This alert is in force until 4 September 2026, 08:15 UTC.
It is the 29th strongest of the 40 detections recorded within 20 km of this point since 13 March 2026. The last comparable one was on 1 August 2026.
What the source measured
NOAA reported: Special Marine Warning issued September 4 at 1:17AM 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 March 2026
- May 13, 2026 · score 48 · 4.5 km
- September 4, 2026 · score 41 · 5.9 km
- June 16, 2026 · score 48 · 7.2 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 41 out of 100, at 92 % 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 | 92% |
| Coordinates | 43.4174, -87.6732 |
| Nearest City | Mequon (36 km) |
| Population Exposed | 770.9K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-04T06:17:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.ed8512745436555d0688379c1991beb3b04234e4.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Sheboygan to Port Washington WI; Lake Michigan from Sheboygan to Port Washington WI 5NM offshore to Mid Lake; Sheboygan to Port Washington WI; Port Washington to North Point Light WI; North Point Light to Wind Point WI; Lake Michigan from Sheboygan to Port Washington WI 5NM offshore to Mid Lake; 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 |
| Headline | Special Marine Warning issued September 4 at 1:17AM 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.ed8512745436555d0688379c1991beb3b04234e4.001.1","noaa_urn:oid:2.49.0.1.840.0.d2c69eb438af773906541a1a80540ef87683b093.001.1"] |
| Spc ReportType | wind |
| Spc Speed | UNK |
| Spc Location | 2 NE Hubertus |
| Spc County | Washington |
| Spc State | WI |
| Spc Comments | Washington County EM reports widespread tree damage across Richfield... including uprooted trees. Estimated winds 60 mph... time estimated by radar. (MKX) |
| Google News RssFeed | weather |
| Google News SourceName | WTMJ |
| MergedSources | [{"id":"spc_wind_43.26_-88.19_6","source":"spc","severity":"medium","severityValue":45,"timestamp":1788505534765,"latitude":43.26,"longitude":-88.19},{"id":"gnews_weather_496805_233","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.