Alert archive / Iowa / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 28, NWS Des Moines, IA

April 30, 2003Mahaska County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Apr 30, 2003, 8:10 PM CDT for Mahaska County, Iowa. It was in force for 50 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: Apr 30, 2003, 8:10 PM CDT (01:10 UTC)
Expired: Apr 30, 2003, 9:00 PM CDT
In force: 50 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

County Mahaska County, IA

The radar

The Des Moines radar (KDMX), 94 km from the middle of the area, began a volume at 01:12 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
Apr 30, 5:15 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.2 hours before the alert went out and 183 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: 1022 J/kg
Mixed-layer CIN: -104 J/kg
Mixed-layer LCL: 839 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 457 m²/s²
0-3 km storm-relative helicity: 611 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 12.6

Open this sounding in Storm Lab

The text

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

491 
WUUS53 KDMX 010110
SVRDMX
IAC123-010200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
810 PM CDT WED APR 30 2003

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MAHASKA COUNTY IN SOUTH CENTRAL IOWA

* UNTIL 900 PM CDT

* AT 807 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER LEIGHTON...OR ABOUT 29 MILES NORTHWEST OF
  OTTUMWA...MOVING NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE...

  6 MILES NORTHWEST OF OSKALOOSA AROUND 815 PM...
  5 MILES SOUTHEAST OF NEW SHARON AROUND 825 PM AND
  8 MILES NORTHWEST OF ROSE HILL AROUND 830 PM.

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

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1100 PM WEDNESDAY EVENING FOR
SOUTHERN IOWA.

LAT...LON 4150 9286 4124 9285 4127 9242 4149 9243

KINNEY

$$

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 Apr 30, 3:25 PM CDT, 4 hours 45 minutes earlier.

Area forecast discussion, Apr 30, 3:25 PM CDT, 4 hours 45 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
325 PM CDT WED APR 30 2003

SHORTER TERM...EYES ARE ON THE SVR THREAT WHICH IS BUILDING ALG AND
S OF THE WRMFNT. FNT LOCATED FM LOW IN XTRM SERN NEB THEN EWD ACRS
THE NRN TIER OF COUNTIES IN NRN MO. WL TREND ALG WITH THE RUC NXT
18-24 HRS WHICH HAS PRIMARY CONVECTION FOCUS OVR THE SERN HALF OF
THE FA. MRNG H8 FNT WL LIKELY COME INTO PLAY OVRNGT AS WELL WHICH IS
SITUATED FARTHER TO THE N ESTIMATED FM OMA-FOD-DBQ. ANY ERLY MRNG
ACTIVITY SHOULD BE EAST OF A ALO-LWD LN BY 09Z. TMPS ABT AS
PREVIOUSLY FCST NXT FEW DAYS. GRDLY IMPVG WX TMR WITH A DECENT WX
DAY FRI AND INTO SAT UNDER S/W RDGG ALF.

LONGER TERM...NXT MAJOR S/W ARRIVES SUN WHICH HAS BEEN RELATIVELY
CONSISTENT THE PAST COUPLE OF RUNS. ENSEMBLES AND CANADIAN SUPPORT
INCRG PCPN CHC BY SUN..LASTING INTO ERLY TUE. TMPS DAY3-7 NOT CHGD
MUCH FM PREV FCSTS.

.DSM...NONE

MYERS

Hazardous weather outlook, Apr 30, 11:27 AM CDT, 8 hours 43 minutes before

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-011100-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1127 AM CDT WED APR 30 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL IOWA.

...SCATTERED SEVERE THUNDERSTORMS LIKELY AFTER 2 PM IN CENTRAL AND
SOUTHERN IOWA...

.DAY ONE...TODAY AND TONIGHT

A MODERATE RISK OF SEVERE THUNDERSTORMS EXISTS ACROSS THE SOUTHERN
HALF OF CENTRAL IOWA...MAINLY ALONG AND SOUTH OF TAMA...AMES...AND
ATLANTIC...WITH A SLIGHT RISK ACROSS NORTH CENTRAL IOWA.  THREATS
INCLUDE SCATTERED SUPERCELL THUNDERSTORMS CAPABLE OF VERY LARGE HAIL
GREATER THAN 1 INCH...DAMAGING WIND...AND ISOLATED TORNADOES.  RAPID
THUNDERSTORM DEVELOPMENT IS ANTICIPATED  BETWEEN 2 AND 4 PM
IN WEST CENTRAL AND SOUTHWEST IOWA...SPREADING ACROSS THE REMAINDER
OF CENTRAL AND SOUTH CENTRAL IOWA LATE THIS AFTERNOON AND EARLY
EVENING.

A WARM FRONT WILL MOVE FROM NORTHERN MISSOURI TO NEAR CRESTON...DES
MOINES AND ALONG THE INTERSTATE 80 CORRIDOR EAST OF DES MOINES BY
MID AFTERNOON.  VERY UNSTABLE AIR SOUTH OF THE FRONT WILL DEVELOP
COMBINED WITH ALREADY FAVORABLE WIND SHEAR PROFILES SHOULD CREATE A
DANGEROUS SEVERE WEATHER THREAT AS THUNDERSTORMS RAPIDLY DEVELOP AND
BECOME SEVERE.  ISOLATED TORNADOES ARE ALSO POSSIBLE...ALONG OR NEAR
STORMS ALONG THE WARM FRONT...AND NEAR STORMS THAT FORM CLOSE TO A
LOW PRESSURE CENTER MOVING INTO SOUTHERN IOWA THIS EVENING.

