Alert archive / Iowa / Shelby County
Weather alerts in Shelby County, Iowa, 2011
130 weather alerts in 2011, 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 2011. Tap one for its archive.
- Alerts
- 130
- Warnings
- 30
- Watches
- 28
- Advisories
- 38
- Busiest month
- June35 alerts
- Busiest day
- June 20, 20119 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
0 of 2 tornado warnings covering Shelby County in 2011 had a tornado report inside them.
Shelby County, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 2 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 20 | 15 | 25% | 11 | 82% | 27 min |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Omaha, NE: tornado warnings | 31 | 5 | 84% | 9 | 78% | 18 min |
| NWS Omaha, NE: severe thunderstorm warnings | 364 | 244 | 33% | 491 | 86% | 22 min |
| NWS Omaha, NE: flash flood warnings | 31 | 9 | 71% | 16 | 94% | 86 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 7, 4:47 AM CST | Wind Advisory | OAX | 11 hr |
| Jan 8, 2:26 PM CST | Winter Weather Advisory | OAX | 69 hr |
| Jan 11, 3:46 PM CST | Wind Chill Advisory | OAX | 18 hr |
| Jan 18, 11:47 AM CST | Winter Storm Watch | OAX | 319 days |
| Jan 21, 3:24 PM CST | Winter Storm Watch | OAX | 13 hr |
| Jan 22, 4:26 AM CST | Winter Weather Advisory | OAX | 29 hr |
| Jan 30, 4:00 AM CST | Winter Storm Watch | OAX | 13 hr |
| Jan 30, 4:55 PM CST | Winter Storm Warning | OAX | 58 hr |
| Feb 1, 4:05 AM CST | Wind Chill Advisory | OAX | 31 hr |
| Feb 2, 3:24 PM CST | Wind Chill Advisory | OAX | 17 hr |
| Feb 7, 3:24 PM CST | Wind Chill Advisory | OAX | 21 hr |
| Feb 8, 3:24 PM CST | Wind Chill Advisory | OAX | 17 hr |
| Feb 15, 11:56 PM CST | Dense Fog Advisory | OAX | 10 hr |
| Feb 16, 6:17 PM CST | Dense Fog Advisory | OAX | 11 hr |
| Mar 7, 3:47 PM CST | Winter Weather Advisory | OAX | 30 hr |
| Mar 22, 1:19 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Mar 22, 2:03 PM CDT | Tornado Watch | SPC | 7 hr |
| Mar 22, 5:19 PM CDT | Tornado Warning | OAX | 26 min |
| Mar 22, 5:31 PM CDT | Tornado Warning | OAX | 29 min |
| Mar 22, 5:33 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Apr 3, 11:08 AM CDT | Wind Advisory | OAX | 28 hr |
| Apr 9, 5:00 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Apr 9, 5:48 PM CDT | Tornado Watch | SPC | 7 hr |
| Apr 9, 9:06 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Apr 10, 3:52 AM CDT | Wind Advisory | OAX | 11 hr |
| Apr 13, 10:07 PM CDT | Wind Advisory | OAX | 27 hr |
| Apr 28, 3:57 PM CDT | Wind Advisory | OAX | 28 hr |
| May 1, 11:58 AM CDT | Red Flag Warning | OAX | 4 hr |
| May 2, 3:58 PM CDT | Frost Advisory | OAX | 16 hr |
| May 4, 11:47 AM CDT | Wind Advisory | OAX | 6 hr |
| May 11, 2:31 PM CDT | Mesoscale Discussion | SPC | 59 min |
| May 11, 2:53 PM CDT | Tornado Watch | SPC | 6 hr |
| May 12, 2:37 PM CDT | Tornado Watch | SPC | 7 hr |
| May 12, 5:35 PM CDT | Mesoscale Discussion | SPC | 85 min |
| May 12, 10:27 PM CDT | Mesoscale Discussion | SPC | 63 min |
| May 21, 12:51 PM CDT | Mesoscale Discussion | SPC | 114 min |
| May 21, 2:25 PM CDT | Severe Thunderstorm Watch | SPC | 10 hr |
| May 21, 6:07 PM CDT | Mesoscale Discussion | SPC | 53 min |
| May 21, 7:40 PM CDT | Severe Thunderstorm Warning | OAX | 50 min |
