Alert archive / Kentucky / Flash Flood Warnings in 2021

Flash Flood Warning 8, NWS Louisville, KY

April 28, 2021Jefferson County, Kentucky

NWS Louisville, KY issued this flash flood warning at Apr 28, 2021, 4:26 PM EDT for Jefferson County, Kentucky. It was in force for 64 min. 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: Apr 28, 2021, 4:26 PM EDT (20:26 UTC)
Expired: Apr 28, 2021, 5:30 PM EDT
In force: 64 min
Issued by: NWS Louisville, KY
Area: Storm-based polygon
Flood severity: None

County Jefferson County, KY

The radar

The Louisville radar (KLVX), 45 km from the middle of the area, began a volume at 20:29 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

Time	Report	Where	Remark
Apr 28, 5:15 PM EDT	FLOOD	1 W Saint Matthews, KY	WATER UP TO TOPS OF CAR TIRES ON CORNELL PLACE.

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

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 12:00Z, 8.4 hours before the alert went out and 202 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 42 J/kg
Mixed-layer CIN: -374 J/kg
Mixed-layer LCL: 1045 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 237 m²/s²
0-3 km storm-relative helicity: 145 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

241 
WGUS53 KLMK 282026
FFWLMK
KYC111-282230-
/O.NEW.KLMK.FF.W.0008.210428T2026Z-210428T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Louisville KY
426 PM EDT Wed Apr 28 2021

The National Weather Service in Louisville has issued a

* Flash Flood Warning for...
  Jefferson County in central Kentucky...

* Until 630 PM EDT.

* At 425 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Louisville, Jeffersonville, Jeffersontown, St. Matthews, Shively, 
  Lyndon, Middletown, Douglass Hills, Prospect and Hurstbourne.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

&&

LAT...LON 3814 8543 3810 8590 3828 8582 3827 8573
      3831 8566 3836 8562 3834 8557 3834 8558
      3833 8557 3834 8556 3829 8547 3826 8541

FLASH FLOOD...RADAR INDICATED

$$

13

1 follow-up statement

751 
WGUS73 KLMK 282130
FFSLMK

Flash Flood Statement
National Weather Service Louisville KY
530 PM EDT Wed Apr 28 2021

KYC111-282140-
/O.CAN.KLMK.FF.W.0008.000000T0000Z-210428T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson KY-
530 PM EDT Wed Apr 28 2021

...FLASH FLOOD WARNING IS CANCELLED FOR JEFFERSON COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

A Flash Flood Watch remains in effect until 800 PM EDT Thursday.

LAT...LON 3814 8543 3810 8590 3828 8582 3827 8573
      3831 8566 3836 8562 3834 8557 3834 8558
      3833 8557 3834 8556 3829 8547 3826 8541

$$

13

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 28, 3:52 PM EDT	Special Weather Statement	LMK	Jefferson, Shelby	23 min
Apr 28, 4:03 PM EDT	Special Weather Statement	LMK	Jefferson	27 min
Apr 28, 4:53 PM EDT	Areal Flood Advisory	LMK	Grayson, Hardin, Ohio	2 hr

Nearby

Flash Flood Warnings in Kentucky, 2021 Every 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.