Alert archive / Missouri / Flash Flood Warnings in 2020

Flash Flood Warning 48, NWS St. Louis, MO

July 31, 20204 counties in Missouri

NWS St. Louis, MO issued this flash flood warning at Jul 31, 2020, 12:10 PM CDT for 4 counties in Missouri. It was in force for 6 hr. 13 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 31, 2020, 12:10 PM CDT (17:10 UTC)
Expired
Jul 31, 2020, 6:15 PM CDT
In force
6 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

Counties Franklin County, MO, Gasconade County, MO, Montgomery County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 71 km from the middle of the area, began a volume at 17:11 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 31, 12:15 PM CDTFLOODHermann, MOHIGHWAY 19 IN HERMANN, MO CLOSED DUE TO FLOODING.
Jul 31, 12:30 PM CDTFLASH FLOOD3 Sw Hermann, MOFACEBOOK VIDEO SHOWS FLASH FLOODING OF FRENE CREEK NEAR THE ADAM PUTCHA WINERY.
Jul 31, 1:02 PM CDTFLOODHermann, MOMULTIPLE ROADS NOW FLOODED IN AND JUST OUTSIDE OF TOWN.
Jul 31, 1:30 PM CDTFLOODRhineland, MOHIGHWAY 94 CLOSED DUE TO FLOODING.
Jul 31, 1:40 PM CDTFLOODHermann, MODELAYED REPORT: WATER OVER ROAD IN DOWNTOWN HERMANN FROM FRENE CREEK OVERFLOWING ITS BANKS.
Jul 31, 1:56 PM CDTFLOOD2 E Holstein, MOFLOODING CLOSED A ROADWAY IN CONCORD HILL.
Jul 31, 2:18 PM CDTFLOODBerger, MODIEDERICH ROAD CLOSED DUE TO FLOODING SOUTHEAST OF BERGER.
Jul 31, 5:21 PM CDTHEAVY RAIN 7.11 Ssw Hermann, MO
Jul 31, 5:23 PM CDTHEAVY RAIN 6.11Hermann, MO
Jul 31, 5:27 PM CDTHEAVY RAIN 6.74 Ene Berger, MO
Jul 31, 6:00 PM CDTFLOODBerger, MOROUTE B FROM BERGER TO ETLAH WAS CLOSED DUE TO FLOODING FROM THE HEAVY RAIN EARLIER TODAY.
Jul 31, 6:23 PM CDTHEAVY RAIN 3.292 Nw Rhineland, MO
Jul 31, 6:24 PM CDTHEAVY RAIN 3.913 Ssw Berger, MO

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

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 5.2 hours before the alert went out and 286 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, Springfield, MO at 12:00Z on 2020-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 590 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, Springfield, MO at 12:00Z on 2020-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 square meters per square second.19395878Sfc1 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
590 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
484 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
25 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

322 
WGUS53 KLSX 311710
FFWLSX
MOC071-073-139-219-312315-
/O.NEW.KLSX.FF.W.0048.200731T1710Z-200731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
1210 PM CDT Fri Jul 31 2020

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Southwestern Montgomery County in east central Missouri...
  Northwestern Franklin County in east central Missouri...
  Central Warren County in east central Missouri...
  Northeastern Gasconade County in east central Missouri...

* Until 615 PM CDT Friday.

* At 1208 PM CDT, Doppler radar indicated showers producing heavy 
  rain across the warned area. Two to four inches of rain has fallen 
  in the last few hours. Flash flooding is ongoing or expected to 
  begin shortly.

  HAZARD...Flash flooding caused by heavy showers.

  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...
  Warrenton, Hermann, Truesdale, Big Spring, Treloar, Gasconade,
  Berger, Rhineland, McKittrick, Americus and Holstein.

