Alert archive / Missouri / Flash Flood Warnings in 2021

Flash Flood Warning 33, NWS St. Louis, MO

July 25, 2021Jefferson County, Saint Louis County, Missouri

NWS St. Louis, MO issued this flash flood warning at Jul 25, 2021, 10:11 AM CDT for Jefferson County, Saint Louis County, Missouri. It was in force for 3 hr. 11 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
Jul 25, 2021, 10:11 AM CDT (15:11 UTC)
Expired
Jul 25, 2021, 1:15 PM CDT
In force
3 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), 27 km from the middle of the area, began a volume at 15:11 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 25, 11:00 AM CDTFLOOD1 E Mehlville, MOWATER MAIN BREAK AT SAPPINGTON BARRACKS ROAD AND TELEGRAPH ROAD ATTRIBUTED TO HEAVY RAIN, CAUSING FLOODING AT INTERSECTION.
Jul 25, 11:00 AM CDTFLASH FLOOD1 Sw Fenton, MOFLOODING ON MAY VALLEY LANE NEAR FENTON CREEK.
Jul 25, 11:00 AM CDTFLASH FLOOD1 Sw Peerless Park, MOSEVERAL CARS STUCK IN FLOODED INTERSECTION AT HILLSBORO ROAD AND MERAMEC STATION ROAD.
Jul 25, 11:00 AM CDTFLASH FLOOD1 Sw Peerless Park, MOROAD FLOODED AT MERAMEC STATION ROAD AND SMIZER MILL ROAD.
Jul 25, 11:10 AM CDTFLASH FLOOD1 Sw Peerless Park, MOTHE SMALL STREAM GAGE PPKM7 ON THE WILLIAMS CREEK IN PEERLESS PARK WENT ABOVE FLOOD STAGE (7 FEET) AT 1015 AM. THE MAXIMUM STAGE RECORDED WAS 9.28 FEET AT 1110 AM WHICH IS 2.28 FEET ABOVE FLOOD STAGE.
Jul 25, 11:50 AM CDTFLOOD3 Ese Murphy, MOFLOODING AT ROMAINE CREEK ROAD AND SPRING VALLEY DRIVE.
Jul 25, 11:50 AM CDTFLASH FLOOD3 Ese Murphy, MOFLASH FLOODING ON SPRING CREEK RESULTED IN FLOODING ON PARTS OF ROMAINE CREEK ROAD. SEVERAL CARS BECAME STRANDED IN FLOOD WATERS.
Jul 25, 11:51 AM CDTHEAVY RAIN 4.041 Nnw Murphy, MOMEASURED STORM TOTAL RAINFALL FROM 808-1058 AM.
Jul 25, 11:55 AM CDTFLOOD4 Se Murphy, MOWATER OVER THE ROAD AT OLD SR 21 AND KONERT ROAD.
Jul 25, 12:30 PM CDTHEAVY RAIN 1.953 Wnw Arnold, MOTOTAL RAINFALL. CW7014 APRSWXNET/CWOP.
Jul 25, 12:33 PM CDTHEAVY RAIN 2.594 Sse Sunset Hills, MOTOTAL RAINFALL. FW1318 (APRSWXNET/CWOP).

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, 3.2 hours before the alert went out and 248 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, Lincoln, IL at 12:00Z on 2021-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 295 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, Lincoln, IL at 12:00Z on 2021-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -27 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
295 J/kg
Mixed-layer CIN
-85 J/kg
Mixed-layer LCL
960 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
-27 m²/s²
0-3 km storm-relative helicity
27 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

142 
WGUS53 KLSX 251511
FFWLSX
MOC099-189-251815-
/O.NEW.KLSX.FF.W.0033.210725T1511Z-210725T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
1011 AM CDT Sun Jul 25 2021

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Northeastern Jefferson County in east central Missouri...
  Southwestern Saint Louis County in east central Missouri...

* Until 115 PM CDT.

* At 1011 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. 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...
  Wildwood, Ballwin, Kirkwood, Arnold, Manchester, Crestwood, 
  Eureka, Ellisville, Sunset Hills, Valley Park, Fenton, Byrnes 
  Mill, Lakeshire, Murphy, High Ridge, Affton, Mehlville, Oakville, 
  Lemay and Green Park.

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

This includes the following highways...
	Interstate 44 in Missouri between exits 261 and 277.
	Interstate 55 in Missouri between exits 190 and 191.

This includes the following streams and drainages...
  Fenton Creek, Bonhomme Creek, Spring Branch, Hamilton Creek, 
  Martigney Creek, Keifer Creek, Little Fox Creek, Grand Glaize 
  Creek, Big River, Carr Creek, Caulks Creek, Mississippi River, 
  Gravois Creek, Meramec River, Rock Creek, Black Creek, Antire 
  Creek, Saline Creek, Heads Creek, Fishpot Creek, Little Antire 
  Creek, Mattese Creek, Flat Creek, Fox Creek, Sugar Creek and Pomme 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3849 9073 3851 9072 3860 9062 3853 9026
      3843 9030 3838 9035

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

Glass
2 follow-up statements
431 
WGUS73 KLSX 251627
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
1127 AM CDT Sun Jul 25 2021

MOC099-189-251815-
/O.CON.KLSX.FF.W.0033.000000T0000Z-210725T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson MO-Saint Louis MO-
1127 AM CDT Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 115 PM CDT THIS 
AFTERNOON FOR NORTHEASTERN JEFFERSON AND SOUTHWESTERN SAINT LOUIS 
COUNTIES...

At 1127 AM CDT, local law enforcement reported flash flooding across 
the warned area. A number of streets in the Fenton and Valley Park 
have standing water or are flooded and water covered. Between 3 and 
4 inches of rain have fallen.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Law enforcement 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...
  Wildwood, Ballwin, Kirkwood, Arnold, Manchester, Crestwood, 
  Eureka, Ellisville, Sunset Hills, Valley Park, Fenton, Byrnes 
  Mill, Lakeshire, Murphy, High Ridge, Affton, Mehlville, Oakville, 
  Lemay and Green Park.

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

This includes the following highways...
	Interstate 44 in Missouri between exits 261 and 276.
	Interstate 55 in Missouri between exits 190 and 191.

This includes the following streams and drainages...
  Fenton Creek, Bonhomme Creek, Spring Branch, Hamilton Creek, 
  Martigney Creek, Keifer Creek, Little Fox Creek, Grand Glaize 
  Creek, Big River, Carr Creek, Caulks Creek, Mississippi River, 
  Gravois Creek, Meramec River, Rock Creek, Black Creek, Antire 
  Creek, Saline Creek, Heads Creek, Fishpot Creek, Little Antire 
  Creek, Mattese Creek, Flat Creek, Fox Creek, Sugar Creek and Pomme 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3849 9073 3851 9072 3860 9062 3853 9026
      3843 9030 3838 9035

FLASH FLOOD...OBSERVED

$$

Glass
526 
WGUS73 KLSX 251813
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
113 PM CDT Sun Jul 25 2021

MOC099-189-251823-
/O.EXP.KLSX.FF.W.0033.000000T0000Z-210725T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson MO-Saint Louis MO-
113 PM CDT Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 115 PM CDT THIS AFTERNOON FOR 
NORTHEASTERN JEFFERSON AND SOUTHWESTERN SAINT LOUIS COUNTIES...

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

LAT...LON 3849 9073 3851 9072 3860 9062 3853 9026
      3843 9030 3838 9035

$$

Glass

Nearby

Flash Flood Warnings in Missouri, 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.