Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 79, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 19, 1998, 5:49 PM CDT for Polk County, Iowa. It was in force for 31 min. 5 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 19, 1998, 5:49 PM CDT (22:49 UTC)
- Expired
- May 19, 1998, 6:20 PM CDT
- In force
- 31 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Polk County, IA
The radar
The Des Moines radar (KDMX), 13 km from the middle of the area, began a volume at 22:49 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 19, 5:50 PM CDT | Hail 0.88 | Johnston, IA | |
| May 19, 6:00 PM CDT | Hail 1.75 | Johnston, IA | |
| May 19, 6:12 PM CDT | Hail 0.88 | Ankeny, IA | |
| May 19, 6:13 PM CDT | Hail 1.75 | Ankeny, IA | |
| May 19, 6:20 PM CDT | Hail 0.75 | Grimes, 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 19, 4:30 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 12:00Z, 10.8 hours before the alert went out and 236 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
- 1590 J/kg
- Mixed-layer CIN
- -196 J/kg
- Mixed-layer LCL
- 1416 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- -21 m²/s²
- 0-3 km storm-relative helicity
- 16 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.2
The text
As transmitted, in the capitals the NWS used until 2016.
268 WUUS1 KDSM 192250 RRA SVRDSM IAC153-192320- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE DES MOINES IA 549 PM CDT TUE MAY 19 1998 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... SOUTHERN POLK COUNTY IN CENTRAL IOWA * UNTIL 620 PM CDT * AT 547 PM CDT... STORM SPOTTERS REPORTED A SEVERE THUNDERSTORM 5 MILES NORTHWEST OF DES MOINES OR 2 MILES NORTHEAST OF URBANDALE MOVING SOUTH AT 15 MPH. * THIS STORM CAN BE EXPECTED NEAR... URBANDALE BY 552 PM CDT CLIVE BY 552 PM CDT WINDSOR HEIGHTS BY 552 PM CDT DES MOINES BY 555 PM CDT WEST DES MOINES BY 557 PM CDT THIS STORM HAS A HISTORY OF LARGE HAIL. GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS NICKEL HAIL WAS REPORTED IN SOUTHERN CITY OF JOHNSTON AT 546 PM CDT. 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.
In the hours before
Special weather statement, May 19, 2:28 PM CDT, 3 hours 21 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-200130- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 228 PM CDT TUE MAY 19 1998 HAZARD--WIDELY SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING HAIL UP TO GOLFBALL SIZE...HEAVY RAIN AND WIND GUSTS TO 70 MPH. AREA OF CONCERN--SOUTH OF HIGHWAY 20. TIMING DETAILS--AFTER 400 PM. METEOROLOGICAL COMMENTS--THE COLD FRONT HAS PRETTY MUCH STALLED OUT FROM NEAR WATERLOO TO AROUND ATLANTIC. TOWERING CUMULUS CLOUDS WERE DEVELOPING ALONG AND SOUTH OF THIS FRONT WHICH INDICATED THAT THE TEMPERATURE INVERSION SUPPRESSING THUNDERSTORM DEVELOPMENT WAS CLOSE TO BREAKING. IN FAR NORTHEAST IOWA AND SOUTHERN WISCONSIN...THE CAP HAS ALREADY RUPTURED RESULTING IN A FEW SEVERE STORMS. AS THE EVENING PROGRESSES AN UPPER LEVEL DISTURBANCE WILL MOVE OUT OF COLORADO... COOLING THE MID LEVELS AND BREAKING DOWN THE CAP. THUNDERSTORMS SHOULD THEN BECOME MORE WIDESPREAD ALONG THE BOUNDARY FROM IOWA ALL THE WAY BACK INTO THE NEBRASKA/KANSAS BORDER AREA. THE DEGREE OF INSTABILITY AND PRESENCE OF DRY AIR ALOFT INDICATES LARGE HAIL AND DAMAGING DOWNBURSTS WILL BE THE MAIN HAZARDS. BECAUSE THE FRONT WILL ALSO BE STATIONARY FOR MUCH OF THE NIGHT...UP TO 2 INCHES OF RAIN COULD FALL IN A FEW SPOTS BUT PARTICULARLY EXCESSIVE RAIN IS NOT EXPECTED SINCE GULF OF MEXICO INFLOW IS RATHER WEAK AND THERE IS CONSIDERABLE DRY AIR ALOFT. PRECAUTIONS--A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR EXTREME EASTERN IOWA AND MAY BE NEEDED FURTHER WEST LATER THIS EVENING. PYTLAK
