Alert archive / Iowa / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 121, NWS Des Moines, IA

May 21, 2004Hamilton County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 21, 2004, 12:50 PM CDT for Hamilton County, Iowa. It was in force for 40 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 21, 2004, 12:50 PM CDT (17:50 UTC)
Expired: May 21, 2004, 1:30 PM CDT
In force: 40 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

County Hamilton County, IA

The radar

The Des Moines radar (KDMX), 77 km from the middle of the area, began a volume at 17:53 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 severe thunderstorm 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 21, 10:25 AM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 5.8 hours before the alert went out and 253 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: 718 J/kg
Mixed-layer CIN: -227 J/kg
Mixed-layer LCL: 1161 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 160 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

235 
WUUS53 KDMX 211750
SVRDMX
IAC079-211830-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1250 PM CDT FRI MAY 21 2004

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN HAMILTON COUNTY IN CENTRAL IOWA

* UNTIL 130 PM CDT

* AT 1248 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER JEWELL...OR ABOUT 28 MILES SOUTHEAST OF
  FORT DODGE...MOVING NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE...

  NEAR JEWELL AROUND 1255 PM...
  NEAR ELLSWORTH AROUND 100 PM AND
  9 MILES SOUTHEAST OF WILLIAMS AROUND 115 PM.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM FRIDAY
AFTERNOON FOR NORTHERN IOWA.

LAT...LON 4255 9383 4223 9377 4223 9350 4254 9353

$$

What forecasters said that day

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

NWS Des Moines, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 21, 5:15 AM CDT, 7 hours 35 minutes earlier.

Area forecast discussion, May 21, 5:15 AM CDT, 7 hours 35 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
515 AM CDT FRI MAY 21 2004

.DISCUSSION...
FORECAST CONCERNS INCLUDE CONVECTIVE TRENDS AND HEAVY RAIN POTENTIAL
THROUGH THE WEEKEND. FAVORED GFS GIVEN INTIALIZATION PROBLEMS OF ETA
AS OF LATE. FRONTAL BOUNDARY CURRENTLY WORKING ITS WAY BACK NORTH
INTO CENTRAL IOWA AS HEAVY RAIN PRODUCING THUNDERSTORMS TRACK
THROUGH NORTH CENTRAL IOWA. THE MOST INTENSE CELL PRODUCED SEVERE
WIND GUST IN FRANKLIN COUNTY AROUND 430 AM. THE BOUNDARY WILL
PROVIDE THE FOCUS FOR CONTINUED LOCALLY HEAVY RAIN AND THE THREAT OF
SEVERE WEATHER THROUGH THE WEEKEND. THE GFS PERSISTS IN FOCUSING ON
AREAS NORTH OF INTERSTATE 80 FOR HEAVY RAINS...WITH 1-3 AND LOCALLY
HIGHER AMOUNTS POSSIBLE. WILL HOLD OFF ON FLOOD WATCH ATTM DUE TO
UNCERTAINTIES WITH FRONTAL PLACEMENT...BUT WILL FINE TUNE HYDROLOGIC
OUTLOOK TO FAVOR AREAS NORTH OF HIGHWAY 20 FOR POTENTIAL RIVER
FLOODING AND FLASH FLOODING. AFTER A BRIEF BREAK SUNDAY NIGHT INTO
EARLY MONDAY...ACTIVE WEATHER WILL RESUME LATER MONDAY INTO TUESDAY
WITH ANOTHER FRONT THROUGH THE REGION.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

KINNEY

Hazardous weather outlook, May 21, 6:49 AM CDT, 6 hours 1 minute before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
649 AM CDT FRI MAY 21 2004

IAZ004>007-015>017-023>028-033>039-221100-
BLACK HAWK-BREMER-BUTLER-CALHOUN-CERRO GORDO-EMMET-FRANKLIN-GRUNDY-
HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-
WEBSTER-WINNEBAGO-WORTH-WRIGHT-
649 AM CDT FRI MAY 21 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN IOWA...NORTH OF THE
HIGHWAY 30 CORRIDOR.

