This alert expired on 18 June 2026 at 21:08 UTC. It is kept here as a record.
It is the 2nd strongest of the 44 detections recorded within 20 km of this point since 17 March 2026. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued June 18 at 4:58PM EDT until June 18 at 5:00PM EDT by NWS Gray ME
An estimated 769,700 people live within 50 km of this point.
Nearby, since 17 March 2026
- June 18, 2026 · score 48 · 16.1 km
- March 17, 2026 · score 52 · 23.6 km
How we know
Confirmed by 6 independent sources, including NOAA.
Our own score for this event is 48 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) | 48 / 100 |
| Our confidence | 89% |
| Coordinates | 43.1506, -71.1472 |
| Nearest City | Rochester (21 km) |
| Population Exposed | 769.7K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-18T20:58:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.728aca70dfdb78e90e66269668678a35 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Cheshire, NH; Hillsborough, NH; Merrimack, NH; Rockingham, NH; Cumberland, ME; York, ME; York, ME; Hillsborough, NH; Rockingham, NH; Strafford, NH and 2 more areas |
| Headline | Severe Thunderstorm Warning issued June 18 at 4:58PM EDT until June 18 at 5:00PM EDT by NWS Gray ME |
| Expires | 2026-06-18T17:08:00-04:00 |
| SenderName | NWS Gray ME |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.728aca70dfdb78e90e66269668678a35a6c9d7be.001.1","noaa_urn:oid:2.49.0.1.840.0.4e70ec03974d8667d47198bbb0e9fa96c449d148.001.1","noaa_urn:oid:2.49.0.1.840.0.f7b7648785d8b31fd27c09d95eb5d6bed4efe2d8.001.1","noaa_urn:oid:2.49.0.1.840.0.36b57b4c4394fcde39b11d05bd97209bd03c3738.001.1","noaa_urn:oid:2.49.0.1.840.0.4fb56a9fa2e08381cb13c126670e091984ffe3a5.001.1"] |
| Iem TypeSummary | D |
| Iem City | 3 NNW Franklin |
| Iem County | Merrimack |
| Iem State | NH |
| Iem Wfo | GYX |
| Iem Remark | Wires down blocking NH-3A in Franklin. Time estimated by radar. |
| MergedSources | [{"id":"iem_D_43.500_-71.570_1781812500000","source":"iem","severity":"low","severityValue":25,"timestamp":1781812500000,"latitude":43.5,"longitude":-71.57},{"id":"iem_D_43.580_-71.700_1781811780000","source":"iem","severity":"low","severityValue":25,"timestamp":1781811780000,"latitude":43.58,"longitude":-71.7},{"id":"iem_D_43.630_-71.730_1781811780000","source":"iem","severity":"low","severityValue":25,"timestamp":1781811780000,"latitude":43.63,"longitude":-71.73},{"id":"iem_D_42.900_-71.780_1781814180000","source":"iem","severity":"low","severityValue":25,"timestamp":1781814180000,"latitude":42.9,"longitude":-71.78},{"id":"iem_D_43.490_-71.660_1781812380000","source":"iem","severity":"low","severityValue":25,"timestamp":1781812380000,"latitude":43.49,"longitude":-71.66}] |
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 Rochester?
Calamity.live data shows a weather event with CalamityScore 48/100, near Rochester (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.