Alert archive / Illinois / Flash Flood Warnings in 2021

Flash Flood Warning 1, NWS Quad Cities, IA

June 9, 2021Carroll County, Illinois

NWS Quad Cities, IA issued this flash flood warning at Jun 9, 2021, 9:35 PM CDT for Carroll County, Illinois. It was in force for 3 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
Jun 9, 2021, 9:35 PM CDT (02:35 UTC)
Expired
Jun 10, 2021, 12:48 AM CDT
In force
3 hr
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Flood severity
None

County Carroll County, IL

The radar

The Quad Cities radar (KDVN), 64 km from the middle of the area, began a volume at 02:38 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.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.6 hours before the alert went out and 59 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 00:00Z on 2021-06-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 402 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2021-06-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -18 square meters per square second.1939Sfc1 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
402 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
1694 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-18 m²/s²
0-3 km storm-relative helicity
4 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

547 
WGUS53 KDVN 100235
FFWDVN
ILC015-100830-
/O.NEW.KDVN.FF.W.0001.210610T0235Z-210610T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Quad Cities IA IL
935 PM CDT Wed Jun 9 2021

The National Weather Service in Quad Cities has issued a

* Flash Flood Warning for...
  Central Carroll County in northwestern Illinois...

* Until 330 AM CDT.

* At 935 PM CDT, Doppler radar indicated slow moving thunderstorms 
  producing heavy rain across the warned area. Between 2 and 4 
  inches of rain have fallen. Flash flooding is already occurring.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  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 flash flooding include...
  Mount Carroll, Savanna, Argo Fay, Thomson, Center Hill and Wacker.

At 923 PM, a trained spotter reported 3.85 inches of rain has fallen 
in Mount Carroll.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4197 9006 4197 9004 4204 8990 4219 8993
      4217 9013 4198 9013 4197 9012

FLASH FLOOD...RADAR INDICATED

$$

Sheets
2 follow-up statements
489 
WGUS73 KDVN 100352
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
1052 PM CDT Wed Jun 9 2021

ILC015-100830-
/O.CON.KDVN.FF.W.0001.000000T0000Z-210610T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carroll IL-
1052 PM CDT Wed Jun 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 AM CDT THURSDAY 
FOR CENTRAL CARROLL COUNTY...

At 1052 PM CDT, Doppler radar indicated slow moving thunderstorms 
producing heavy rain were redeveloping over the warned area. Radar 
and spotter reports indicated rainfall amounts between 2 and 4 
inches has already fallen this evening over the Mount Carroll area. 
Additional rainfall of one half to one inch can be expected through 
midnight, leading to flash flooding.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Doppler radar.

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 flash flooding include...
  Mount Carroll, Savanna, Argo Fay, Thomson, Center Hill and Wacker.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4197 9006 4197 9004 4204 8990 4219 8993
      4217 9013 4198 9013 4197 9012

FLASH FLOOD...RADAR INDICATED

$$

Sheets
441 
WGUS73 KDVN 100548
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
1248 AM CDT Thu Jun 10 2021

ILC015-100558-
/O.CAN.KDVN.FF.W.0001.000000T0000Z-210610T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carroll IL-
1248 AM CDT Thu Jun 10 2021

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL CARROLL COUNTY...

The heavy rain has ended so additional flooding is no longer 
expected to pose a threat. Please continue to heed any road closures 
or be aware of high water across the area as rainfall runoff moves 
into area streams and creeks.

LAT...LON 4197 9006 4197 9004 4204 8990 4219 8993
      4217 9013 4198 9013 4197 9012

$$

Brooks

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 8:43 PM CDTSpecial Weather StatementDVNCarroll32 min
Jun 9, 9:02 PM CDTSpecial Weather StatementDVNCarroll28 min
Jun 9, 9:50 PM CDTSpecial Weather StatementDVNJo Daviess40 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.