Alert archive / Illinois / Flash Flood Warnings in 2020
Flash Flood Warning 64, NWS St. Louis, MO
NWS St. Louis, MO issued this flash flood warning at Aug 15, 2020, 9:19 PM CDT for Monroe County, Saint Clair County, Illinois; Saint Louis County, City of Saint Louis, Missouri. It was in force for 3 hr. 5 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
- Aug 15, 2020, 9:19 PM CDT (02:19 UTC)
- Expired
- Aug 16, 2020, 12:39 AM CDT
- In force
- 3 hr
- Issued by
- NWS St. Louis, MO
- Area
- Storm-based polygon
- Flood severity
- None
Counties Monroe County, IL, Saint Clair County, IL, City of Saint Louis, MO, Saint Louis County, MO
The radar
The St Louis radar (KLSX), 38 km from the middle of the area, began a volume at 02:23 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 |
|---|---|---|---|
| Aug 15, 9:41 PM CDT | HEAVY RAIN 1.4 | Crestwood, MO | 1.40 INCHES OF RAIN THIS EVENING. |
| Aug 15, 9:55 PM CDT | FLASH FLOOD | 1 Wsw Lemay, MO | THE SMALL STREAM GAGE ON GRAVOIS CREEK IN MEHLVILLE ROSE NEARLY 12 FEET IN LESS THAN 2 HOURS AND EXCEEDED FLOOD STAGE (15 FT) AT 955 PM. |
| Aug 15, 9:59 PM CDT | FLASH FLOOD | Shrewsbury, MO | WATER 1 FEET DEEP ON PARTS OF WATSON ROAD. |
| Aug 15, 10:02 PM CDT | FLASH FLOOD | East Carondelet, IL | FLOODING AT INTERSTATE 55 AND CARONDELET PARK. |
| Aug 15, 10:07 PM CDT | FLASH FLOOD | Mehlville, MO | FLOODING AT INTERSTATE 55 AND UNION ROAD. |
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 00:00Z, 2.3 hours before the alert went out and 241 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.
- Mixed-layer CAPE
- 1538 J/kg
- Mixed-layer CIN
- -29 J/kg
- Mixed-layer LCL
- 1036 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -10 m²/s²
- 0-3 km storm-relative helicity
- 44 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
446
WGUS53 KLSX 160219
FFWLSX
ILC133-163-MOC189-510-160815-
/O.NEW.KLSX.FF.W.0064.200816T0219Z-200816T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
919 PM CDT Sat Aug 15 2020
The National Weather Service in St Louis has issued a
* Flash Flood Warning for...
Northwestern Monroe County in southwestern Illinois...
West central St. Clair County in southwestern Illinois...
Southwestern St. Louis City in east central Missouri...
South central St. Louis County in east central Missouri...
* Until 315 AM CDT.
* At 919 PM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. 2 to 3 inches of rain have
fallen. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
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 flooding include...
St. Louis, Kirkwood, Webster Groves, Arnold, Manchester, Crestwood,
Columbia, Ladue, Sunset Hills, Des Peres, Brentwood, Maplewood,
Valley Park, Shrewsbury, Glendale, Dupo, Fenton, Frontenac, Warson
Woods and Lakeshire.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3836 9023 3841 9035 3845 9034 3846 9036
3845 9039 3846 9039 3846 9042 3848 9042
3849 9040 3850 9041 3850 9054 3865 9041
3851 9012
FLASH FLOOD...RADAR INDICATED
$$
Glass3 follow-up statements
118
WGUS73 KLSX 160300
FFSLSX
Flash Flood Statement
National Weather Service St Louis MO
1000 PM CDT Sat Aug 15 2020
ILC133-163-MOC189-510-160815-
/O.CON.KLSX.FF.W.0064.000000T0000Z-200816T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monroe IL-St. Clair IL-St. Louis City MO-St. Louis MO-
1000 PM CDT Sat Aug 15 2020
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 AM CDT SUNDAY
FOR NORTHWESTERN MONROE...WEST CENTRAL ST. CLAIR AND SOUTH CENTRAL
ST. LOUIS COUNTIES AND SOUTHWESTERN ST. LOUIS CITY...