Special weather statement, May 19, 2:28 PM CDT, 3 hours 21 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-200130- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 228 PM CDT TUE MAY 19 1998 HAZARD--WIDELY SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING HAIL UP TO GOLFBALL SIZE...HEAVY RAIN AND WIND GUSTS TO 70 MPH. AREA OF CONCERN--SOUTH OF HIGHWAY 20. TIMING DETAILS--AFTER 400 PM. METEOROLOGICAL COMMENTS--THE COLD FRONT HAS PRETTY MUCH STALLED OUT FROM NEAR WATERLOO TO AROUND ATLANTIC. TOWERING CUMULUS CLOUDS WERE DEVELOPING ALONG AND SOUTH OF THIS FRONT WHICH INDICATED THAT THE TEMPERATURE INVERSION SUPPRESSING THUNDERSTORM DEVELOPMENT WAS CLOSE TO BREAKING. IN FAR NORTHEAST IOWA AND SOUTHERN WISCONSIN...THE CAP HAS ALREADY RUPTURED RESULTING IN A FEW SEVERE STORMS. AS THE EVENING PROGRESSES AN UPPER LEVEL DISTURBANCE WILL MOVE OUT OF COLORADO... COOLING THE MID LEVELS AND BREAKING DOWN THE CAP. THUNDERSTORMS SHOULD THEN BECOME MORE WIDESPREAD ALONG THE BOUNDARY FROM IOWA ALL THE WAY BACK INTO THE NEBRASKA/KANSAS BORDER AREA. THE DEGREE OF INSTABILITY AND PRESENCE OF DRY AIR ALOFT INDICATES LARGE HAIL AND DAMAGING DOWNBURSTS WILL BE THE MAIN HAZARDS. BECAUSE THE FRONT WILL ALSO BE STATIONARY FOR MUCH OF THE NIGHT...UP TO 2 INCHES OF RAIN COULD FALL IN A FEW SPOTS BUT PARTICULARLY EXCESSIVE RAIN IS NOT EXPECTED SINCE GULF OF MEXICO INFLOW IS RATHER WEAK AND THERE IS CONSIDERABLE DRY AIR ALOFT. PRECAUTIONS--A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR EXTREME EASTERN IOWA AND MAY BE NEEDED FURTHER WEST LATER THIS EVENING. PYTLAK
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 19, 3:09 PM CDT | Severe Thunderstorm Warning | DMX | Polk, Warren | 31 min |
| May 19, 3:31 PM CDT | Severe Thunderstorm Warning | DMX | Polk | 34 min |
| May 19, 3:56 PM CDT | Severe Thunderstorm Warning | DMX | Jasper | 34 min |
| May 19, 4:03 PM CDT | Severe Thunderstorm Warning | DMX | Polk | 32 min |
| May 19, 4:11 PM CDT | Tornado Warning | DMX | Polk | 34 min |
| May 19, 4:23 PM CDT | Tornado Warning | DMX | Jasper | 32 min |
| May 19, 4:34 PM CDT | Tornado Warning | DMX | Marion, Polk | 36 min |
| May 19, 4:44 PM CDT | Severe Thunderstorm Warning | DMX | Poweshiek | 46 min |
| May 19, 4:49 PM CDT | Severe Thunderstorm Warning | DMX | Polk | 46 min |
| May 19, 4:53 PM CDT | Tornado Warning | DMX | Marion | 32 min |
| May 19, 4:56 PM CDT | Severe Thunderstorm Warning | DMX | Jasper | 49 min |
| May 19, 5:11 PM CDT | Severe Thunderstorm Warning | DMX | Story | 34 min |
| May 19, 5:24 PM CDT | Severe Thunderstorm Warning | DMX | Marshall | 51 min |
| May 19, 5:27 PM CDT | Severe Thunderstorm Warning | DMX | Marion | 33 min |
| May 19, 6:02 PM CDT | Severe Thunderstorm Warning | DMX | Dallas, Warren | 33 min |
| May 19, 6:15 PM CDT | Severe Thunderstorm Warning | DMX | Polk | 45 min |
| May 19, 6:24 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marshall, Story | 31 min |
| May 19, 6:44 PM CDT | Severe Thunderstorm Warning | DMX | Wapello | 46 min |
| May 19, 6:57 PM CDT | Severe Thunderstorm Warning | DMX | Polk | 48 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.