Alert archive / Iowa / Flash Flood Warnings in 2021

Flash Flood Warning 17, NWS Quad Cities, IA

August 28, 2021Buchanan County, Delaware County, Iowa

NWS Quad Cities, IA issued this flash flood warning at Aug 28, 2021, 5:27 AM CDT for Buchanan County, Delaware County, Iowa. It was in force for 4 hr. 3 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 28, 2021, 5:27 AM CDT (10:27 UTC)
Expired: Aug 28, 2021, 9:17 AM CDT
In force: 4 hr
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Flood severity: None

Counties Buchanan County, IA, Delaware County, IA

The radar

The Quad Cities radar (KDVN), 143 km from the middle of the area, began a volume at 10:29 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 28, 8:00 AM CDT	FLASH FLOOD	1 N Independence, IA	SPOTTER REPORTS DEBRIS FROM WATER FLOW OVER MANY ROADS, INCLUDING HIGHWAY 150. DITCHES REMAINED FULL WITH LOTS OF STANDING WATER AT THE FAIRGROUNDS INTO LATE MORNING.
Aug 28, 8:41 AM CDT	HEAVY RAIN 2.97	1 N Independence, IA	COCORAHS.
Aug 28, 8:42 AM CDT	HEAVY RAIN 2.74	1 Ese Independence, IA	COCORAHS.

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, 10.5 hours before the alert went out and 147 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 995 J/kg
Mixed-layer CIN: -68 J/kg
Mixed-layer LCL: 1707 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 148 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

644 
WGUS53 KDVN 281027
FFWDVN
IAC019-055-281630-
/O.NEW.KDVN.FF.W.0017.210828T1027Z-210828T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Quad Cities IA IL
527 AM CDT Sat Aug 28 2021

The National Weather Service in Quad Cities has issued a

* Flash Flood Warning for...
  Buchanan County in northeastern Iowa...
  Northwestern Delaware County in northeastern Iowa...

* Until 1130 AM CDT Saturday.

* At 527 AM 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.

  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...
  Independence, Jesup, Winthrop, Hazleton, Lamont, Brandon, Aurora, 
  Dundee, Masonville, Stanley, Buchanan County Fairgrounds, Jakway 
  Park, Wapsipinicon Golf Course, Fontana County Park, Fontana Park, 
  Otterville, Winthrop Golf Course, Independence Airport, Littleton 
  and Lime Creek County Park.

This includes the following highways...
	Interstate 380 between mile markers 49 and 55.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4240 9182 4230 9194 4230 9206 4246 9206
      4247 9208 4253 9208 4264 9196 4264 9144
      4252 9144

FLASH FLOOD...RADAR INDICATED

$$

Ervin

2 follow-up statements

051 
WGUS73 KDVN 281140
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
640 AM CDT Sat Aug 28 2021

IAC019-055-281630-
/O.CON.KDVN.FF.W.0017.000000T0000Z-210828T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Buchanan IA-Delaware IA-
640 AM CDT Sat Aug 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1130 AM CDT THIS 
MORNING FOR BUCHANAN AND NORTHWESTERN DELAWARE COUNTIES...

At 640 AM CDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 2 
and 3 inches of rain have fallen. Additional rainfall amounts of 1 
to 2 inches are possible in the warned area over the next few hours. 
Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

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...
  Independence, Jesup, Winthrop, Hazleton, Lamont, Brandon, Aurora, 
  Dundee, Masonville, Stanley, Buchanan County Fairgrounds, Jakway 
  Park, Wapsipinicon Golf Course, Fontana County Park, Fontana Park, 
  Otterville, Winthrop Golf Course, Independence Airport, Littleton 
  and Lime Creek County Park.

This includes the following highways...
	Interstate 380 between mile markers 49 and 55.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4240 9182 4230 9194 4230 9206 4246 9206
      4247 9208 4253 9208 4264 9196 4264 9144
      4252 9144

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Speck

511 
WGUS73 KDVN 281417
FFSDVN

Flash Flood Statement
National Weather Service Quad Cities IA IL
917 AM CDT Sat Aug 28 2021

IAC019-055-281427-
/O.CAN.KDVN.FF.W.0017.000000T0000Z-210828T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Buchanan IA-Delaware IA-
917 AM CDT Sat Aug 28 2021

...FLASH FLOOD WARNING IS CANCELLED FOR BUCHANAN AND NORTHWESTERN 
DELAWARE COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4240 9182 4230 9194 4230 9206 4246 9206
      4247 9206 4247 9208 4253 9208 4264 9196
      4264 9144 4252 9144

$$

Cousins

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 28, 2:33 AM CDT	Special Weather Statement	DVN	Buchanan	42 min
Aug 28, 4:32 AM CDT	Special Weather Statement	DVN	Buchanan	43 min
Aug 28, 5:21 AM CDT	Special Weather Statement	DVN	Buchanan	24 min
Aug 28, 11:34 AM CDT	River Flood Watch	DVN	Delaware, Jones	9 hr

Nearby

Flash Flood Warnings in Iowa, 2021 Every 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.