This alert expired on 7 August 2026 at 21:00 UTC. It is kept here as a record.
It is the 51st strongest of the 95 detections recorded within 20 km of this point since 16 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: Severe Thunderstorm Warning issued August 7 at 4:02PM EDT until August 7 at 5:00PM EDT by NWS Baltimore MD/Washington DC
An estimated 211,595 people live within 50 km of this point.
Nearby, since 16 March 2026
- August 10, 2026 · score 43 · 7.0 km
- July 9, 2026 · score 43 · 9.2 km
- March 17, 2026 · score 43 · 11.2 km
How we know
Confirmed by 10 independent sources, including NOAA.
Our own score for this event is 37 out of 100, at 90 % 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) | 37 / 100 |
| Our confidence | 90% |
| Coordinates | 39.9425, -76.7043 |
| Nearest City | York (3 km) |
| Population Exposed | 211.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-07T20:02:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.af7428b039d60d11ffef6535759848ec |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Baltimore, MD; Harford, MD; Warren, NJ; Carbon, PA; Lehigh, PA; Monroe, PA; Northampton, PA; Frederick, MD; Washington, MD; Loudoun, VA and 2 more areas |
| Headline | Severe Thunderstorm Warning issued August 7 at 4:02PM EDT until August 7 at 5:00PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-08-07T17:00:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.af7428b039d60d11ffef6535759848ecc95ec73b.001.1","noaa_urn:oid:2.49.0.1.840.0.f3a82cbccab8b194d4f9352937d898d3479c60c4.002.1","noaa_urn:oid:2.49.0.1.840.0.bad22379332e56de62f5af649e2bc0b6224ea0cf.001.1","noaa_urn:oid:2.49.0.1.840.0.31b4efc2a2d7d97ad17a1c7947259a4d363c9a72.001.1","noaa_urn:oid:2.49.0.1.840.0.c6678cc8d090b84ea6458e92c83692333478fd14.001.1"] |
| Iem TypeSummary | F |
| Iem City | 2 SSW East Petersburg |
| Iem County | Lancaster |
| Iem State | PA |
| Iem Wfo | CTP |
| Iem Remark | Roadway flooding. |
| MergedSources | [{"id":"iem_F_40.060_-76.360_1786130580000","source":"iem","severity":"low","severityValue":25,"timestamp":1786130580000,"latitude":40.06,"longitude":-76.36},{"id":"iem_F_40.120_-76.390_1786128180000","source":"iem","severity":"low","severityValue":25,"timestamp":1786128180000,"latitude":40.12,"longitude":-76.39},{"id":"iem_F_40.070_-76.380_1786131180000","source":"iem","severity":"low","severityValue":25,"timestamp":1786131180000,"latitude":40.07,"longitude":-76.38},{"id":"iem_F_40.080_-76.340_1786128600000","source":"iem","severity":"low","severityValue":25,"timestamp":1786128600000,"latitude":40.08,"longitude":-76.34},{"id":"iem_F_40.120_-76.210_1786131900000","source":"iem","severity":"low","severityValue":25,"timestamp":1786131900000,"latitude":40.12,"longitude":-76.21},{"id":"iem_H_40.220_-77.160_1786126800000","source":"iem","severity":"low","severityValue":25,"timestamp":1786126800000,"latitude":40.22,"longitude":-77.16},{"id":"iem_F_40.050_-76.380_1786129620000","source":"iem","severity":"low","severityValue":25,"timestamp":1786129620000,"latitude":40.05,"longitude":-76.38},{"id":"iem_D_40.220_-77.160_1786125960000","source":"iem","severity":"low","severityValue":25,"timestamp":1786125960000,"latitude":40.22,"longitude":-77.16},{"id":"iem_F_40.070_-76.360_1786128540000","source":"iem","severity":"low","severityValue":25,"timestamp":1786128540000,"latitude":40.07,"longitude":-76.36}] |
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 37/100, near York (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.