Alert archive / Missouri / Flash Flood Warnings in 2021

Flash Flood Warning 30, NWS St. Louis, MO

July 16, 2021Washington County, Missouri

NWS St. Louis, MO issued this flash flood warning at Jul 16, 2021, 2:18 AM CDT for Washington County, Missouri. It was in force for 6 hr. 1 report 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 16, 2021, 2:18 AM CDT (07:18 UTC)
Expired: Jul 16, 2021, 8:30 AM CDT
In force: 6 hr
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Flood severity: None

County Washington County, MO

The radar

The St Louis radar (KLSX), 72 km from the middle of the area, began a volume at 07:17 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
Jul 16, 4:50 AM CDT	FLASH FLOOD	Potosi, MO	OFFICER REPORTED WATER OVER NORTH WATER STREET IN POTOSI CITY LIMITS.

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 00:00Z, 7.3 hours before the alert went out and 296 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1362 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 1225 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 3.0

Open this sounding in Storm Lab

The text

As transmitted.

139 
WGUS53 KLSX 160718
FFWLSX
MOC221-161330-
/O.NEW.KLSX.FF.W.0030.210716T0718Z-210716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
218 AM CDT Fri Jul 16 2021

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Washington County in east central Missouri...

* Until 830 AM CDT Friday.

* At 218 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 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...
  Potosi, Anthonies Mill, Mineral Point, Old Mines, Richwoods, 
  Latty, Shirley and Cadet.

This includes the following State Parks...
	Washington State Park.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3812 9110 3818 9076 3810 9068 3809 9068
      3809 9066 3810 9066 3809 9065 3808 9066
      3808 9064 3790 9064 3777 9110

FLASH FLOOD...RADAR INDICATED

$$

Maples

2 follow-up statements

342 
WGUS73 KLSX 161006
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
506 AM CDT Fri Jul 16 2021

MOC221-161330-
/O.CON.KLSX.FF.W.0030.000000T0000Z-210716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington MO-
506 AM CDT Fri Jul 16 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 AM CDT THIS 
MORNING FOR WASHINGTON COUNTY IN EAST CENTRAL MISSOURI...

At 506 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 4 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement observed water over North Water Street
         in Potosi, MO

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...
  Potosi, Anthonies Mill, Mineral Point, Old Mines, Richwoods, 
  Latty, Shirley and Cadet.

This includes the following State Parks...
	Washington State Park.

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.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3812 9110 3818 9076 3810 9068 3809 9068
      3809 9066 3810 9066 3809 9065 3808 9066
      3808 9064 3790 9064 3777 9110

FLASH FLOOD...RADAR INDICATED

$$

Maples

503 
WGUS73 KLSX 161326
FFSLSX

Flash Flood Statement
National Weather Service St Louis MO
826 AM CDT Fri Jul 16 2021

MOC221-161336-
/O.EXP.KLSX.FF.W.0030.000000T0000Z-210716T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington MO-
826 AM CDT Fri Jul 16 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 830 AM CDT THIS MORNING FOR 
WASHINGTON COUNTY IN EAST CENTRAL MISSOURI...

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

LAT...LON 3812 9110 3818 9076 3810 9068 3809 9068
      3809 9066 3810 9066 3809 9065 3808 9066
      3808 9064 3790 9064 3777 9110

$$

BRC

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 15, 11:04 PM CDT	Areal Flood Advisory	LSX	Crawford, Iron, Reynolds, Sainte Genevieve, Saint Francois, Washington	3 hr
Jul 15, 11:22 PM CDT	Flash Flood Warning	LSX	Sainte Genevieve, Saint Francois	5 hr
Jul 16, 1:40 AM CDT	Areal Flood Advisory	LSX	Crawford, Jefferson, Sainte Genevieve, Saint Francois, Washington	3 hr

Nearby

Flash Flood Warnings in Missouri, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.