Right now
The most recent data we hold from NOAA arrived 14 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 June 2026 at 22:15 UTC. It is kept here as a record.
It is the 3rd strongest of the 45 detections recorded within 20 km of this point since 16 March 2026. The last comparable one was on 12 June 2026. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued June 18 at 5:20PM EDT until June 18 at 6:15PM EDT by NWS Charleston SC
Urban PEI: 77,611 within a heuristic 50 km radius; not unique people.
Nearby, since 16 March 2026
- August 2, 2026 · score 32 · 6.7 km
- June 2, 2026 · score 39 · 9.6 km
- August 3, 2026 · score 39 · 14.4 km
How we know
10 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 39 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) | 39 / 100 |
| Legacy data-support index | 0.89/1 |
| Coordinates | 32.4353, -80.3553 |
| Nearest City | Hilton Head (44 km) |
| Urban exposure index (PEI) | 77.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-18T21:20:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.bc81031301b1fcdcb2995dc3728b6436b560a5a7.001.1 |
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: 2026-06-18T21:20:00.000Z.
First archived: 2026-06-18T21:48:08.752Z. 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 South Santee River to Edisto Beach SC out 20 NM; Coastal waters from Edisto Beach SC to Savannah GA out 20 NM |
| Headline | Special Marine Warning issued June 18 at 5:20PM EDT until June 18 at 6:15PM EDT by NWS Charleston SC |
| Expires | 2026-06-18T18:15:00-04:00 |
| SenderName | NWS Charleston SC |
| HasExactCoords | true |
| Iem TypeSummary | M |
| Iem Magnitude | 49 |
| Iem Unit | mph |
| Iem City | 6 WSW Forest Beach |
| Iem County | AMZ362 |
| Iem State | SC |
| Iem Wfo | CHS |
| Iem Remark | Wxflow station at Calibogue Sound reported a peak wind gusts of 43 kts. |
| MergedSources | [{"id":"iem_D_32.720_-80.800_1781816400000","source":"iem","severity":"low","severityValue":25,"timestamp":1781816400000,"latitude":32.72,"longitude":-80.8},{"id":"iem_R_32.810_-79.960_1781807400000","source":"iem","severity":"low","severityValue":25,"timestamp":1781807400000,"latitude":32.81,"longitude":-79.96},{"id":"iem_D_32.840_-80.820_1781816940000","source":"iem","severity":"low","severityValue":25,"timestamp":1781816940000,"latitude":32.84,"longitude":-80.82},{"id":"iem_D_32.690_-80.850_1781816100000","source":"iem","severity":"low","severityValue":25,"timestamp":1781816100000,"latitude":32.69,"longitude":-80.85},{"id":"iem_D_32.480_-80.940_1781814720000","source":"iem","severity":"low","severityValue":25,"timestamp":1781814720000,"latitude":32.48,"longitude":-80.94},{"id":"iem_E_32.780_-79.940_1781807520000","source":"iem","severity":"low","severityValue":25,"timestamp":1781807520000,"latitude":32.78,"longitude":-79.94},{"id":"iem_D_32.260_-80.900_1781814420000","source":"iem","severity":"low","severityValue":25,"timestamp":1781814420000,"latitude":32.26,"longitude":-80.9},{"id":"iem_D_32.690_-80.830_1781816220000","source":"iem","severity":"low","severityValue":25,"timestamp":1781816220000,"latitude":32.69,"longitude":-80.83},{"id":"iem_M_32.110_-80.840_1781815140000","source":"iem","severity":"low","severityValue":25,"timestamp":1781815140000,"latitude":32.11,"longitude":-80.84}] |
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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