During the evening hours on May 17th, a line of severe storms moved into northeast Iowa and produced a 70 mph wind gust in Nora Springs.
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The episode as NWS ARX wrote it up.
During the evening hours on May 17th, a line of severe storms moved into northeast Iowa and produced a 70 mph wind gust in Nora Springs.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS La Crosse, WI wrote its last area forecast discussion before the first event at May 17, 7:19 PM CST, 2 hours 15 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service La Crosse WI 819 PM CDT Sun May 17 2026 .KEY MESSAGES... - Severe weather possible between 7 PM and 1 AM tonight. All hazards are possible mainly west of the Mississippi River. - Another round of severe weather possible on Monday night between 9 PM and 4 AM. The main threat will be damaging winds. With isolated threats of hail and maybe a few QLCS tornadoes. && .UPDATE... Issued at 805 PM CDT Sun May 17 2026 Ongoing non-severe scattered storms across the local area are inhibiting northward progression of warm front seen through north-central Iowa on surface observations this evening, keeping local severe threat conditional, i.e., lower overall confidence. Intensification of the low level jet, 45 kt south wind on DMX VWP, suggests a northern shift in warm front surging instability farther north in the next 1-2 hours. Therefore, initial threat of surface based, semi-discrete storm mode remains a low confidence scenario to remain cognizant of until the eventual MCS on radar imagery quickly shifting east through central Minnesota arrives in 3+ hours. While main threat with this line will be damaging winds, should the warm front reach farther north, a QLCS tornado threat would exist primarily along the frontal boundary. Therefore, the ongoing Tornado Watch may require a switch to Severe Thunderstorm Watch. && .DISCUSSION... Issued at 1257 PM CDT Sun May 17 2026 This Afternoon The remnant MCV which brought rain mainly south of Interstate 94 will continue to move northeast away from the area this afternoon. As it does, the showers and isolated storms currently along Interstates 90 and 94 will move east northeast away from the area. Additional rainfall amounts will be up to a half inch. As a warm front gradually lifts northward, temperatures along and south of Interstate 94 will warm into the 60s and lower 70s, and into 60s north of this Interstate. This will result in surface-based CAPES climbing into the 1000 to 2500 J/kg along and south of Interstate 90 by 7 pm. Tonight Late this afternoon and evening, 2-3K J/kg CAPES will develop ahead of a squall line moving east across eastern South Dakota, eastern Nebraska, northern Iowa, and southern Minnesota. with 0-6 km shear approaching 40 knots, there could potentially be some supercells located along the line (these would likely stay west of the Upper Mississippi River Vally) and along the warm front near the Minnesota and Iowa boarder. In addition to the deep shear, there is 200-300 EHI along the Minnesota and Iowa boarder and downdraft CAPEs up to 1K J/kg. The discrete supercells ahead of the squall line would be capable of producing wet microbursts, large hail, and isolated tornadoes between 7 PM and 10 PM in southeast Minnesota and northeast Iowa. The threat will then shift to more damaging winds and maybe a few QLCS tornadoes as the squall line moves into southeast Minnesota and northeast Iowa between 10 PM and 11 PM. This line will then gradually weaken as the instability wanes. The severe weather threat will likely wane by 1 AM Monday. Monday night A cold front will move east through the area. There will be 1-2K J/kg CAPES ahead of this front. With much of the deep (0-6 km) shear located post frontal, not anticipating any supercells. As a result, if there is severe weather, it would be located along the cold front as a squall line. The primary threat would be damaging winds with secondary threats as hail and QLCS tornadoes. Timing looks to be rather similar tonight with the squall line moving into northeast Iowa and southeast Minnesota between 9 PM and 10 PM. It will exit the area between 2 AM and 4 AM. By this time, the winds will likely be sub-severe. Friday into Saturday A shortwave trough will move east through the area. This will result in another round of showers and isolated storms. With CAPES less than 250 J/kg and 0-3 km and 0-6 km shear less than 25 knots, not anticipating any organized severe weather at this time. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 636 PM CDT Sun May 17 2026 MVFR to IFR conditions currently present across the region with some isolated instances of LIFR along and south of the I-90 corridor. Low clouds are expected to linger for most areas through later tonight with some low precip chances. The main chance for storms looks to push east into the region late this evening - likely between 04-08Z for the terminals. The main threat with this line of storms will be strong winds and heavy rainfall so have continued with the TEMPO groups that bring stronger winds in for a short time period. Lower rain chances will continue into tomorrow morning behind the line of storms with most locations lifting back to VFR CIGs through the morning. Some lower MVFR/IFR CIGs may linger across portions of SE Minnesota and WC Wisconsin so have kept them at the KRST terminal through the end of the period. && .HYDROLOGY... Issued at 106 AM CDT Sun May 17 2026 One to two inch totals are still forecast across the area, with areas further west more favored for the 2 inch totals. This will likely not cause river flooding, only within bank rises. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && UPDATE...JAR DISCUSSION...Boyne AVIATION...Barendse HYDROLOGY...Baumgardt
Hazardous Weather Outlook National Weather Service La Crosse WI 129 PM CDT Sun May 17 2026 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ032>034-041- 181100- Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette- Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston- Buffalo-Trempealeau-Jackson-La Crosse- 129 PM CDT Sun May 17 2026 This Hazardous Weather Outlook is for portions of north central Iowa...northeast Iowa...southeast Minnesota and west central Wisconsin. .DAY ONE...This Afternoon and Tonight Scattered severe storms are possible later this evening and early overnight with damaging wind as the main threat as a line of storms progresses from west to east. .DAYS TWO THROUGH SEVEN...Monday through Saturday Scattered severe storms possible Monday evening and overnight with damaging wind the main threat. .SPOTTER INFORMATION STATEMENT... Severe storm reports would be greatly appreciated. .EMERGENCY MANAGEMENT COORDINATION... No webinar is scheduled. WIZ017-029-042>044-053>055-061-181100- Taylor-Clark-Monroe-Juneau-Adams-Vernon-Crawford-Richland-Grant- 129 PM CDT Sun May 17 2026 This Hazardous Weather Outlook is for portions of central Wisconsin...north central Wisconsin...southwest Wisconsin and west central Wisconsin. .DAY ONE...This Afternoon and Tonight Scattered strong storms are possible overnight with wind gusts as high as 45 mph as a line of storms progresses from west to east. .DAYS TWO THROUGH SEVEN...Monday through Saturday Scattered severe storms possible late Monday evening and overnight with damaging wind as the main threat. .SPOTTER INFORMATION STATEMENT... Severe storm reports would be greatly appreciated. .EMERGENCY MANAGEMENT COORDINATION... No webinar is scheduled. Boyne
The La Crosse radar (KARX), 165 km away, was scanning. The volume nearest the first event began at 03:35 UTC.
1 thunderstorm wind. Local standard time, as filed.
Local fire and rescue reported a 70 mph wind gust in Nora Springs.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2026Every state in 2026This day in weather historyWarnings in Iowa, May 2026
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1339702.