Alert archive / Michigan / Mason County
Weather alerts in Mason County, Michigan, 2009
79 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Mason County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 79
- Warnings
- 17
- Watches
- 10
- Advisories
- 42
- Busiest month
- December15 alerts
- Busiest day
- February 11, 20093 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Mason County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 1 | 0 | 100% | 0 | ||
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Grand Rapids, MI: tornado warnings | 2 | 0 | 100% | 3 | 0% | |
| NWS Grand Rapids, MI: severe thunderstorm warnings | 40 | 22 | 45% | 85 | 62% | 24 min |
| NWS Grand Rapids, MI: flash flood warnings | 3 | 3 | 0% | 25 | 88% | 109 min |
An office's figures cover every county it serves, including across state lines.
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.
The alerts
Every alert, in the order issued. Times are local, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 3, 3:24 PM EST | Freezing Rain Advisory | GRR | 22 hr |
| Jan 4, 1:08 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Jan 11, 3:38 PM EST | Winter Storm Watch | GRR | 23 hr |
| Jan 12, 2:32 PM EST | Winter Storm Warning | GRR | 24 hr |
| Jan 12, 2:32 PM EST | Winter Weather Advisory | GRR | 20 hr |
| Jan 13, 10:37 AM EST | Winter Weather Advisory | GRR | 4 hr |
| Jan 14, 4:23 AM EST | Wind Chill Advisory | GRR | 3 days |
| Jan 14, 3:39 PM EST | Lake Effect Snow Advisory | GRR | 36 hr |
| Jan 16, 2:56 PM EST | Winter Storm Watch | GRR | 13 hr |
| Jan 17, 3:37 AM EST | Winter Storm Warning | GRR | 43 hr |
| Jan 17, 6:35 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Jan 29, 11:45 AM EST | Lake Effect Snow Advisory | GRR | 28 hr |
| Feb 10, 12:04 PM EST | Flood Watch | GRR | 24 hr |
| Feb 10, 3:38 PM EST | Wind Advisory | GRR | 37 hr |
| Feb 11, 6:39 AM EST | Dense Fog Advisory | GRR | 5 hr |
| Feb 11, 11:56 AM EST | Areal Flood Warning | GRR | 23 hr |
| Feb 11, 11:58 AM EST | River Flood Warning | GRR | 72 hr |
| Feb 17, 3:44 PM EST | Winter Weather Advisory | GRR | 51 hr |
| Feb 20, 3:43 PM EST | Winter Storm Warning | GRR | 27 hr |
| Feb 20, 3:43 PM EST | Winter Weather Advisory | GRR | 12 hr |
| Feb 21, 6:35 AM EST | Mesoscale Discussion | SPC | 5 hr |
| Feb 21, 4:17 PM EST | Lake Effect Snow Advisory | GRR | 35 hr |
| Feb 26, 3:01 AM EST | Winter Weather Advisory | GRR | 12 hr |
| Feb 26, 8:38 PM EST | Areal Flood Advisory | GRR | 102 days |
| Feb 26, 9:39 PM EST | Winter Weather Advisory | GRR | 10 hr |
| Mar 8, 11:30 AM EDT | Winter Weather Advisory | GRR | 12 hr |
| Mar 8, 7:42 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Mar 9, 10:30 PM EDT | River Flood Advisory | GRR | 60 hr |
| Mar 10, 4:09 AM EDT | Wind Advisory | GRR | 36 hr |
| Mar 27, 3:21 PM EDT | Winter Storm Watch | GRR | 24 hr |
| Mar 28, 3:27 PM EDT | Winter Weather Advisory | GRR | 20 hr |
