Right now
The most recent data we hold from NOAA arrived 30 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 21 July 2026 at 02:45 UTC. It is kept here as a record.
It is the 6th strongest of the 29 detections recorded within 20 km of this point since 15 March 2026. The last comparable one was on 13 July 2026. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued July 20 at 9:00PM CDT until July 20 at 9:45PM CDT by NWS Green Bay WI
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 16 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) | 16 / 100 |
| Legacy data-support index | 0.60/1 |
| Coordinates | 45.3798, -85.4661 |
| Nearest City | Traverse City (70 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-07-21T02:00:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.6d86188e64c806fe911cd073706c1185 |
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: 2026-07-21T02:00:00.000Z.
First archived: 2026-07-21T02:16:55.255Z. 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 | Rock Island Passage to Sturgeon Bay WI; Lake Michigan from Rock Island Passage to Sturgeon Bay WI 5NM offshore to mid lake; Straits of Mackinac within 5 nm of Mackinac Bridge including Mackinac Island; Seul Choix Point to 5NM West of Mackinac Bridge; Norwood MI to 5NM West of Mackinac Bridge including Little Traverse Bay; Sleeping Bear Point to Grand Traverse Light MI; Lake Michigan South of a line from Seul Choix Point to the Mackinac Bridge and North of a line from Charlevoix MI to South Fox Island 5NM offshore; Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to mid lake; Grand Traverse Bay south of a line Grand Traverse Light to Norwood MI; Sleeping Bear Point to Grand Traverse Light MI; Point Betsie to Sleeping Bear Point MI; Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to mid lake and 1 more areas |
| Headline | Special Marine Warning issued July 20 at 9:00PM CDT until July 20 at 9:45PM CDT by NWS Green Bay WI |
| Expires | 2026-07-20T21:45:00-05:00 |
| SenderName | NWS Green Bay WI |
| HasExactCoords | true |
| MergedCount | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.6d86188e64c806fe911cd073706c11854b60e96e.001.1","noaa_urn:oid:2.49.0.1.840.0.2f683d16cbac517b83aae0129cc447eab74f8649.001.1","noaa_urn:oid:2.49.0.1.840.0.d2b896bae345969180af41f13e2cd49cda375280.001.1","noaa_urn:oid:2.49.0.1.840.0.20a9468add5937b57fce15bf3b02ed2e3b381bd7.001.1"] |
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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