This alert expired on 18 May 2026 at 18:15 UTC. It is kept here as a record.
It is the 21st strongest of the 47 detections recorded within 20 km of this point since 10 March 2026. Another comparable one was recorded here earlier the same day. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued May 18 at 11:42AM CDT until May 18 at 1:15PM CDT by NWS Milwaukee/Sullivan WI
Nearby, since 10 March 2026
- August 10, 2026 · score 22 · 8.1 km
- June 8, 2026 · score 43 · 10.9 km
- June 8, 2026 · score 34 · 15.7 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 22 out of 100, at 60 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 22 / 100 |
| Our confidence | 60% |
| Coordinates | 42.2188, -87.0393 |
| Nearest City | Rogers Park (57 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-18T16:42:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.d49371dcb7ba0a7d32071f6fb9f2c21b |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Wind Point WI to Winthrop Harbor IL; Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM offshore to Mid Lake; St Joseph to South Haven MI; South Haven to Holland MI; Holland to Grand Haven MI; Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid Lake; Lake Michigan from South Haven to Holland MI 5NM offshore to Mid lake; Lake Michigan from St Joseph to South Haven MI 5NM offshore to Mid Lake; New Buffalo MI to St Joseph MI; Michigan City IN to New Buffalo MI; Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to mid-line of lake. and 1 more areas |
| Headline | Special Marine Warning issued May 18 at 11:42AM CDT until May 18 at 1:15PM CDT by NWS Milwaukee/Sullivan WI |
| Expires | 2026-05-18T13:15:00-05:00 |
| SenderName | NWS Milwaukee/Sullivan WI |
| HasExactCoords | true |
| MergedCount | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.d49371dcb7ba0a7d32071f6fb9f2c21b582a1d48.001.1","noaa_urn:oid:2.49.0.1.840.0.2c35388502c0f9480cb0dfdccbbf290d51a676ce.001.1","noaa_urn:oid:2.49.0.1.840.0.9c09acd13247425de3828f508e397963a6266548.001.1","noaa_urn:oid:2.49.0.1.840.0.03e506535187c138bb6e2a5b32fa511270ea1536.001.1"] |
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 8 March 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.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 22/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.