Alert archive / Missouri / Flash Flood Warnings in 2020
Flash Flood Warning 55, NWS St. Louis, MO
NWS St. Louis, MO issued this flash flood warning at Aug 9, 2020, 2:41 AM CDT for Jefferson County, Saint Louis County, City of Saint Louis, Missouri; Madison County, Monroe County, Saint Clair County, Illinois. It was in force for 6 hr. 3 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 9, 2020, 2:41 AM CDT (07:41 UTC)
- Expired
- Aug 9, 2020, 8:45 AM CDT
- In force
- 6 hr
- Issued by
- NWS St. Louis, MO
- Area
- Storm-based polygon
- Flood severity
- None
Counties Madison County, IL, Monroe County, IL, Saint Clair County, IL, City of Saint Louis, MO, Jefferson County, MO, Saint Louis County, MO
The radar
The St Louis radar (KLSX), 39 km from the middle of the area, began a volume at 07:43 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 |
|---|---|---|---|
| Aug 9, 3:15 AM CDT | FLOOD | 1 Wsw Lemay, MO | THE SMALL STREAM GAUGE ON GRAVOIS CREEK AT MVLM7 ROSE ABOVE FLOOD STAGE (15 FEET) AT 315 AM AND PEAKED AT 16.07 FEET AT 430 AM. |
| Aug 9, 7:24 AM CDT | HEAVY RAIN 2.66 | 1 Sw Fenton, MO | |
| Aug 9, 8:46 AM CDT | HEAVY RAIN 3 | 1 Se Fenton, MO |
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, 7.7 hours before the alert went out and 227 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
- 1146 J/kg
- Mixed-layer CIN
- -15 J/kg
- Mixed-layer LCL
- 1029 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 25 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
953
WGUS53 KLSX 090741
FFWLSX
ILC119-133-163-MOC099-189-510-091345-
/O.NEW.KLSX.FF.W.0055.200809T0741Z-200809T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
241 AM CDT Sun Aug 9 2020
The National Weather Service in St Louis has issued a
* Flash Flood Warning for...
Northwestern Monroe County in southwestern Illinois...
Southwestern Madison County in southwestern Illinois...
Northwestern St. Clair County in southwestern Illinois...
St. Louis City in east central Missouri...
Northeastern Jefferson County in east central Missouri...
Southeastern St. Louis County in east central Missouri...
* Until 845 AM CDT Sunday.
* At 241 AM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Up to three inches of rain have
already 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, University City, Granite City, Kirkwood, East St. Louis,
Collinsville, Edwardsville, Webster Groves, Arnold, Clayton,
Cahokia, Jennings, Glen Carbon, Crestwood, Bellefontaine Neighbors,
Columbia, Richmond Heights, Sunset Hills, Brentwood and Maplewood.
This also includes Scott Joplin Historic Site and Horseshoe Lake
State Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
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 3837 9022 3838 9041 3850 9056 3859 9038
3871 9026 3881 9012 3879 8996
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
Byrd2 follow-up statements
074
WGUS73 KLSX 091134
FFSLSX
Flash Flood Statement
National Weather Service St Louis MO
634 AM CDT Sun Aug 9 2020
ILC119-133-163-MOC099-189-510-091345-
/O.CON.KLSX.FF.W.0055.000000T0000Z-200809T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monroe IL-Madison IL-St. Clair IL-St. Louis City MO-Jefferson MO-
St. Louis MO-
634 AM CDT Sun Aug 9 2020
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 AM CDT SUNDAY
FOR NORTHWESTERN MONROE...SOUTHWESTERN MADISON AND NORTHWESTERN ST.
CLAIR COUNTIES IN SOUTHWESTERN ILLINOIS...NORTHEASTERN JEFFERSON AND
SOUTHEASTERN ST. LOUIS COUNTIES IN EAST CENTRAL MISSOURI AND ST.
LOUIS CITY...
