Alert archive / Iowa / Flash Flood Warnings in 2017

Flash Flood Warning 15, NWS La Crosse, WI

July 21, 2017Howard County, Iowa

NWS La Crosse, WI issued this flash flood warning at Jul 21, 2017, 9:22 AM CDT for Howard County, Iowa. 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: Jul 21, 2017, 9:22 AM CDT (14:22 UTC)
Expired: Jul 21, 2017, 12:15 PM CDT
In force: 3 hr
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Flood severity: None

County Howard County, IA

The radar

The La Crosse radar (KARX), 106 km from the middle of the area, began a volume at 14:24 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

Minneapolis, MN (KMPX), launched 12:00Z, 2.4 hours before the alert went out and 191 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2450 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 156 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

121 
WGUS53 KARX 211422
FFWARX
IAC089-211715-
/O.NEW.KARX.FF.W.0015.170721T1422Z-170721T1715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service La Crosse WI
922 AM CDT FRI JUL 21 2017

The National Weather Service in La Crosse has issued a

* Flash Flood Warning for...
  Howard County in northeastern Iowa...

* Until 1215 PM CDT

* At 921 AM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Flash flooding is expected to 
  begin shortly. More thunderstorms are moving into this area as 
  well.

* Some locations that will experience flooding include...
  Cresco, Riceville, Elma, Lime Springs, Protivin, and Chester.

LAT...LON 4350 9255 4350 9208 4321 9208 4321 9255

$$

Shea

2 follow-up statements

970 
WGUS73 KARX 211532
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
1032 AM CDT FRI JUL 21 2017

IAC089-211715-
/O.CON.KARX.FF.W.0015.000000T0000Z-170721T1715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Howard IA-
1032 AM CDT FRI JUL 21 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 PM CDT FOR
HOWARD COUNTY...

At 1028 AM CDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area.  Flash flooding is expected to begin
shortly.

Some street flooding has been reported in Cresco Iowa but no other 
problems have been noted by area law enforcement. Between 1 and 2 
inches of rain has fallen so far, which more rain moving in.

Areas that may see flooding include Riceville, Cresco, and Elma. 
Branches of the Wapsipinicon River and Crane Creek may see quick 
rises.

LAT...LON 4350 9255 4350 9208 4321 9208 4321 9255

$$

Shea

684 
WGUS73 KARX 211627
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
1127 AM CDT FRI JUL 21 2017

IAC089-211635-
/O.CAN.KARX.FF.W.0015.000000T0000Z-170721T1715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Howard IA-
1127 AM CDT FRI JUL 21 2017

...THE FLASH FLOOD WARNING FOR HOWARD COUNTY IS CANCELLED...

The heaviest rain has ended and area law enforcement is not 
reporting any water related issues on roads. Some flooding in fields 
is noted though.

Please continue to heed any remaining road closures.

LAT...LON 4350 9255 4350 9208 4321 9208 4321 9255

$$

Shea

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 21, 10:18 AM CDT	Flash Flood Warning	ARX	Fayette	3 hr
Jul 21, 10:45 AM CDT	Flash Flood Warning	ARX	Chickasaw	3 hr
Jul 21, 5:08 PM CDT	Severe Thunderstorm Warning	ARX	Clayton	35 min
Jul 21, 5:57 PM CDT	Severe Thunderstorm Warning	ARX	Clayton, Fayette	48 min
Jul 21, 6:20 PM CDT	Severe Thunderstorm Warning	ARX	Fayette	25 min
Jul 21, 6:45 PM CDT	Special Weather Statement	ARX	Clayton	60 min
Jul 21, 6:54 PM CDT	Flash Flood Warning	ARX	Clayton	15 hr

Nearby

Flash Flood Warnings in Iowa, 2017 Every flash flood warning in 2017

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.