Alert archive / Kentucky / Flash Flood Warnings in 2021

Flash Flood Warning 45, NWS Louisville, KY

August 18, 2021Simpson County, Kentucky

NWS Louisville, KY issued this flash flood warning at Aug 18, 2021, 4:20 PM CDT for Simpson County, Kentucky. 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, 4:20 PM CDT (21:20 UTC)
Expired
Aug 18, 2021, 7:30 PM CDT
In force
3 hr
Issued by
NWS Louisville, KY
Area
Storm-based polygon
Flood severity
None

County Simpson County, KY

The radar

The Nashville radar (KOHX), 57 km from the middle of the area, began a volume at 21:21 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, 4:30 PM CDTFLASH FLOOD4 W Franklin, KYDISPATCH REPORTS WATER OVER KY 100.

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, 9.3 hours before the alert went out and 70 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 2021-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 259 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 2021-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 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
259 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
919 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

480 
WGUS53 KLMK 182120
FFWLMK
KYC213-190030-
/O.NEW.KLMK.FF.W.0045.210818T2120Z-210819T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Louisville KY
420 PM CDT Wed Aug 18 2021

The National Weather Service in Louisville has issued a

* Flash Flood Warning for...
  Central Simpson County in south central Kentucky...

* Until 730 PM CDT.

* At 420 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.5 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...
  Franklin, Salmons, Hillsdale, Neosheo and Prices Mill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3681 8640 3667 8658 3668 8673 3674 8667
      3683 8658

FLASH FLOOD...RADAR INDICATED

$$

MJ
2 follow-up statements
781 
WGUS73 KLMK 182217
FFSLMK

Flash Flood Statement
National Weather Service Louisville KY
517 PM CDT Wed Aug 18 2021

KYC213-190030-
/O.CON.KLMK.FF.W.0045.000000T0000Z-210819T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Simpson KY-
517 PM CDT Wed Aug 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM CDT THIS 
EVENING FOR CENTRAL SIMPSON COUNTY...

At 517 PM CDT, Doppler radar continued to indicate thunderstorms 
producing heavy rain across the warned area. Between 2 and 3 inches 
of rain have fallen. Additional rainfall amounts of 0.5 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...
  Franklin, Salmons, Hillsdale, Neosheo and Prices Mill.

Law enforcement reported at 430 PM that water was covering Kentucky 
Road 100 between Franklin and Middleton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3681 8640 3667 8658 3668 8673 3674 8667
      3683 8658

FLASH FLOOD...RADAR INDICATED

$$

MJ
840 
WGUS73 KLMK 190025
FFSLMK

Flash Flood Statement
National Weather Service Louisville KY
725 PM CDT Wed Aug 18 2021

KYC213-190035-
/O.EXP.KLMK.FF.W.0045.000000T0000Z-210819T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Simpson KY-
725 PM CDT Wed Aug 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 730 PM CDT THIS EVENING FOR 
CENTRAL SIMPSON COUNTY...

Light to moderate rainfall will continue through the evening.  
However, the threat of heavy rainfall and flash flooding has ended.  
Water levels in creeks, streams, and drainage ditches will continue 
to run high for a while.

Stay tuned to NOAA weather radio and your local media for the latest 
updates.

LAT...LON 3681 8640 3667 8658 3668 8673 3674 8667
      3683 8658

$$

MJ

The office that day

Everything else NWS Louisville, KY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 18, 3:08 PM CDTAreal Flood AdvisoryLMKClinton, Cumberland, Monroe112 min
Aug 18, 3:09 PM CDTAreal Flood AdvisoryLMKButler, Grayson111 min
Aug 18, 3:32 PM CDTAreal Flood AdvisoryLMKAllen, Simpson, Warren3 hr
Aug 18, 4:47 PM CDTAreal Flood AdvisoryLMKLogan118 min

Nearby

Flash Flood Warnings in Kentucky, 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.