This alert expired on 3 September 2026 at 17:45 UTC. It is kept here as a record.
It is the 15th strongest of the 25 detections recorded within 20 km of this point since 8 June 2026. The last comparable one was on 11 August 2026.
What the source measured
NOAA reported: Special Marine Warning issued September 3 at 11:19AM CDT until September 3 at 12:45PM CDT by NWS Chicago IL
An estimated 4,969,462 people live within 50 km of this point.
Nearby, since 8 June 2026
- July 27, 2026 · score 52 · 3.2 km
- August 11, 2026 · score 52 · 5.0 km
- July 27, 2026 · score 52 · 6.2 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 46 out of 100, at 87 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 46 / 100 |
| Our confidence | 87% |
| Coordinates | 42.2229, -87.4057 |
| Nearest City | Wilmette (31 km) |
| Population Exposed | 5.0M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-03T16:19:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.b4afa1a41ea31f56899dfd16a10920b1821aa21d.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Winthrop Harbor to Wilmette Harbor IL; Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued September 3 at 11:19AM CDT until September 3 at 12:45PM CDT by NWS Chicago IL |
| Expires | 2026-09-03T12:45:00-05:00 |
| SenderName | NWS Chicago IL |
| HasExactCoords | true |
| Google News RssFeed | weather |
| Google News SourceName | ABC7 Chicago |
| MergedSources | [{"id":"gnews_weather_496786_165","source":"google_news","severity":"medium","severityValue":40,"timestamp":1788432008000,"latitude":41.85,"longitude":-87.65}] |
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 46/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.