Alert archive / Delaware

Weather alerts in Sussex County, Delaware

4,366 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Sussex County and its neighbors

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

Alerts
4,366
Warnings
1,066
Watches
544
Advisories
1,296
Busiest year
2011303 alerts
Average year
106over 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, 57% of tornado reports in Sussex County fell inside a tornado warning issued on average 6 minutes before, and 85% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200910100%0
20113167%1100%13 min
201310100%0
201720100%10%
20192150%2100%7 min
20204175%1100%7 min
20218188%2100%4 min
20235180%540%3 min
202420100%0
202550100%20%
Share of tornado reports inside a tornado warning, by year.

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008291259%12100%43 min
2009241154%1090%26 min
2010191332%12100%28 min
2011251060%1275%28 min
201215847%1688%20 min
201310370%250%37 min
201412558%1100%34 min
201512467%667%28 min
201621862%1242%25 min
2017241058%683%29 min
20189544%367%30 min
2019432835%3889%23 min
2020271641%3789%35 min
2021231248%2966%20 min
2022281739%2580%18 min
2023341556%1580%28 min
202411373%683%21 min
202533779%1450%12 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
20084175%0
2009110%0
201010100%0
20117186%1100%37 min
20123167%1100%47 min
20139456%667%88 min
20143167%1100%28 min
20154175%1100%38 min
20165260%2100%72 min
201740100%0
201814564%888%66 min
201910100%0
20204250%4100%40 min
2021110%0
20234250%2100%95 min
20246183%250%46 min
20255260%3100%35 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 22, 4:14 PM EDTCoastal Flood WarningPHI3 days
Sep 4, 1:35 AM EDTSevere Thunderstorm WarningPHI25 min
Sep 4, 12:52 AM EDTSevere Thunderstorm WarningPHI53 min
Sep 2, 2:38 PM EDTSevere Thunderstorm WarningPHI47 min
Sep 2, 2:05 PM EDTSevere Thunderstorm WarningPHI40 min
Sep 1, 9:40 PM EDTSevere Thunderstorm WarningPHI65 min
Aug 28, 1:11 PM EDTFlash Flood WarningPHI4 hr
Aug 20, 6:57 PM EDTSevere Thunderstorm WarningPHI48 min
Aug 20, 6:21 PM EDTSevere Thunderstorm WarningPHI39 min
Aug 10, 7:04 PM EDTSevere Thunderstorm WarningPHI41 min
Aug 10, 6:22 PM EDTSevere Thunderstorm WarningPHI23 min
Aug 10, 6:07 PM EDTSevere Thunderstorm WarningPHI38 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.