Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 7, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Mar 30, 1998, 3:50 PM CST for Mahaska County, Poweshiek County, Iowa. It was in force for 30 min. 1 report 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
- Mar 30, 1998, 3:50 PM CST (21:50 UTC)
- Expired
- Mar 30, 1998, 4:20 PM CST
- In force
- 30 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
Counties Mahaska County, IA, Poweshiek County, IA
The radar
The Des Moines radar (KDMX), 98 km from the middle of the area, began a volume at 21:53 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 |
|---|---|---|---|
| Mar 30, 4:00 PM CST | Thunderstorm Wind 61 | New Sharon, 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 |
|---|---|---|---|
| Mar 30, 3:45 PM CST | Severe Thunderstorm Watch | SPC | 5 hr |
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 174 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
- 1173 J/kg
- Mixed-layer CIN
- -43 J/kg
- Mixed-layer LCL
- 828 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 268 m²/s²
- 0-3 km storm-relative helicity
- 302 m²/s²
- Significant tornado parameter
- 1.8
- Supercell composite
- 8.5
The text
As transmitted, in the capitals the NWS used until 2016.
238
WUUS1 KDSM 302151 RRA
SVRDSM
IAC123-157-302220-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
350 PM CST MON MAR 30 1998
* SEVERE THUNDERSTORM WARNING FOR
NORTHERN MAHASKA COUNTY - SOUTHEASTERN IOWA
POWESHIEK COUNTY - CENTRAL IOWA
* UNTIL 420 PM CST
* SOME AREAS AFFECTED
NEW SHARON
MONTEZUMA
GRINNELL
BROOKLYN
* AT 348 PM CST STORM SPOTTERS REPORTED A SEVERE THUNDERSTORM JUST
NORTH OF PELLA OR 40 MILES SOUTHEAST OF DES MOINES MOVING NORTHEAST
AT 50 MPH.
* THE STORM WILL BE NEAR MONTEZUMA BY 420 PM.
THIS STORM HAS A HISTORY OF PRODUCING LARGE HAIL. WIND GUSTS TO 60 MPH
ARE ALSO LIKELY WITH THIS STORM.
PYTLAKWhat 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, Mar 30, 11:16 AM CST, 4 hours 34 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-302100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 1116 AM CST MON MAR 30 1998 HAZARD--THUNDERSTORMS THIS AFTERNOON COULD PRODUCE HEAVY RAINS AND GUSTY WINDS IN EXCESS OF 58 MPH. TIMING AND AREA OF CONCERN -SOUTHEAST OF A LINE FROM MASON CITY TO CARROLL...WITH THE THREAT OF STRONG WINDS SOUTHEAST OF A LINE FROM WATERLOO TO DES MOINES TO CRESTON. TIMING IS AFTER 200 PM. METEOROLOGICAL COMMENTS -A STATIONARY FRONT EXTENDS FROM NORTHWEST OF WATERLOO THROUGH DES MOINES AND TO THE SOUTHEAST OF CRESTON...PROVIDING A STRONG CONTRAST IN WEATHER ACROSS IOWA. THE FRONT WILL MOVE LITTLE TODAY AS A LOW PRESSURE CENTER IS FORECAST TO MOVE NORTH ALONG THE FRONT TONIGHT. AS A RESULT...THE ATMOSPHERE WILL BECOME QUITE WARM AND UNSTABLE THIS AFTERNOON OVER SOUTHEAST IOWA WHILE REMAINING COOL AND DAMP IN THE NORTHWEST. DIVERGENT AIR FLOW ALOFT WILL ALLOW THUNDERSTORMS TO REDEVELOP IN VICINITY OF THE FRONT THIS AFTERNOON WITH STORMS TRACKING RAPIDLY TO THE NORTHEAST. SOUTHEAST OF THE WATERLOO TO CRESTON LINE...INSTABILITY AND WIND SHEAR WILL BE FAVORABLE FOR A FEW STORMS TO BECOME SEVERE...PRODUCING HAIL UP TO 1 INCH AND WINDS OVER 58 MPH. NORTHWEST OF THIS AREA TO MASON CITY AND CARROLL...THE THREAT IS ORIENTED MORE TOWARD EMBEDDED THUNDERSTORMS WITH BRIEF HEAVY RAINS. THIS WILL OCCUR AS VERY MOIST AIR OVERRUNS THE FRONTAL BOUNDARY. AVERAGE RAINFALL IS EXPECTED TO BE IN THE ONE HALF TO THREE QUARTER INCH RANGE THROUGH THIS EVENING...WITH ISOLATED HEAVIER AMOUNTS. SINCE ONE HALF TO 1.5 INCHES OF RAIN HAS ALREADY FALLEN OVER PORTIONS OF CENTRAL IOWA...RIVERS AND STREAMS ARE RISING AND CHANCES FOR MINOR FLOODING WILL CONTINUE. PRECAUTIONS SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON SOUTHEAST OF THE WATERLOO TO CRESTON LINE. AS STREAMS CONTINUE TO RISE...USE CAUTION IN FLOOD PRONE AREAS AND KEEP ABREAST OF THE LATEST FORECASTS. JUNGBLUTH
