Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 94, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 20, 1998, 10:21 AM CDT for Marion County, Iowa. It was in force for 34 min. 2 reports came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- May 20, 1998, 10:21 AM CDT (15:21 UTC)
- Expired
- May 20, 1998, 10:55 AM CDT
- In force
- 34 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Marion County, IA
The radar
The Des Moines radar (KDMX), 68 km from the middle of the area, began a volume at 15:23 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 20, 10:25 AM CDT | Hail 1 | Knoxville, IA | |
| May 20, 10:53 AM CDT | Hail 2.5 | Knoxville, IA |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 3.4 hours before the alert went out and 219 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2431 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 50 m²/s²
- 0-3 km storm-relative helicity
- 176 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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.
In the hours before
Special weather statement, May 20, 6:37 AM CDT, 3 hours 44 minutes before
IAZ044>046-057-058-070-071-081-082-092-093-201205- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 637 AM CDT WED MAY 20 1998 SEVERE THUNDERSTORM WATCH 377 HAS BEEN CANCELLED FOR WEST CENTRAL AND SOUTHWEST IOWA. AREAS ALONG AND WEST OF A LINE FROM JEFFERSON TO GUTHRIE CENTER TO CRESTON TO MOUNT AYR ARE NO LONGER INCLUDED IN THE WATCH. THE CITIES OF DENISON...CARROLL...AUDUBON...ATLANTIC... GREENFIELD...CORNING AND BEDFORD HAVE BEEN CLEARED. THE WATCH REMAINS IN EFFECT UNTIL 8 AM FOR AREAS TO THE EAST. STARK
Special weather statement, May 20, 7:44 AM CDT, 2 hours 37 minutes before
IAZ047>050-059>062-072>075-083>086-094>097-201315- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 744 AM CDT WED MAY 20 1998 SEVERE THUNDERSTORM WATCH 377 WILL BE ALLOWED TO EXPIRE AT 8 AM FOR THE CENTRAL AND SOUTH CENTRAL PORTIONS OF IOWA. NO WATCHES ARE IN EFFECT FOR IOWA AT THIS TIME. STARK
Special weather statement, May 20, 7:44 AM CDT, 2 hours 37 minutes before
IAZ047>050-059>062-072>075-083>086-094>097-201315- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 744 AM CDT WED MAY 20 1998 SEVERE THUNDERSTORM WATCH 377 WILL BE ALLOWED TO EXPIRE AT 8 AM FOR THE CENTRAL AND SOUTH CENTRAL PORTIONS OF IOWA. NO WATCHES ARE IN EFFECT FOR IOWA AT THIS TIME. STARK
Local storm report, May 20, 8:24 AM CDT, 1 hour 57 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
824 AM CDT WED MAY 20 1998
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0413 AM DOW CITY IA 70 MPH TSTM GUST
05/20/98 CRAWFORD
0533 AM DOW CITY IA 60 MPH TSTM GUST
05/20/98 CRAWFORD
0540 AM CUMMING IA 63 MPH TSTM GUST
05/20/98 WARREN
0555 AM DES MOINES ARPT IA 60 MPH TSTM GUST
05/20/98 POLK PILOT REPORT ON GROUNDLocal storm report, May 20, 8:24 AM CDT, 1 hour 57 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
824 AM CDT WED MAY 20 1998
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0413 AM DOW CITY IA 70 MPH TSTM GUST
05/20/98 CRAWFORD
0533 AM DOW CITY IA 60 MPH TSTM GUST
05/20/98 CRAWFORD
0540 AM CUMMING IA 63 MPH TSTM GUST
05/20/98 WARREN
0555 AM DES MOINES ARPT IA 60 MPH TSTM GUST
05/20/98 POLK PILOT REPORT ON GROUNDThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 19, 7:23 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose | 47 min |
| May 19, 7:31 PM CDT | Severe Thunderstorm Warning | DMX | Warren | 34 min |
| May 19, 7:59 PM CDT | Severe Thunderstorm Warning | DMX | Lucas | 36 min |
| May 20, 3:46 AM CDT | Severe Thunderstorm Warning | DMX | Crawford | 49 min |
| May 20, 3:53 AM CDT | Severe Thunderstorm Warning | DMX | Audubon, Cass | 62 min |
| May 20, 4:31 AM CDT | Severe Thunderstorm Warning | DMX | Carroll | 49 min |
| May 20, 5:20 AM CDT | Severe Thunderstorm Warning | DMX | Dallas, Madison, Polk, Warren | 60 min |
| May 20, 5:47 AM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marion | 48 min |
| May 20, 10:19 AM CDT | Severe Thunderstorm Warning | DMX | Marion | 36 min |
| May 20, 10:50 AM CDT | Severe Thunderstorm Warning | DMX | Monroe | 35 min |
| May 20, 11:05 AM CDT | Severe Thunderstorm Warning | DMX | Wapello | 35 min |
| May 20, 11:45 AM CDT | Severe Thunderstorm Warning | DMX | Mahaska | 20 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 1998Every severe thunderstorm warning in 1998
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.