Right now
The most recent data we hold from NOAA arrived 44 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 03:30 UTC. It is kept here as a record.
It is the 4th strongest of the 9 detections recorded within 20 km of this point since 29 June 2026. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued July 20 at 9:27PM CDT until July 20 at 10:30PM CDT by NWS Green Bay WI
Nearby, since 29 June 2026
- July 13, 2026 · score 22 · 5.8 km
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 | 45.3007, -86.0282 |
| Nearest City | Traverse City (68 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-07-21T02:27:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.1d165064e4f7f048c373baa711fba884 |
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: 2026-07-21T02:27:00.000Z.
First archived: 2026-07-21T02:43:20.464Z. 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; Green Bay south of line from Cedar River to Rock Island Passage and north of a line from Oconto WI to Little Sturgeon Bay WI and 2 more areas |
| Headline | Special Marine Warning issued July 20 at 9:27PM CDT until July 20 at 10:30PM CDT by NWS Green Bay WI |
| Expires | 2026-07-20T22:30:00-05:00 |
| SenderName | NWS Green Bay WI |
| HasExactCoords | true |
| MergedCount | 6 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.1d165064e4f7f048c373baa711fba88496d71210.001.1","noaa_urn:oid:2.49.0.1.840.0.ac494567c91582f928d422f131cee2530a7346c7.001.1","noaa_urn:oid:2.49.0.1.840.0.929d09735705af9de28441c18063020d4199c950.001.1","noaa_urn:oid:2.49.0.1.840.0.f546c0a6395c108a9604a6c3e4c36aab89fd2b99.001.1","noaa_urn:oid:2.49.0.1.840.0.6d86188e64c806fe911cd073706c11854b60e96e.001.1","noaa_urn:oid:2.49.0.1.840.0.d2b896bae345969180af41f13e2cd49cda375280.001.1"] |
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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