| May 21, 8:32 PM CDT | Severe Thunderstorm Warning | OAX | 43 min |
| May 21, 8:55 PM CDT | Mesoscale Discussion | SPC | 65 min |
| May 29, 3:28 PM CDT | Wind Advisory | OAX | 34 hr |
| May 29, 7:16 PM CDT | Tornado Watch | SPC | 4 hr |
| May 29, 9:24 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Jun 9, 1:44 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 9, 9:39 AM CDT | Severe Thunderstorm Warning | OAX | 28 min |
| Jun 9, 9:50 AM CDT | Mesoscale Discussion | SPC | 55 min |
| Jun 9, 9:48 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 9, 11:45 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Jun 10, 1:39 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 13, 9:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Jun 16, 11:03 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 17, 6:44 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jun 17, 7:09 PM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Jun 17, 8:15 PM CDT | Severe Thunderstorm Warning | OAX | 45 min |
| Jun 18, 10:12 AM CDT | Areal Flood Advisory | OAX | 3 hr |
| Jun 19, 9:16 PM CDT | Mesoscale Discussion | SPC | 59 min |
| Jun 19, 9:49 PM CDT | Tornado Watch | SPC | 6 hr |
| Jun 20, 2:49 AM CDT | Severe Thunderstorm Warning | OAX | 41 min |
| Jun 20, 3:27 AM CDT | Severe Thunderstorm Warning | OAX | 48 min |
| Jun 20, 3:27 AM CDT | Mesoscale Discussion | SPC | 33 min |
| Jun 20, 3:46 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 20, 3:08 PM CDT | Tornado Watch | SPC | 7 hr |
| Jun 20, 3:31 PM CDT | Flash Flood Watch | OAX | 7 hr |
| Jun 20, 6:53 PM CDT | Tornado Watch | SPC | 6 hr |
| Jun 20, 7:46 PM CDT | Mesoscale Discussion | SPC | 59 min |
| Jun 20, 8:16 PM CDT | Severe Thunderstorm Warning | OAX | 44 min |
| Jun 20, 8:56 PM CDT | Severe Thunderstorm Warning | OAX | 49 min |
| Jun 20, 9:02 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Jun 20, 9:23 PM CDT | Areal Flood Advisory | OAX | 6 hr |
| Jun 26, 6:16 AM CDT | Mesoscale Discussion | SPC | 59 min |
| Jun 26, 3:31 PM CDT | Flash Flood Watch | OAX | 12 hr |
| Jun 26, 4:56 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 26, 7:33 PM CDT | Severe Thunderstorm Warning | OAX | 42 min |
| Jun 26, 8:07 PM CDT | Severe Thunderstorm Warning | OAX | 38 min |
| Jun 26, 8:41 PM CDT | Severe Thunderstorm Warning | OAX | 49 min |
| Jun 26, 8:45 PM CDT | Areal Flood Advisory | OAX | 3 hr |
| Jun 26, 9:08 PM CDT | Areal Flood Advisory | OAX | 2 hr |
| Jun 29, 3:05 PM CDT | Heat Advisory | OAX | 28 hr |
| Jul 5, 3:32 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 10, 10:57 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jul 12, 2:09 AM CDT | Mesoscale Discussion | SPC | 66 min |
| Jul 14, 3:09 AM CDT | Excessive Heat Watch | OAX | 36 hr |
| Jul 14, 2:30 PM CDT | Excessive Heat Warning | OAX | 6 days |
| Jul 15, 2:21 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Jul 16, 12:58 AM CDT | Flash Flood Warning | OAX | 3 hr |
| Jul 22, 3:00 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Jul 22, 3:31 PM CDT | Heat Advisory | OAX | 28 hr |
| Jul 28, 4:23 AM CDT | Severe Thunderstorm Warning | OAX | 52 min |
| Jul 28, 5:12 AM CDT | Severe Thunderstorm Warning | OAX | 33 min |
