Alert archive / Iowa / Flash Flood Warnings in 2004

Flash Flood Warning 30, NWS Sioux Falls, SD

September 14, 20045 counties in Iowa

NWS Sioux Falls, SD issued this flash flood warning at Sep 14, 2004, 7:12 PM CDT for 5 counties in Iowa. It was in force for 4 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 14, 2004, 7:12 PM CDT (00:12 UTC)
Expired: Sep 14, 2004, 11:15 PM CDT
In force: 4 hr
Issued by: NWS Sioux Falls, SD
Area: Counties, with a storm outline in the text

Counties Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, O'Brien County, IA

The radar

The Sioux Falls radar (KFSD), 125 km from the middle of the area, began a volume at 00:14 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 14, 8:01 PM CDT	FLOOD	Spencer, IA	STREET FLOODING DUE TO HEAVY RAINFALL.
Sep 14, 10:24 PM CDT	HEAVY RAIN 0	Cherokee, IA	4.5 INCHES OF RAINFALL SINCE MIDNIGHT.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.2 hours before the alert went out and 195 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: 1520 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 1898 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 183 m²/s²
0-3 km storm-relative helicity: 290 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 8.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS53 KFSD 150017
FFWFSD
IAC021-035-041-059-141-150415-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
712 PM CDT TUE SEP 14 2004

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BUENA VISTA COUNTY IN NORTHWEST IOWA
  CHEROKEE COUNTY IN NORTHWEST IOWA
  CLAY COUNTY IN NORTHWEST IOWA
  DICKINSON COUNTY IN NORTHWEST IOWA
  OBRIEN COUNTY IN NORTHWEST IOWA

* UNTIL 1115 PM CDT

* AT 709 PM CDT...TRAINED WEATHER SPOTTERS REPORTED VERY HEAVY RAIN  
  FROM A SERIES OF THUNDERSTORMS THAT MOVED OVER THE WARNED AREA.

RAINFALL AMOUNTS OF TWO TO FOUR INCHES HAVE BEEN REPORTED THROUGHOUT 
THE AREA. THIS HAS CAUSE CONSIDERABLE PONDING OF WATER IN LOW LYING 
AREAS WITH SOME STREET FLOODING. 

ADDITIONAL RAINFALL AMOUNTS OF ONE TO THREE INCHES ARE POSSIBLE IN 
THE WARNED AREA DURING NEXT TWO TO FOUR HOURS.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL 
CREEKS AND STREAMS...COUNTRY ROADS...URBAN STREETS... AS WELL AS 
FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS.

LAT...LON 4260 9581 4263 9499 4345 9503 4318 9539
      4317 9577

$$
WB

1 follow-up statement

000 
WGUS73 KFSD 150216
FFSFSD
IAC021-035-041-059-141-150240-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
915 PM CDT TUE SEP 14 2004

...THE FLASH FLOOD WARNING FOR BUENA VISTA...CHEROKEE...CLAY...
OBRIEN AND DICKINSON COUNTIES IS CANCELLED...

SHOWERS AND THUNDERSTORMS EARLIER THIS EVENING PRODUCED RAINFALL 
AMOUNTS OF 2 TO 5 INCHES OVER THE AREA. CONSIDERABLE PONDING OF 
WATER...ALONG WITH SOME WITH STREET AND LOW LAND FLOODING DID OCCUR. 
SCATTERED SHOWERS AND THUNDERSTORMS WERE CONTINUING THIS 
EVENING...HOWEVER NO SERIOUS FLOODING PROBLEMS HAVE BEEN REPORTED. 
PONDING OF WATER IN LOW LYING AREAS WILL REMAIN TONIGHT DUE TO 
SATURATED GROUND AND ADDITIONAL RAINFALL. MOTORIST ARE ADVISED NOT 
TO DRIVE THROUGH STANDING WATER...AS THE WATER MAY BE DEEPER THAN 
YOU THINK. 

A FLASH FLOOD WATCH DOES REMAIN IN EFFECT THROUGH 300 AM CDT FOR THE 
POSSIBILITY OF STRONG THUNDERSTORMS PRODUCING ADDITIONAL HEAVY 
RAINFALL.  

LAT...LON 4260 9581 4263 9499 4345 9503 4318 9539
      4317 9577

$$

WB

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 15, 3:20 AM CDT	Flash Flood Warning	FSD	Lyon	3 hr
Sep 15, 4:06 AM CDT	Flash Flood Warning	FSD	Clay, Dickinson, O'Brien, Osceola	114 min
Sep 15, 5:26 AM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	34 min
Sep 15, 7:01 AM CDT	Flash Flood Warning	FSD	Clay, Dickinson, O'Brien	119 min

Nearby

Flash Flood Warnings in Iowa, 2004 Every flash flood warning in 2004

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.