Alert archive / Iowa / Flash Flood Warnings in 2004

Flash Flood Warning 31, NWS Sioux Falls, SD

September 15, 2004Lyon County, Iowa; Lincoln County, South Dakota

NWS Sioux Falls, SD issued this flash flood warning at Sep 15, 2004, 3:20 AM CDT for Lyon County, Iowa; Lincoln County, South Dakota. 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
Sep 15, 2004, 3:20 AM CDT (08:20 UTC)
Expired
Sep 15, 2004, 6:15 AM CDT
In force
3 hr
Issued by
NWS Sioux Falls, SD
Area
Counties, with a storm outline in the text

Counties Lyon County, IA, Lincoln County, SD

The radar

The Sioux Falls radar (KFSD), 33 km from the middle of the area, began a volume at 08:22 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 8.3 hours before the alert went out and 223 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, Omaha, NE at 00:00Z on 2004-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1520 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, Omaha, NE at 00:00Z on 2004-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 183 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
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 150820
FFWFSD
IAC119-SDC083-151115-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
320 AM CDT WED SEP 15 2004

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  LYON COUNTY IN NORTHWEST IOWA
  LINCOLN COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 615 AM CDT

* AT 318 AM CDT...DOPPLER RADAR INDICATED RAINFALL AMOUNTS OF 2 TO 3 
INCHES ACROSS BOTH LINCOLN AND LYON COUNTY. MORE RAINFALL IS 
EXPECTED AS THUNDERSTORMS CONTINUE TO MOVE TO THE NORTHEAST AT 25 
MPH OVER THE SAME AREAS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

LAT...LON 4332 9693 4310 9692 4310 9650 4328 9659
      4326 9608 4349 9598 4349 9626 4350 9692

$$

JRM
1 follow-up statement
000 
WGUS73 KFSD 150913
FFSFSD
IAC119-SDC083-150920-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
410 AM CDT WED SEP 15 2004

...THE FLASH FLOOD WARNING FOR LINCOLN AND LYON COUNTIES IS
CANCELLED...

AT 410 AM CDT...THE HEAVY RAINS HAVE MOVED EAST OF THE AREA AND THE 
THREAT FOR FLASH FLOODING HAS DIMINISHED. SOME MODERATE TO HEAVY 
RAIN SHOULD MOVE OVER THE AREA THROUGH 6 AM...BUT IT IS NOT EXPECTED 
TO PRODUCE ADDITIONAL FLOODING.


LAT...LON 4332 9693 4310 9692 4310 9650 4328 9659
      4326 9608 4349 9598 4349 9626 4350 9692

$$
RSR

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sioux Falls, SD wrote its last area forecast discussion before this flash flood warning went out at Sep 14, 9:40 PM CDT, 5 hours 40 minutes earlier.

Area forecast discussion, Sep 14, 9:40 PM CDT, 5 hours 40 minutes before
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
940 PM CDT CDT TUE SEP 14 2004

.DISCUSSION..
HAVE CANCELLED FLASH FLOOD WARMING FOR PARTS OF NORTHWEST IOWA WITH
NO SERIOUS FLOODING PROBLEM BEING REPORTED AS OF 02Z. DID HOWEVER
KEEP THE FLASH FLOOD WATCH GOING FOR NERN NEBRASKA ACROSS NW IOWA IN
SW MINNESOTA UNTIL 300 AM FOR POSSIBLE HEAVY RAIN IN TSTMS THAT
CONTINUE TO DEVELOP. QUESTION COMES IN HOW FAR NORTH BOUNDARY TO
SOUTH WILL LIFT NORTH TONIGHT AS WAVE COMES UP FROM THE SOUTHWEST.
AS 0230Z TSTMS WERE DEVELOPING FURTHER BACK TO THE SW ALONG THE
MISSOURI RIVER. FOR NOW DO NOT SEE ANYTHING SEVERE AND TALKING TO
SPC THEY WILL NOT ISSUE ANY ADDITIONAL WATCH FOR OUR AREA...WILL LET
CURRENT WATCH EXPIRE AT 03Z. WILL DO UPDATE TO ZONES AND GRIDS TO
ADJUST TIMING AND LOCATION OF PCP AREA OTHERWISE LOW TEMPS FOR
TONIGHT LOOK OK.

