Alert archive / New York

Weather alerts in Chemung County, New York

2,685 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Chemung County and its neighbors

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

Alerts
2,685
Warnings
655
Watches
447
Advisories
597
Busiest year
2011180 alerts
Average year
67over 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, 50% of tornado reports in Chemung County fell inside a tornado warning issued on average 17 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
2009110%0
201010100%0
20113233%333%2 min
2012220%2100%24 min
201410100%10%
201910100%0
202430100%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
2008161038%5100%27 min
200911736%15100%21 min
201011736%0
2011301937%2282%21 min
201215147%1794%22 min
201314843%1080%28 min
2014161225%989%19 min
20154325%20%
20163233%2100%42 min
201713746%450%35 min
201814750%580%14 min
2019171418%1989%16 min
202011109%1070%17 min
2021261638%888%15 min
202214936%5100%24 min
2023201430%475%20 min
202414843%1593%21 min
2025181422%12100%17 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200810100%0
200910100%0
20105340%1100%233 min
20118625%10%
2013330%367%128 min
201420100%0
2015220%1100%56 min
2017220%0
201810730%1681%69 min
20194250%0
2020330%1100%62 min
20212150%0
20233167%10%
20244325%450%0 min
20254325%0

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, 9:06 PM EDTSevere Thunderstorm Warning Considerable damage threatBGM69 min
Sep 2, 8:53 PM EDTSevere Thunderstorm WarningBGM67 min
Sep 2, 8:37 PM EDTSevere Thunderstorm Warning Considerable damage threatBGM53 min
Sep 1, 6:14 PM EDTSevere Thunderstorm WarningBGM61 min
Aug 12, 7:39 PM EDTSevere Thunderstorm WarningBGM51 min
Aug 12, 5:46 PM EDTFlash Flood WarningBGM3 hr
Aug 6, 4:04 PM EDTSevere Thunderstorm WarningBGM56 min
Jul 21, 12:32 PM EDTSevere Thunderstorm WarningBGM58 min
Jul 18, 5:44 PM EDTSevere Thunderstorm WarningBGM61 min
Jul 18, 5:30 PM EDTSevere Thunderstorm WarningBGM30 min
Jul 18, 5:00 PM EDTSevere Thunderstorm WarningBGM60 min
Jun 30, 11:58 AM EDTExtreme Heat WarningBGM3 days

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.