This alert expired on 18 June 2026 at 23:45 UTC. It is kept here as a record.
It is the 2nd strongest of the 20 detections recorded within 20 km of this point since 15 March 2026. The last comparable one was on 28 May 2026.
What the source measured
NOAA reported: Special Marine Warning issued June 18 at 6:57PM EDT until June 18 at 7:45PM EDT by NWS Charleston SC
An estimated 58,464 people live within 50 km of this point.
Nearby, since 15 March 2026
- July 26, 2026 · score 39 · 7.8 km
- May 12, 2026 · score 39 · 13.1 km
- March 15, 2026 · score 22 · 14.5 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 39 out of 100, at 85 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
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 |
| Our confidence | 85% |
| Coordinates | 30.3590, -80.8979 |
| Nearest City | Jacksonville Beach (48 km) |
| Population Exposed | 58.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-18T22:57:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.3a39fbd85c7d51ba317227e1fe452b38 |
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; Coastal waters from Savannah GA to Altamaha Sound GA out 20 nm, including Grays Reef National Marine Sanctuary; Waters from Altamaha Sound GA to Fernandina Beach FL from 20 to 60 NM; Waters from Fernandina Beach to St. Augustine FL from 20 to 60 NM; Flagler Beach to Volusia-Brevard County Line 0-20 nm and 1 more areas |
| Headline | Special Marine Warning issued June 18 at 6:57PM EDT until June 18 at 7:45PM EDT by NWS Charleston SC |
| Expires | 2026-06-18T19:45:00-04:00 |
| SenderName | NWS Charleston SC |
| HasExactCoords | true |
| MergedCount | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.3a39fbd85c7d51ba317227e1fe452b3850327279.001.1","noaa_urn:oid:2.49.0.1.840.0.5d4393d0913ee6a8339598653d276da22318e813.001.1","noaa_urn:oid:2.49.0.1.840.0.187360f03fdbea368464ffd031839dc373a583c1.001.1","noaa_urn:oid:2.49.0.1.840.0.7037d52e0e54d7ae50d4578e33c0652afd74692d.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 45 |
| Iem Unit | MPH |
| Iem City | 1 NNE Saint Augustine B |
| Iem County | St. Johns |
| Iem State | FL |
| Iem Wfo | JAX |
| Iem Remark | CMAN station SAUF1 1 NNE Saint Augustine Beach reported a gust to 39 knots or 45 mph from the southwest. |
| MergedSources | [{"id":"iem_G_29.860_-81.270_1781817780000","source":"iem","severity":"low","severityValue":25,"timestamp":1781817780000,"latitude":29.86,"longitude":-81.27}] |
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.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 39/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.