Right now
The most recent data we hold from NOAA arrived 5 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 22:15 UTC. It is kept here as a record.
No stronger detection stands among the 16 recorded within 20 km of this point since 18 May 2026 — 12 others scored the same.
What the source measured
NOAA reported: Special Marine Warning issued May 18 at 4:45PM EDT until May 18 at 6:15PM EDT by NWS Detroit/Pontiac MI
Nearby, since 18 May 2026
- May 18, 2026 · score 22 · 8.0 km
- July 21, 2026 · score 22 · 24.4 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 | 0.59/1 |
| Coordinates | 43.3498, -82.9501 |
| Nearest City | Port Huron (60 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-05-18T20:45:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.2905a386576ce1a46a0d04dcc829db07 |
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: 2026-05-18T20:45:00.000Z.
First archived: 2026-05-18T20:47:45.577Z. 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 | Detroit River; Lake St. Clair Open Lake (U.S. Portion); Michigan Waters of Lake Erie from Detroit River to North Cape MI; Harbor Beach to Port Sanilac MI; Port Sanilac to Port Huron MI; Lake Huron from Harbor Beach to Port Sanilac 5NM Off Shore to US/Canadian border; Lake Huron from Port Sanilac to Port Huron 5NM Off Shore to US/Canadian border; Outer Saginaw Bay SW of Alabaster to Port Austin MI to Inner Saginaw Bay; Inner Saginaw Bay SW of Point Au Gres to Bay Port MI and 1 more areas |
| Headline | Special Marine Warning issued May 18 at 4:45PM EDT until May 18 at 6:15PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-05-18T18:15:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| MergedCount | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.2905a386576ce1a46a0d04dcc829db0798e72480.001.1","noaa_urn:oid:2.49.0.1.840.0.e2e54ebae713dd814300bfe7e7e538e6b15d7e14.001.1","noaa_urn:oid:2.49.0.1.840.0.2edc256ed997d0e51d150db05be0b53e35fc218f.001.1","noaa_urn:oid:2.49.0.1.840.0.e3d0705f3dd4bd44e638cbfbaaea61c95c8a6298.001.1"] |
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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