Alert archive / Illinois / Flash Flood Watches in 2021

Flash Flood Watch 4, NWS Quad Cities, IA

August 12, 20214 counties in Illinois; Des Moines County, Lee County, Van Buren County, Iowa; Clark County, Scotland County, Missouri

NWS Quad Cities, IA issued this flash flood watch at Aug 12, 2021, 12:44 PM CDT for 4 counties in Illinois; Des Moines County, Lee County, Van Buren County, Iowa; Clark County, Scotland County, Missouri. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Aug 12, 2021, 12:44 PM CDT (17:44 UTC)
Expired
Aug 12, 2021, 9:08 PM CDT
In force
8 hr
Issued by
NWS Quad Cities, IA
Flood severity
None

Counties Des Moines County, IA, Lee County, IA, Van Buren County, IA, Hancock County, IL, Henderson County, IL, McDonough County, IL, Warren County, IL, Clark County, MO, Scotland County, MO

The radar

The Quad Cities radar (KDVN), 125 km from the middle of the area, began a volume at 17:43 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 12:00Z, 5.7 hours before the alert went out and 129 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 2021-08-12Temperature 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 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
2463 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
27 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.

941 
WGUS63 KDVN 121744
FFADVN

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Quad Cities IA IL
1244 PM CDT Thu Aug 12 2021

IAZ089-098-099-ILZ025-026-034-035-MOZ009-010-130145-
/O.NEW.KDVN.FF.A.0004.210812T1744Z-210813T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Des Moines-Van Buren-Lee-Henderson-Warren-Hancock-McDonough-Scotland-
Clark-
Including the cities of Carthage, Monmouth, Kahoka, Oquawka, Macomb, 
Keosauqua, Burlington, Fort Madison, and Memphis
1244 PM CDT Thu Aug 12 2021

...FLASH FLOOD WATCH IN EFFECT THROUGH FRIDAY MORNING...

The National Weather Service in Quad Cities has issued a

* Flash Flood Watch for portions of west central Illinois, southeast 
  Iowa and northeast Missouri, including the following areas, in 
  west central Illinois, Hancock, Henderson, McDonough and Warren. 
  In southeast Iowa, Des Moines, Lee and Van Buren. In northeast 
  Missouri, Clark and Scotland.

* Through Friday morning.

* Torrential rainfall from storms this morning will continue into 
  the afternoon and sink south into Missouri and central Illinois. 
  However, an approaching cold front is expected to bring additional 
  storms, with more heavy rainfall. This next round of storms will 
  continue the threat for flash flooding into the night time hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Ervin
2 follow-up statements
083 
WGUS63 KDVN 122355
FFADVN

Flood Watch
National Weather Service Quad Cities IA IL
655 PM CDT Thu Aug 12 2021

IAZ089-098-099-ILZ025-026-034-035-MOZ009-010-130800-
/O.CON.KDVN.FF.A.0004.000000T0000Z-210813T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Des Moines-Van Buren-Lee-Henderson-Warren-Hancock-McDonough-Scotland-
Clark-
Including the cities of Carthage, Monmouth, Kahoka, Oquawka, Macomb, 
Keosauqua, Burlington, Fort Madison, and Memphis
655 PM CDT Thu Aug 12 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY MORNING...

The Flash Flood Watch continues for

* Portions of west central Illinois, southeast Iowa and northeast 
  Missouri, including the following areas, in west central Illinois, 
  Hancock, Henderson, McDonough and Warren. In southeast Iowa, Des 
  Moines, Lee and Van Buren. In northeast Missouri, Clark and 
  Scotland.

* Through Friday morning.

* Between 2 and 5 inches of rain has fallen over the past 24 hours. 
  Scattered thunderstorms are possible overnight along a cold front 
  which may bring heavy rainfall and a threat for flash flooding. 
  However, the coverage of storms may remain low which would limit 
  the potential for additional flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Uttech
414 
WGUS63 KDVN 130208
FFADVN

Flood Watch
National Weather Service Quad Cities IA IL
908 PM CDT Thu Aug 12 2021

IAZ089-098-099-ILZ025-026-034-035-MOZ009-010-130315-
/O.CAN.KDVN.FF.A.0004.000000T0000Z-210813T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Des Moines-Van Buren-Lee-Henderson-Warren-Hancock-McDonough-Scotland-
Clark-
Including the cities of Carthage, Monmouth, Kahoka, Oquawka, Macomb, 
Keosauqua, Burlington, Fort Madison, and Memphis
908 PM CDT Thu Aug 12 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of west central Illinois, 
southeast Iowa and northeast Missouri, including the following 
areas, in west central Illinois, Hancock, Henderson, McDonough and 
Warren. In southeast Iowa, Des Moines, Lee and Van Buren. In 
northeast Missouri, Clark and Scotland has been cancelled.

The Flood Watch is cancelled. Flooding is no longer expected to pose 
a significant threat. Although isolated thunderstorms remain 
possible through the night, the risk for widespread heavy rainfall 
has decreased. Please continue to heed remaining road closures.

$$

Uttech

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 8:34 PM CDTSpecial Weather StatementDVNBureau26 min
Aug 12, 2:39 AM CDTSpecial Weather StatementDVNHenderson36 min
Aug 12, 2:43 AM CDTSpecial Weather StatementDVNPutnam32 min
Aug 12, 2:57 AM CDTHeat AdvisoryDVNHancock, McDonough8 hr
Aug 12, 2:59 AM CDTSpecial Weather StatementDVNHenderson, Warren31 min
Aug 12, 9:54 AM CDTSpecial Weather StatementDVNHancock, Henderson, McDonough96 min
Aug 12, 11:10 AM CDTSpecial Weather StatementDVNPutnam35 min
Aug 12, 11:29 AM CDTSpecial Weather StatementDVNHancock, McDonough91 min
Aug 12, 12:55 PM CDTSpecial Weather StatementDVNHancock, McDonough95 min
Aug 12, 1:39 PM CDTRiver Flood WatchDVNHancock, McDonough8 hr
Aug 12, 2:09 AM CDTSpecial Weather StatementDVNLee21 min
Aug 12, 7:24 AM CDTSpecial Weather StatementDVNVan Buren36 min
Aug 12, 7:26 AM CDTSevere Thunderstorm WarningDVNVan Buren33 min
Aug 12, 9:10 AM CDTSpecial Weather StatementDVNVan Buren50 min
Aug 12, 9:23 AM CDTFlash Flood WarningDVNVan Buren4 hr
Aug 12, 10:32 AM CDTFlash Flood WarningDVNLee, Van Buren6 hr
Aug 12, 8:35 AM CDTSpecial Weather StatementDVNScotland25 min
Aug 12, 2:29 PM CDTFlash Flood WarningDVNScotland4 hr

Nearby

Flash Flood Watches in Illinois, 2021Flash Flood Watches in Iowa, 2021Flash Flood Watches in Missouri, 2021Every flash flood watch 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.