Right now
The most recent data we hold from NOAA arrived 7 hours 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 13 May 2026 at 02:30 UTC. It is kept here as a record.
It is the 4th strongest of the 18 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 5 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued May 12 at 9:52PM EDT until May 12 at 10:30PM EDT by NWS Grand Rapids MI
Nearby, since 16 March 2026
- May 13, 2026 · score 39 · 14.7 km
- July 9, 2026 · score 22 · 21.5 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 22 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) | 22 / 100 |
| Legacy data-support index | 0.62/1 |
| Coordinates | 43.6333, -86.6375 |
| Nearest City | Muskegon (55 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-05-13T01:52:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.97aded28c223943eaea589226afcf3f7 |
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: 2026-05-13T01:52:00.000Z.
First archived: 2026-05-13T01:58:00.326Z. 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 | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Grand Haven to Whitehall MI; Whitehall to Pentwater MI; Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid Lake; Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to Mid Lake; Whitehall to Pentwater MI; Pentwater to Manistee MI; Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid Lake; Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued May 12 at 9:52PM EDT until May 12 at 10:30PM EDT by NWS Grand Rapids MI |
| Expires | 2026-05-12T22:30:00-04:00 |
| SenderName | NWS Grand Rapids MI |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.97aded28c223943eaea589226afcf3f714cd83cd.001.1","noaa_urn:oid:2.49.0.1.840.0.6c71c5938005bdc1a8f6b8caa5fbed14e893800e.001.1"] |
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.
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