ADDITIONAL HEAVY RAINFALL MAY POSE A LOCAL URBAN FLOODING THREAT
...MAINLY ACROSS AREAS THAT RECEIVED HEAVY RAINFALL THIS MORNING.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE NEXT CHANCE FOR THUNDERSTORM ACTIVITY OVER CENTRAL IOWA WILL
COME LATE SUNDAY THROUGH THROUGH TUESDAY.  A SLIGHT RISK OF SEVERE
WEATHER EXISTS WITH THESE STORMS.

.SPOTTER INFORMATION STATEMENT...

MID IOWA SKYWARN...SPOTTER GROUPS AND EMERGENCY MANAGEMENT SHOULD
PREPARE FOR ACTIVATION THIS AFTERNOON AND EVENING FOR AN ACTIVE
SEVERE WEATHER EVENT.
&&

MORE INFORMATION CAN BE OBTAINED AT WWW.CRH.NOAA.GOV/DMX (ALL LOWER
CASE).

KULA

In the hours before

Local storm report, Apr 30, 6:42 PM CDT, 1 hour 28 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0642 PM CDT WED APR 30 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0630 PM    8 W CHILLICOTHE           IA   FX TORNADO
04/30/03   MONROE                         BRIEF 2 MINUTE TOUCHDOWN.

0630 PM    8 W CHILLICOTHE           IA   FX TORNADO
04/30/03   MONROE                         BRIEF 2 MINUTE TOUCHDOWN.

MR

Local storm report, Apr 30, 6:50 PM CDT, 1 hour 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0650 PM CDT WED APR 30 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0641 PM    CHILLICOTHE               IA   0.75 IN HAIL
04/30/03   WAPELLO                        REPORTED BY TRAINED
                                          SPOTTER.

0637 PM    5 SSW BENTON              IA   0.75 IN HAIL
04/30/03   RINGGOLD

0637 PM    5 SSW BENTON              IA   0.75 IN HAIL
04/30/03   RINGGOLD                       REPORTED BY TRAINED
                                          SPOTTER.

MR

Local storm report, Apr 30, 6:52 PM CDT, 1 hour 18 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0652 PM CDT WED APR 30 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0647 PM    1 S EDDYVILLE             IA   2.75 IN HAIL
04/30/03   WAPELLO                        REPORTED BY IOWA STATE
                                          PATROL.

MR

Local storm report, Apr 30, 7:03 PM CDT, 1 hour 7 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0703 PM CDT WED APR 30 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0645 PM    7 S MOUNT AYR MUNICIPAL A IA   0.88 IN HAIL
04/30/03   RINGGOLD                       REPORTED BY TRAINED
                                          SPOTTER.

0645 PM    7 S MOUNT AYR             IA   0.88 IN HAIL
04/30/03   RINGGOLD                       REPORTED BY TRAINED
                                          SPOTTER.

MR

Local storm report, Apr 30, 7:20 PM CDT, 50 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0720 PM CDT WED APR 30 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0704 PM    LAMONI                    IA   1.75 IN HAIL
04/30/03   DECATUR

0712 PM    LAMONI                    IA   1.00 IN HAIL
04/30/03   DECATUR                        REPORTED BY TRAINED
                                          SPOTTER.

0713 PM    1 N LAMONI                IA   DOWNBURST
04/30/03   DECATUR                        REPORTED BY STORM SPOTTER.

MR

Local storm report, Apr 30, 7:50 PM CDT, 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0750 PM CDT WED APR 30 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0748 PM    3 E ADEL                  IA   1.00 IN HAIL
04/30/03   DALLAS

SEARCY

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 30, 7:24 PM CDT	Severe Thunderstorm Warning	DMX	Wapello	66 min
Apr 30, 7:34 PM CDT	Severe Thunderstorm Warning	DMX	Wayne	41 min
Apr 30, 7:41 PM CDT	Tornado Warning	DMX	Wapello	49 min
Apr 30, 7:54 PM CDT	Tornado Warning	DMX	Wayne	51 min
Apr 30, 8:01 PM CDT	Severe Thunderstorm Warning	DMX	Dallas, Polk	44 min
Apr 30, 8:09 PM CDT	Severe Thunderstorm Warning	DMX	Wayne	51 min
Apr 30, 8:12 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose	48 min
Apr 30, 8:25 PM CDT	Severe Thunderstorm Warning	DMX	Madison	20 min
Apr 30, 8:35 PM CDT	Tornado Warning	DMX	Appanoose	40 min
Apr 30, 8:36 PM CDT	Severe Thunderstorm Warning	DMX	Warren	54 min
Apr 30, 8:38 PM CDT	Severe Thunderstorm Warning	DMX	Jasper	67 min
Apr 30, 8:47 PM CDT	Severe Thunderstorm Warning	DMX	Polk	43 min
Apr 30, 9:09 PM CDT	Severe Thunderstorm Warning	DMX	Davis	66 min
Apr 30, 9:33 PM CDT	Severe Thunderstorm Warning	DMX	Poweshiek	42 min
Apr 30, 9:57 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marshall	48 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2003 Every severe thunderstorm warning in 2003

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.