Alert archive / Missouri / Flash Flood Warnings in 2021

Flash Flood Warning 25, NWS St. Louis, MO

July 12, 2021Warren County, Missouri

NWS St. Louis, MO issued this flash flood warning at Jul 12, 2021, 4:26 AM CDT for Warren County, Missouri. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 12, 2021, 4:26 AM CDT (09:26 UTC)
Expired
Jul 12, 2021, 8:00 AM CDT
In force
4 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

County Warren County, MO

The radar

The St Louis radar (KLSX), 33 km from the middle of the area, began a volume at 09:30 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 9.4 hours before the alert went out and 271 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 00:00Z on 2021-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 460 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 00:00Z on 2021-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 78 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
460 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
553 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
78 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

754 
WGUS53 KLSX 120926
FFWLSX
MOC219-121300-
/O.NEW.KLSX.FF.W.0025.210712T0926Z-210712T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
426 AM CDT Mon Jul 12 2021

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Southeastern Warren County in east central Missouri...

* Until 800 AM CDT.

* At 426 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 3 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...
  Washington, Marthasville and Dutzow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3860 9113 3870 9107 3869 9096 3855 9096
      3857 9102 3860 9104 3861 9106 3861 9108

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-3 INCHES IN 1 HOUR

$$

Gosselin
2 follow-up statements
716 
WGUS73 KLSX 121115
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
615 AM CDT Mon Jul 12 2021

MOC219-121300-
/O.CON.KLSX.FF.W.0025.000000T0000Z-210712T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren MO-
615 AM CDT Mon Jul 12 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 AM CDT THIS MORNING 
FOR SOUTHEASTERN WARREN COUNTY...

At 615 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 5 inches of rain have 
fallen. 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...
  Washington, Marthasville and Dutzow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3860 9113 3870 9107 3869 9096 3855 9096
      3857 9102 3860 9104 3861 9106 3861 9108

FLASH FLOOD...RADAR INDICATED

$$

Gosselin
412 
WGUS73 KLSX 121256
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
756 AM CDT Mon Jul 12 2021

MOC219-121306-
/O.EXP.KLSX.FF.W.0025.000000T0000Z-210712T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren MO-
756 AM CDT Mon Jul 12 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 AM CDT THIS MORNING FOR 
SOUTHEASTERN WARREN COUNTY...

The heavy rain has ended, yet light to moderate showers continue 
this morning. Flooding of low lying areas is likely to continue but 
flash flooding is no longer expected. Please continue to heed 
remaining road closures.

LAT...LON 3860 9113 3870 9107 3869 9096 3855 9096
      3857 9102 3860 9104 3861 9106 3861 9108

$$

CVKING

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 8:05 PM CDTRiver Flood WarningLSXLewis58 hr
Jul 12, 1:42 AM CDTAreal Flood AdvisoryLSXFranklin5 hr
Jul 12, 3:46 AM CDTAreal Flood AdvisoryLSXWarren40 min
Jul 12, 5:09 AM CDTFlash Flood WarningLSXSaint Charles4 hr
Jul 12, 5:56 AM CDTAreal Flood AdvisoryLSXCallaway, Gasconade, Osage5 hr
Jul 12, 1:12 PM CDTAreal Flood AdvisoryLSXLincoln3 hr
Jul 12, 2:14 PM CDTFlash Flood WarningLSXLincoln, Montgomery4 hr
Jul 12, 6:27 PM CDTAreal Flood AdvisoryLSXPike3 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.