Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 155, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 30, 1998, 1:34 PM CDT for Story County, Iowa. It was in force for 51 min. 8 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 30, 1998, 1:34 PM CDT (18:34 UTC)
- Expired
- May 30, 1998, 2:25 PM CDT
- In force
- 51 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Story County, IA
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 30, 1:43 PM CDT | Hail 1.25 | Gilbert, IA | |
| May 30, 1:50 PM CDT | Hail 4 | Gilbert, IA | |
| May 30, 1:51 PM CDT | Hail 5 | Gilbert, IA | |
| May 30, 1:53 PM CDT | Hail 1.75 | Gilbert, IA | |
| May 30, 1:56 PM CDT | Tornado F1 | Nevada, IA | Intermittent path |
| May 30, 2:07 PM CDT | Hail 2.75 | Nevada, IA | |
| May 30, 2:08 PM CDT | Hail 1.75 | Nevada, IA | |
| May 30, 2:09 PM CDT | Hail 3 | Ames, 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 30, 12:00 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 30, 1:00 PM CDT | Tornado Watch | SPC | 4 hr |
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 6.6 hours before the alert went out and 250 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
- 616 J/kg
- Mixed-layer CIN
- -69 J/kg
- Mixed-layer LCL
- 1133 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 3 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.9
The text
As transmitted, in the capitals the NWS used until 2016.
774 WUUS1 KDSM 301835 RRA SVRDSM IAC169-301925- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE DES MOINES IA 134 PM CDT SAT MAY 30 1998 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... STORY COUNTY IN CENTRAL IOWA * UNTIL 225 PM CDT * AT 133 PM CDT... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 33 MILES SOUTHEAST OF FORT DODGE OR 5 MILES WEST NORTHWEST OF GILBERT MOVING EAST SOUTHEAST AT 40 MPH. * THIS STORM CAN BE EXPECTED NEAR... AMES BY 138 PM CDT ROLAND BY 142 PM CDT NEVADA BY 150 PM CDT GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS A TORNADO WATCH IS IN EFFECT. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE WARNING. FAB
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 30, 10:32 AM CDT, 3 hours 2 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-310130- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 1032 AM CDT SAT MAY 30 1998 HAZARD--THUNDERSTORMS WITH LARGE HAIL...DAMAGING WINDS...VERY HEAVY RAINFALL AND ISOLATED TORNADOES. TIMING AND AREA OF CONCERN--THE PRIMARY THREAT FOR SEVERE WEATHER WILL BE ALONG AND NORTH OF INTERSTATE 80 FROM NOON THROUGH EARLY EVENING. A LESSER THREAT FOR SEVERE WEATHER WILL OCCUR SOUTH OF INTERSTATE 80 SOUTH TO THE IOWA/MISSOURI BORDER. METEOROLOGICAL COMMENTS--A VERY UNSTABLE AIRMASS IS IN PLACE OVER IOWA TODAY. IN ADDITION...THERE IS A RICH SUPPLY OF MOISTURE ORIGINATING FROM THE PACIFIC...KNOWN AS THE PINEAPPLE CONNECTION. AS A SOUTHERLY WIND INCREASES ACROSS THE STATE THEY WILL INTERACT WITH A NEARLY STATIONARY FRONT EXTENDING ACROSS THE STATE FROM A DAVENPORT TO SIOUX FALLS LINE. LIFTED INDICES OF -8 TO -12 ARE FORECAST OVER THE STATE WITH CAPES INCREASING TO ALMOST 5000 J/KG AND HELICITY VALUES IN THE 400 TO 500 RANGE. PRECAUTIONS--EMERGENCY MANAGERS FOR COUNTIES ALONG AND NORTH OF INTERSTATE 80 SHOULD PREPARE THEIR SPOTTER NETWORKS FOR DEPLOYMENT AROUND OR JUST AFTER THE NOON HOUR. EMERGENCY MANAGERS FOR COUNTIES TO THE SOUTH OF INTERSTATE 80 SHOULD ALERT THEIR SPOTTERS FOR POSSIBLE DEPLOYMENT LATER THIS AFTERNOON OR EVENING. FAB
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 30, 11:39 AM CDT | Severe Thunderstorm Warning | DMX | Sac | 51 min |
| May 30, 12:10 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun | 50 min |
| May 30, 12:38 PM CDT | Severe Thunderstorm Warning | DMX | Greene, Webster | 47 min |
| May 30, 12:46 PM CDT | Tornado Warning | DMX | Calhoun, Greene | 34 min |
| May 30, 1:05 PM CDT | Severe Thunderstorm Warning | DMX | Boone | 50 min |
| May 30, 1:25 PM CDT | Tornado Warning | DMX | Boone | 35 min |
| May 30, 1:50 PM CDT | Tornado Warning | DMX | Boone | 50 min |
| May 30, 2:12 PM CDT | Severe Thunderstorm Warning | DMX | Marshall | 48 min |
| May 30, 2:20 PM CDT | Tornado Warning | DMX | Marshall | 50 min |
| May 30, 2:52 PM CDT | Severe Thunderstorm Warning | DMX | Tama | 48 min |
| May 30, 3:08 PM CDT | Tornado Warning | DMX | Marshall | 22 min |
| May 30, 3:08 PM CDT | Tornado Warning | DMX | Marshall | 17 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.