Alert archive / Mississippi / Flash Flood Warnings in 2021

Flash Flood Warning 79, NWS Memphis, TN

August 18, 2021Alcorn County, Prentiss County, Tippah County, Mississippi

NWS Memphis, TN issued this flash flood warning at Aug 18, 2021, 4:18 PM CDT for Alcorn County, Prentiss County, Tippah County, Mississippi. 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
Aug 18, 2021, 4:18 PM CDT (21:18 UTC)
Expired
Aug 18, 2021, 7:15 PM CDT
In force
3 hr
Issued by
NWS Memphis, TN
Area
Storm-based polygon
Flood severity
None

Counties Alcorn County, MS, Prentiss County, MS, Tippah County, MS

The radar

The Columbus AFB radar (KGWX), 91 km from the middle of the area, began a volume at 21:19 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
Aug 18, 4:22 PM CDTFLASH FLOODBooneville, MSFLOODING IN LOW LYING AREAS AND ROADWAYS. EM ESTIMATES OVER 2+ INCHES OF RAIN ON ROADWAYS.

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 12:00Z, 9.3 hours before the alert went out and 117 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 12:00Z on 2021-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1042 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 12:00Z on 2021-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 square meters per square second.193958Sfc1 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
1042 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
701 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted.

612 
WGUS54 KMEG 182118
FFWMEG
MSC003-117-139-190015-
/O.NEW.KMEG.FF.W.0079.210818T2118Z-210819T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Memphis TN
418 PM CDT Wed Aug 18 2021

The National Weather Service in Memphis has issued a

* Flash Flood Warning for...
  South Central Alcorn County in northeastern Mississippi...
  Northern Prentiss County in northeastern Mississippi...
  Southeastern Tippah County in northeastern Mississippi...

* Until 715 PM CDT.

* At 418 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 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...
  Booneville, Baldwyn, Jumpertown, Hinkle, Wheeler, Thrashers, 
  Rienzi, Gaston, Blackland, Frankstown, Geeville and Biggersville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3460 8881 3461 8883 3476 8869 3485 8860
      3486 8860 3473 8835 3452 8869 3455 8874
      3459 8874 3460 8873

FLASH FLOOD...RADAR INDICATED

$$
2 follow-up statements
992 
WGUS74 KMEG 182208
FFSMEG

Flash Flood Statement
National Weather Service Memphis TN
508 PM CDT Wed Aug 18 2021

MSC003-117-139-190015-
/O.CON.KMEG.FF.W.0079.000000T0000Z-210819T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Alcorn MS-Prentiss MS-Tippah MS-
508 PM CDT Wed Aug 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 715 PM CDT THIS 
EVENING FOR SOUTH CENTRAL ALCORN, NORTHERN PRENTISS AND SOUTHEASTERN 
TIPPAH COUNTIES...

At 508 PM CDT, Emergency management reported flooding of roadways in 
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.

HAZARD...Flash flooding caused by thunderstorms and runoff.

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...
  Booneville, Baldwyn, Jumpertown, Hinkle, Wheeler, Thrashers, 
  Rienzi, Gaston, Blackland, Frankstown, Geeville and Biggersville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3460 8881 3461 8883 3476 8869 3485 8860
      3486 8860 3473 8835 3452 8869 3455 8874
      3459 8874 3460 8873

FLASH FLOOD...OBSERVED

$$
055 
WGUS74 KMEG 190015
FFSMEG

Flash Flood Statement
National Weather Service Memphis TN
715 PM CDT Wed Aug 18 2021

MSC003-117-139-190025-
/O.EXP.KMEG.FF.W.0079.000000T0000Z-210819T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Alcorn MS-Prentiss MS-Tippah MS-
715 PM CDT Wed Aug 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 715 PM CDT THIS EVENING FOR 
SOUTH CENTRAL ALCORN, NORTHERN PRENTISS AND SOUTHEASTERN TIPPAH 
COUNTIES...

The heavy rain has ended. However, runoff could still post a threat. 
Please continue to heed remaining road closures.

LAT...LON 3460 8881 3461 8883 3476 8869 3485 8860
      3486 8860 3473 8835 3452 8869 3455 8874
      3459 8874 3460 8873

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 3:22 AM CDTAreal Flood AdvisoryMEGPanola113 min
Aug 18, 8:24 AM CDTAreal Flood AdvisoryMEGMarshall2 hr
Aug 18, 10:44 AM CDTSpecial Weather StatementMEGLafayette31 min
Aug 18, 12:07 PM CDTSpecial Weather StatementMEGTunica38 min
Aug 18, 12:46 PM CDTSpecial Weather StatementMEGQuitman29 min
Aug 18, 1:28 PM CDTSpecial Weather StatementMEGPanola32 min
Aug 18, 1:35 PM CDTSpecial Weather StatementMEGTate25 min
Aug 18, 1:49 PM CDTAreal Flood AdvisoryMEGPanola, Tate2 hr
Aug 18, 2:02 PM CDTSpecial Weather StatementMEGLafayette28 min
Aug 18, 2:48 PM CDTSpecial Weather StatementMEGCalhoun, Chickasaw27 min
Aug 18, 3:19 PM CDTSpecial Weather StatementMEGPontotoc26 min
Aug 18, 3:52 PM CDTSpecial Weather StatementMEGPrentiss38 min
Aug 18, 4:23 PM CDTFlash Flood WarningMEGTishomingo3 hr
Aug 18, 6:20 PM CDTSpecial Weather StatementMEGChickasaw25 min

Nearby

Flash Flood Warnings in Mississippi, 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.