Right now
The most recent data we hold from NOAA arrived 18 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 15 September 2026 at 14:45 UTC. It is kept here as a record.
It is the 7th strongest of the 15 detections recorded within 20 km of this point since 16 March 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 September 15 at 10:07AM EDT until September 15 at 10:45AM EDT by NWS Charleston SC
Urban PEI: 257,257 within a heuristic 50 km radius; not unique people.
Nearby, since 16 March 2026
- August 13, 2026 · score 43 · 9.4 km
- June 18, 2026 · score 43 · 12.2 km
- July 12, 2026 · score 43 · 13.8 km
How we know
2 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 37 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 v5. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 37 / 100 |
| Legacy data-support index | 0.87/1 |
| Coordinates | 32.0150, -80.5825 |
| Nearest City | Hilton Head Island (24 km) |
| Urban exposure index (PEI) | 257.3K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-15T14:07:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.6b908a3eacdf3e62fcf3538698ee5e3ea18ca603.001.1 |
Physical priority index · v5. 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: 2026-09-15T14:07:00.000Z.
First archived: 2026-09-15T14:14:03.510Z. 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 from Edisto Beach SC to Savannah GA out 20 NM; Waters from Edisto Beach SC to Savannah GA extending from 20 to 60 NM |
| Headline | Special Marine Warning issued September 15 at 10:07AM EDT until September 15 at 10:45AM EDT by NWS Charleston SC |
| Expires | 2026-09-15T10:45:00-04:00 |
| SenderName | NWS Charleston SC |
| HasExactCoords | true |
| Iem TypeSummary | W |
| Iem City | 10 SE Folly Field |
| Iem County | AMZ362 |
| Iem State | SC |
| Iem Wfo | CHS |
| Iem Remark | Hilton Head Shore Beach Service observed a waterspout off the south end of the island. Video was relayed via Hilton Head Emergency Management. Time estimated. |
| MergedSources | [{"id":"iem_W_32.090_-80.600_1789480980000","source":"iem","severity":"low","severityValue":25,"timestamp":1789480980000,"latitude":32.09,"longitude":-80.6}] |
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.
Review the area, threshold and delivery channel in your account.
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