Right now
The most recent data we hold from NOAA arrived 13 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 18 May 2026 at 21:45 UTC. It is kept here as a record.
It is the 2nd strongest of the 102 detections recorded within 20 km of this point since 13 March 2026. Another comparable one was recorded here earlier the same day. 6 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 18 at 4:43PM EDT until May 18 at 5:45PM EDT by NWS Detroit/Pontiac MI
Urban PEI: 1,987,525 within a heuristic 50 km radius; not unique people.
Nearby, since 13 March 2026
- April 4, 2026 · score 52 · 7.1 km
- March 31, 2026 · score 52 · 7.1 km
- June 16, 2026 · score 52 · 8.9 km
How we know
7 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 52 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
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) | 52 / 100 |
| Legacy data-support index | 0.89/1 |
| Coordinates | 42.6996, -83.4783 |
| Nearest City | Waterford (6 km) |
| Urban exposure index (PEI) | 2.0M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-18T20:43:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.4424aa5f9dc1c480c54e1b055b617a30 |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-05-18T20:43:00.000Z.
First archived: 2026-05-18T20:52:51.396Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Huron, MI; Lapeer, MI; Tuscola, MI and 6 more areas |
| Headline | Severe Thunderstorm Warning issued May 18 at 4:43PM EDT until May 18 at 5:45PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-05-18T17:45:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| MergedCount | 9 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.4424aa5f9dc1c480c54e1b055b617a30f8c6a5bf.001.1","noaa_urn:oid:2.49.0.1.840.0.040ae71d28ba915a1aa3317b0350e34ea92542e0.001.1","noaa_urn:oid:2.49.0.1.840.0.90f0b274cd18b4b7ac39eaed223c85fc28f82537.001.1","noaa_urn:oid:2.49.0.1.840.0.bb37b469d4e8376236e2e1fd0a00f0cc705e46e6.001.1","noaa_urn:oid:2.49.0.1.840.0.b87ade078e0907622c98b46b088ef4cbced654ea.001.1","noaa_urn:oid:2.49.0.1.840.0.e5f00ad9cb800b231a0dba49a2bb9237fac78436.001.1","noaa_urn:oid:2.49.0.1.840.0.dede36097957833f88d16daaa336532f07c18f58.001.1","noaa_urn:oid:2.49.0.1.840.0.24639ea2e53c9ffab7b3a03a64bb5d5e941bdb02.001.1","noaa_urn:oid:2.49.0.1.840.0.5f4d4f06aebdd09c46d818307e6968851f070515.001.1"] |
| Iem TypeSummary | D |
| Iem City | 1 NW Rochester Hills |
| Iem County | Oakland |
| Iem State | MI |
| Iem Wfo | DTX |
| Iem Remark | Report of large tree limb down on house causing damage to roofing |
| Google News RssFeed | weather |
| Google News SourceName | ClickOnDetroit | WDIV Local 4 |
| MergedSources | [{"id":"iem_D_42.660_-83.170_1779132240000","source":"iem","severity":"low","severityValue":25,"timestamp":1779132240000,"latitude":42.66,"longitude":-83.17},{"id":"gnews_weather_494202_117","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779130324000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494203_121","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779131397000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494203_127","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779133500000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494204_131","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779134883000,"latitude":42.33,"longitude":-83.05},{"id":"gnews_weather_494201_140","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779124179000,"latitude":42.33,"longitude":-83.05}] |
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.
Review the area, threshold and delivery channel in your account.
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