Alert archive / Pennsylvania

Weather alerts in Somerset County, Pennsylvania

3,416 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Somerset County and its neighbors

Each county as a circle sized by its count since 1986. Tap one for its archive.

Alerts
3,416
Warnings
870
Watches
574
Advisories
906
Busiest year
2011189 alerts
Average year
83over 41 years on file

Over time

By year

Before late 2005 the archive holds only tornado, severe thunderstorm, flash flood and marine warnings, and from 1997 SPC's watches, so the jump that year is the archive widening, not the weather.

By month of the year

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

From 2008 to 2025, 20% of tornado reports in Somerset County fell inside a tornado warning issued on average 14 minutes before, and 71% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
201110100%0
201320100%10%
201610100%0
201810100%20%
2019110%0
2021110%1100%14 min
2024010%
Share of tornado reports inside a tornado warning, by year.

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200810640%4100%32 min
20096267%4100%31 min
201018950%967%22 min
2011171041%1385%11 min
2012271544%1392%29 min
2013252020%1968%40 min
20149811%3100%42 min
201510550%580%28 min
20166350%580%29 min
20177614%1090%25 min
201814936%1794%31 min
20199722%771%10 min
2020171135%3566%32 min
2021121017%1275%21 min
2022141029%1377%18 min
20238625%1292%22 min
202410820%1560%17 min
202513931%11100%26 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200930100%0
201030100%0
20116350%367%39 min
20122150%0
20138450%580%32 min
2014220%1100%125 min
20172150%367%79 min
2018220%580%133 min
20195340%1080%38 min
2020110%2100%33 min
2021220%580%226 min
20242150%1100%116 min
20256350%7100%75 min

Years from 2008, the first full year of storm-based warnings. The year still running is on its own page.

Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.

By product

Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.

The latest warnings

The most recent on file, newest first.

IssuedProductOfficeLasted
Sep 17, 9:16 PM EDTFlash Flood WarningCTP3 hr
Sep 3, 7:42 PM EDTSevere Thunderstorm Warning Considerable damage threatCTP48 min
Sep 3, 7:39 PM EDTTornado WarningCTP36 min
Sep 3, 7:21 PM EDTFlash Flood WarningCTP3 hr
Sep 3, 7:20 PM EDTSevere Thunderstorm Warning Destructive damage threatCTP25 min
Sep 3, 7:01 PM EDTSevere Thunderstorm Warning Considerable damage threatCTP44 min
Sep 3, 9:34 AM EDTSevere Thunderstorm WarningCTP41 min
Sep 3, 8:55 AM EDTSevere Thunderstorm WarningCTP50 min
Sep 2, 11:39 AM EDTSevere Thunderstorm WarningCTP51 min
Sep 2, 11:02 AM EDTSevere Thunderstorm WarningCTP43 min
Aug 22, 6:48 PM EDTFlash Flood WarningCTP3 hr
Aug 22, 6:44 PM EDTFlash Flood WarningCTP3 hr

Nearby

Alerts in force nowTornadoes on recordForecastThe radar archive

Sources

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.