| Mar 29, 6:01 AM EDT | Mesoscale Discussion | SPC | 4 hr |
| Apr 26, 11:04 PM EDT | River Flood Advisory | GRR | 7 days |
| Apr 27, 3:18 AM EDT | Wind Advisory | GRR | 14 hr |
| May 10, 3:47 AM EDT | Freeze Warning | GRR | 28 hr |
| May 11, 12:44 PM EDT | Freeze Warning | GRR | 19 hr |
| May 13, 9:58 PM EDT | River Flood Advisory | GRR | 5 days |
| May 15, 3:40 PM EDT | Flood Watch | GRR | 12 hr |
| May 17, 2:58 PM EDT | Freeze Warning | GRR | 17 hr |
| May 18, 3:41 PM EDT | Fire Weather Watch | GRR | 23 hr |
| May 19, 2:35 PM EDT | Red Flag Warning | GRR | 29 hr |
| May 30, 12:28 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 3, 3:47 PM EDT | Frost Advisory | GRR | 15 hr |
| Jun 19, 4:29 AM EDT | Flash Flood Watch | GRR | 20 hr |
| Jul 22, 1:57 PM EDT | Special Weather Statement | GRR | 48 min |
| Jul 24, 4:25 AM EDT | Dense Fog Advisory | GRR | 4 hr |
| Aug 8, 11:16 PM EDT | Special Weather Statement | GRR | 59 min |
| Aug 9, 3:40 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 31, 3:46 PM EDT | Frost Advisory | GRR | 16 hr |
| Sep 19, 2:46 PM EDT | Frost Advisory | GRR | 17 hr |
| Sep 22, 2:54 AM EDT | Dense Fog Advisory | GRR | 7 hr |
| Sep 27, 3:00 PM EDT | High Wind Warning | GRR | 31 hr |
| Sep 28, 9:52 PM EDT | Wind Advisory | GRR | 11 hr |
| Sep 30, 3:56 AM EDT | Frost Advisory | GRR | 17 hr |
| Sep 30, 3:56 AM EDT | Freeze Warning | GRR | 29 hr |
| Oct 6, 12:04 PM EDT | Wind Advisory | GRR | 22 hr |
| Oct 6, 9:32 PM EDT | Severe Thunderstorm Warning | GRR | 35 min |
| Oct 9, 3:50 PM EDT | Freeze Warning | GRR | 17 hr |
| Oct 10, 2:41 AM EDT | Dense Fog Advisory | GRR | 6 hr |
| Oct 10, 2:41 AM EDT | Freeze Warning | GRR | 29 hr |
| Oct 30, 3:46 PM EDT | Wind Advisory | GRR | 12 hr |
| Nov 2, 9:03 PM EST | River Flood Advisory | GRR | 36 hr |
| Nov 8, 12:25 AM EST | Dense Fog Advisory | GRR | 9 hr |
| Nov 21, 9:34 PM EST | Dense Fog Advisory | GRR | 12 hr |
| Dec 7, 4:00 AM EST | Winter Storm Watch | GRR | 49 hr |
| Dec 7, 3:47 PM EST | Winter Storm Warning | GRR | 37 hr |
| Dec 9, 12:09 AM EST | Mesoscale Discussion | SPC | 6 hr |
| Dec 9, 4:30 AM EST | Blizzard Warning | GRR | 48 hr |
| Dec 9, 4:30 AM EST | Winter Weather Advisory | GRR | 48 hr |
| Dec 12, 8:04 PM EST | Winter Weather Advisory | GRR | 15 hr |
| Dec 14, 10:02 AM EST | Winter Weather Advisory | GRR | 6 hr |
| Dec 14, 3:36 PM EST | Lake Effect Snow Advisory | GRR | 24 hr |
| Dec 22, 4:14 PM EST | Winter Storm Watch | GRR | 36 hr |
| Dec 23, 9:50 PM EST | Winter Weather Advisory | GRR | 10 hr |
| Dec 24, 3:45 AM EST | Winter Weather Advisory | GRR | 33 hr |
| Dec 24, 7:28 PM EST | Mesoscale Discussion | SPC | 4 hr |
| Dec 26, 12:54 AM EST | Winter Weather Advisory | GRR | 10 hr |
| Dec 26, 3:48 PM EST | Winter Weather Advisory | GRR | 2 hr |
| Dec 26, 6:08 PM EST | Winter Storm Warning | GRR | 17 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20082010
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.