At 629 AM CDT, radar indicated that the heavier rain has moved out
of the warned area. Up to three inches of rain have already fallen
with less than half an inch additional rain expected. Flash flooding
is already occurring, though a number of creeks and streams are
beginning to fall.
HAZARD...Flash flooding caused by heavy rain.
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, University City, Granite City, Kirkwood, East St. Louis,
Collinsville, Edwardsville, Webster Groves, Arnold, Clayton, Cahokia,
Jennings, Glen Carbon, Crestwood, Bellefontaine Neighbors, Columbia,
Richmond Heights, Sunset Hills, Brentwood and Maplewood.
This also includes Scott Joplin Historic Site and Horseshoe Lake
State Park.
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 3837 9022 3838 9041 3850 9056 3859 9038
3871 9026 3881 9012 3879 8996
FLASH FLOOD...RADAR INDICATED
$$
Byrd041
WGUS73 KLSX 091340
FFSLSX
Flash Flood Statement
National Weather Service St Louis MO
840 AM CDT Sun Aug 9 2020
ILC119-133-163-MOC099-189-510-091350-
/O.EXP.KLSX.FF.W.0055.000000T0000Z-200809T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monroe IL-Madison IL-St. Clair IL-St. Louis City MO-Jefferson MO-
St. Louis MO-
840 AM CDT Sun Aug 9 2020
...THE FLASH FLOOD WARNING FOR NORTHWESTERN MONROE...SOUTHWESTERN
MADISON AND NORTHWESTERN ST. CLAIR COUNTIES IN SOUTHWESTERN
ILLINOIS...NORTHEASTERN JEFFERSON AND SOUTHEASTERN ST. LOUIS COUNTIES
IN EAST CENTRAL MISSOURI AND ST. LOUIS CITY WILL EXPIRE AT 845 AM CDT
SUNDAY...
The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining road closures.
LAT...LON 3837 9022 3838 9041 3850 9056 3859 9038
3871 9026 3881 9012 3879 8996
$$
GlassThe office that day
Everything else NWS St. Louis, MO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 10:50 PM CDT | Areal Flood Advisory | LSX | Lincoln, Pike | 6 hr |
| Aug 8, 11:03 PM CDT | Flash Flood Warning | LSX | Lincoln, Pike | 6 hr |
| Aug 9, 12:01 AM CDT | Flash Flood Warning | LSX | Saint Charles | 6 hr |
| Aug 9, 12:56 AM CDT | Areal Flood Advisory | LSX | Saint Louis | 3 hr |
| Aug 9, 1:15 AM CDT | River Flood Warning | LSX | Saint Charles | 22 hr |
| Aug 9, 1:25 AM CDT | Flash Flood Warning | LSX | Saint Louis | 6 hr |
| Aug 9, 2:27 AM CDT | Areal Flood Advisory | LSX | Saint Charles, Warren | 4 hr |
| Aug 9, 3:54 AM CDT | Areal Flood Advisory | LSX | Franklin, Gasconade | 4 hr |
| Aug 9, 7:29 AM CDT | Areal Flood Warning | LSX | Saint Louis | 3 hr |
| Aug 9, 1:54 PM CDT | Heat Advisory | LSX | Franklin, Iron, Jefferson, Lincoln, Madison, Reynolds and 7 more | 29 hr |
| Aug 9, 9:55 AM CDT | Areal Flood Advisory | LSX | Madison, Saint Clair | 3 hr |
| Aug 9, 10:06 AM CDT | Flash Flood Warning | LSX | Madison | 4 hr |
| Aug 9, 10:23 AM CDT | Flash Flood Warning | LSX | Saint Clair | 4 hr |
| Aug 9, 2:07 PM CDT | Areal Flood Warning | LSX | Saint Clair | 3 hr |
Nearby
Flash Flood Warnings in Missouri, 2020Flash Flood Warnings in Illinois, 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.