Right now
The most recent data we hold from NOAA arrived 3 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 22 July 2026 at 03:30 UTC. It is kept here as a record.
It is one of only 4 we have recorded within 20 km of this point since 30 May 2026. The last comparable one was on 19 July 2026. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued July 21 at 10:37PM EDT until July 21 at 11:30PM EDT by NWS Boston/Norton MA
Nearby, since 30 May 2026
- July 19, 2026 · score 22 · 13.3 km
- May 30, 2026 · score 22 · 15.1 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 | 0.60/1 |
| Coordinates | 41.1204, -70.0234 |
| Nearest City | Yarmouth (68 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-07-22T02:37:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.9e03e9e4718a2ea1d48d4ec0ad30b8d5 |
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: 2026-07-22T02:37:00.000Z.
First archived: 2026-07-22T03:24:27.002Z. 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 | Coastal Waters extending out to 25 NM South of Marthas Vineyard and Nantucket; Ocean Waters from Marthas Vineyard to Nantucket from 25 to 60 NM; Ocean Waters from Montauk NY to Marthas Vineyard from 25 to 60 NM; Cape Cod Bay; Nantucket Sound; Coastal waters east of Ipswich Bay and the Stellwagen Bank National Marine Sanctuary; Coastal waters from Provincetown MA to Chatham MA to Nantucket MA out 20 NM; Coastal Waters extending out to 25 NM South of Marthas Vineyard and Nantucket; Ocean Waters from the Merrimack River to Plymouth from 40 to 60 NM; Ocean Waters from Provincetown to Nantucket from 20 to 60 NM |
| Headline | Special Marine Warning issued July 21 at 10:37PM EDT until July 21 at 11:30PM EDT by NWS Boston/Norton MA |
| Expires | 2026-07-21T23:30:00-04:00 |
| SenderName | NWS Boston/Norton MA |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.9e03e9e4718a2ea1d48d4ec0ad30b8d5f828fa66.001.1","noaa_urn:oid:2.49.0.1.840.0.d7a8e15a4ba78629f8f454ef883bf5e309a244b2.001.1"] |
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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