.DAY ONE...TODAY AND TONIGHT

SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND
TONIGHT...WITH DAMAGING STRAIGHT LINE WINDS AND LARGE HAIL
POSSIBLE. LOCALLY HEAVY RAINFALL AMOUNTS FROM 1 TO 3 INCHES ARE ALSO
EXPECTED...AND COULD PRODUCE FLASH FLOODING ACROSS AREAS THAT
RECEIVED SUBSTANTIAL RAINFALL LAST EVENING AND OVERNIGHT...MAINLY
ALONG AND NORTH OF HIGHWAY 20.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A RISK OF ISOLATED SEVERE STORMS SATURDAY AND SATURDAY
NIGHT...AND AGAIN SUNDAY AND MONDAY. A BIGGER THREAT...HOWEVER WILL
BE FLASH FLOOD PRODUCING RAINS...ESPECIALLY SATURDAY AND SATURDAY
NIGHT.

.SPOTTER ACTIVATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED LATER THIS AFTERNOON AND
TONIGHT. SPOTTER ACTIVATION MAY ALSO BE NEEDED AT VARIOUS TIMES
THROUGH MONDAY NIGHT.

IAZ044>050-057>062-070>075-081>086-092>097-221100-
ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CARROLL-CASS-CLARKE-CRAWFORD-
DALLAS-DAVIS-DECATUR-GREENE-GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-
MARION-MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-
UNION-WAPELLO-WARREN-WAYNE-
649 AM CDT FRI MAY 21 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND SOUTHERN IOWA...
ALONG AND SOUTH OF THE HIGHWAY 30 CORRIDOR.

.DAY ONE...TODAY AND TONIGHT

ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND
TONIGHT...WITH DAMAGING STRAIGHT LINE WINDS AND LARGE HAIL
POSSIBLE. HEAVIER RAINFALL AMOUNTS ARE EXPECTED TO STAY TO THE
NORTH. HOWEVER...ISOLATED FLASH FLOODING IS NOT OUT OF THE
QUESTION...ACROSS AREAS THAT RECEIVED HEAVY RAIN RECENTLY...ALONG AND
SOUTH OF A LINE FROM AUDUBON...TO WINTERSET...TO OTTUMWA.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A RISK OF SEVERE STORMS SATURDAY AND SATURDAY
NIGHT...AND AGAIN SUNDAY AND MONDAY. ISOLATED FLASH FLOODING IS ALSO
POSSIBLE THROUGH THE PERIOD.

.SPOTTER ACTIVATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE THIS AFTERNOON AND TONIGHT. SPOTTER
ACTIVATION MAY ALSO BE NEEDED AT VARIOUS TIMES THROUGH MONDAY NIGHT.

KINNEY

In the hours before

Local storm report, May 21, 11:23 AM CDT, 1 hour 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1123 AM CDT FRI MAY 21 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

1115 AM     HAIL             BRITT                   43.10N 93.80W
05/21/2004  0.88 INCH        HANCOCK            IA   PUBLIC

&&

BF

Local storm report, May 21, 11:26 AM CDT, 1 hour 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1126 AM CDT FRI MAY 21 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

1125 AM     HAIL             BRITT                   43.10N 93.80W
05/21/2004  1.00 INCH        HANCOCK            IA   TRAINED SPOTTER

&&

BF

Local storm report, May 21, 11:44 AM CDT, 1 hour 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1144 AM CDT FRI MAY 21 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

1125 AM     HAIL             5 NW NORTHWOOD          43.50N 93.29W
05/21/2004  1.00 INCH        WORTH              IA   LAW ENFORCEMENT

1131 AM     HAIL             RUTHVEN                 43.13N 94.90W
05/21/2004  1.00 INCH        PALO ALTO          IA   LAW ENFORCEMENT

&&

BF

Local storm report, May 21, 11:50 AM CDT, 1 hour before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1150 AM CDT FRI MAY 21 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

1130 AM     HAIL             2 E RUTHVEN             43.13N 94.86W
05/21/2004  1.75 INCH        PALO ALTO          IA   BROADCAST MEDIA

            REPORT RECEIVED FROM KICD RADIO

&&

BF

Local storm report, May 21, 12:25 PM CDT, 25 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1225 PM CDT FRI MAY 21 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

1140 AM     HAIL             1 S NORTHWOOD           43.43N 93.22W
05/21/2004  0.75 INCH        WORTH              IA   TRAINED SPOTTER

&&

BF

Local storm report, May 21, 12:39 PM CDT, 11 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1239 PM CDT FRI MAY 21 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

1235 PM     HAIL             3 W GREENE              42.90N 92.86W
05/21/2004  0.75 INCH        BUTLER             IA   TRAINED SPOTTER

