This alert expired on 3 August 2026 at 21:30 UTC. It is kept here as a record.
It is the 14th strongest of the 237 detections recorded within 20 km of this point since 17 March 2026. The last comparable one was on 2 August 2026. 10 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued August 3 at 4:37PM EDT until August 3 at 5:30PM EDT by NWS Baltimore MD/Washington DC
An estimated 137,507 people live within 50 km of this point.
Nearby, since 17 March 2026
- July 21, 2026 · score 37 · 0.9 km
- May 27, 2026 · score 43 · 3.0 km
- August 8, 2026 · score 43 · 5.5 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 86 % 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 | 86% |
| Coordinates | 38.2278, -76.8267 |
| Nearest City | Saint Charles (43 km) |
| Population Exposed | 137.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-03T20:37:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.22bad28c0fd2fb79b295e037b0c3d200eb8f1ae9.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Tidal Potomac from Indian Head to Cobb Island MD; Tidal Potomac from Cobb Island MD to Smith Point VA |
| Headline | Special Marine Warning issued August 3 at 4:37PM EDT until August 3 at 5:30PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-08-03T17:30:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| Iem TypeSummary | M |
| Iem Magnitude | 39 |
| Iem Unit | mph |
| Iem City | 2 NNE North Beach |
| Iem County | ANZ532 |
| Iem State | MD |
| Iem Wfo | LWX |
| Iem Remark | A thunderstorm produced an estimated wind gust to 34 knots (39 MPH) near the Herring Bay WeatherFlow sensor (XHEB). |
| MergedSources | [{"id":"iem_M_38.730_-76.530_1785782100000","source":"iem","severity":"low","severityValue":25,"timestamp":1785782100000,"latitude":38.73,"longitude":-76.53}] |
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 43/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.