Alert archive / Illinois / Flash Flood Warnings in 2021
Flash Flood Warning 20, NWS Quad Cities, IA
NWS Quad Cities, IA issued this flash flood warning at Aug 31, 2021, 3:49 PM CDT for Henry County, Mercer County, Illinois. It was in force for 4 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, 3:49 PM CDT (20:49 UTC)
- Expired
- Aug 31, 2021, 8:03 PM CDT
- In force
- 4 hr
- Issued by
- NWS Quad Cities, IA
- Area
- Storm-based polygon
- Flood severity
- None
Counties Henry County, IL, Mercer County, IL
The radar
The Quad Cities radar (KDVN), 53 km from the middle of the area, began a volume at 20:51 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 |
|---|---|---|---|
| Aug 31, 4:15 PM CDT | HEAVY RAIN 2.17 | 2 E Griffin, IL | RAINFALL IN PAST 2 HOURS - STILL RAINING. |
| Aug 31, 8:00 PM CDT | HEAVY RAIN 3.1 | 2 E Griffin, IL | RAINFALL IN THE PAST 6 HOURS. |
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, 8.8 hours before the alert went out and 53 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.
- 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
The text
As transmitted.
162
WGUS53 KDVN 312049
FFWDVN
ILC073-131-010300-
/O.NEW.KDVN.FF.W.0020.210831T2049Z-210901T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Quad Cities IA IL
349 PM CDT Tue Aug 31 2021
The National Weather Service in Quad Cities has issued a
* Flash Flood Warning for...
Southwestern Henry IL County in northwestern Illinois...
Southeastern Mercer County in northwestern Illinois...
* Until 1000 PM CDT Tuesday.
* At 349 PM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 2 and 4 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.
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...
Woodhull, New Windsor, Alpha, Andover, North Henderson, Cable,
Lynn Center, Alexis, Griffin, Ophiem and Swedona.
This includes the following highways...
Interstate 74 in Illinois between mile markers 24 and 33.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4129 9054 4131 9027 4115 9032 4115 9036
4115 9044 4111 9044 4109 9044 4106 9044
4106 9045 4106 9046 4106 9050 4106 9055
4107 9058 4128 9055
FLASH FLOOD...RADAR INDICATED
$$
Gibbs2 follow-up statements
489
WGUS73 KDVN 312138
FFSDVN
Flash Flood Statement
National Weather Service Quad Cities IA IL
438 PM CDT Tue Aug 31 2021
ILC073-131-010300-
/O.CON.KDVN.FF.W.0020.000000T0000Z-210901T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Henry IL IL-Mercer IL-
438 PM CDT Tue Aug 31 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 PM CDT THIS
EVENING FOR SOUTHWESTERN HENRY IL AND SOUTHEASTERN MERCER COUNTIES...
At 438 PM CDT, Doppler radar indicated heavy rain across the warned
area. Between 2 and 5 inches of rain have fallen. Flash flooding is
ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Woodhull, New Windsor, Alpha, Andover, North Henderson, Cable,
Lynn Center, Alexis, Griffin, Ophiem and Swedona.
This includes the following highways...
Interstate 74 in Illinois between mile markers 24 and 33.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4129 9054 4131 9027 4115 9032 4115 9036
4115 9044 4111 9044 4109 9044 4106 9044
4106 9045 4106 9046 4106 9050 4106 9055
4107 9058 4128 9055
FLASH FLOOD...RADAR INDICATED
$$
Gibbs090
WGUS73 KDVN 010103
FFSDVN
Flash Flood Statement
National Weather Service Quad Cities IA IL
803 PM CDT Tue Aug 31 2021
ILC073-131-010113-
/O.CAN.KDVN.FF.W.0020.000000T0000Z-210901T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Henry IL IL-Mercer IL-
803 PM CDT Tue Aug 31 2021
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN HENRY IL AND
SOUTHEASTERN MERCER COUNTIES...
Flood waters have receded. The heavy rain has ended. Flooding is no
longer expected to pose a threat. Please continue to heed remaining
road closures.
LAT...LON 4129 9054 4131 9027 4115 9032 4115 9036
4115 9044 4111 9044 4109 9044 4106 9044
4106 9045 4106 9046 4106 9050 4106 9055
4107 9058 4128 9055
$$
McClureThe office that day
Everything else NWS Quad Cities, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 31, 1:17 PM CDT | Special Weather Statement | DVN | Rock Island | 58 min |
| Aug 31, 1:22 PM CDT | Special Weather Statement | DVN | Rock Island | 23 min |
| Aug 31, 2:01 PM CDT | Flash Flood Warning | DVN | Henry, Mercer, Rock Island | 6 hr |
| Aug 31, 2:46 PM CDT | Special Weather Statement | DVN | Henry, Rock Island | 59 min |
| Aug 31, 3:09 PM CDT | Flash Flood Warning | DVN | Henry, Rock Island | 2 hr |
| Aug 31, 3:41 PM CDT | Special Weather Statement | DVN | Mercer | 64 min |
Nearby
Flash Flood Warnings in Illinois, 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.