Alert archive / Iowa / Flash Flood Warnings in 2021

Flash Flood Warning 4, NWS Quad Cities, IA

June 25, 2021Linn County, Iowa

NWS Quad Cities, IA issued this flash flood warning at Jun 25, 2021, 11:37 PM CDT for Linn County, Iowa. It was in force for 101 min. 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
Jun 25, 2021, 11:37 PM CDT (04:37 UTC)
Expired
Jun 26, 2021, 1:18 AM CDT
In force
101 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Flood severity
None

County Linn County, IA

The radar

The Quad Cities radar (KDVN), 96 km from the middle of the area, began a volume at 04:35 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
Jun 25, 11:41 PM CDTFLASH FLOOD1 Ne Marion, IACORRECTS PREVIOUS FLASH FLOOD REPORT FROM 1 NE MARION. DEEP FLOWING WATER AT 35TH STREET AND MCGOWAN BOULEVARD.
Jun 26, 12:02 AM CDTHEAVY RAIN 6.761 Ne Marion, IACORRECTS PREVIOUS HEAVY RAIN REPORT FROM 1 NE MARION.

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 00:00Z, 4.6 hours before the alert went out and 101 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 2021-06-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 316 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 2021-06-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 square meters per square second.19395878Sfc1 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
316 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
897 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.8

Open this sounding in Storm Lab

The text

As transmitted.

538 
WGUS53 KDVN 260437
FFWDVN
IAC113-260730-
/O.NEW.KDVN.FF.W.0004.210626T0437Z-210626T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Quad Cities IA IL
1137 PM CDT Fri Jun 25 2021

The National Weather Service in Quad Cities has issued a

* Flash Flood Warning for...
  Central Linn County in east central Iowa...

* Until 230 AM CDT.

* At 1137 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 6 inches of rain 
  have fallen. Additional rainfall amounts of 0.5 to 1 inch 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...
  Cedar Rapids, Marion, Springville, Whittier, Marion Airport and 
  Squaw Creek Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4204 9166 4215 9153 4208 9139 4199 9161

FLASH FLOOD...RADAR INDICATED

$$

Uttech
2 follow-up statements
570 
WGUS73 KDVN 260500
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
1200 AM CDT Sat Jun 26 2021

IAC113-260730-
/O.CON.KDVN.FF.W.0004.000000T0000Z-210626T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Linn IA-
1200 AM CDT Sat Jun 26 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM CDT SATURDAY 
FOR CENTRAL LINN COUNTY...

At 1200 AM CDT, trained spotters reported thunderstorms producing 
heavy rain across the warned area. Between 3 and 6 inches of rain 
have fallen. Flash flooding is ongoing or expected to begin shortly. 
Additional rainfall of less than a half inch is anticipated.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters.

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...
  Cedar Rapids, Marion, Springville, Whittier, Marion Airport and 
  Squaw Creek Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4204 9166 4215 9153 4208 9139 4199 9161

FLASH FLOOD...OBSERVED

$$

Uttech
272 
WGUS73 KDVN 260618
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
118 AM CDT Sat Jun 26 2021

IAC113-260628-
/O.CAN.KDVN.FF.W.0004.000000T0000Z-210626T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Linn IA-
118 AM CDT Sat Jun 26 2021

...FLASH FLOOD WARNING FOR CENTRAL LINN COUNTY HAS BEEN REPLACED 
WITH A FLOOD WARNING...

The heavy rain across the warned area has ended and little 
additional rainfall is expected overnight. Any residual flood waters 
should continue to slowly recede. If you encounter water over 
roadways do not attempt to drive through it.

LAT...LON 4204 9166 4215 9153 4208 9139 4199 9161

$$

Uttech

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 25, 7:54 PM CDTSpecial Weather StatementDVNLinn21 min
Jun 25, 9:18 PM CDTSpecial Weather StatementDVNDes Moines, Henry, Lee27 min
Jun 25, 10:51 PM CDTSpecial Weather StatementDVNLinn39 min
Jun 25, 10:59 PM CDTSpecial Weather StatementDVNBenton46 min
Jun 26, 12:05 AM CDTSpecial Weather StatementDVNBenton40 min
Jun 26, 1:18 AM CDTAreal Flood WarningDVNLinn5 hr
Jun 26, 6:49 PM CDTSpecial Weather StatementDVNIowa26 min

Nearby

Flash 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.