Alert archive / Illinois / Flash Flood Warnings in 2021

Flash Flood Warning 19, NWS Quad Cities, IA

August 31, 2021Henry County, Rock Island County, Illinois; Scott County, Iowa

NWS Quad Cities, IA issued this flash flood warning at Aug 31, 2021, 3:09 PM CDT for Henry County, Rock Island County, Illinois; Scott County, Iowa. It was in force for 2 hr. 2 reports 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
Aug 31, 2021, 3:09 PM CDT (20:09 UTC)
Expired
Aug 31, 2021, 5:16 PM CDT
In force
2 hr
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Flood severity
None

Counties Scott County, IA, Henry County, IL, Rock Island County, IL

The radar

The Quad Cities radar (KDVN), 17 km from the middle of the area, began a volume at 20:12 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

TimeReportWhereRemark
Aug 31, 3:42 PM CDTHEAVY RAIN 1.031 W Bettendorf, IARAINFALL SINCE 1:15 PM.
Aug 31, 4:47 PM CDTHEAVY RAIN 11 Ene Green River, ILSTILL RAINING.

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, 8.2 hours before the alert went out and 12 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, Davenport, at 12:00Z on 2021-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 12:00Z on 2021-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1564 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

607 
WGUS53 KDVN 312009
FFWDVN
IAC163-ILC073-161-010600-
/O.NEW.KDVN.FF.W.0019.210831T2009Z-210901T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Quad Cities IA IL
309 PM CDT Tue Aug 31 2021

The National Weather Service in Quad Cities has issued a

* Flash Flood Warning for...
  Central Scott County in east central Iowa...
  Northwestern Henry IL County in northwestern Illinois...
  Southeastern Rock Island County in northwestern Illinois...

* Until 100 AM CDT Wednesday.

* At 309 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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 ongoing or expected 
  to begin shortly. Minor flooding has been reported and is expected 
  to worsen.

  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...
  Davenport, Moline, Rock Island, Bettendorf, East Moline, Silvis, 
  Eldridge, Milan, Colona, Le Claire, Coal Valley, Hampton, Port 
  Byron, Walcott, Blue Grass, Buffalo, Andalusia, Rapids City, 
  Princeton and Riverdale.

This includes the following highways...
	Interstate 280 between mile markers 1 and 18.
	Interstate 74 in Illinois between mile markers 1 and 16.
	Interstate 80 in Iowa between mile markers 287 and 306.
	Interstate 74 in Iowa between mile markers 1 and 5.
	Interstate 80 in Illinois between mile markers 1 and 14.
	Interstate 88 between mile markers 1 and 11.

This includes the following streams and drainages...
  Shaffer Creek, Duck Creek, Case Creek, Geneseo Creek, Canoe Creek, 
  Glynn Creek, Mosquito Creek, Mineral Creek, Lost Creek, Black Hawk 
  Creek, Coal Creek, Goose Creek, Zuma Creek, Bud Creek, Walnut 
  Creek, Mill Creek, Silver Creek, Sugar Creek, Mud Creek, Sand 
  Creek and Hickory Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4157 9077 4168 9069 4168 9044 4162 9017
      4159 9017 4159 9018 4159 9019 4158 9018
      4158 9017 4150 9014 4137 9037 4138 9051
      4138 9055 4139 9075

FLASH FLOOD...RADAR INDICATED

$$

Gibbs
2 follow-up statements
048 
WGUS73 KDVN 312134
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
434 PM CDT Tue Aug 31 2021

IAC163-ILC073-161-010600-
/O.CON.KDVN.FF.W.0019.000000T0000Z-210901T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Scott IA-Henry IL IL-Rock Island IL-
434 PM CDT Tue Aug 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1 AM CDT WEDNESDAY 
FOR SOUTHERN SCOTT, WEST CENTRAL HENRY IL AND SOUTHEASTERN ROCK 
ISLAND COUNTIES...

At 434 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 4 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...
  Davenport, Moline, Rock Island, Bettendorf, East Moline, Silvis, 
  Milan, Colona, Le Claire, Coal Valley, Hampton, Blue Grass, 
  Buffalo, Andalusia, Rapids City, Riverdale, Oak Grove, Warner, 
  Carbon Cliff and Panorama Park.

This includes the following highways...
	Interstate 280 between mile markers 2 and 18.
	Interstate 74 in Illinois between mile markers 1 and 16.
	Interstate 80 in Iowa between mile markers 293 and 304.
	Interstate 74 in Iowa between mile markers 1 and 5.
	Interstate 80 in Illinois between mile markers 1 and 4...and
	between mile markers 7 and 11.
	Interstate 88 near mile marker 1.

This includes the following streams and drainages...
  Mill Creek, Mineral Creek, Mississippi River, Shaffer Creek, Rock 
  River, Black Hawk Creek, Mud Creek, Spencer Creek, Sugar Creek, 
  Walnut Creek, Silver Creek, Green River, Goose Creek, Coal Creek, 
  Sand Creek, Mosquito Creek, Duck Creek, Case Creek and Zuma Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4157 9077 4160 9063 4160 9041 4159 9037
      4156 9033 4155 9029 4151 9036 4144 9030
      4137 9037 4138 9051 4138 9055 4143 9059
      4143 9075

FLASH FLOOD...RADAR INDICATED

$$

Gibbs
977 
WGUS73 KDVN 312216
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
516 PM CDT Tue Aug 31 2021

IAC163-ILC073-161-312226-
/O.CAN.KDVN.FF.W.0019.000000T0000Z-210901T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Scott IA-Henry IL IL-Rock Island IL-
516 PM CDT Tue Aug 31 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHERN SCOTT, WEST CENTRAL 
HENRY IL AND SOUTHEASTERN ROCK ISLAND COUNTIES...

Flood waters have receded. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4157 9077 4160 9063 4160 9041 4159 9037
      4156 9033 4155 9029 4151 9036 4144 9030
      4137 9037 4138 9051 4138 9055 4143 9059
      4143 9075

$$

Gibbs

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 1:17 PM CDTSpecial Weather StatementDVNRock Island58 min
Aug 31, 1:22 PM CDTSpecial Weather StatementDVNRock Island23 min
Aug 31, 2:01 PM CDTFlash Flood WarningDVNHenry, Mercer, Rock Island6 hr
Aug 31, 2:46 PM CDTSpecial Weather StatementDVNHenry, Rock Island59 min
Aug 31, 3:41 PM CDTSpecial Weather StatementDVNMercer64 min
Aug 31, 3:49 PM CDTFlash Flood WarningDVNHenry, Mercer4 hr

Nearby

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