This alert expired on 20 May 2026 at 01:30 UTC. It is kept here as a record.
It is the 5th strongest of the 45 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 19 at 8:49PM EDT until May 19 at 9:30PM EDT by NWS Wilmington OH
An estimated 1,335,280 people live within 50 km of this point.
Nearby, since 15 March 2026
- May 20, 2026 · score 52 · 4.1 km
- August 11, 2026 · score 76 · 4.5 km
- August 16, 2026 · score 52 · 7.0 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 52 out of 100, at 86 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 52 / 100 |
| Our confidence | 86% |
| Coordinates | 39.8919, -83.3013 |
| Nearest City | Grove City (18 km) |
| Population Exposed | 1.3M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T00:49:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.16fdca84a200f13d26c9674b77e21090 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Delaware, OH; Franklin, OH; Licking, OH; Madison, OH; Union, OH; Clark, OH; Fayette, OH; Greene, OH; Madison, OH; Fayette, OH; Franklin, OH; Madison, OH; Pickaway, OH |
| Headline | Severe Thunderstorm Warning issued May 19 at 8:49PM EDT until May 19 at 9:30PM EDT by NWS Wilmington OH |
| Expires | 2026-05-19T21:30:00-04:00 |
| SenderName | NWS Wilmington OH |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.16fdca84a200f13d26c9674b77e21090bcb91b2d.001.1","noaa_urn:oid:2.49.0.1.840.0.53d4861d7cc10cc1dcc0ec8bc73dd42e7e4efc05.002.1","noaa_urn:oid:2.49.0.1.840.0.f69eb45a66cadfd8d21f25fba73085579b0fcdce.001.1"] |
| Iem TypeSummary | D |
| Iem City | Bellbrook |
| Iem County | Greene |
| Iem State | OH |
| Iem Wfo | ILN |
| Iem Remark | Top 20 feet of a very large tree down. |
| MergedSources | [{"id":"iem_D_39.640_-84.070_1779235980000","source":"iem","severity":"low","severityValue":25,"timestamp":1779235980000,"latitude":39.64,"longitude":-84.07}] |
Safety Information
Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.
Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Calamity.live data shows a weather event with CalamityScore 52/100, near Grove City (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.