Alert archive / Illinois / Flash Flood Warnings in 2020

Flash Flood Warning 7, NWS St. Louis, MO

May 16, 2020Greene County, Illinois

NWS St. Louis, MO issued this flash flood warning at May 16, 2020, 2:30 PM CDT for Greene County, Illinois. It was in force for 6 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: May 16, 2020, 2:30 PM CDT (19:30 UTC)
Expired: May 16, 2020, 8:30 PM CDT
In force: 6 hr
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Flood severity: None

County Greene County, IL

The radar

The St Louis radar (KLSX), 90 km from the middle of the area, began a volume at 19:31 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 12:00Z, 7.5 hours before the alert went out and 166 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 818 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

437 
WGUS53 KLSX 161930
FFWLSX
ILC061-170130-
/O.NEW.KLSX.FF.W.0007.200516T1930Z-200517T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service St Louis MO
230 PM CDT Sat May 16 2020

The National Weather Service in St Louis has issued a

* Flash Flood Warning for...
  Northern Greene County in southwestern Illinois...

* Until 830 PM CDT Saturday.

* At 229 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain over White Hall. The storm is nearly stationary. Up to
  two inches of rain have already fallen. Flash flooding is ongoing
  or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  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...
  White Hall, Roodhouse, Patterson, Hillview, Walkersville, Belltown,
  Berdan and Barrow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 3952 9015 3940 9023 3931 9050 3952 9055

FLASH FLOOD...RADAR INDICATED

$$

Carney

The office that day

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

Issued	Product	Office	Counties	Lasted
May 16, 11:04 AM CDT	River Flood Warning	LSX	Jersey	35 days
May 16, 2:20 PM CDT	Severe Thunderstorm Warning	LSX	Greene	40 min
May 16, 3:06 PM CDT	Areal Flood Advisory	LSX	Madison	4 hr
May 16, 3:50 PM CDT	Severe Thunderstorm Warning	LSX	Macoupin	40 min
May 16, 4:35 PM CDT	Areal Flood Advisory	LSX	Macoupin	3 hr

Nearby

Flash Flood Warnings in Illinois, 2020 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.