Special weather statement, Mar 30, 11:16 AM CST, 4 hours 34 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-302100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 1116 AM CST MON MAR 30 1998 HAZARD--THUNDERSTORMS THIS AFTERNOON COULD PRODUCE HEAVY RAINS AND GUSTY WINDS IN EXCESS OF 58 MPH. TIMING AND AREA OF CONCERN -SOUTHEAST OF A LINE FROM MASON CITY TO CARROLL...WITH THE THREAT OF STRONG WINDS SOUTHEAST OF A LINE FROM WATERLOO TO DES MOINES TO CRESTON. TIMING IS AFTER 200 PM. METEOROLOGICAL COMMENTS -A STATIONARY FRONT EXTENDS FROM NORTHWEST OF WATERLOO THROUGH DES MOINES AND TO THE SOUTHEAST OF CRESTON...PROVIDING A STRONG CONTRAST IN WEATHER ACROSS IOWA. THE FRONT WILL MOVE LITTLE TODAY AS A LOW PRESSURE CENTER IS FORECAST TO MOVE NORTH ALONG THE FRONT TONIGHT. AS A RESULT...THE ATMOSPHERE WILL BECOME QUITE WARM AND UNSTABLE THIS AFTERNOON OVER SOUTHEAST IOWA WHILE REMAINING COOL AND DAMP IN THE NORTHWEST. DIVERGENT AIR FLOW ALOFT WILL ALLOW THUNDERSTORMS TO REDEVELOP IN VICINITY OF THE FRONT THIS AFTERNOON WITH STORMS TRACKING RAPIDLY TO THE NORTHEAST. SOUTHEAST OF THE WATERLOO TO CRESTON LINE...INSTABILITY AND WIND SHEAR WILL BE FAVORABLE FOR A FEW STORMS TO BECOME SEVERE...PRODUCING HAIL UP TO 1 INCH AND WINDS OVER 58 MPH. NORTHWEST OF THIS AREA TO MASON CITY AND CARROLL...THE THREAT IS ORIENTED MORE TOWARD EMBEDDED THUNDERSTORMS WITH BRIEF HEAVY RAINS. THIS WILL OCCUR AS VERY MOIST AIR OVERRUNS THE FRONTAL BOUNDARY. AVERAGE RAINFALL IS EXPECTED TO BE IN THE ONE HALF TO THREE QUARTER INCH RANGE THROUGH THIS EVENING...WITH ISOLATED HEAVIER AMOUNTS. SINCE ONE HALF TO 1.5 INCHES OF RAIN HAS ALREADY FALLEN OVER PORTIONS OF CENTRAL IOWA...RIVERS AND STREAMS ARE RISING AND CHANCES FOR MINOR FLOODING WILL CONTINUE. PRECAUTIONS SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON SOUTHEAST OF THE WATERLOO TO CRESTON LINE. AS STREAMS CONTINUE TO RISE...USE CAUTION IN FLOOD PRONE AREAS AND KEEP ABREAST OF THE LATEST FORECASTS. JUNGBLUTH
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 30, 1:52 PM CST | Severe Thunderstorm Warning | DMX | Tama | 33 min |
| Mar 30, 2:27 PM CST | Severe Thunderstorm Warning | DMX | Dallas, Madison | 33 min |
| Mar 30, 2:44 PM CST | Severe Thunderstorm Warning | DMX | Polk | 31 min |
| Mar 30, 3:10 PM CST | Severe Thunderstorm Warning | DMX | Polk, Story | 35 min |
| Mar 30, 3:18 PM CST | Severe Thunderstorm Warning | DMX | Warren | 27 min |
| Mar 30, 3:27 PM CST | Severe Thunderstorm Warning | DMX | Jasper, Marion | 33 min |
| Mar 30, 4:06 PM CST | Severe Thunderstorm Warning | DMX | Lucas, Wayne | 34 min |
| Mar 30, 4:17 PM CST | Severe Thunderstorm Warning | DMX | Poweshiek | 18 min |
| Mar 30, 4:21 PM CST | Severe Thunderstorm Warning | DMX | Poweshiek | 19 min |
| Mar 30, 4:49 PM CST | Severe Thunderstorm Warning | DMX | Monroe, Wapello | 31 min |
| Mar 30, 5:06 PM CST | Severe Thunderstorm Warning | DMX | Mahaska | 34 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.