This alert expired on 9 August 2026 at 16:15 UTC. It is kept here as a record.
It is the 10th strongest of the 45 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 10 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 9 at 11:05AM CDT until August 9 at 11:15AM CDT by NWS Milwaukee/Sullivan WI
An estimated 485,366 people live within 50 km of this point.
Nearby, since 16 March 2026
- June 24, 2026 · score 76 · 5.6 km
- June 24, 2026 · score 72 · 5.8 km
- July 27, 2026 · score 76 · 8.3 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 43 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) | 43 / 100 |
| Our confidence | 86% |
| Coordinates | 42.8317, -88.5194 |
| Nearest City | Waukesha (31 km) |
| Population Exposed | 485.4K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-09T16:05:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.2206a518b7b9f51e7bbb3d1899be2180 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Jefferson, WI; Racine, WI; Walworth, WI; Waukesha, WI |
| Headline | Severe Thunderstorm Warning issued August 9 at 11:05AM CDT until August 9 at 11:15AM CDT by NWS Milwaukee/Sullivan WI |
| Expires | 2026-08-09T11:15:00-05:00 |
| SenderName | NWS Milwaukee/Sullivan WI |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.2206a518b7b9f51e7bbb3d1899be21802e087d83.001.1","noaa_urn:oid:2.49.0.1.840.0.3f4321cf550fdeac02386250f97dc604d55aae4f.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 59 |
| Iem Unit | MPH |
| Iem City | 4 NE Edgerton |
| Iem County | Dane |
| Iem State | WI |
| Iem Wfo | MKX |
| Iem Remark | 59 mph wind gust recorded via weather station mounted to roof. |
| MergedSources | [{"id":"iem_G_42.890_-89.020_1786289280000","source":"iem","severity":"low","severityValue":25,"timestamp":1786289280000,"latitude":42.89,"longitude":-89.02}] |
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.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 43/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.