Alert archive / New Jersey

Weather alerts in Somerset County, New Jersey

4,128 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
4,128
Warnings
1,354
Watches
665
Advisories
911
Busiest year
2011293 alerts
Average year
103over 40 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, 0% of tornado reports in Somerset County fell inside a tornado warning, and 80% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200810100%0
200910100%0
201510100%0
201810100%0
201910100%0
2021330%0
202360100%10%
202510100%0

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008201335%3100%26 min
2009181139%540%18 min
2010161319%20%
2011201335%580%27 min
2012211814%9100%34 min
201312833%1182%17 min
201413838%450%40 min
201550100%0
2016161038%967%27 min
2017181422%3100%24 min
201811645%633%26 min
2019443618%4090%26 min
2020363114%2584%25 min
2021473623%2596%23 min
20229544%475%57 min
2023382729%1989%22 min
2024281739%2496%22 min
202520195%2882%25 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008330%1100%56 min
20096183%560%165 min
20117271%0
2012110%2100%97 min
20136517%3100%102 min
20149544%367%26 min
20153167%250%32 min
20168450%0
20173233%0
201811736%967%140 min
201911918%9100%64 min
20208713%1100%32 min
202115150%4298%216 min
20224325%475%19 min
20236517%1100%173 min
20246350%580%48 min
20255420%1191%55 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 1, 6:52 PM EDTSevere Thunderstorm WarningPHI38 min
Aug 27, 8:09 PM EDTAreal Flood WarningPHI5 hr
Aug 27, 4:59 PM EDTAreal Flood WarningPHI4 hr
Aug 27, 1:17 PM EDTFlash Flood WarningPHI7 hr
Aug 27, 1:07 PM EDTFlash Flood WarningPHI4 hr
Aug 8, 3:22 PM EDTSevere Thunderstorm WarningPHI53 min
Aug 7, 5:42 PM EDTFlash Flood WarningPHI3 hr
Aug 7, 5:40 PM EDTSevere Thunderstorm WarningPHI50 min
Aug 7, 5:18 PM EDTFlash Flood WarningPHI3 hr
Aug 7, 4:50 PM EDTSevere Thunderstorm WarningPHI55 min
Aug 5, 11:40 PM EDTFlash Flood WarningPHI4 hr
Aug 3, 10:36 AM EDTFlash Flood WarningPHI6 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.