Alert archive / Michigan

Weather alerts in Allegan County, Michigan

3,119 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Allegan County and its neighbors

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

Alerts
3,119
Warnings
688
Watches
448
Advisories
876
Busiest year
2008197 alerts
Average year
76over 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, 23% of tornado reports in Allegan County fell inside a tornado warning issued on average 27 minutes before, and 67% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008020%
2009010%
20105180%250%32 min
201110100%20%
201210100%0
201310100%0
20164250%250%24 min
2017010%
2021010%
202210100%0
202420100%0
2025330%250%26 min
Share of tornado reports inside a tornado warning, by year.

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008261638%1974%31 min
200911827%1644%14 min
2010301453%2446%23 min
201113746%1070%27 min
20124250%1338%18 min
20138538%863%32 min
20149722%786%30 min
20159633%5100%35 min
20169544%967%19 min
20177271%10%
20188450%250%23 min
20198450%683%18 min
202012742%2268%37 min
202112925%1878%24 min
2022121017%683%21 min
202310460%888%38 min
202412833%1070%27 min
20257443%1090%54 min

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008110%1100%362 min
2009220%8100%127 min
2010110%1100%122 min
20113167%30%
2013110%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 10, 3:15 AM EDTSevere Thunderstorm WarningGRR30 min
Aug 9, 3:55 PM EDTSevere Thunderstorm WarningGRR50 min
Aug 9, 2:37 PM EDTSevere Thunderstorm WarningGRR83 min
Jul 3, 3:15 PM EDTSevere Thunderstorm Warning Considerable damage threatGRR90 min
Jun 28, 1:26 PM EDTExtreme Heat WarningGRR4 days
Jun 16, 6:04 PM EDTSevere Thunderstorm WarningGRR29 min
Jun 11, 8:11 PM EDTSevere Thunderstorm Warning Considerable damage threatGRR94 min
Jun 10, 6:59 PM EDTSevere Thunderstorm WarningGRR18 min
Jun 10, 6:02 PM EDTSevere Thunderstorm WarningGRR58 min
May 18, 2:24 PM EDTSevere Thunderstorm Warning Destructive damage threatGRR36 min
May 18, 1:58 PM EDTSevere Thunderstorm WarningGRR79 min
May 18, 1:20 PM EDTSevere Thunderstorm WarningGRR55 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.