Alert archive / Iowa / Shelby County
Weather alerts in Shelby County, Iowa, 2012
108 weather alerts in 2012, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Shelby County and its neighbors
Each county as a circle sized by its count in 2012. Tap one for its archive.
- Alerts
- 108
- Warnings
- 19
- Watches
- 19
- Advisories
- 25
- Busiest month
- May23 alerts
- Busiest day
- May 20, 20125 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Shelby County, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 4 | 1 | 75% | 0 | ||
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Omaha, NE: tornado warnings | 19 | 5 | 74% | 19 | 21% | 19 min |
| NWS Omaha, NE: severe thunderstorm warnings | 225 | 124 | 45% | 230 | 81% | 16 min |
| NWS Omaha, NE: flash flood warnings | 14 | 7 | 50% | 14 | 79% | 36 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, Central Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 1, 3:55 AM CST | Wind Advisory | OAX | 14 hr |
| Jan 10, 3:25 PM CST | Wind Advisory | OAX | 30 hr |
| Feb 1, 9:58 PM CST | Winter Storm Watch | OAX | 41 hr |
| Feb 3, 3:21 PM CST | Winter Storm Warning | OAX | 32 hr |
| Feb 5, 7:21 PM CST | Dense Fog Advisory | OAX | 17 hr |
| Feb 10, 3:24 PM CST | Wind Chill Advisory | OAX | 17 hr |
| Feb 12, 3:27 AM CST | Winter Weather Advisory | OAX | 36 hr |
| Feb 13, 10:00 PM CST | Dense Fog Advisory | OAX | 12 hr |
| Feb 22, 4:02 PM CST | Wind Advisory | OAX | 26 hr |
| Feb 22, 10:02 PM CST | Winter Weather Advisory | OAX | 26 hr |
| Feb 28, 3:22 PM CST | Wind Advisory | OAX | 25 hr |
| Mar 3, 8:17 PM CST | Wind Advisory | OAX | 22 hr |
| Mar 16, 5:24 AM CDT | Dense Fog Advisory | OAX | 6 hr |
| Mar 19, 1:34 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Mar 26, 3:25 AM CDT | Fire Weather Watch | OAX | 24 hr |
| Mar 30, 3:20 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Apr 8, 3:14 PM CDT | Freeze Watch | OAX | 24 hr |
| Apr 9, 4:05 AM CDT | Freeze Warning | OAX | 29 hr |
| Apr 10, 3:56 AM CDT | Freeze Warning | OAX | 29 hr |
| Apr 14, 12:00 PM CDT | Tornado Watch | SPC | 7 hr |
| Apr 14, 2:15 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Apr 14, 9:17 PM CDT | Wind Advisory | OAX | 31 hr |
| Apr 14, 10:09 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Apr 14, 11:28 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Apr 15, 3:25 AM CDT | Mesoscale Discussion | SPC | 95 min |
| Apr 19, 2:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Apr 23, 2:07 AM CDT | Freeze Warning | OAX | 7 hr |
| Apr 27, 10:42 AM CDT | Wind Advisory | OAX | 7 hr |
| Apr 27, 5:12 PM CDT | Special Weather Statement | OAX | 33 min |
| May 1, 9:18 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 1, 11:08 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 2, 2:02 AM CDT | Mesoscale Discussion | SPC | 58 min |
| May 2, 3:10 AM CDT | Special Weather Statement | OAX | 35 min |
| May 4, 5:31 PM CDT | Mesoscale Discussion | SPC | 29 min |
| May 4, 5:52 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 6, 4:55 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 19, 3:25 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 19, 5:41 PM CDT | Mesoscale Discussion | SPC | 64 min |
| May 19, 8:06 PM CDT | Severe Thunderstorm Warning | OAX | 39 min |
| May 19, 8:11 PM CDT | Mesoscale Discussion | SPC | 64 min |
| May 19, 8:32 PM CDT | Severe Thunderstorm Warning | OAX | 28 min |
| May 19, 8:44 PM CDT | Severe Thunderstorm Warning | OAX | 31 min |
| May 19, 10:33 PM CDT | Mesoscale Discussion | SPC | 57 min |
| May 23, 10:26 AM CDT | Wind Advisory | OAX | 8 hr |
| May 23, 2:56 PM CDT | Mesoscale Discussion | SPC | 94 min |
| May 23, 4:07 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 23, 6:49 PM CDT | Mesoscale Discussion | SPC | 86 min |
| May 23, 8:56 PM CDT | Mesoscale Discussion | SPC | 94 min |
| May 25, 3:09 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 25, 9:17 PM CDT | Mesoscale Discussion | SPC | 88 min |
| May 26, 12:46 AM CDT | Mesoscale Discussion | SPC | 89 min |
