This alert expired on 20 May 2026 at 23:00 UTC. It is kept here as a record.
It is the 15th strongest of the 294 detections recorded within 20 km of this point since 11 March 2026. Another comparable one was recorded here earlier the same day. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued May 20 at 5:01PM EDT until May 20 at 7:00PM EDT by NWS Mount Holly NJ
An estimated 1,663,011 people live within 50 km of this point.
Nearby, since 11 March 2026
- July 27, 2026 · score 52 · 2.9 km
- June 6, 2026 · score 52 · 5.2 km
- July 9, 2026 · score 52 · 5.2 km
How we know
Confirmed by 15 independent sources, including NOAA.
Our own score for this event is 52 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) | 52 / 100 |
| Our confidence | 89% |
| Coordinates | 39.0450, -76.2699 |
| Nearest City | Lake Shore (20 km) |
| Population Exposed | 1.7M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T21:01:00.000Z |
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; Chesapeake Bay north of Pooles Island MD; Chesapeake Bay from Pooles Island to Sandy Point MD; Patapsco River including Baltimore Harbor; Chester River to Queenstown MD; Chesapeake Bay from Sandy Point to North Beach MD; Eastern Bay and 1 more areas |
| Headline | Special Marine Warning issued May 20 at 5:01PM 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 | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.1ee38cf00b3ccdcc5ba2175489f2ea0518ca4ae1.001.1","noaa_urn:oid:2.49.0.1.840.0.609aa03f1e152850a049cc137ce70e92aa048d98.001.1","noaa_urn:oid:2.49.0.1.840.0.c39a36be21ec25f17ff8990b9e439ef1d036ad77.001.1","noaa_urn:oid:2.49.0.1.840.0.209b5edb71adaf3be454108e311b5437d322584f.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. |
| Google News RssFeed | weather |
| Google News SourceName | Baltimore Sun |
| 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_39.270_-76.580_1779309360000","source":"iem","severity":"low","severityValue":25,"timestamp":1779309360000,"latitude":39.27,"longitude":-76.58},{"id":"iem_M_39.230_-76.580_1779310800000","source":"iem","severity":"low","severityValue":25,"timestamp":1779310800000,"latitude":39.23,"longitude":-76.58},{"id":"iem_M_38.850_-77.030_1779309960000","source":"iem","severity":"low","severityValue":25,"timestamp":1779309960000,"latitude":38.85,"longitude":-77.03},{"id":"iem_G_39.270_-76.590_1779309540000","source":"iem","severity":"low","severityValue":25,"timestamp":1779309540000,"latitude":39.27,"longitude":-76.59},{"id":"iem_M_38.880_-76.480_1779312780000","source":"iem","severity":"low","severityValue":25,"timestamp":1779312780000,"latitude":38.88,"longitude":-76.48},{"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_39.270_-76.590_1779309240000","source":"iem","severity":"low","severityValue":25,"timestamp":1779309240000,"latitude":39.27,"longitude":-76.59},{"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_39.350_-76.690_1779308820000","source":"iem","severity":"low","severityValue":25,"timestamp":1779308820000,"latitude":39.35,"longitude":-76.69},{"id":"iem_D_39.610_-76.330_1779310440000","source":"iem","severity":"low","severityValue":25,"timestamp":1779310440000,"latitude":39.61,"longitude":-76.33},{"id":"gnews_weather_494252_161","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779308905000,"latitude":39.29,"longitude":-76.61},{"id":"gnews_weather_494251_168","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779305073000,"latitude":39.29,"longitude":-76.61}] |
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.
Calamity.live data shows a weather event with CalamityScore 52/100, near Lake Shore (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.