Low top, brief storms developed in western Iowa which produced some hail reports. One report met severe criteria in Monona County.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS OAX wrote it up.
Low top, brief storms developed in western Iowa which produced some hail reports. One report met severe criteria in Monona County.
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 Omaha, NE wrote its last area forecast discussion before the first event at May 8, 5:25 PM CST, 1 hour 4 minutes earlier.
Area Forecast Discussion National Weather Service Omaha/Valley NE 625 PM CDT Mon May 8 2023 ...Updated Aviation Forecast Discussion... .DISCUSSION... Issued at 144 PM CDT Mon May 8 2023 Key Messages: - A few isolated strong to severe thunderstorms possible this afternoon and evening in northeast Nebraska north of the Platte River. Large hail is the primary threat. - Additional chances for showers and thunderstorms in the forecast through the end of the week. - Temperatures at or just above seasonal norms through the end of the work week. We have mostly clear skies across eastern Nebraska and western Iowa this afternoon, though a couple fields of cu are starting to develop over northeast Nebraska and down near Falls City in southeast Nebraska. We do have some potential for a few isolated strong to severe thunderstorms this afternoon across northeast Nebraska, where a weak boundary seen in the obs field will be triggering convection in a narrow band of modest instability, where MUCAPE jumps up in excess of 1000 J/kg. Bulk shear in excess of 40 kt could support a couple supercells capable of up to quarter-size hail. Would likely need more CAPE for any larger hail than quarter-size. South of the Platte River, not expecting anything this evening through the overnight hours. Tuesday, we see a shift back to southerly flow, advecting more moisture back into the region. This brings back the shower and thunderstorm potential across our entire area. Showers will be fairly scattered in nature, with some places getting rain and others not. Dynamics look fairly weak so not anticipating anything severe. Chances for showers and thunderstorms remain in the forecast through at least next weekend. General troughiness to our west will continue to eject bands of energy east towards the Central Plains, but timing and location of these waves is difficult to determine at this time as deterministic models are not in agreement. Keeping the NBM's broad-brushed likely PoPs Wednesday through Friday, with decreasing chances over the weekend. Friday, the upper-low approaches our area which could provide our best chance for organized severe thunderstorms, but much is still to be determined, including the track and areas where severe weather will be expected. Temperatures through the rest of this week remain seasonable, with highs in the upper 70s to low 80s, and overnight lows will drop into the 50s to low 60s. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 619 PM CDT Mon May 8 2023 Main weather concern for the TAF period is the possibility of weak thunderstorms or rain showers tomorrow morning between 12 and 18Z. At this issuance, it looks like KOFK has the best chance to observe precipitation but confidence is too low to include. Outside of precipitation chances, there will be wind shift. Over the next 24 hours, winds will shift from the north to the east, and then from the east to the south. Winds will also increase in strength with gusts up to 20 mph forecast. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && DISCUSSION...McCoy AVIATION...Fajman
Hazardous Weather Outlook National Weather Service Omaha/Valley NE 212 PM CDT Mon May 8 2023 IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034- 042>045-050>053-065>068-078-088>093-090915- Monona-Harrison-Shelby-Pottawattamie-Mills-Montgomery-Fremont- Page-Knox-Cedar-Thurston-Antelope-Pierce-Wayne-Boone-Madison- Stanton-Cuming-Burt-Platte-Colfax-Dodge-Washington-Butler- Saunders-Douglas-Sarpy-Seward-Lancaster-Cass-Otoe-Saline- Jefferson-Gage-Johnson-Nemaha-Pawnee-Richardson- 212 PM CDT Mon May 8 2023 This Hazardous Weather Outlook is for portions of southwest Iowa...west central Iowa...east central Nebraska...northeast Nebraska and southeast Nebraska. .DAY ONE...This Afternoon and Tonight Isolated thunderstorms are possible mostly north of the Platte River this afternoon. SPC has a Marginal Risk of severe weather for this area. These storms could become strong or severe but will be few in number. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday The probability for widespread hazardous weather is low. There will be chances for thunderstorms recurrent in the forecast through Friday, with some potential for stronger storms on Friday. Low confidence in the potential for severe weather at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The Omaha radar (KOAX), 106 km away, was scanning. The volume nearest the first event began at 00:29 UTC.
1 hail. Local standard time, as filed.
Monona County dispatch relayed a report from an officer in Mapleton of pea to quarter size hail.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2023Every state in 2023This day in weather historyWarnings in Iowa, May 2023
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: 1097142.