Alert archive / Iowa / Story County
Weather alerts in Story County, Iowa, 2018
179 weather alerts in 2018, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Story County and its neighbors
Each county as a circle sized by its count in 2018. Tap one for its archive.
- Alerts
- 179
- Warnings
- 56
- Watches
- 28
- Advisories
- 42
- Busiest month
- June40 alerts
- Busiest day
- September 2, 201812 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
2 of 4 tornado warnings covering Story County in 2018 had a tornado report inside them; 1 of 3 tornado reports fell inside a warning, on average 15 minutes after it went out.
Story County, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 4 | 2 | 50% | 3 | 33% | 15 min |
| Severe thunderstorm warnings | 32 | 18 | 44% | 36 | 92% | 23 min |
| Flash flood warnings | 6 | 3 | 50% | 7 | 71% | 60 min |
Each office's whole area, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Des Moines, IA: tornado warnings | 72 | 23 | 68% | 69 | 55% | 15 min |
| NWS Des Moines, IA: severe thunderstorm warnings | 308 | 143 | 54% | 427 | 74% | 22 min |
| NWS Des Moines, IA: flash flood warnings | 39 | 20 | 49% | 70 | 74% | 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 3, 3:46 AM CST | Wind Chill Advisory | DMX | 30 hr |
| Jan 5, 4:04 PM CST | Wind Chill Advisory | DMX | 18 hr |
| Jan 10, 2:08 PM CST | Winter Weather Advisory | DMX | 28 hr |
| Jan 11, 2:24 PM CST | Wind Chill Advisory | DMX | 20 hr |
| Jan 12, 3:46 PM CST | Wind Chill Advisory | DMX | 18 hr |
| Jan 14, 3:47 AM CST | Wind Chill Advisory | DMX | 56 hr |
| Jan 14, 3:10 PM CST | Wind Chill Warning | DMX | 43 hr |
| Jan 21, 2:35 PM CST | Winter Weather Advisory | DMX | 33 hr |
| Jan 21, 6:18 PM CST | Dense Fog Advisory | DMX | 6 hr |
| Feb 4, 2:32 PM CST | Winter Weather Advisory | DMX | 28 hr |
| Feb 5, 11:36 AM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 7, 2:23 PM CST | Winter Weather Advisory | DMX | 40 hr |
| Feb 8, 11:05 AM CST | Winter Storm Warning | DMX | 19 hr |
| Feb 8, 9:07 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 18, 3:27 AM CST | Wind Advisory | DMX | 11 hr |
| Feb 18, 3:45 AM CST | Winter Storm Watch | DMX | 24 hr |
| Feb 18, 3:45 AM CST | Winter Weather Advisory | DMX | 56 hr |
| Feb 21, 3:42 PM CST | Winter Weather Advisory | DMX | 35 hr |
| Feb 23, 3:24 PM CST | Winter Weather Advisory | DMX | 30 hr |
| Mar 16, 4:10 AM CDT | Winter Weather Advisory | DMX | 30 hr |
| Mar 23, 4:00 AM CDT | Winter Storm Warning | DMX | 39 hr |
| Mar 23, 4:00 AM CDT | Winter Weather Advisory | DMX | 39 hr |
| Mar 28, 2:51 AM CDT | Dense Fog Advisory | DMX | 9 hr |
| Mar 30, 3:19 PM CDT | Wind Advisory | DMX | 25 hr |
| Apr 2, 2:00 PM CDT | Winter Weather Advisory | DMX | 35 hr |
| Apr 3, 4:19 AM CDT | Wind Advisory | DMX | 21 hr |
| Apr 7, 3:05 PM CDT | Winter Weather Advisory | DMX | 40 hr |
| Apr 13, 3:22 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Apr 13, 3:54 PM CDT | Winter Weather Advisory | DMX | 48 hr |
| Apr 13, 7:23 PM CDT | Severe Thunderstorm Warning | DMX | 52 min |
| Apr 13, 7:52 PM CDT | Severe Thunderstorm Warning | DMX | 39 min |
| Apr 14, 1:31 AM CDT | Wind Advisory | DMX | 14 hr |
| Apr 17, 3:54 AM CDT | Winter Weather Advisory | DMX | 42 hr |
| Apr 27, 2:42 PM CDT | Red Flag Warning | DMX | 4 hr |
