Alert archive / Iowa / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 173, NWS Des Moines, IA

July 6, 2003Cass County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 6, 2003, 4:11 AM CDT for Cass County, Iowa. It was in force for 34 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: Jul 6, 2003, 4:11 AM CDT (09:11 UTC)
Expired: Jul 6, 2003, 4:45 AM CDT
In force: 34 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

County Cass County, IA

The radar

The Omaha radar (KOAX), 112 km from the middle of the area, began a volume at 09:10 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
Jul 5, 11:50 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 9.2 hours before the alert went out and 112 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: 2840 J/kg
Mixed-layer CIN: -46 J/kg
Mixed-layer LCL: 1471 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 133 m²/s²
0-3 km storm-relative helicity: 232 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 11.5

Open this sounding in Storm Lab

The text

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

046 
WUUS53 KDMX 060911
SVRDMX
IAC029-060945-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
411 AM CDT SUN JUL 6 2003

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN CASS COUNTY IN SOUTHWEST IOWA

* UNTIL 445 AM CDT

* AT 409 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 6 MILES WEST OF MARNE...OR ABOUT 36 MILES
  NORTHEAST OF COUNCIL BLUFFS...MOVING EAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE...

  NEAR MARNE AROUND 420 AM...
  NEAR ATLANTIC MUNICIPAL AIRPORT AROUND 425 AM AND
  NEAR WIOTA AROUND 440 AM.

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

MOVE TO AN INTERIOR ROOM AND STAY AWAY FROM WINDOWS. IF YOU LIVE IN A
MOBILE HOME...SEEK SHELTER IN A STURDY BUILDING.

LAT...LON 4151 9517 4134 9517 4135 9482 4149 9483


$$

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 Jul 6, 3:59 AM CDT, 12 minutes earlier.

Area forecast discussion, Jul 6, 3:59 AM CDT, 12 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
359 AM CDT SUN JUL 6 2003

MAIN FORECAST FOCUS WILL BE SVR/FF POTENTIAL AND COVERAGE TODAY INTO
TUESDAY.

ANOTHER ACTIVE NIGHT WITH YET ANOTHER MCS WHICH PRODUCED WIND DAMAGE
ACRS WEST CENTRAL COUNTIES. ISOLD SVR POSBL FOR NEXT COUPLE HOURS SW
PTNS...BUT LEADING EDGE IN CENTRAL IOWA IS DIMINISHING RAPIDLY IN
INTENSITY AS IT MOVES INTO A MUCH LESS UNSTABLE AIRMASS. WL CONTINUE
POPS THUR MID MORNING WITH SCATTERED WEST AND CATEGORICAL EAST. ONLY
SMALL CHANGES TO GOING FCST...AS ACTIVE PATTERN CONTINUES WITH POPS
IN EVERY PERIOD THRU TUES NT. POTENTIAL MCS TONIGHT OVER THE
NORTH...WITH MORE SVR PSBL MONDAY AFT/NT...AND ANOTHER CHC TUES.
ACCUMULATIONS OF RAIN WILL INCREASE RIVER AND FLASH FLOODING
POTENTIAL. WITH VARIOUS BOUNDARIES AND ASSOCIATED UNCERTAINTY IN
FOCUS FOR CONVECTION...TENDED TO BROAD BRUSH PRECIP AREAS AND POPS
ON MONDAY AND TUESDAY.

IN THE EXTENDED PERIOD (WED-SAT): THE ONLY CHANGE IS TO ADD POPS
DURING THE DAY WEDNESDAY AS LATEST GFS BRINGS ANOTHER SW THROUGH
REGION. DRY FORECAST CONTINUES WEDNESDAY NIGHT WITH A GRADUAL
WARMING TREND.

.DSM...NONE

KINNEY

Hazardous weather outlook, Jul 5, 10:45 PM CDT, 5 hours 26 minutes before

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-071100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1045 PM CDT SAT JUL 5 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL IOWA.

