Alert archive / Iowa / Story County
Weather alerts in Story County, Iowa, 2011
105 weather alerts in 2011, 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 2011. Tap one for its archive.
- Alerts
- 105
- Warnings
- 30
- Watches
- 20
- Advisories
- 32
- Busiest month
- June42 alerts
- Busiest day
- June 10, 201110 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
1 of 2 tornado warnings covering Story County in 2011 had a tornado report inside them.
Story County, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 2 | 1 | 50% | 0 | ||
| Severe thunderstorm warnings | 22 | 14 | 36% | 19 | 74% | 21 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 Des Moines, IA: tornado warnings | 58 | 19 | 67% | 53 | 75% | 27 min |
| NWS Des Moines, IA: severe thunderstorm warnings | 313 | 174 | 44% | 468 | 74% | 22 min |
| NWS Des Moines, IA: flash flood warnings | 34 | 13 | 62% | 30 | 87% | 136 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 9, 3:20 PM CST | Winter Weather Advisory | DMX | 51 hr |
| Jan 16, 3:38 PM CST | Winter Weather Advisory | DMX | 26 hr |
| Jan 20, 3:46 AM CST | Wind Chill Advisory | DMX | 30 hr |
| Jan 30, 4:01 AM CST | Winter Storm Watch | DMX | 36 hr |
| Jan 30, 4:01 AM CST | Winter Weather Advisory | DMX | 68 hr |
| Jan 31, 4:20 PM CST | Blizzard Warning | DMX | 42 hr |
| Feb 1, 3:36 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 2, 3:48 AM CST | Winter Weather Advisory | DMX | 8 hr |
| Feb 2, 3:09 PM CST | Wind Chill Advisory | DMX | 18 hr |
| Feb 7, 3:35 AM CST | Wind Chill Advisory | DMX | 32 hr |
| Feb 8, 3:44 PM CST | Wind Chill Advisory | DMX | 20 hr |
| Feb 16, 6:00 PM CST | Dense Fog Advisory | DMX | 16 hr |
| Mar 8, 4:15 AM CST | Winter Storm Watch | DMX | 11 hr |
| Mar 8, 3:39 PM CST | Winter Storm Warning | DMX | 18 hr |
| Mar 8, 3:39 PM CST | Winter Weather Advisory | DMX | 18 hr |
| Mar 20, 2:51 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Mar 22, 2:03 PM CDT | Tornado Watch | SPC | 7 hr |
| Apr 3, 3:47 PM CDT | Wind Advisory | DMX | 26 hr |
| Apr 10, 3:54 AM CDT | Wind Advisory | DMX | 15 hr |
| Apr 15, 6:59 AM CDT | Wind Advisory | DMX | 9 hr |
| May 1, 3:36 PM CDT | Frost Advisory | DMX | 16 hr |
| May 2, 3:48 PM CDT | Frost Advisory | DMX | 15 hr |
| May 3, 4:05 PM CDT | Frost Advisory | DMX | 15 hr |
| May 11, 8:09 AM CDT | Mesoscale Discussion | SPC | 66 min |
| May 11, 2:53 PM CDT | Tornado Watch | SPC | 6 hr |
| May 12, 6:05 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 12, 10:27 PM CDT | Mesoscale Discussion | SPC | 63 min |
| May 21, 8:55 PM CDT | Mesoscale Discussion | SPC | 65 min |
| May 24, 3:26 PM CDT | Severe Thunderstorm Warning | DMX | 34 min |
| May 25, 4:22 AM CDT | Wind Advisory | DMX | 17 hr |
| Jun 5, 5:17 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jun 8, 5:18 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 8, 5:50 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| Jun 8, 6:03 PM CDT | Severe Thunderstorm Warning | DMX | 57 min |
| Jun 8, 6:26 PM CDT | Severe Thunderstorm Warning | DMX | 35 min |
| Jun 9, 1:44 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 9, 3:44 PM CDT | Flash Flood Watch | DMX | 12 hr |
| Jun 9, 8:13 PM CDT | Severe Thunderstorm Warning | DMX | 47 min |
| Jun 9, 8:47 PM CDT | Severe Thunderstorm Warning | DMX | 43 min |
| Jun 9, 8:58 PM CDT | Severe Thunderstorm Warning | DMX | 47 min |
