Alert archive / Missouri / Flash Flood Warnings in 2023

Flash Flood Warning 3, NWS St. Louis, MO

April 15, 2023Jefferson County, Saint Louis County, Missouri

NWS St. Louis, MO issued this flash flood warning at Apr 15, 2023, 6:39 PM CDT for Jefferson County, Saint Louis County, Missouri. It was in force for 4 hr. 2 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: Apr 15, 2023, 6:39 PM CDT (23:39 UTC)
Expired: Apr 15, 2023, 10:45 PM CDT
In force: 4 hr
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Flood severity: None

Counties Jefferson County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 15 km from the middle of the area, began a volume at 23:43 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 15, 7:27 PM CDT	FLASH FLOOD	2 S Ballwin, MO	HYDROLOGIC GAGE ON KIEFER CREEK AT BALLWIN HAS RISEN ABOVE FLOOD STAGE.
Apr 15, 7:29 PM CDT	FLASH FLOOD	3 Ese Chesterfield, MO	HYDROLOGIC GAGE ON CREVE COEUR CREEK AT CHESTERFIELD HAS RISEN ABOVE FLOOD STAGE.

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

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 11.7 hours before the alert went out and 245 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: 40 J/kg
Mixed-layer CIN: -164 J/kg
Mixed-layer LCL: 1437 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 63 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

629 
WGUS53 KLSX 152339
FFWLSX
MOC099-189-160345-
/O.NEW.KLSX.FF.W.0003.230415T2339Z-230416T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
639 PM CDT Sat Apr 15 2023

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Northwestern Jefferson County in east central Missouri...
  Western Saint Louis County in east central Missouri...

* Until 1045 PM CDT.

* At 639 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 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...
  St. Charles, Chesterfield, Wildwood, Ballwin, Kirkwood, Maryland 
  Heights, Manchester, Creve Coeur, Overland, St. Ann, Bridgeton, 
  Town and Country, Eureka, Ellisville, Ladue, Des Peres, Olivette, 
  Pacific, Valley Park and Fenton.

This includes the following State Parks...
Babler Memorial State Park, Route 66 State Park and Castlewood State 
Park.

This includes the following highways...
	Interstate 70 in Missouri near exit 231.
	Interstate 44 in Missouri between exits 261 and 274.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3861 9073 3868 9062 3868 9054 3870 9053
      3873 9053 3879 9046 3872 9037 3822 9061
      3821 9077 3842 9074

FLASH FLOOD...RADAR INDICATED

$$

Gosselin

2 follow-up statements

520 
WGUS73 KLSX 160036
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
736 PM CDT Sat Apr 15 2023

MOC099-189-160345-
/O.CON.KLSX.FF.W.0003.000000T0000Z-230416T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson MO-Saint Louis MO-
736 PM CDT Sat Apr 15 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT THIS 
EVENING FOR NORTHWESTERN JEFFERSON AND WESTERN SAINT LOUIS 
COUNTIES...

At 736 PM CDT, gauge reports indicated thunderstorms producing heavy 
rain across the warned area. 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...Gauges on both Kiefer Creek near Ballwin and Creve Coeur
         Creek in Chesterfield have rapidly climbed above flood
         stage over the past 1-2 hours.

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...
  St. Charles, Chesterfield, Wildwood, Ballwin, Kirkwood, Maryland 
  Heights, Manchester, Creve Coeur, Overland, St. Ann, Bridgeton, 
  Town and Country, Eureka, Ellisville, Ladue, Des Peres, Olivette, 
  Pacific, Valley Park and Fenton.

This includes the following State Parks...
Babler Memorial State Park, Route 66 State Park and Castlewood State 
Park.

This includes the following highways...
	Interstate 70 in Missouri near exit 231.
	Interstate 44 in Missouri between exits 261 and 274.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3861 9073 3868 9062 3868 9054 3870 9053
      3873 9053 3879 9046 3872 9037 3822 9061
      3821 9077 3842 9074

FLASH FLOOD...GAUGE INDICATED

$$

Gosselin

893 
WGUS73 KLSX 160337
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
1037 PM CDT Sat Apr 15 2023

MOC099-189-160347-
/O.EXP.KLSX.FF.W.0003.000000T0000Z-230416T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson MO-Saint Louis MO-
1037 PM CDT Sat Apr 15 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 1045 PM CDT THIS EVENING FOR 
NORTHWESTERN JEFFERSON AND WESTERN SAINT LOUIS COUNTIES...

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

LAT...LON 3861 9073 3868 9062 3868 9054 3870 9053
      3873 9053 3879 9046 3872 9037 3822 9061
      3821 9077 3842 9074

$$

MRB

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 15, 3:48 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Gasconade, Montgomery, Warren	42 min
Apr 15, 3:54 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LSX	Cole, Osage	51 min
Apr 15, 4:28 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LSX	Franklin, Gasconade, Montgomery, Warren	47 min
Apr 15, 4:36 PM CDT	Tornado Warning	LSX	Crawford, Franklin, Gasconade	39 min
Apr 15, 4:43 PM CDT	Severe Thunderstorm Warning	LSX	Montgomery	35 min
Apr 15, 4:55 PM CDT	Severe Thunderstorm Warning	LSX	Franklin	50 min
Apr 15, 4:58 PM CDT	Areal Flood Advisory	LSX	Osage	3 hr
Apr 15, 5:13 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LSX	Crawford, Franklin, Gasconade, Washington	47 min
Apr 15, 5:28 PM CDT	Flash Flood Warning	LSX	Franklin	5 hr
Apr 15, 5:31 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Saint Louis	44 min
Apr 15, 5:47 PM CDT	Areal Flood Advisory	LSX	Franklin, Gasconade	3 hr
Apr 15, 5:52 PM CDT	Severe Thunderstorm Warning	LSX	Franklin, Jefferson, Saint Louis, Washington	38 min
Apr 15, 6:07 PM CDT	Tornado Warning	LSX	Franklin, Jefferson	35 min
Apr 15, 6:11 PM CDT	Severe Thunderstorm Warning	LSX	Saint Louis	49 min
Apr 15, 6:13 PM CDT	Flash Flood Warning	LSX	Franklin	4 hr
Apr 15, 6:17 PM CDT	Severe Thunderstorm Warning	LSX	Saint Charles, Saint Louis	43 min
Apr 15, 6:19 PM CDT	Tornado Warning	LSX	Saint Louis, City of Saint Louis	41 min
Apr 15, 6:23 PM CDT	Severe Thunderstorm Warning	LSX	Jefferson, Sainte Genevieve, Saint Francois	53 min
Apr 15, 6:27 PM CDT	Severe Thunderstorm Warning	LSX	Jefferson, Saint Louis	52 min
Apr 15, 6:34 PM CDT	Tornado Warning	LSX	Jefferson	41 min
Apr 15, 6:36 PM CDT	Severe Thunderstorm Warning	LSX	Saint Charles, Saint Louis	39 min
Apr 15, 6:39 PM CDT	Tornado Warning	LSX	Saint Louis, City of Saint Louis	51 min

Nearby

Flash Flood Warnings in Missouri, 2023 Every flash flood warning in 2023

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.