Woodstock, Brunswick and Lenow.

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 3515 9008 3529 9002 3530 8965 3523 8968
      3511 8971 3506 9011 3512 9009 3512 9008
      3513 9007 3514 9007 3514 9006 3515 9007

FLASH FLOOD...RADAR INDICATED

$$
075 
WGUS74 KMEG 111112
FFSMEG

Flash Flood Statement
National Weather Service Memphis TN
612 AM CDT Sun Jul 11 2021

TNC157-111122-
/O.EXP.KMEG.FF.W.0070.000000T0000Z-210711T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Shelby TN-
612 AM CDT Sun Jul 11 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 615 AM CDT THIS MORNING FOR 
CENTRAL SHELBY COUNTY...

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

LAT...LON 3515 9008 3529 9002 3530 8965 3523 8968
      3511 8971 3506 9011 3512 9009 3512 9008
      3513 9007 3514 9007 3514 9006 3515 9007

$$

The office that day

Everything else NWS Memphis, TN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 10, 11:21 PM CDTSpecial Weather StatementMEGLake24 min
Jul 10, 11:46 PM CDTSpecial Weather StatementMEGDyer, Lake, Obion44 min
Jul 10, 11:55 PM CDTSevere Thunderstorm WarningMEGLauderdale, Tipton50 min
Jul 11, 12:24 AM CDTSevere Thunderstorm WarningMEGCrockett, Fayette, Haywood, Lauderdale, Shelby, Tipton51 min
Jul 11, 12:28 AM CDTSpecial Weather StatementMEGDyer, Gibson, Lake, Obion, Weakley47 min
Jul 11, 1:09 AM CDTSpecial Weather StatementMEGCarroll, Gibson, Henry, Weakley51 min
Jul 11, 1:13 AM CDTSpecial Weather StatementMEGCrockett, Fayette, Haywood, Madison32 min
Jul 11, 1:18 AM CDTSpecial Weather StatementMEGShelby27 min
Jul 11, 2:52 AM CDTAreal Flood AdvisoryMEGShelby3 hr
Jul 11, 4:15 AM CDTAreal Flood AdvisoryMEGFayette, Hardeman3 hr
Jul 11, 4:27 AM CDTAreal Flood AdvisoryMEGShelby3 hr
Jul 11, 5:09 AM CDTFlash Flood WarningMEGFayette, Hardeman, Shelby2 hr

Nearby

Flash Flood Warnings in Tennessee, 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.