Alert archive / Iowa / Flash Flood Warnings in 2016

Flash Flood Warning 40, NWS La Crosse, WI

September 21, 2016Floyd County, Iowa

NWS La Crosse, WI issued this flash flood warning at Sep 21, 2016, 6:03 PM CDT for Floyd County, Iowa. It was in force for 3 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
Sep 21, 2016, 6:03 PM CDT (23:03 UTC)
Expired
Sep 21, 2016, 9:00 PM CDT
In force
3 hr
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Flood severity
None

County Floyd County, IA

The radar

The La Crosse radar (KARX), 159 km from the middle of the area, began a volume at 23:04 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
Sep 21, 6:35 PM CDTFLASH FLOODCharles City, IANUMEROUS ROADS WITH WATER OVER THEM THROUGHOUT THE COUNTY.
Sep 21, 7:40 PM CDTFLASH FLOODCharles City, IAFLOODING IN SOUTHWEST TWO THIRDS OF CITY.
Sep 21, 8:00 PM CDTFLASH FLOODMarble Rock, IANEARLY EVERY ROAD ACROSS THE SOUTHWEST TWO-THIRDS OF FLOYD COUNTY IS UNDER WATER WITH TRAVEL IMPOSSIBLE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 11.1 hours before the alert went out and 214 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, Minneapolis, MN at 12:00Z on 2016-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 515 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, Minneapolis, MN at 12:00Z on 2016-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 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
515 J/kg
Mixed-layer CIN
-331 J/kg
Mixed-layer LCL
738 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.5

Open this sounding in Storm Lab

The text

As transmitted.

251 
WGUS53 KARX 212303
FFWARX
IAC067-220200-
/O.NEW.KARX.FF.W.0040.160921T2303Z-160922T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
603 PM CDT WED SEP 21 2016

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN FLOYD COUNTY IN NORTH CENTRAL IOWA...

* UNTIL 900 PM CDT

* AT 602 PM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA. 1 TO 3 INCHES OF RAIN HAVE
  ALREADY FALLEN AND ANOTHER 1 TO 3 INCHES IS LIKELY BY 9 PM. FLASH
  FLOODING IS EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  CHARLES CITY...FLOYD...MARBLE ROCK...OAKWOOD...POWERSVILLE...
  ROSEVILLE...MIDWAY...BUNNS WOODS COUNTY PARK...
  CARRVILLE AND FLOYD CROSSING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4293 9302 4312 9278 4316 9272 4310 9255
      4291 9256 4291 9303

$$

AJ
2 follow-up statements
042 
WGUS73 KARX 212356
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
656 PM CDT WED SEP 21 2016

IAC067-220200-
/O.CON.KARX.FF.W.0040.000000T0000Z-160922T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FLOYD IA-
656 PM CDT WED SEP 21 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM CDT FOR
SOUTHEASTERN FLOYD COUNTY...

AT 654 PM CDT...LAW ENFORCEMENT REPORTED NUMEROUS ROADS WITH WATER
ON THEM. DOPPLER RADAR INDICATED THUNDERSTORMS STILL PRODUCING HEAVY
RAIN ACROSS THE WARNED AREA...WITH 3 TO 5 INCHES FALLEN SO FAR. AN
ADDITIONAL 1 TO 3 INCHES IS POSSIBLE BY 9 PM...WHICH WILL ONLY
EXACERABATE ONGOING FLOODING.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
CHARLES CITY...FLOYD...MARBLE ROCK...OAKWOOD...POWERSVILLE...
ROSEVILLE...MIDWAY...BUNNS WOODS COUNTY PARK...
CARRVILLE AND FLOYD CROSSING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4293 9302 4312 9278 4316 9272 4310 9255
      4291 9256 4291 9303

$$

AJ
246 
WGUS73 KARX 220047
FFSARX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
747 PM CDT WED SEP 21 2016

IAC067-220200-
/O.CON.KARX.FF.W.0040.000000T0000Z-160922T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FLOYD IA-
747 PM CDT WED SEP 21 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM CDT FOR
SOUTHEASTERN FLOYD COUNTY...

AT 746 PM CDT...LOCAL LAW ENFORCEMENT REPORTED NUMEROUS FLOODED
ROADWAYS. ANY TRAVEL IS STRONGLY DISCOURAGED...ESPECIALLY NOW THAT
IT IS NIGHT. DOPPLER RADAR RAINFALL ESTIMATES WERE 4 TO 8 INCHES AND
ANOTHER 2 INCHES IS POSSIBLE BY 9 PM. THE FLASH FLOOD WARNING
WILL LIKELY BE EXTENDED WELL INTO THE NIGHT.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
CHARLES CITY...FLOYD...MARBLE ROCK...OAKWOOD...POWERSVILLE...
ROSEVILLE...MIDWAY...BUNNS WOODS COUNTY PARK...
CARRVILLE AND FLOYD CROSSING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4293 9302 4312 9278 4316 9272 4310 9255
      4291 9256 4291 9303

$$

AJ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 6:44 AM CDTFlash Flood WarningARXAllamakee6 hr
Sep 21, 4:09 PM CDTSpecial Weather StatementARXFloyd51 min
Sep 21, 4:21 PM CDTSevere Thunderstorm WarningARXFloyd39 min
Sep 21, 4:47 PM CDTFlash Flood WarningARXFloyd4 hr
Sep 21, 5:03 PM CDTSevere Thunderstorm WarningARXFloyd57 min
Sep 21, 5:20 PM CDTTornado WarningARXFloyd40 min
Sep 21, 5:52 PM CDTSevere Thunderstorm WarningARXFloyd, Mitchell35 min
Sep 21, 6:01 PM CDTSevere Thunderstorm WarningARXFloyd44 min
Sep 21, 6:18 PM CDTTornado WarningARXFloyd42 min
Sep 21, 6:23 PM CDTFlash Flood WarningARXMitchell6 hr
Sep 21, 6:53 PM CDTTornado WarningARXChickasaw, Floyd32 min

Nearby

Flash Flood Warnings in Iowa, 2016Every flash flood warning in 2016

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.