| May 27, 3:42 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 3, 8:04 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Jun 10, 3:10 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Jun 10, 3:42 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 10, 4:46 PM CDT | Severe Thunderstorm Warning | OAX | 22 min |
| Jun 10, 6:20 PM CDT | Mesoscale Discussion | SPC | 55 min |
| Jun 10, 7:34 PM CDT | Special Weather Statement | OAX | 41 min |
| Jun 10, 10:22 PM CDT | Mesoscale Discussion | SPC | 53 min |
| Jun 14, 3:27 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 14, 6:07 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Jun 14, 7:06 PM CDT | Special Weather Statement | OAX | 24 min |
| Jun 20, 3:24 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Jun 26, 3:23 PM CDT | Heat Advisory | OAX | 3 days |
| Jul 3, 3:26 AM CDT | Heat Advisory | OAX | 17 hr |
| Jul 4, 3:55 AM CDT | Heat Advisory | OAX | 65 hr |
| Jul 4, 3:42 PM CDT | Excessive Heat Warning | OAX | 53 hr |
| Jul 14, 4:19 PM CDT | Special Weather Statement | OAX | 56 min |
| Jul 14, 4:32 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 17, 2:56 PM CDT | Heat Advisory | OAX | 29 hr |
| Jul 20, 4:18 AM CDT | Heat Advisory | OAX | 5 days |
| Jul 20, 3:05 PM CDT | Excessive Heat Warning | OAX | 5 days |
| Jul 25, 4:28 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 25, 7:21 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Aug 8, 12:28 PM CDT | Mesoscale Discussion | SPC | 62 min |
| Aug 8, 4:10 PM CDT | Mesoscale Discussion | SPC | 95 min |
| Aug 8, 4:53 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 16, 2:15 AM CDT | Special Weather Statement | OAX | 30 min |
| Aug 22, 3:09 AM CDT | Red Flag Warning | OAX | 16 hr |
| Aug 25, 5:54 AM CDT | Special Weather Statement | OAX | 66 min |
| Aug 25, 6:50 AM CDT | Special Weather Statement | OAX | 55 min |
| Aug 27, 5:28 AM CDT | Dense Fog Advisory | OAX | 4 hr |
| Sep 3, 8:47 AM CDT | Special Weather Statement | OAX | 43 min |
| Sep 5, 1:14 AM CDT | Mesoscale Discussion | SPC | 91 min |
| Sep 10, 4:10 AM CDT | Fire Weather Watch | OAX | 11 hr |
| Sep 10, 3:39 PM CDT | Red Flag Warning | OAX | 27 hr |
| Sep 18, 3:36 PM CDT | Fire Weather Watch | OAX | 11 hr |
| Sep 21, 3:28 PM CDT | Freeze Watch | OAX | 12 hr |
| Sep 22, 3:35 AM CDT | Freeze Warning | OAX | 29 hr |
| Oct 2, 3:30 PM CDT | Fire Weather Watch | OAX | 12 hr |
| Oct 3, 3:49 AM CDT | Red Flag Warning | OAX | 15 hr |
| Oct 4, 3:28 PM CDT | Freeze Warning | OAX | 18 hr |
| Oct 5, 3:40 PM CDT | Freeze Warning | OAX | 18 hr |
| Oct 8, 3:33 AM CDT | Red Flag Warning | OAX | 14 hr |
| Oct 16, 3:38 PM CDT | Wind Advisory | OAX | 27 hr |
| Oct 17, 3:28 PM CDT | Wind Advisory | OAX | 37 hr |
| Oct 22, 1:08 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 23, 9:25 PM CDT | Dense Fog Advisory | OAX | 10 hr |
| Oct 24, 11:20 PM CDT | Mesoscale Discussion | SPC | 115 min |
| Oct 25, 1:55 AM CDT | Special Weather Statement | OAX | 35 min |
| Nov 10, 7:56 PM CST | Mesoscale Discussion | SPC | 94 min |
| Dec 1, 3:30 AM CST | Dense Fog Advisory | OAX | 9 hr |
| Dec 1, 7:39 PM CST | Dense Fog Advisory | OAX | 13 hr |
| Dec 17, 3:31 PM CST | Winter Storm Watch | OAX | 24 hr |
| Dec 18, 3:57 PM CST | Winter Storm Warning | OAX | 37 hr |
| Dec 19, 11:31 AM CST | Blizzard Warning | OAX | 24 hr |
| Dec 19, 2:08 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Dec 19, 9:32 PM CST | Mesoscale Discussion | SPC | 5 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
| Product | Alerts |
|---|---|
| Severe storms | |
| Severe Thunderstorm Warning | 4 |
| Severe Thunderstorm Watch | 10 |
| Tornado Watch | 1 |
| Mesoscale Discussion | 35 |
| Special Weather Statement | 10 |
| Winter | |
| Blizzard Warning | 1 |
| Winter Storm Warning | 2 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 2 |
| Heat | |
| Excessive Heat Warning | 2 |
| Heat Advisory | 5 |
| Cold | |
| Freeze Warning | 6 |
| Freeze Watch | 2 |
| Wind Chill Advisory | 1 |
| Wind and dust | |
| Wind Advisory | 10 |
| Fire | |
| Red Flag Warning | 4 |
| Fire Weather Watch | 4 |
| Fog and smoke | |
| Dense Fog Advisory | 7 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20112013
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.