Alert archive / Missouri / Flash Flood Warnings in 2021

Flash Flood Warning 36, NWS St. Louis, MO

August 10, 2021Reynolds County, Missouri

NWS St. Louis, MO issued this flash flood warning at Aug 10, 2021, 3:38 AM CDT for Reynolds County, Missouri. It was in force for 3 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
Aug 10, 2021, 3:38 AM CDT (08:38 UTC)
Expired
Aug 10, 2021, 6:30 AM CDT
In force
3 hr
Issued by
NWS St. Louis, MO
Area
Storm-based polygon
Flood severity
None

County Reynolds County, MO

The radar

The St Louis radar (KLSX), 175 km from the middle of the area, began a volume at 08:38 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

Springfield, MO (KSGF), launched 00:00Z, 8.6 hours before the alert went out and 259 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 00:00Z on 2021-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3719 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 00:00Z on 2021-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.1939Sfc1 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
3719 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
1477 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
211 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

703 
WGUS53 KLSX 100838
FFWLSX
MOC179-101130-
/O.NEW.KLSX.FF.W.0036.210810T0838Z-210810T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
338 AM CDT Tue Aug 10 2021

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Southeastern Reynolds County in southeastern Missouri...

* Until 630 AM CDT.

* At 338 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 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...
  Garwood.

This includes the following State Parks...
	Clearwater Lake Recreational Area.

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 3719 9103 3719 9074 3717 9074 3717 9076
      3714 9076 3714 9078 3705 9078 3705 9096
      3710 9096 3710 9101 3710 9102 3714 9102
      3714 9104

FLASH FLOOD...RADAR INDICATED

$$

Carney
1 follow-up statement
555 
WGUS73 KLSX 101127
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
627 AM CDT Tue Aug 10 2021

MOC179-101137-
/O.EXP.KLSX.FF.W.0036.000000T0000Z-210810T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Reynolds MO-
627 AM CDT Tue Aug 10 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 630 AM CDT THIS MORNING FOR 
SOUTHEASTERN REYNOLDS COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3719 9103 3719 9074 3717 9074 3717 9076
      3714 9076 3714 9078 3705 9078 3705 9096
      3710 9096 3710 9101 3710 9102 3714 9102
      3714 9104

$$

Carney

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 3:20 AM CDTExcessive Heat WarningLSXSaint Charles, Saint Louis, City of Saint Louis65 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.