Alert archive / Iowa / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 135, NWS Des Moines, IA

May 21, 2004Grundy County, Hardin County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 21, 2004, 5:52 PM CDT for Grundy County, Hardin County, Iowa. It was in force for 53 min. 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: May 21, 2004, 5:52 PM CDT (22:52 UTC)
Expired: May 21, 2004, 6:45 PM CDT
In force: 53 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

Counties Grundy County, IA, Hardin County, IA

The radar

The Des Moines radar (KDMX), 98 km from the middle of the area, began a volume at 22:52 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
May 21, 6:00 PM CDT	HAIL 0.75	1 Ssw Grundy Center, IA
May 21, 6:02 PM CDT	HAIL 1.75	Grundy Center, IA	WEST SIDE OF CITY.

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

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 10 minutes after it went out.

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, 2:45 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.9 hours before the alert went out and 277 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 732 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 216 m²/s²
0-3 km storm-relative helicity: 321 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.

371 
WUUS53 KDMX 212252
SVRDMX
IAC075-083-212345-

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

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  GRUNDY COUNTY IN CENTRAL IOWA
  EASTERN HARDIN COUNTY IN CENTRAL IOWA

* UNTIL 645 PM CDT

* AT 547 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE
  OF SEVERE THUNDERSTORMS FROM IOWA FALLS TO 4 MILES SOUTHWEST OF
  MORRISON...OR FROM 44 MILES SOUTH OF MASON CITY TO 23 MILES
  SOUTHWEST OF WATERLOO...MOVING NORTHEAST AT 35 MPH.

* SEVERE THUNDERSTORMS WILL BE...

  NEAR ACKLEY AROUND 600 PM AND
  NEAR STOUT AROUND 610 PM.

HAIL UP TO THE SIZE OF QUARTERS IS LIKELY IN THE WARNED AREA.

LARGE HAIL CAN CAUSE INJURY AND PROPERTY DAMAGE. SEEK SAFETY INDOORS
UNTIL THE STORM PASSES.

A TORNADO WATCH REMAINS IN EFFECT FOR THE AREA. REMEMBER...SEVERE
THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO WARNING.

LAT...LON 4255 9333 4233 9332 4221 9279 4230 9281
      4231 9255 4256 9256

$$

JUNGBLUTH

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, 4:06 PM CDT, 1 hour 46 minutes earlier.

Area forecast discussion, May 21, 4:06 PM CDT, 1 hour 46 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
406 PM CDT FRI MAY 21 2004

.DISCUSSION...
SYNOPTIC SITUATION REMAINS THE SAME FROM SVRL DAYS AGO WITH
BROADSCALE WSW FLOW ALF...IA ON THE SRN EDGE OF THE UPR JET...PLENTY
OF LOW LVL MOIST FLY FLOW AND SFC DEWPTS IN THE 60S. MRNG OUTFLOW
THAT SAGGED SWD OVR ERN IA IS NOW RETURNING NWD AS VIEWED IN VSB
IMAGERY AND MORE SPECIFICALLY 88D. SFC WNDS HAVE INCRSED NRLY 100PCT
S OF THE BNDRY WHICH XTENDS ALG A LN FM SPENCER TO EAGLE GROVE TO
THE WATERLOO AREA. TORNADIC SUPERCELL WILL CONTINUE TO CURVE ESE OUT
OF THE FA AS NEW DVLPMT IS XPCD IN THE MO RVR VLY SOON...OR AT THE
VRY LEAST BFR MIDN. I HAVE OPTED NOT TO GO WITH A FLOOD WATCH AT THE
MOMENT DEPENDING HOW AND WHERE NEW DVLPMT TAKES PLACE AND EVOLVES.
FLASH FLOOD VALUES ARE RELATIVELY HIGH IN N IA XCP FOR SOME SMALL
AREAS. WE MAY ISSUE ONE ANYTIME THIS EVENING HOWEVER. AS MENTIONED
ALRDY...SITUATION DOES NOT CHG FOR SAT OR SAT NGT. WE ARE LOOKING
FOR MORE TSTMS AND A INCRG FLOOD THREAT...IF THE STORMS REMAIN IN
NRN IA INSTEAD OF SRN MN. MAIN CDFNT SWINGS THRU SUN AFTN WITH SVR
THREAT OVR ERN THIRD. WX SETTLES DOWN SUN NGT INTO MONDAY WITH A
CHANCE OF MORE THUNDERSTORMS MON AFTN INTO TUE MRNG. AFT
THAT...LOOKS LIKE A QUIET PD AS CANADIAN HIGH PRESSURE PREVAILS
UNTIL LATE NXT WEEK.

&&

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

&&

MYERS

Hazardous weather outlook, May 21, 6:49 AM CDT, 11 hours 3 minutes 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, 4:35 PM CDT, 1 hour 17 minutes before

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

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

0420 PM     HAIL             2 NW DYSART             42.19N 92.34W
05/21/2004  0.88 INCH        TAMA               IA   TRAINED SPOTTER

&&

Local storm report, May 21, 4:55 PM CDT, 57 minutes before

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

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

0253 PM     TSTM WND DMG     9 ESE POPEJOY           42.54N 93.26W
05/21/2004                   HARDIN             IA   PUBLIC

            OUTBUILDINGS DAMAGED. TREES DOWN.

&&

GRAMS

Local storm report, May 21, 5:25 PM CDT, 27 minutes before

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

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

0335 PM     TSTM WND DMG     EVANSDALE               42.46N 92.28W
05/21/2004                   BLACK HAWK         IA   AMATEUR RADIO

            TREES DOWN ON LAFAYETTE ST.

&&

GRAMS

Local storm report, May 21, 5:33 PM CDT, 19 minutes before

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

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

0253 PM     TSTM WND DMG     9 E POPEJOY             42.59N 93.25W
05/21/2004                   FRANKLIN           IA   PUBLIC

            OUTBUILDINGS DAMAGED. TREES DOWN.

&&

GRAMS

Local storm report, May 21, 5:37 PM CDT, 15 minutes before

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

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

0315 PM     TORNADO          10 W GRUNDY CENTER      42.36N 92.97W
05/21/2004                   GRUNDY             IA   AMATEUR RADIO

            ON STATE HIGHWAY 175

&&

GRAMS

Local storm report, May 21, 5:42 PM CDT, 10 minutes before

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

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

0539 PM     HAIL             5 N MESERVEY            42.98N 93.46W
05/21/2004  1.00 INCH        CERRO GORDO        IA   TRAINED SPOTTER

&&

GRAMS

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, 12:50 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton	40 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, 5:54 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.