This also includes Deutschheim Historic Site.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3882 9164 3883 9112 3865 9109 3861 9152
      3871 9147 3869 9151 3867 9157 3869 9161
      3870 9164 3872 9165

FLASH FLOOD...RADAR INDICATED

$$

KD
3 follow-up statements
132 
WGUS73 KLSX 311804
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
104 PM CDT Fri Jul 31 2020

MOC071-073-139-219-312315-
/O.CON.KLSX.FF.W.0048.000000T0000Z-200731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery MO-Franklin MO-Warren MO-Gasconade MO-
104 PM CDT Fri Jul 31 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FRIDAY
FOR SOUTHWESTERN MONTGOMERY...NORTHWESTERN FRANKLIN...CENTRAL WARREN
AND NORTHEASTERN GASCONADE COUNTIES...

At 103 PM CDT, law enforcement reported flash flooding in the town 
of Hermann, Missouri. Two to four inches of rain have already 
fallen, with additional rainfall continuing. Flash flooding is 
ongoing.

HAZARD...Flash flooding caused by heavy showers.

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...
Warrenton, Hermann, Truesdale, Big Spring, Treloar, Gasconade,
Berger, Rhineland, McKittrick, Americus and Holstein.

This also includes Deutschheim Historic Site.
 
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, country roads, farmland, and other low lying
spots.

&&

LAT...LON 3882 9164 3883 9112 3865 9109 3861 9152
      3871 9147 3869 9151 3867 9157 3869 9161
      3870 9164 3872 9165

FLASH FLOOD...OBSERVED

$$

KD
987 
WGUS73 KLSX 312211
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
511 PM CDT Fri Jul 31 2020

MOC071-073-139-219-312315-
/O.CON.KLSX.FF.W.0048.000000T0000Z-200731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery MO-Franklin MO-Warren MO-Gasconade MO-
511 PM CDT Fri Jul 31 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FRIDAY
FOR SOUTHWESTERN MONTGOMERY...NORTHWESTERN FRANKLIN...CENTRAL WARREN
AND NORTHEASTERN GASCONADE COUNTIES...

At 509 PM CDT, Doppler radar and automated gauges indicate that as 
much as 3 to 7 inches of rain fell across southern Warren and 
southern Montgomery County earlier today. Flooding has been reported 
on some roads in the warned area. 

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar and 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...
Warrenton, Hermann, Truesdale, Big Spring, Treloar, Gasconade,
Berger, Rhineland, McKittrick, Americus and Holstein.

This also includes Deutschheim Historic Site.
 
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, country roads, farmland, and other low lying
spots.

&&

LAT...LON 3882 9164 3883 9112 3865 9109 3861 9152
      3871 9147 3869 9151 3867 9157 3869 9161
      3870 9164 3872 9165

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Glass
815 
WGUS73 KLSX 312313
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
613 PM CDT Fri Jul 31 2020

MOC071-073-139-219-312322-
/O.EXP.KLSX.FF.W.0048.000000T0000Z-200731T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery MO-Franklin MO-Warren MO-Gasconade MO-
613 PM CDT Fri Jul 31 2020

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN MONTGOMERY...NORTHWESTERN
FRANKLIN...CENTRAL WARREN AND NORTHEASTERN GASCONADE COUNTIES WILL
EXPIRE AT 615 PM CDT FRIDAY...

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 3882 9164 3883 9112 3865 9109 3861 9152
      3871 9147 3869 9151 3867 9157 3869 9161
      3870 9164 3872 9165

$$

Glass

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 8:52 PM CDTFlash Flood WarningLSXCole, Osage4 hr
Jul 31, 3:25 AM CDTFlash Flood WatchLSXCrawford, Franklin, Iron, Jefferson, Lincoln, Madison and 8 more21 hr
Jul 31, 7:28 AM CDTAreal Flood AdvisoryLSXBoone, Callaway, Cole, Gasconade, Moniteau, Montgomery and 1 more3 hr
Jul 31, 8:33 AM CDTFlash Flood WarningLSXGasconade6 hr
Jul 31, 11:31 AM CDTAreal Flood AdvisoryLSXFranklin, Gasconade, Montgomery, Warren3 hr
Jul 31, 1:19 PM CDTFlash Flood WarningLSXFranklin, Gasconade, Warren6 hr
Jul 31, 4:18 PM CDTFlash Flood WarningLSXIron, Reynolds5 hr
Jul 31, 4:29 PM CDTAreal Flood AdvisoryLSXSaint Charles3 hr

Nearby

Flash 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.