Alert archive / Pennsylvania

Weather alerts in Lebanon County, Pennsylvania

3,708 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Lebanon County and its neighbors

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

Alerts
3,708
Warnings
937
Watches
647
Advisories
820
Busiest year
2011274 alerts
Average year
93over 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 Lebanon County fell inside a tornado warning, and 92% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008010%
201010100%20%
20115180%30%
201510100%0
201730100%10%
201910100%0
202010100%0
2021010%
Share of tornado reports inside a tornado warning, by year.

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200817759%2100%33 min
2009261735%1070%28 min
2010302710%2195%29 min
2011311939%1258%32 min
2012332524%3100%6 min
2013221914%10100%29 min
201413128%13100%17 min
2015241633%1788%27 min
201610730%367%45 min
2017191237%13100%38 min
20189633%2100%10 min
2019282318%2592%14 min
202013128%1675%25 min
2021292514%4100%21 min
2022990%8100%21 min
2023221627%1292%13 min
2024121017%967%9 min
202515147%1267%23 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2009330%1100%54 min
20103167%1100%168 min
201113838%888%169 min
20123233%0
2013330%5100%120 min
201410100%0
201520100%10%
20172150%1100%49 min
20189722%475%41 min
20194325%5100%75 min
20202150%0
2021330%250%250 min
20256517%3100%120 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 3, 4:11 AM EDTFlash Flood WarningCTP4 hr
Sep 3, 3:53 AM EDTAreal Flood WarningCTP3 hr
Sep 3, 12:03 AM EDTFlash Flood WarningCTP4 hr
Sep 2, 11:26 PM EDTSevere Thunderstorm WarningCTP49 min
Sep 2, 12:12 PM EDTSevere Thunderstorm WarningCTP33 min
Sep 2, 11:49 AM EDTSevere Thunderstorm WarningCTP56 min
Sep 1, 6:33 PM EDTSevere Thunderstorm Warning Considerable damage threatCTP57 min
Aug 27, 11:14 PM EDTAreal Flood WarningCTP6 hr
Aug 27, 10:08 PM EDTAreal Flood WarningCTP67 min
Aug 27, 9:41 PM EDTFlash Flood WarningCTP106 min
Aug 27, 8:42 PM EDTFlash Flood WarningCTP3 hr
Aug 27, 7:22 PM EDTSevere Thunderstorm WarningCTP38 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.