This alert expired on 20 May 2026 at 23:00 UTC. It is kept here as a record.
It is the 7th strongest of the 254 detections recorded within 20 km of this point since 17 March 2026. The last comparable one was on 1 April 2026.
What the source measured
NOAA reported: Special Marine Warning issued May 20 at 6:07PM EDT until May 20 at 7:00PM EDT by NWS Mount Holly NJ
An estimated 119,959 people live within 50 km of this point.
Nearby, since 17 March 2026
- September 1, 2026 · score 37 · 10.9 km
- May 27, 2026 · score 43 · 13.9 km
- July 5, 2026 · score 43 · 14.6 km
How we know
Confirmed by 6 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 89 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 43 / 100 |
| Our confidence | 89% |
| Coordinates | 39.1849, -75.6590 |
| Nearest City | Dover (12 km) |
| Population Exposed | 120.0K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T22:07:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.48031688f0c4e6a8c287d6c664de9669 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Delaware Bay waters north of East Point NJ to Slaughter Beach DE; Delaware Bay waters south of East Point NJ to Slaughter Beach DE; Coastal waters from Great Egg Inlet to Cape May NJ out 20 NM; Coastal waters from Cape May NJ to Cape Henlopen DE out 20 NM; Delaware Bay waters north of East Point NJ to Slaughter Beach DE; Chesapeake Bay from Sandy Point to North Beach MD; Eastern Bay |
| Headline | Special Marine Warning issued May 20 at 6:07PM EDT until May 20 at 7:00PM EDT by NWS Mount Holly NJ |
| Expires | 2026-05-20T19:00:00-04:00 |
| SenderName | NWS Mount Holly NJ |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.48031688f0c4e6a8c287d6c664de9669310c072b.001.1","noaa_urn:oid:2.49.0.1.840.0.9d62057f8aa441ae88d62ea094a5574d3e5be33a.001.1","noaa_urn:oid:2.49.0.1.840.0.5e5ed7fbe2701456c388ec76fdaf4efb213a4817.001.1"] |
| Iem TypeSummary | D |
| Iem City | 2 NNE Hickory |
| Iem County | Harford |
| Iem State | MD |
| Iem Wfo | LWX |
| Iem Remark | Trees blew down on MD-543 Ady Road at Smithson Drive. |
| MergedSources | [{"id":"iem_M_39.300_-76.360_1779310500000","source":"iem","severity":"low","severityValue":25,"timestamp":1779310500000,"latitude":39.3,"longitude":-76.36},{"id":"iem_M_38.970_-76.460_1779312300000","source":"iem","severity":"low","severityValue":25,"timestamp":1779312300000,"latitude":38.97,"longitude":-76.46},{"id":"iem_M_39.340_-76.420_1779309960000","source":"iem","severity":"low","severityValue":25,"timestamp":1779309960000,"latitude":39.34,"longitude":-76.42},{"id":"iem_M_39.200_-76.520_1779310080000","source":"iem","severity":"low","severityValue":25,"timestamp":1779310080000,"latitude":39.2,"longitude":-76.52},{"id":"iem_D_39.610_-76.330_1779310440000","source":"iem","severity":"low","severityValue":25,"timestamp":1779310440000,"latitude":39.61,"longitude":-76.33}] |
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 10 February 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 near Dover?
Calamity.live data shows a weather event with CalamityScore 43/100, near Dover (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.