| Jul 30, 3:26 PM CDT | Heat Advisory | OAX | 60 hr |
| Aug 2, 3:40 AM CDT | Excessive Heat Warning | OAX | 15 hr |
| Aug 6, 2:58 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 6, 5:32 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Aug 6, 8:10 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 6, 8:14 PM CDT | Severe Thunderstorm Warning | OAX | 46 min |
| Aug 7, 10:28 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 7, 11:34 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 18, 12:31 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Aug 18, 1:27 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 18, 2:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Aug 18, 3:34 PM CDT | Severe Thunderstorm Warning | OAX | 41 min |
| Aug 18, 4:07 PM CDT | Severe Thunderstorm Warning | OAX | 38 min |
| Aug 18, 6:15 PM CDT | Areal Flood Advisory | OAX | 6 hr |
| Aug 18, 6:42 PM CDT | Severe Thunderstorm Warning | OAX | 48 min |
| Aug 18, 7:15 PM CDT | Severe Thunderstorm Warning | OAX | 45 min |
| Aug 22, 1:42 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 28, 8:00 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 28, 10:41 AM CDT | Mesoscale Discussion | SPC | 94 min |
| Aug 31, 5:54 AM CDT | Dense Fog Advisory | OAX | 3 hr |
| Sep 2, 2:41 PM CDT | Mesoscale Discussion | SPC | 94 min |
| Sep 2, 9:01 PM CDT | Severe Thunderstorm Warning | OAX | 44 min |
| Sep 2, 9:43 PM CDT | Severe Thunderstorm Warning | OAX | 41 min |
| Sep 14, 4:12 AM CDT | Frost Advisory | OAX | 28 hr |
| Sep 18, 10:51 PM CDT | Dense Fog Advisory | OAX | 10 hr |
| Sep 22, 3:40 PM CDT | Frost Advisory | OAX | 16 hr |
| Sep 30, 7:45 PM CDT | Frost Advisory | OAX | 12 hr |
| Oct 3, 3:32 PM CDT | Fire Weather Watch | OAX | 12 hr |
| Oct 4, 3:45 AM CDT | Fire Weather Watch | OAX | 24 hr |
| Oct 4, 3:45 AM CDT | Red Flag Warning | OAX | 15 hr |
| Oct 5, 3:35 AM CDT | Red Flag Warning | OAX | 15 hr |
| Oct 7, 11:07 AM CDT | Wind Advisory | OAX | 6 hr |
| Oct 11, 2:28 AM CDT | Dense Fog Advisory | OAX | 6 hr |
| Oct 11, 8:37 AM CDT | Dense Fog Advisory | OAX | 83 min |
| Oct 18, 4:04 AM CDT | Freeze Watch | OAX | 11 hr |
| Oct 18, 3:07 PM CDT | Freeze Warning | OAX | 18 hr |
| Nov 19, 6:38 AM CST | Winter Weather Advisory | OAX | 8 hr |
| Nov 25, 3:34 PM CST | Wind Advisory | OAX | 26 hr |
| Dec 3, 3:41 AM CST | Winter Weather Advisory | OAX | 19 hr |
| Dec 30, 3:54 PM CST | Wind Advisory | OAX | 35 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 | 20 |
| Tornado Warning | 2 |
| Severe Thunderstorm Watch | 11 |
| Tornado Watch | 8 |
| Mesoscale Discussion | 34 |
| Flooding | |
| Flash Flood Warning | 1 |
| Flash Flood Watch | 2 |
| Areal Flood Advisory | 5 |
| Winter | |
| Winter Storm Warning | 1 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 5 |
| Heat | |
| Excessive Heat Warning | 2 |
| Excessive Heat Watch | 1 |
| Heat Advisory | 3 |
| Cold | |
| Freeze Warning | 1 |
| Freeze Watch | 1 |
| Frost Advisory | 4 |
| Wind Chill Advisory | 5 |
| Wind and dust | |
| Wind Advisory | 10 |
| Fire | |
| Red Flag Warning | 3 |
| Fire Weather Watch | 2 |
| Fog and smoke | |
| Dense Fog Advisory | 6 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20102012
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.