| Apr 29, 3:26 AM CDT | Red Flag Warning | DMX | 18 hr |
| Apr 30, 3:18 AM CDT | Wind Advisory | DMX | 17 hr |
| May 1, 3:16 PM CDT | Mesoscale Discussion | SPC | 89 min |
| May 1, 4:35 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| May 1, 5:09 PM CDT | Severe Thunderstorm Warning | DMX | 51 min |
| May 1, 5:47 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 1, 5:54 PM CDT | Severe Thunderstorm Warning | DMX | 36 min |
| May 1, 7:55 PM CDT | Mesoscale Discussion | SPC | 95 min |
| May 1, 9:38 PM CDT | Mesoscale Discussion | SPC | 67 min |
| May 3, 5:43 PM CDT | Tornado Warning | DMX | 21 min |
| May 3, 7:50 PM CDT | Severe Thunderstorm Warning | DMX | 55 min |
| May 12, 1:04 AM CDT | Mesoscale Discussion | SPC | 116 min |
| May 22, 2:05 AM CDT | Dense Fog Advisory | DMX | 7 hr |
| May 25, 5:48 PM CDT | Severe Thunderstorm Warning | DMX | 42 min |
| May 25, 6:25 PM CDT | Severe Thunderstorm Warning | DMX | 50 min |
| May 28, 2:31 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 28, 2:50 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| May 29, 1:43 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 29, 3:30 PM CDT | Severe Thunderstorm Warning | DMX | 18 min |
| May 29, 3:36 PM CDT | Severe Thunderstorm Warning | DMX | 24 min |
| May 29, 3:54 PM CDT | Mesoscale Discussion | SPC | 96 min |
| May 29, 3:59 PM CDT | Severe Thunderstorm Warning | DMX | 16 min |
| May 29, 6:50 PM CDT | Severe Thunderstorm Warning | DMX | 15 min |
| Jun 6, 3:23 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 6, 4:15 PM CDT | Severe Thunderstorm Warning | DMX | 45 min |
| Jun 6, 4:40 PM CDT | Severe Thunderstorm Warning | DMX | 50 min |
| Jun 6, 4:47 PM CDT | Severe Thunderstorm Warning | DMX | 43 min |
| Jun 6, 5:00 PM CDT | Severe Thunderstorm Warning | DMX | 48 min |
| Jun 6, 5:19 PM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jun 6, 5:28 PM CDT | Severe Thunderstorm Warning | DMX | 47 min |
| Jun 6, 6:20 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Jun 10, 1:23 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 10, 7:52 AM CDT | Special Weather Statement | DMX | 38 min |
| Jun 10, 9:53 PM CDT | Flash Flood Watch | DMX | 10 hr |
| Jun 11, 7:39 AM CDT | Special Weather Statement | DMX | 3 hr |
| Jun 11, 10:26 PM CDT | Special Weather Statement | DMX | 34 min |
| Jun 12, 6:31 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 14, 3:25 AM CDT | Severe Thunderstorm Warning | DMX | 18 min |
| Jun 14, 6:36 AM CDT | Special Weather Statement | DMX | 54 min |
| Jun 14, 9:13 AM CDT | Flash Flood Warning | DMX | 6 hr |
| Jun 14, 12:14 PM CDT | River Flood Warning | DMX | 29 hr |
| Jun 14, 3:00 PM CDT | Heat Advisory | DMX | 4 days |
| Jun 14, 7:51 PM CDT | River Flood Warning | DMX | 35 hr |
| Jun 18, 1:34 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jun 18, 3:05 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 18, 3:41 PM CDT | Flash Flood Watch | DMX | 16 hr |
| Jun 18, 5:46 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 18, 7:24 PM CDT | Special Weather Statement | DMX | 66 min |
| Jun 20, 4:28 AM CDT | Flash Flood Watch | DMX | 23 hr |
| Jun 20, 10:43 AM CDT | River Flood Watch | DMX | 7 hr |
| Jun 20, 1:01 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 20, 2:43 PM CDT | Special Weather Statement | DMX | 62 min |
