Right now
The most recent data we hold from NOAA arrived 1 minute 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 17 May 2026 at 22:00 UTC. It is kept here as a record.
No stronger detection stands among the 30 recorded within 20 km of this point since 15 March 2026 — 6 others scored the same. Another comparable one was recorded here earlier the same day. 7 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 17 at 5:32PM EDT until May 17 at 6:00PM EDT by NWS Detroit/Pontiac MI
Urban PEI: 150,458 within a heuristic 50 km radius; not unique people.
Nearby, since 15 March 2026
- June 25, 2026 · score 43 · 11.9 km
- May 17, 2026 · score 43 · 14.6 km
- July 21, 2026 · score 43 · 21.2 km
How we know
2 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 43 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) | 43 / 100 |
| Legacy data-support index | 0.84/1 |
| Coordinates | 43.6542, -83.9060 |
| Nearest City | Bay City (7 km) |
| Urban exposure index (PEI) | 150.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-17T21:32:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.420b6312e8f0c8b1d838aa54a74e315a |
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: 2026-05-17T21:32:00.000Z.
First archived: 2026-05-17T21:47:52.237Z. 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 | Bay, MI; Bay, MI; Midland, MI; Saginaw, MI |
| Headline | Severe Thunderstorm Warning issued May 17 at 5:32PM EDT until May 17 at 6:00PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-05-17T18:00:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.420b6312e8f0c8b1d838aa54a74e315a8d49fa21.002.1","noaa_urn:oid:2.49.0.1.840.0.66a01e903ca9d73366c33f55030ccf56eb0452d7.001.1"] |
| Iem TypeSummary | H |
| Iem Magnitude | 1 |
| Iem Unit | inch |
| Iem City | 2 SE Tri Cities Intl Ai |
| Iem County | Saginaw |
| Iem State | MI |
| Iem Wfo | DTX |
| Iem Remark | Quarter sized hail reported by trained spotter. Photo also relayed via social media. |
| MergedSources | [{"id":"iem_H_43.510_-84.050_1779052080000","source":"iem","severity":"low","severityValue":25,"timestamp":1779052080000,"latitude":43.51,"longitude":-84.05}] |
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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