Alert archive / Missouri / Flash Flood Warnings in 2020

Flash Flood Warning 49, NWS St. Louis, MO

July 31, 2020Franklin County, Gasconade County, Warren County, Missouri

NWS St. Louis, MO issued this flash flood warning at Jul 31, 2020, 1:19 PM CDT for Franklin County, Gasconade County, Warren County, Missouri. It was in force for 6 hr. 6 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, 1:19 PM CDT (18:19 UTC)
Expired
Jul 31, 2020, 7:15 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, Warren County, MO

The radar

The St Louis radar (KLSX), 47 km from the middle of the area, began a volume at 18:18 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, 1:30 PM CDTFLASH FLOODTreloar, MOSEVERAL ROADS IN AND AROUND TOWN WERE FLOODED. ALSO, SEVERAL BASEMENTS IN TOWN WERE FLOODED.
Jul 31, 1:47 PM CDTFLOODTreloar, MOHIGHWAY N CLOSED DUE TO HIGH WATER.
Jul 31, 2:45 PM CDTHEAVY RAIN 2.023 Ese Washington, MORAINFALL IN THE PAST 2.5 HOURS.
Jul 31, 6:25 PM CDTHEAVY RAIN 3.022 Nw Lyon, MO
Jul 31, 6:26 PM CDTHEAVY RAIN 3.041 Wnw Washington, MO
Jul 31, 6:27 PM CDTHEAVY RAIN 3.311 Se Dutzow, 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 12:00Z, 6.3 hours before the alert went out and 282 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 2020-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2020-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1082 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

654 
WGUS53 KLSX 311819
FFWLSX
MOC071-073-219-010015-
/O.NEW.KLSX.FF.W.0049.200731T1819Z-200801T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in St Louis has issued a

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

* Until 715 PM CDT.

* At 117 PM CDT, Doppler radar and automated gauges indicated 
  showers producing heavy rain across the warned area. Two to four 
  inches of rain have fallen in the last two to three hours. Flash 
  flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by heavy showers.

  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...
  Washington, New Haven, Marthasville, Dutzow and Lyon. 

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 3861 9150 3865 9109 3874 9110 3874 9096
      3847 9096 3851 9140

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

KD
3 follow-up statements
190 
WGUS73 KLSX 312010
FFSLSX

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

MOC071-073-219-010015-
/O.CON.KLSX.FF.W.0049.000000T0000Z-200801T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin MO-Warren MO-Gasconade MO-
310 PM CDT Fri Jul 31 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 715 PM CDT FOR
NORTHWESTERN FRANKLIN...SOUTHEASTERN WARREN AND NORTHEASTERN
GASCONADE COUNTIES...

At 309 PM CDT, Doppler radar and automated gauges indicated heavy 
showers producing heavy rain across the warned area. Two to as much 
as four inches of rain have fallen. Flash flooding is ongoing or 
expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

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...
Washington, New Haven, Marthasville, Dutzow and Lyon. 

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 3861 9150 3865 9109 3874 9110 3874 9096
      3847 9096 3851 9140

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

KD
054 
WGUS73 KLSX 312215
FFSLSX

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

MOC071-073-219-010015-
/O.CON.KLSX.FF.W.0049.000000T0000Z-200801T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin MO-Warren MO-Gasconade MO-
515 PM CDT Fri Jul 31 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 715 PM CDT FRIDAY
FOR NORTHWESTERN FRANKLIN...SOUTHEASTERN WARREN AND NORTHEASTERN
GASCONADE COUNTIES...

At 513 PM CDT, Doppler radar and automated gauges indicate that as 
much as 3 to 5 inches of rain fell across northwest Franklin County 
and northeast Gasconade 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...
Washington, New Haven, Marthasville, Dutzow and Lyon. 

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 3861 9150 3865 9109 3874 9110 3874 9096
      3847 9096 3851 9140

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Glass
414 
WGUS73 KLSX 010011
FFSLSX

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

MOC071-073-219-010021-
/O.EXP.KLSX.FF.W.0049.000000T0000Z-200801T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin MO-Warren MO-Gasconade MO-
711 PM CDT Fri Jul 31 2020

...THE FLASH FLOOD WARNING FOR NORTHWESTERN FRANKLIN...SOUTHEASTERN
WARREN AND NORTHEASTERN GASCONADE COUNTIES WILL EXPIRE AT 715 PM
CDT...

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 3861 9150 3865 9109 3874 9110 3874 9096
      3847 9096 3851 9140

$$

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, 12:10 PM CDTFlash Flood WarningLSXFranklin, Gasconade, Montgomery, 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.