| Jun 20, 3:04 PM CDT | Tornado Watch | SPC | 4 hr |
| Jun 20, 5:13 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 20, 5:20 PM CDT | River Flood Warning | DMX | 3 hr |
| Jun 20, 6:45 PM CDT | Severe Thunderstorm Warning | DMX | 30 min |
| Jun 25, 9:33 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Jun 27, 3:29 PM CDT | Heat Advisory | DMX | 54 hr |
| Jun 28, 10:57 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 30, 2:59 AM CDT | Flash Flood Watch | DMX | 27 hr |
| Jun 30, 3:12 AM CDT | Heat Advisory | DMX | 16 hr |
| Jun 30, 1:39 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 30, 6:47 PM CDT | Severe Thunderstorm Warning | DMX | 43 min |
| Jun 30, 7:05 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| Jun 30, 7:24 PM CDT | Severe Thunderstorm Warning | DMX | 36 min |
| Jun 30, 7:33 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Jun 30, 10:47 PM CDT | River Flood Watch | DMX | 7 hr |
| Jun 30, 10:47 PM CDT | River Flood Watch | DMX | 10 hr |
| Jul 1, 1:21 AM CDT | Flash Flood Warning | DMX | 8 hr |
| Jul 1, 9:08 AM CDT | Areal Flood Warning | DMX | 12 hr |
| Jul 3, 2:39 PM CDT | Heat Advisory | DMX | 29 hr |
| Jul 4, 10:27 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 10, 11:51 AM CDT | Mesoscale Discussion | SPC | 84 min |
| Jul 11, 3:44 PM CDT | Heat Advisory | DMX | 28 hr |
| Jul 13, 3:48 AM CDT | Flash Flood Watch | DMX | 18 hr |
| Jul 15, 6:08 AM CDT | Dense Fog Advisory | DMX | 3 hr |
| Jul 19, 2:32 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jul 19, 3:11 PM CDT | Tornado Watch | SPC | 6 hr |
| Jul 19, 3:22 PM CDT | Tornado Warning | DMX | 38 min |
| Jul 19, 3:26 PM CDT | Tornado Warning | DMX | 34 min |
| Jul 19, 3:54 PM CDT | Tornado Warning | DMX | 51 min |
| Jul 19, 5:18 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Jul 25, 9:43 PM CDT | Special Weather Statement | DMX | 62 min |
| Aug 1, 6:52 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 1, 6:53 PM CDT | Severe Thunderstorm Warning | DMX | 52 min |
| Aug 1, 8:16 PM CDT | Severe Thunderstorm Warning | DMX | 44 min |
| Aug 5, 4:10 AM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Aug 5, 5:41 AM CDT | Special Weather Statement | DMX | 34 min |
| Aug 5, 10:15 AM CDT | Special Weather Statement | DMX | 60 min |
| Aug 5, 9:32 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 16, 12:28 PM CDT | Special Weather Statement | DMX | 62 min |
| Aug 25, 3:19 AM CDT | Dense Fog Advisory | DMX | 6 hr |
| Aug 26, 9:53 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 28, 11:25 AM CDT | Special Weather Statement | DMX | 50 min |
| Aug 28, 11:34 AM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Aug 28, 11:50 AM CDT | Special Weather Statement | DMX | 55 min |
| Aug 28, 12:14 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 28, 12:51 PM CDT | Special Weather Statement | DMX | 54 min |
| Aug 28, 1:14 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 28, 1:38 PM CDT | Severe Thunderstorm Warning | DMX | 52 min |
| Aug 31, 1:10 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 1, 4:38 AM CDT | Flash Flood Watch | DMX | 24 hr |
| Sep 1, 6:34 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Sep 1, 7:02 PM CDT | Special Weather Statement | DMX | 58 min |