&&

BF

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 21, 2:18 AM CDT	Severe Thunderstorm Warning	DMX	Crawford	42 min
May 21, 2:37 AM CDT	Severe Thunderstorm Warning	DMX	Sac	53 min
May 21, 4:32 AM CDT	Severe Thunderstorm Warning	DMX	Franklin	28 min
May 21, 5:23 AM CDT	Severe Thunderstorm Warning	DMX	Bremer	37 min
May 21, 10:59 AM CDT	Severe Thunderstorm Warning	DMX	Palo Alto	61 min
May 21, 11:08 AM CDT	Severe Thunderstorm Warning	DMX	Hancock	67 min
May 21, 11:40 AM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Worth	50 min
May 21, 12:20 PM CDT	Severe Thunderstorm Warning	DMX	Butler	40 min
May 21, 12:29 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Worth	16 min
May 21, 1:17 PM CDT	Severe Thunderstorm Warning	DMX	Webster	58 min
May 21, 1:25 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun	35 min
May 21, 1:27 PM CDT	Severe Thunderstorm Warning	DMX	Hardin	48 min
May 21, 1:55 PM CDT	Severe Thunderstorm Warning	DMX	Grundy	35 min
May 21, 2:02 PM CDT	Tornado Warning	DMX	Grundy	43 min
May 21, 2:05 PM CDT	Severe Thunderstorm Warning	DMX	Franklin, Wright	25 min
May 21, 2:06 PM CDT	Tornado Warning	DMX	Hamilton	39 min
May 21, 2:20 PM CDT	Severe Thunderstorm Warning	DMX	Hardin	55 min
May 21, 2:28 PM CDT	Severe Thunderstorm Warning	DMX	Franklin, Wright	47 min
May 21, 2:39 PM CDT	Tornado Warning	DMX	Hardin	51 min
May 21, 2:43 PM CDT	Tornado Warning	DMX	Black Hawk	57 min
May 21, 2:45 PM CDT	Tornado Warning	DMX	Grundy	45 min
May 21, 3:06 PM CDT	Severe Thunderstorm Warning	DMX	Butler	39 min
May 21, 3:07 PM CDT	Severe Thunderstorm Warning	DMX	Tama	23 min
May 21, 3:27 PM CDT	Tornado Warning	DMX	Grundy	48 min
May 21, 3:35 PM CDT	Tornado Warning	DMX	Black Hawk	40 min
May 21, 3:38 PM CDT	Flash Flood Warning	DMX	Black Hawk, Palo Alto, Pocahontas	119 days
May 21, 3:44 PM CDT	Tornado Warning	DMX	Marshall, Tama	31 min
May 21, 4:16 PM CDT	Tornado Warning	DMX	Tama	29 min
May 21, 5:01 PM CDT	Severe Thunderstorm Warning	DMX	Wright	44 min
May 21, 5:27 PM CDT	Flash Flood Warning	DMX	Palo Alto, Pocahontas, Taylor	120 days
May 21, 5:27 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Hancock	48 min
May 21, 5:30 PM CDT	Severe Thunderstorm Warning	DMX	Palo Alto	45 min
May 21, 5:47 PM CDT	Severe Thunderstorm Warning	DMX	Franklin	43 min
May 21, 5:52 PM CDT	Severe Thunderstorm Warning	DMX	Grundy, Hardin	53 min
May 21, 5:54 PM CDT	Tornado Warning	DMX	Palo Alto, Pocahontas	51 min
May 21, 6:09 PM CDT	Flash Flood Warning	DMX	Adams, Cerro Gordo, Franklin, Hancock, Humboldt, Kossuth and 1 more	120 days
May 21, 6:15 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo	45 min
May 21, 6:15 PM CDT	Tornado Warning	DMX	Humboldt, Kossuth	45 min
May 21, 6:22 PM CDT	Severe Thunderstorm Warning	DMX	Butler	53 min
May 21, 6:36 PM CDT	Severe Thunderstorm Warning	DMX	Pocahontas	24 min
May 21, 6:41 PM CDT	Tornado Warning	DMX	Humboldt	34 min
May 21, 6:54 PM CDT	Severe Thunderstorm Warning	DMX	Bremer	36 min
May 21, 6:54 PM CDT	Severe Thunderstorm Warning	DMX	Wright	51 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2004 Every severe thunderstorm 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.