Alert archive / New Hampshire

Weather alerts in Coos County, New Hampshire

2,683 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Coos County and its neighbors

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

Alerts
2,683
Warnings
758
Watches
393
Advisories
773
Busiest year
2011187 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, 0% of tornado reports in Coos County fell inside a tornado warning, and 100% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2010020%
201110100%0
201510100%0
201610100%20%
201820100%0
202010100%0
202410100%0

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200815473%2100%17 min
200916288%10%
201011645%5100%18 min
2011312810%3087%16 min
201213931%1100%22 min
2013393121%2090%18 min
201412925%9100%29 min
2015241825%11100%16 min
201614936%875%23 min
201713931%786%30 min
201813128%1292%19 min
20196350%450%27 min
2020141029%1292%19 min
202110910%5100%22 min
20229544%2467%35 min
20236517%956%13 min
2024880%1080%18 min
20254325%250%52 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
20082150%0
2010110%0
2011440%580%131 min
20127186%20%
20135340%2100%29 min
20145340%1100%57 min
2015220%4100%46 min
20162150%0
20178625%2100%155 min
201820100%0
201910100%0
20205180%2100%46 min
2021010%
202313377%1100%28 min
20245420%1894%125 min
202510100%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
Aug 8, 7:22 PM EDTFlash Flood WarningGYX2 hr
Aug 3, 2:50 PM EDTSevere Thunderstorm WarningGYX40 min
Jul 14, 9:51 PM EDTSevere Thunderstorm WarningGYX39 min
Jul 14, 9:20 PM EDTSevere Thunderstorm WarningGYX40 min
Jul 14, 5:50 PM EDTSevere Thunderstorm WarningGYX39 min
Jul 9, 6:42 PM EDTSevere Thunderstorm WarningGYX63 min
Jul 1, 9:30 PM EDTSevere Thunderstorm WarningGYX45 min
Jul 1, 8:42 PM EDTSevere Thunderstorm WarningGYX48 min
Jun 26, 3:58 PM EDTSevere Thunderstorm WarningGYX62 min
Jun 18, 3:07 PM EDTSevere Thunderstorm WarningGYX53 min
May 21, 2:27 AM EDTFreeze WarningGYX28 hr
Apr 16, 8:15 PM EDTSevere Thunderstorm WarningGYX45 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.