.DAY ONE...TONIGHT
AN AREA OF THUNDERSTORMS OVER NEBRASKA WILL ADVANCE EAST INTO IOWA
OVERNIGHT.  IN ADDITION...THERE IS THE POSSIBILITY OF STRONG
THUNDERSTORM DEVELOPMENT OVER SOUTHEAST SOUTH DAKOTA INTO SOUTHWEST
MINNESOTA LATER TONIGHT.  THESE TWO AREAS WILL LIKELY MOVE INTO IOWA
DURING THE PREDAWN HOURS.  THE THREAT OF THUNDERSTORMS WILL INCREASE
OVER THE WESTERN PART OF THE DES MOINES WARNING AREA AROUND 300 AM
OR SO...THEN SPREAD EAST INTO THE MORNING HOURS.  THE MAIN THREAT
FROM THESE STORMS IS FOR DAMAGING WINDS AND HAIL.  ISOLATED
LOCATIONS COULD RECEIVE ONE TO TWO INCHES OF RAINFALL...BUT HEAVY
RAINFALL WILL BE ISOLATED.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

A FRONT STRETCHED ACROSS SOUTHERN IOWA WILL PROVIDE THE FOCUS FOR
RENEWED SHOWER AND THUNDERSTORM DEVELOPMENT MONDAY AFTERNOON. A FEW
SUPERCELL THUNDERSTORMS ARE POSSIBLE...WITH LARGE HAIL AND DAMAGING
WINDS. THERE IS ALSO A CHANCE FOR ANOTHER THUNDERSTORM COMPLEX TO
MOVE ACROSS CENTRAL IOWA MONDAY NIGHT...WITH THE THREAT OF MORE
LOCALLY HEAVY RAIN AND DAMAGING WINDS. CENTRAL IOWA WILL REMAIN
UNDER A SLIGHT RISK FOR SEVERE THUNDERSTORMS TUESDAY
AFTERNOON...MAINLY ACROSS AREAS SOUTH OF HIGHWAY 30. THUNDERSTORMS
ARE POSSIBLE OVER CENTRAL IOWA AGAIN ON WEDNESDAY. LITTLE OR NO
PRECIPITATION IS EXPECTED THURSDAY THROUGH SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY TONIGHT NORTH OF HIGHWAY 20...AND
POSSIBLE SOUTH OF HIGHWAY 20. ACTIVATION IS POSSIBLE AGAIN MONDAY
AFTERNOON AND NIGHT OVER ALL OF CENTRAL IOWA.
&&

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

MS JUL 03

In the hours before

Local storm report, Jul 5, 11:50 PM CDT, 4 hours 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1150 PM CDT SAT JUL 05 2003

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

1251 AM    10 NE AMES                IA   WIND DAMAGE
07/05/03   STORY                          6 TO 7 INCH TREES DOWN.

BF

Local storm report, Jul 5, 11:53 PM CDT, 4 hours 18 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1153 PM CDT SAT JUL 05 2003

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

1250 AM    AMES                      IA   WIND DAMAGE
07/05/03   STORY                          NORTH SIDE OF IOWA ST
                                          CAMPUS. 12 INCH TREE DOWN.
                                          REPORTED BY AMATEUR RADIO.

BF

Local storm report, Jul 6, 1:44 AM CDT, 2 hours 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0144 AM CDT SUN JUL 06 2003

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

1230 AM    4 NNW DUNLAP              IA   65 MPH TSTORM WIND
07/06/03   CRAWFORD                       REPORTED BY TRAINED
                                          SPOTTER.

BF

Local storm report, Jul 6, 2:17 AM CDT, 1 hour 54 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0217 AM CDT SUN JUL 06 2003

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

0115 AM    ATLANTIC                  IA   WIND DAMAGE
07/06/03   CASS                           TREES DOWN. REPORTED BY
                                          LAW ENFORCEMENT.

BF

Local storm report, Jul 6, 2:49 AM CDT, 1 hour 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
0249 AM CDT SUN JUL 06 2003

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

0130 AM    AUDUBON                   IA   60 MPH TSTORM WIND
07/06/03   AUDUBON                        TREE LIMBS DOWN. REPORTED
                                          BY AMATEUR RADIO OPERATOR.

BF

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 5, 7:27 PM CDT	Severe Thunderstorm Warning	DMX	Decatur	63 min
Jul 5, 8:09 PM CDT	Severe Thunderstorm Warning	DMX	Wayne	36 min
Jul 5, 9:04 PM CDT	Severe Thunderstorm Warning	DMX	Ringgold	41 min
Jul 6, 12:09 AM CDT	Severe Thunderstorm Warning	DMX	Crawford	66 min
Jul 6, 12:56 AM CDT	Severe Thunderstorm Warning	DMX	Audubon, Cass	49 min
Jul 6, 1:25 AM CDT	Severe Thunderstorm Warning	DMX	Adair, Guthrie	50 min
Jul 6, 2:13 AM CDT	Severe Thunderstorm Warning	DMX	Hardin	47 min
Jul 6, 7:20 AM CDT	Severe Thunderstorm Warning	DMX	Dallas	40 min
Jul 6, 7:50 AM CDT	Severe Thunderstorm Warning	DMX	Madison	40 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.