.FSD...WATCHES/WARNINGS/ADVISORIES...
SD...FLOOD WATCH    TNGT       XTRM SERN SD UNION CO
MN...FLOOD WATCH    TNGT       JACKSON CO
IA...FLOOD WATCH    TNGT       ALL OF NWRN IA XCP LYON CO
NE...FLOOD WATCH    TNGT       DIXON AND DAKOTA COS

&&

WB
Hazardous weather outlook, Sep 14, 11:47 AM CDT, 15 hours 33 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1147 AM CDT TUE SEP 14 2004

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-151200-
AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA-
CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE-
DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON-
IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN-
LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN-
OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN-
SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON-
1147 AM CDT TUE SEP 14 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA...
SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
THUNDERSTORMS WILL REDEVELOP NEAR A VERMILLION TO SPENCER IOWA
LINE AFTER 4 PM THIS AFTERNOON. SOME STORMS MAY BECOME SEVERE
LATE THIS AFTERNOON AND EARLY THIS EVENING ALONG AND SOUTH OF A
VERMILLION TO SPIRIT LAKE LINE. VERY HEAVY RAINFALL...HAIL THE
SIZE OF HALF DOLLARS AND WIND GUSTS TO 60 MPH ARE THE MAIN
THREATS. AN ISOLATED TORNADO WILL ALSO BE POSSIBLE ALONG AND JUST
SOUTH OF THIS FRONT. THE THREAT FOR TORNADOES WILL BE MAINLY
SOUTH OF A SIOUX CITY TO LINN GROVE LINE.

FLOODING...
THUNDERSTORMS THAT DEVELOP THIS AFTERNOON AND EVENING OVER
NORTHEAST NEBRASKA...NORTHWEST IOWA...FAR SOUTHEAST SOUTH DAKOTA
AND FAR SOUTHERN MINNESOTA WILL HAVE THE POTENTIAL TO PRODUCE
VERY HEAVY RAINFALL. SOME LOCATIONS COULD SEE AMOUNTS OF 2 TO 4
INCHES...WITH HOURLY RAINFALL RATES APPROACHING TWO INCHES. A FEW
RIVERS....CREEKS AND STREAMS COULD APPROACH BANKFULL AND URBAN
FLOODING WILL ALSO BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY AFTER 500 PM CDT.

&&

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.CRH.NOAA.GOV/FSD. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.

08

In the hours before

Special weather statement, Sep 14, 9:52 PM CDT, 5 hours 28 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
952 PM CDT TUE SEP 14 2004

IAZ014-021-022-031-032-NEZ013-014-150310-
BUENA VISTA IA-CHEROKEE IA-CLAY IA-DAKOTA NE-DIXON NE-IDA IA-
WOODBURY IA-
952 PM CDT TUE SEP 14 2004

...SEVERE THUNDERSTORM WATCH NUMBER 819 WILL BE ALLOWED
TO EXPIRE AT 10 PM CDT...

THE VALID PORTIONS OF SEVERE THUNDERSTORM WATCH NUMBER 819
WILL BE ALLOWED TO EXPIRE AT 10 PM CDT. THIS INCLUDES BUENA VISTA...
CHEROKEE...CLAY...IDA AND WOODBURY COUNTIES OF NORTHWEST IOWA...AND
DIXON AND DAKOTA COUNTIES IN EXTREME NORTHEAST NEBRASKA.
THUNDERSTORMS WILL CONTINUE AT TIMES OVERNIGHT...BUT THE THREAT OF
WIDESPREAD SEVERE WEATHER HAS ENDED ACROSS THE AREA. LOCALLY HEAVY
RAINFALL WILL BE THE MAIN THREAT FROM THESE STORMS OVERNIGHT...AND A
FLOOD WATCH FOR FLASH FLOODING REMAINS IN EFFECT UNTIL 3 AM CDT.

CHAPMAN

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 14, 7:12 PM CDTFlash Flood WarningFSDBuena Vista, Cherokee, Clay, Dickinson, O'Brien4 hr
Sep 15, 4:06 AM CDTFlash Flood WarningFSDClay, Dickinson, O'Brien, Osceola114 min
Sep 15, 5:26 AM CDTSevere Thunderstorm WarningFSDBuena Vista34 min
Sep 15, 7:01 AM CDTFlash Flood WarningFSDClay, Dickinson, O'Brien119 min

Nearby

Flash Flood Warnings in Iowa, 2004Flash Flood Warnings in South Dakota, 2004Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.