Alert archive / Maryland

Weather alerts in Harford County, Maryland

3,430 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Harford County and its neighbors

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

Alerts
3,430
Warnings
1,073
Watches
635
Advisories
700
Busiest year
2021214 alerts
Average year
86over 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, 57% of tornado reports in Harford County fell inside a tornado warning issued on average 18 minutes before, and 76% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200810100%0
200920100%10%
201030100%0
20119456%2100%26 min
20125180%250%15 min
2013220%250%5 min
201410100%0
201510100%0
20192150%0
20203167%0
20217271%0
202220100%0
202320100%0
20246183%0
202540100%0
Share of tornado reports inside a tornado warning, by year.

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008211052%1471%23 min
2009201430%1688%20 min
2010241538%16100%24 min
2011262119%2488%26 min
2012282318%4982%27 min
201310820%2259%16 min
2014231535%2886%27 min
2015231726%2378%18 min
2016191237%1883%24 min
2017211910%6075%18 min
2018262119%6070%19 min
2019423810%10688%25 min
2020362725%5283%30 min
2021423614%5589%22 min
2022181422%3087%21 min
2023312423%5684%27 min
2024221627%1283%29 min
202534319%4391%18 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008220%2100%94 min
20095180%4100%45 min
20107614%4100%98 min
201115847%683%201 min
20124250%0
20136350%1100%70 min
20143233%1100%25 min
2015171135%1788%73 min
201620100%0
20176433%3158%77 min
20182150%3100%59 min
2019220%1392%68 min
20204325%5100%56 min
20213167%1354%63 min
20223167%250%37 min
20235260%1100%12 min
2024220%5100%71 min
202511918%1385%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 2, 1:06 PM EDTSevere Thunderstorm WarningLWX39 min
Sep 2, 12:39 PM EDTSevere Thunderstorm WarningLWX51 min
Sep 2, 12:00 PM EDTSevere Thunderstorm WarningLWX45 min
Aug 27, 4:11 PM EDTSevere Thunderstorm WarningLWX34 min
Aug 10, 5:40 PM EDTFlash Flood WarningLWX88 min
Aug 10, 4:33 PM EDTSevere Thunderstorm WarningLWX42 min
Aug 10, 3:55 PM EDTSevere Thunderstorm Warning Considerable damage threatLWX50 min
Aug 10, 3:12 PM EDTSevere Thunderstorm WarningLWX48 min
Aug 10, 2:56 PM EDTSevere Thunderstorm WarningLWX38 min
Aug 8, 1:18 PM EDTSevere Thunderstorm WarningLWX57 min
Aug 7, 4:43 PM EDTFlash Flood WarningLWX3 hr
Aug 7, 4:02 PM EDTSevere Thunderstorm WarningLWX41 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.