Alert archive / Iowa / Shelby County
Weather alerts in Shelby County, Iowa, 2017
103 weather alerts in 2017, 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 2017. Tap one for its archive.
- Alerts
- 103
- Warnings
- 23
- Watches
- 15
- Advisories
- 26
- Busiest month
- June18 alerts
- Busiest day
- May 17, 20179 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 2017 had a tornado report inside them.
Shelby County, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 2 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 14 | 12 | 14% | 8 | 88% | 20 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Omaha, NE: tornado warnings | 25 | 10 | 60% | 27 | 63% | 14 min |
| NWS Omaha, NE: severe thunderstorm warnings | 258 | 140 | 46% | 412 | 87% | 17 min |
| NWS Omaha, NE: flash flood warnings | 8 | 5 | 38% | 13 | 92% | 69 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 2, 12:36 AM CST | Winter Weather Advisory | OAX | 11 hr |
| Jan 10, 3:46 AM CST | Winter Weather Advisory | OAX | 8 hr |
| Jan 12, 4:00 PM CST | Winter Storm Watch | OAX | 47 hr |
| Jan 14, 2:37 PM CST | Ice Storm Warning | OAX | 52 hr |
| Jan 16, 3:18 PM CST | Winter Weather Advisory | OAX | 8 hr |
| Jan 19, 3:39 PM CST | Dense Fog Advisory | OAX | 17 hr |
| Jan 20, 6:27 PM CST | Dense Fog Advisory | OAX | 17 hr |
| Jan 21, 9:34 PM CST | Dense Fog Advisory | OAX | 7 hr |
| Jan 23, 3:30 PM CST | Winter Weather Advisory | OAX | 49 hr |
| Feb 7, 11:56 AM CST | Winter Weather Advisory | OAX | 23 hr |
| Feb 23, 4:20 AM CST | Winter Weather Advisory | OAX | 38 hr |
| Feb 23, 6:05 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Mar 5, 3:40 PM CST | Red Flag Warning | OAX | 28 hr |
| Mar 5, 3:44 PM CST | Wind Advisory | OAX | 28 hr |
| Mar 6, 1:08 PM CST | Mesoscale Discussion | SPC | 3 hr |
| Mar 6, 1:54 PM CST | Tornado Watch | SPC | 8 hr |
| Mar 6, 3:35 PM CST | Mesoscale Discussion | SPC | 115 min |
| Mar 6, 3:38 PM CST | Severe Thunderstorm Warning | OAX | 37 min |
| Mar 6, 4:02 PM CST | Severe Thunderstorm Warning | OAX | 28 min |
| Mar 6, 4:32 PM CST | Fire Weather Watch | OAX | 11 hr |
| Mar 6, 4:32 PM CST | Red Flag Warning | OAX | 25 hr |
| Mar 7, 3:17 AM CST | Wind Advisory | OAX | 12 hr |
| Apr 3, 1:32 AM CDT | Dense Fog Advisory | OAX | 9 hr |
| Apr 15, 4:01 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Apr 15, 5:05 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Apr 15, 9:14 PM CDT | Severe Thunderstorm Warning | OAX | 46 min |
| Apr 19, 7:42 AM CDT | Special Weather Statement | OAX | 33 min |
| Apr 19, 2:29 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Apr 19, 3:23 PM CDT | Tornado Watch | SPC | 7 hr |
| Apr 19, 5:30 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Apr 19, 7:28 PM CDT | Severe Thunderstorm Warning | OAX | 32 min |
| Apr 26, 3:54 AM CDT | Frost Advisory | OAX | 29 hr |
| May 16, 3:58 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 16, 4:57 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 16, 6:37 PM CDT | Severe Thunderstorm Warning | OAX | 38 min |
| May 16, 7:10 PM CDT | Severe Thunderstorm Warning | OAX | 65 min |
| May 16, 7:20 PM CDT | Tornado Warning | OAX | 20 min |
| May 16, 7:31 PM CDT | Mesoscale Discussion | SPC | 59 min |
| May 16, 9:43 PM CDT | Mesoscale Discussion | SPC | 62 min |
| May 17, 11:39 AM CDT | Mesoscale Discussion | SPC | 66 min |
| May 17, 11:41 AM CDT | Special Weather Statement | OAX | 49 min |
| May 17, 12:08 PM CDT | Tornado Watch | SPC | 7 hr |
| May 17, 2:25 PM CDT | Mesoscale Discussion | SPC | 65 min |
| May 17, 3:48 PM CDT | Special Weather Statement | OAX | 42 min |
| May 22, 5:32 PM CDT | Special Weather Statement | OAX | 43 min |
| May 22, 6:11 PM CDT | Special Weather Statement | OAX | 49 min |
| May 27, 9:13 AM CDT | Special Weather Statement | OAX | 47 min |
| Jun 13, 9:36 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Jun 15, 5:11 PM CDT | Mesoscale Discussion | SPC | 64 min |
| Jun 16, 3:30 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 16, 6:16 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 16, 7:07 PM CDT | Severe Thunderstorm Warning | OAX | 38 min |