At 959 PM CDT, law enforcement reported flooding on Watson Road in
the Shrewsberry Area, I-55 and Linderberg Avenue, and I-55 and East
Carondolet. MacKenzie Creek in Shrewberry was also flooding. This
flooding is the result of 2 to 3 inches of rain in 2 hours.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Law enforcement.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other drainage
and low lying areas.
Some locations that will experience flooding include...
St. Louis, Kirkwood, Webster Groves, Arnold, Crestwood, Columbia,
Ladue, Sunset Hills, Des Peres, Brentwood, Maplewood, Valley Park,
Shrewsbury, Glendale, Dupo, Fenton, Frontenac, Warson Woods,
Lakeshire and Oakland.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3837 9023 3845 9034 3846 9036 3850 9041
3856 9048 3865 9041 3851 9012
FLASH FLOOD...OBSERVED
$$
Glass884
WGUS73 KLSX 160341
FFSLSX
Flash Flood Statement
National Weather Service St Louis MO
1041 PM CDT Sat Aug 15 2020
ILC133-163-160347-
/O.CAN.KLSX.FF.W.0064.000000T0000Z-200816T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monroe IL-St. Clair IL-
1041 PM CDT Sat Aug 15 2020
...THE FLASH FLOOD WARNING FOR NORTHWESTERN MONROE AND WEST CENTRAL
ST. CLAIR COUNTIES IS CANCELLED...
Flooding is no longer expected to pose a threat. Please continue to
heed any remaining road closures.
LAT...LON 3852 9027 3844 9029 3844 9033 3845 9034
3846 9036 3853 9044 3858 9046 3864 9042
3861 9033 3856 9023
$$
MOC189-510-160815-
/O.CON.KLSX.FF.W.0064.000000T0000Z-200816T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Louis City MO-St. Louis MO-
1041 PM CDT Sat Aug 15 2020
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 AM CDT FOR
SOUTH CENTRAL ST. LOUIS COUNTY AND SOUTHWESTERN ST. LOUIS CITY...
At 1037 PM CDT, small stream gauges on the Two Mile Creek in Ladue
and also on the Gravois Creek in Mehlville remained above flood
stage. Street flooding was reported earlier in the Shrewsberry and
Carondolet areas.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Automated gauges.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other drainage
and low lying areas.
Some locations that will experience flooding include...
St. Louis, Kirkwood, Webster Groves, Arnold, Crestwood, Ladue, Sunset
Hills, Des Peres, Brentwood, Maplewood, Shrewsbury, Glendale, Fenton,
Frontenac, Warson Woods, Lakeshire, Oakland, Affton, Lemay and
Mehlville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3852 9027 3844 9029 3844 9033 3845 9034
3846 9036 3853 9044 3858 9046 3864 9042
3861 9033 3856 9023
FLASH FLOOD...GAUGE INDICATED
$$
Glass202
WGUS73 KLSX 160539
FFSLSX
Flash Flood Statement
National Weather Service St Louis MO
1239 AM CDT Sun Aug 16 2020
MOC189-510-160549-
/O.CAN.KLSX.FF.W.0064.000000T0000Z-200816T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
St. Louis City MO-St. Louis MO-
1239 AM CDT Sun Aug 16 2020
...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL ST. LOUIS COUNTY AND
SOUTHWESTERN ST. LOUIS CITY IS CANCELLED...
Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.
LAT...LON 3852 9027 3844 9029 3844 9033 3845 9034
3846 9036 3853 9044 3858 9046 3864 9042
3861 9033 3856 9023
$$
GosselinThe office that day
Everything else NWS St. Louis, MO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 15, 9:15 PM CDT | Areal Flood Advisory | LSX | Monroe, Saint Clair | 3 hr |
Nearby
Flash Flood Warnings in Illinois, 2020Flash Flood Warnings in Missouri, 2020Every flash flood warning in 2020
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.