This alert expired on 4 September 2026 at 08:15 UTC. It is kept here as a record.
It is the 9th strongest of the 15 detections recorded within 20 km of this point since 13 May 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Special Marine Warning issued September 4 at 2:11AM CDT until September 4 at 3:15AM CDT by NWS Milwaukee/Sullivan WI
An estimated 770,881 people live within 50 km of this point.
Nearby, since 13 May 2026
- June 16, 2026 · score 48 · 3.5 km
- July 9, 2026 · score 48 · 9.6 km
- May 13, 2026 · score 48 · 10.1 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 41 out of 100, at 86 % 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) | 41 / 100 |
| Our confidence | 86% |
| Coordinates | 43.3846, -87.6158 |
| Nearest City | Mequon (38 km) |
| Population Exposed | 770.9K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-04T07:11:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.c2f2faa2f4483c9646560cbf7df09d1dedb17f27.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Lake Michigan from Port Washington to North Point Light WI 5NM offshore to Mid Lake; Lake Michigan from North Point Light to Wind Point WI 5NM offshore to Mid Lake; Sheboygan to Port Washington WI; Lake Michigan from Sheboygan to Port Washington WI 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued September 4 at 2:11AM CDT until September 4 at 3:15AM CDT by NWS Milwaukee/Sullivan WI |
| Expires | 2026-09-04T03:15:00-05:00 |
| SenderName | NWS Milwaukee/Sullivan WI |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.c2f2faa2f4483c9646560cbf7df09d1dedb17f27.001.1","noaa_urn:oid:2.49.0.1.840.0.ed8512745436555d0688379c1991beb3b04234e4.001.1"] |
| Google News RssFeed | weather |
| Google News SourceName | WTMJ |
| MergedSources | [{"id":"gnews_weather_496805_240","source":"google_news","severity":"medium","severityValue":40,"timestamp":1788499109000,"latitude":43.04,"longitude":-87.91}] |
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 41/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.