| Sep 1, 7:07 PM CDT | Severe Thunderstorm Warning | DMX | 38 min |
| Sep 1, 7:14 PM CDT | Severe Thunderstorm Warning | DMX | 46 min |
| Sep 1, 7:51 PM CDT | Severe Thunderstorm Warning | DMX | 39 min |
| Sep 1, 8:20 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Sep 1, 8:50 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| Sep 1, 9:20 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Sep 1, 10:27 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Sep 2, 1:37 AM CDT | Flash Flood Warning | DMX | 2 hr |
| Sep 2, 3:47 AM CDT | Areal Flood Warning | DMX | 9 hr |
| Sep 2, 9:45 AM CDT | Flash Flood Watch | DMX | 36 hr |
| Sep 2, 2:24 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 3, 5:47 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Sep 4, 3:33 AM CDT | Flash Flood Watch | DMX | 27 hr |
| Sep 4, 3:35 PM CDT | Tornado Watch | SPC | 7 hr |
| Sep 4, 6:28 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 18, 10:09 AM CDT | Special Weather Statement | DMX | 81 min |
| Sep 19, 7:55 AM CDT | Special Weather Statement | DMX | 65 min |
| Sep 20, 5:48 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Sep 25, 9:27 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 25, 11:05 AM CDT | Special Weather Statement | DMX | 55 min |
| Oct 3, 12:07 PM CDT | Wind Advisory | DMX | 13 hr |
| Oct 5, 2:39 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 7, 3:52 PM CDT | Flood Watch | DMX | 60 hr |
| Oct 8, 7:03 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Oct 9, 2:49 AM CDT | River Flood Warning | DMX | 3 days |
| Oct 9, 1:46 PM CDT | Tornado Watch | SPC | 7 hr |
| Oct 9, 3:22 PM CDT | River Flood Warning | DMX | 7 hr |
| Oct 9, 3:22 PM CDT | River Flood Warning | DMX | 20 hr |
| Oct 9, 3:53 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 13, 3:23 PM CDT | Freeze Watch | DMX | 23 hr |
| Oct 14, 3:45 AM CDT | Freeze Warning | DMX | 30 hr |
| Oct 19, 7:30 PM CDT | Wind Advisory | DMX | 20 hr |
| Nov 3, 4:46 AM CDT | Dense Fog Advisory | DMX | 3 hr |
| Nov 16, 3:49 AM CST | Winter Weather Advisory | DMX | 28 hr |
| Nov 23, 3:30 AM CST | Winter Storm Watch | DMX | 24 hr |
| Nov 24, 3:40 AM CST | Winter Weather Advisory | DMX | 36 hr |
| Nov 30, 2:34 AM CST | Dense Fog Advisory | DMX | 7 hr |
| Nov 30, 3:18 PM CST | Winter Weather Advisory | DMX | 45 hr |
| Dec 28, 12:55 AM CST | Winter Weather Advisory | DMX | 11 hr |
| Dec 31, 3:26 AM CST | Winter Weather Advisory | DMX | 20 hr |
| Dec 31, 11:50 AM CST | Mesoscale Discussion | SPC | 6 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 | 32 |
| Tornado Warning | 4 |
| Severe Thunderstorm Watch | 9 |
| Tornado Watch | 4 |
| Mesoscale Discussion | 36 |
| Special Weather Statement | 17 |
| Flooding | |
| Areal Flood Warning | 2 |
| Flash Flood Warning | 6 |
| River Flood Warning | 6 |
| Flash Flood Watch | 8 |
| Flood Watch | 1 |
| River Flood Watch | 3 |
| Winter | |
| Winter Storm Warning | 2 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 18 |
| Heat | |
| Heat Advisory | 5 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Warning | 1 |
| Freeze Watch | 1 |
| Wind Chill Advisory | 5 |
| Wind and dust | |
| Wind Advisory | 7 |
| Fire | |
| Red Flag Warning | 2 |
| 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 archive20172019
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.