| Jun 16, 7:51 PM CDT | Tornado Warning | OAX | 11 min |
| Jun 16, 8:14 PM CDT | Severe Thunderstorm Warning | OAX | 31 min |
| Jun 16, 8:43 PM CDT | Severe Thunderstorm Warning | OAX | 32 min |
| Jun 27, 11:33 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Jun 28, 2:14 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 28, 2:53 PM CDT | Tornado Watch | SPC | 9 hr |
| Jun 29, 3:42 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 29, 6:08 PM CDT | Mesoscale Discussion | SPC | 67 min |
| Jun 29, 7:13 PM CDT | Severe Thunderstorm Warning | OAX | 32 min |
| Jun 29, 7:56 PM CDT | Severe Thunderstorm Warning | OAX | 34 min |
| Jun 29, 8:26 PM CDT | Special Weather Statement | OAX | 34 min |
| Jun 29, 9:45 PM CDT | Severe Thunderstorm Warning | OAX | 30 min |
| Jun 29, 9:46 PM CDT | Severe Thunderstorm Warning | OAX | 29 min |
| Jul 11, 1:54 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 17, 3:41 PM CDT | Excessive Heat Watch | OAX | 24 hr |
| Jul 18, 3:57 PM CDT | Excessive Heat Warning | OAX | 4 days |
| Jul 18, 3:57 PM CDT | Heat Advisory | OAX | 4 days |
| Jul 21, 1:32 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 22, 3:13 AM CDT | Special Weather Statement | OAX | 62 min |
| Aug 20, 11:14 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Aug 21, 1:47 AM CDT | Special Weather Statement | OAX | 43 min |
| Aug 21, 2:35 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Aug 21, 8:09 PM CDT | Special Weather Statement | OAX | 66 min |
| Aug 26, 1:35 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 3, 5:44 AM CDT | Dense Fog Advisory | OAX | 4 hr |
| Sep 16, 2:58 AM CDT | Special Weather Statement | OAX | 32 min |
| Sep 16, 3:41 AM CDT | Special Weather Statement | OAX | 34 min |
| Sep 16, 9:16 PM CDT | Special Weather Statement | OAX | 44 min |
| Oct 4, 3:22 PM CDT | Flood Watch | OAX | 60 hr |
| Oct 6, 3:14 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Oct 15, 11:11 AM CDT | Frost Advisory | OAX | 23 hr |
| Oct 21, 2:16 AM CDT | Special Weather Statement | OAX | 29 min |
| Oct 21, 2:32 AM CDT | Severe Thunderstorm Warning | OAX | 17 min |
| Oct 21, 3:34 AM CDT | Special Weather Statement | OAX | 41 min |
| Oct 21, 2:57 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 22, 3:08 PM CDT | Wind Advisory | OAX | 28 hr |
| Oct 24, 3:17 AM CDT | Wind Advisory | OAX | 13 hr |
| Oct 25, 3:22 PM CDT | Freeze Watch | OAX | 12 hr |
| Oct 25, 3:22 PM CDT | Freeze Watch | OAX | 12 hr |
| Oct 25, 3:22 PM CDT | Wind Advisory | OAX | 45 hr |
| Oct 26, 3:29 AM CDT | Freeze Warning | OAX | 30 hr |
| Oct 27, 4:03 AM CDT | Freeze Warning | OAX | 30 hr |
| Nov 13, 2:39 AM CST | Dense Fog Advisory | OAX | 7 hr |
| Dec 3, 3:16 PM CST | Wind Advisory | OAX | 33 hr |
| Dec 11, 2:45 AM CST | Wind Advisory | OAX | 15 hr |
| Dec 12, 3:05 PM CST | Wind Advisory | OAX | 25 hr |
| Dec 21, 4:03 AM CST | Winter Weather Advisory | OAX | 19 hr |
| Dec 26, 2:05 PM CST | Wind Chill Advisory | OAX | 20 hr |
| Dec 29, 2:50 PM CST | Wind Chill Watch | OAX | 13 hr |
| Dec 29, 2:50 PM CST | Wind Chill Advisory | OAX | 21 hr |
| Dec 30, 3:55 AM CST | Wind Chill Warning | OAX | 56 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 | 14 |
| Tornado Warning | 2 |
| Severe Thunderstorm Watch | 4 |
| Tornado Watch | 4 |
| Mesoscale Discussion | 24 |
| Special Weather Statement | 15 |
| Flooding | |
| Flood Watch | 1 |
| Winter | |
| Ice Storm Warning | 1 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 7 |
| Heat | |
| Excessive Heat Warning | 1 |
| Excessive Heat Watch | 1 |
| Heat Advisory | 1 |
| Cold | |
| Freeze Warning | 2 |
| Wind Chill Warning | 1 |
| Freeze Watch | 2 |
| Wind Chill Watch | 1 |
| Frost Advisory | 2 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| Wind Advisory | 8 |
| Fire | |
| Red Flag Warning | 2 |
| Fire Weather Watch | 1 |
| 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 archive20162018
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.