This alert expired on 27 August 2026 at 20:45 UTC. It is kept here as a record.
It is the 11th strongest of the 53 detections recorded within 20 km of this point since 19 April 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 27 at 4:11PM EDT until August 27 at 4:45PM EDT by NWS Baltimore MD/Washington DC
An estimated 540,845 people live within 50 km of this point.
Nearby, since 19 April 2026
- June 15, 2026 · score 37 · 11.6 km
- June 15, 2026 · score 67 · 14.6 km
- August 8, 2026 · score 37 · 18.8 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 48 out of 100, at 84 % 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) | 48 / 100 |
| Our confidence | 84% |
| Coordinates | 39.7018, -76.1438 |
| Nearest City | Aberdeen (21 km) |
| Population Exposed | 540.8K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-27T20:11:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.a7ed63d4a1bfec48a2f78105bb742f32 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Baltimore, MD; Harford, MD; Chester, PA |
| Headline | Severe Thunderstorm Warning issued August 27 at 4:11PM EDT until August 27 at 4:45PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-08-27T16:45:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.a7ed63d4a1bfec48a2f78105bb742f3247a4ffd9.001.1","noaa_urn:oid:2.49.0.1.840.0.943700bc55b25224900996d0230fc1d163c915d2.001.1"] |
| Iem TypeSummary | R |
| Iem Magnitude | 1.71 |
| Iem Unit | Inch |
| Iem City | 1 SE New London Twp. |
| Iem County | Chester |
| Iem State | PA |
| Iem Wfo | PHI |
| Iem Remark | Mesonet station AU860 New London. |
| MergedSources | [{"id":"iem_R_39.780_-75.860_1787858400000","source":"iem","severity":"low","severityValue":25,"timestamp":1787858400000,"latitude":39.78,"longitude":-75.86}] |
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 Aberdeen?
Calamity.live data shows a weather event with CalamityScore 48/100, near Aberdeen (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.