Alert archive / North Carolina

Weather alerts in Alamance County, North Carolina

3,300 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Alamance County and its neighbors

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

Alerts
3,300
Warnings
826
Watches
464
Advisories
661
Busiest year
2011206 alerts
Average year
80over 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, 78% of tornado reports in Alamance County fell inside a tornado warning issued on average 6 minutes before, and 58% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
20085340%1100%3 min
20102150%0
20114250%580%8 min
201310100%0
201410100%0
20162150%0
20196267%0
20205260%1100%3 min
2021330%1100%1 min
202210100%0
202310100%0
202410100%0
20254175%10%
Share of tornado reports inside a tornado warning, by year.

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008331652%1191%20 min
200912650%1090%15 min
201022215%2592%17 min
2011191521%22100%24 min
2012252020%3686%29 min
201310820%989%16 min
2014181611%1267%19 min
2015191521%1090%29 min
2016252116%16100%26 min
201716156%1164%18 min
2018161131%13100%16 min
2019282511%2387%26 min
2020141214%1258%19 min
2021211338%1182%13 min
2022322522%1979%22 min
202315147%1894%24 min
2024221723%4100%22 min
2025262312%1173%22 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
20085340%6100%100 min
200910100%0
20102150%0
2011110%1100%42 min
2012110%0
2013220%1100%10 min
20152150%250%59 min
2016330%475%85 min
2017110%10%
20184325%560%65 min
2019220%1100%190 min
20207614%1100%4 min
20223233%1100%35 min
20232150%250%4 min
20248450%333%73 min
2025990%7100%157 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 21, 6:26 PM EDTSevere Thunderstorm WarningRAH64 min
Sep 5, 1:23 PM EDTSevere Thunderstorm WarningRAH52 min
Sep 4, 4:07 PM EDTSevere Thunderstorm WarningRAH38 min
Aug 22, 10:45 PM EDTSevere Thunderstorm WarningRAH45 min
Aug 21, 6:34 PM EDTSevere Thunderstorm WarningRAH41 min
Aug 21, 5:49 PM EDTSevere Thunderstorm WarningRAH41 min
Aug 17, 5:22 PM EDTSevere Thunderstorm WarningRAH38 min
Aug 17, 4:36 PM EDTSevere Thunderstorm WarningRAH39 min
Aug 16, 2:49 PM EDTSevere Thunderstorm WarningRAH41 min
Aug 16, 2:43 PM EDTSevere Thunderstorm WarningRAH27 min
Aug 14, 5:03 PM EDTSevere Thunderstorm WarningRAH42 min
Aug 8, 6:50 PM EDTSevere Thunderstorm WarningRAH55 min

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.