Alert archive / Wisconsin / Flash Flood Warnings in 2018

Flash Flood Warning 27, NWS La Crosse, WI

September 20, 2018Crawford County, Grant County, Wisconsin; Clayton County, Fayette County, Iowa

NWS La Crosse, WI issued this flash flood warning at Sep 20, 2018, 1:16 AM CDT for Crawford County, Grant County, Wisconsin; Clayton County, Fayette County, Iowa. It was in force for 3 hr. 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: Sep 20, 2018, 1:16 AM CDT (06:16 UTC)
Expired: Sep 20, 2018, 4:15 AM CDT
In force: 3 hr
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Flood severity: None

Counties Clayton County, IA, Fayette County, IA, Crawford County, WI, Grant County, WI

The radar

The La Crosse radar (KARX), 95 km from the middle of the area, began a volume at 06:16 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
Sep 20, 3:45 AM CDT	HEAVY RAIN 2.62	1 E Eldorado, IA	MESONET STATION EDRI4, ELDORADO.
Sep 20, 4:00 AM CDT	HEAVY RAIN 2.55	4 Wsw Saint Olaf, IA	MESONET STATION BSHI4, ELKADER 5NW.

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, 6.3 hours before the alert went out and 162 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: 14 J/kg
Mixed-layer CIN: -337 J/kg
Mixed-layer LCL: 1513 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 212 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

805 
WGUS53 KARX 200616
FFWARX
IAC043-065-WIC023-043-200915-
/O.NEW.KARX.FF.W.0027.180920T0616Z-180920T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service La Crosse WI
116 AM CDT THU SEP 20 2018

The National Weather Service in La Crosse has issued a

* Flash Flood Warning for...
  Northwestern Clayton County in northeastern Iowa...
  Northern Fayette County in northeastern Iowa...
  Central Grant County in southwestern Wisconsin...
  Southwestern Crawford County in southwestern Wisconsin...

* Until 415 AM CDT.

* At 113 AM CDT, local law enforcement reported mud slides near 
  McGregor Iowa along with evacuations at a campsite due to high 
  water on Bloody Run creek. Other smaller creeks are running high 
  or out of their banks resulting in localized flooding, and 
  expected additional rainfall upwards of an inch could lead to 
  widespread flash flooding. 

* Some locations that will experience flooding include...
  Prairie Du Chien, Lancaster, West Union, Elkader, Fennimore, 
  Postville, Monona, McGregor, Garnavillo, Bloomington, Clermont, 
  Marquette, Farmersburg, Waucoma, Bridgeport, and Wauzeka.

Excessive rainfall over the warned area will cause mud slides near
steep terrain. The mud slide can consist of rock, mud, vegetation and
other loose materials.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4287 9160 4286 9208 4308 9208 4308 9118
      4309 9099 4310 9083 4296 9043 4280 9043

$$

Rieck

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 19, 9:07 PM CDT	Flash Flood Warning	ARX	Grant	6 hr
Sep 20, 2:51 AM CDT	Areal Flood Warning	ARX	Crawford, Grant	12 hr
Sep 20, 10:35 AM CDT	Special Weather Statement	ARX	La Crosse	40 min
Sep 20, 10:44 AM CDT	River Flood Warning	ARX	Vernon	4 days
Sep 20, 10:44 AM CDT	River Flood Warning	ARX	Crawford	4 days
Sep 20, 10:44 AM CDT	River Flood Warning	ARX	Crawford	6 days
Sep 20, 10:44 AM CDT	River Flood Warning	ARX	Crawford	71 hr
Sep 20, 11:12 AM CDT	Special Weather Statement	ARX	La Crosse, Vernon	33 min
Sep 20, 11:45 AM CDT	Special Weather Statement	ARX	Juneau, Monroe	60 min
Sep 20, 4:00 PM CDT	Special Weather Statement	ARX	Taylor	60 min
Sep 20, 6:56 PM CDT	Special Weather Statement	ARX	Buffalo	94 min
Sep 20, 2:37 AM CDT	River Flood Warning	ARX	Clayton	5 days
Sep 20, 2:37 AM CDT	River Flood Warning	ARX	Clayton	4 days
Sep 20, 10:51 AM CDT	River Flood Warning	ARX	Winneshiek	36 hr
Sep 20, 5:59 PM CDT	Special Weather Statement	ARX	Chickasaw, Floyd, Howard, Mitchell	61 min

Nearby

Flash Flood Warnings in Wisconsin, 2018 Flash Flood Warnings in Iowa, 2018 Every flash flood warning in 2018

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.