Alert archive / Illinois / Flash Flood Warnings in 2021

Flash Flood Warning 9, NWS Quad Cities, IA

July 11, 2021Hancock County, McDonough County, Illinois

NWS Quad Cities, IA issued this flash flood warning at Jul 11, 2021, 2:35 PM CDT for Hancock County, McDonough County, Illinois. It was in force for 3 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 11, 2021, 2:35 PM CDT (19:35 UTC)
Expired: Jul 11, 2021, 5:51 PM CDT
In force: 3 hr
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Flood severity: None

Counties Hancock County, IL, McDonough County, IL

The radar

The Lincoln radar (KILX), 130 km from the middle of the area, began a volume at 19:38 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.

What was reported inside it

Time	Report	Where	Remark
Jul 11, 3:42 PM CDT	FLASH FLOOD	1 Ene Plymouth, IL	5 TO 6 INCHES OF WATER ON STATE HIGHWAY 61.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 7.6 hours before the alert went out and 148 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: 10 J/kg
Mixed-layer CIN: -364 J/kg
Mixed-layer LCL: 532 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 54 m²/s²
0-3 km storm-relative helicity: 60 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

791 
WGUS53 KDVN 111935
FFWDVN
ILC067-109-120145-
/O.NEW.KDVN.FF.W.0009.210711T1935Z-210712T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Quad Cities IA IL
235 PM CDT Sun Jul 11 2021

The National Weather Service in Quad Cities has issued a

* Flash Flood Warning for...
  East Central Hancock County in west central Illinois...
  Southwestern McDonough County in west central Illinois...

* Until 845 PM CDT Sunday.

* At 235 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen, where these storms produced flash flooding in 
  Augusta. Additional rainfall amounts of 1 to 3 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...
  Colmar and Plymouth.

This includes the following streams and drainages...
  Troublesome Creek, Cedar Creek, East Fork La Moine River, Camp 
  Creek, Moine River, La, Middle Creek, Grindstone Creek, Little 
  Creek, Bronson Creek and Prairie Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4028 9091 4035 9100 4036 9108 4042 9105
      4042 9091 4038 9080 4028 9069 4028 9071
      4028 9072 4028 9075 4028 9078 4028 9080
      4028 9086 4028 9088

FLASH FLOOD...RADAR INDICATED

$$

Gunkel

2 follow-up statements

060 
WGUS73 KDVN 112051
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
351 PM CDT Sun Jul 11 2021

ILC067-109-120145-
/O.CON.KDVN.FF.W.0009.000000T0000Z-210712T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hancock IL-McDonough IL-
351 PM CDT Sun Jul 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM CDT THIS 
EVENING FOR EAST CENTRAL HANCOCK AND SOUTHWESTERN MCDONOUGH 
COUNTIES...

At 351 PM CDT, trained weather spotters reported thunderstorms 
producing heavy rain across the warned area, with 6 inches of water 
running over State Highway 61 near Plymouth. Between 1 and 3 inches 
of rain have fallen. Additional rainfall amounts of 1 to 2 inches 
are possible in the warned area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters reported.

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...
  Colmar and Plymouth.

This includes the following streams and drainages...
  Troublesome Creek, Cedar Creek, East Fork La Moine River, Camp 
  Creek, Moine River, La, Middle Creek, Grindstone Creek, Little 
  Creek, Bronson Creek and Prairie Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4028 9091 4035 9100 4036 9108 4042 9105
      4042 9091 4038 9080 4028 9069 4028 9071
      4028 9072 4028 9075 4028 9078 4028 9080
      4028 9086 4028 9088

FLASH FLOOD...OBSERVED

$$

Gunkel

944 
WGUS73 KDVN 112251
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
551 PM CDT Sun Jul 11 2021

ILC067-109-112301-
/O.CAN.KDVN.FF.W.0009.000000T0000Z-210712T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hancock IL-McDonough IL-
551 PM CDT Sun Jul 11 2021

...FLASH FLOOD WARNING IS CANCELLED FOR EAST CENTRAL HANCOCK AND 
SOUTHWESTERN MCDONOUGH COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures. An areal 
flood warning will remain in effect through the night for southwest 
McDonough and southeast Hancock Counties.

LAT...LON 4028 9091 4035 9100 4036 9108 4042 9105
      4042 9091 4038 9080 4028 9069 4028 9071
      4028 9072 4028 9075 4028 9078 4028 9080
      4028 9086 4028 9088

$$

Ervin

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 11, 11:16 AM CDT	Special Weather Statement	DVN	Hancock	89 min
Jul 11, 11:54 AM CDT	Flash Flood Warning	DVN	Hancock	6 hr
Jul 11, 12:31 PM CDT	Special Weather Statement	DVN	Hancock, McDonough	29 min
Jul 11, 5:49 PM CDT	Areal Flood Warning	DVN	Hancock, McDonough	18 hr

Nearby

Flash Flood Warnings in Illinois, 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.