| Jun 9, 9:02 PM CDT | Severe Thunderstorm Warning | DMX | 28 min |
| Jun 9, 9:15 PM CDT | Severe Thunderstorm Warning | DMX | 20 min |
| Jun 9, 9:26 PM CDT | Severe Thunderstorm Warning | DMX | 22 min |
| Jun 9, 9:30 PM CDT | Flash Flood Warning | DMX | 4 hr |
| 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, 11:27 AM CDT | Severe Thunderstorm Warning | DMX | 33 min |
| Jun 13, 11:48 AM CDT | Wind Advisory | DMX | 6 hr |
| Jun 14, 2:27 AM CDT | Severe Thunderstorm Warning | DMX | 63 min |
| Jun 14, 6:00 AM CDT | Severe Thunderstorm Warning | DMX | 45 min |
| Jun 19, 6:51 PM CDT | Tornado Watch | SPC | 7 hr |
| Jun 20, 12:50 AM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| Jun 20, 1:40 AM CDT | Mesoscale Discussion | SPC | 35 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, 7:29 AM CDT | Mesoscale Discussion | SPC | 61 min |
| Jun 20, 5:55 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Jun 20, 6:53 PM CDT | Tornado Watch | SPC | 6 hr |
| Jun 20, 10:22 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Jun 20, 11:26 PM CDT | Severe Thunderstorm Warning | DMX | 49 min |
| Jun 20, 11:49 PM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jun 20, 11:52 PM CDT | Tornado Warning | DMX | 23 min |
| Jun 26, 3:42 PM CDT | Flash Flood Watch | DMX | 14 hr |
| Jun 26, 4:56 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 26, 8:48 PM CDT | Mesoscale Discussion | SPC | 117 min |
| Jun 26, 9:20 PM CDT | Severe Thunderstorm Warning | DMX | 25 min |
| Jun 26, 9:34 PM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jun 26, 9:43 PM CDT | Severe Thunderstorm Warning | DMX | 47 min |
| Jun 26, 9:46 PM CDT | High Wind Warning | DMX | 5 hr |
| Jun 29, 3:44 AM CDT | Excessive Heat Watch | DMX | 12 hr |
| Jun 29, 3:38 PM CDT | Heat Advisory | DMX | 51 hr |
| Jul 5, 6:10 PM CDT | Tornado Watch | SPC | 4 hr |
| Jul 11, 1:08 AM CDT | Severe Thunderstorm Watch | SPC | 13 min |
| Jul 11, 1:21 AM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jul 11, 2:36 AM CDT | Mesoscale Discussion | SPC | 114 min |
| Jul 11, 3:25 AM CDT | Severe Thunderstorm Warning | DMX | 50 min |
| Jul 11, 3:34 AM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jul 11, 3:53 AM CDT | Tornado Warning | DMX | 37 min |
| Jul 14, 3:37 PM CDT | Excessive Heat Watch | DMX | 24 hr |
| Jul 15, 2:21 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Jul 15, 3:32 PM CDT | Excessive Heat Warning | DMX | 6 days |
| Jul 22, 3:00 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Jul 22, 4:12 PM CDT | Heat Advisory | DMX | 24 hr |
| Jul 26, 11:30 AM CDT | Heat Advisory | DMX | 35 hr |
| Jul 30, 3:47 PM CDT | Heat Advisory | DMX | 72 hr |
| Aug 6, 8:10 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 23, 12:45 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 23, 3:00 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 31, 3:45 AM CDT | Dense Fog Advisory | DMX | 5 hr |
| Sep 2, 2:41 PM CDT | Mesoscale Discussion | SPC | 94 min |
| Sep 2, 10:04 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Sep 2, 10:23 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Sep 2, 11:25 PM CDT | Severe Thunderstorm Warning | DMX | 34 min |
| Sep 2, 11:56 PM CDT | Mesoscale Discussion | SPC | 94 min |
| Sep 14, 3:52 AM CDT | Frost Advisory | DMX | 28 hr |
| Sep 28, 3:50 PM CDT | Wind Advisory | DMX | 27 hr |
| Sep 30, 3:29 PM CDT | Frost Advisory | DMX | 17 hr |
| Oct 11, 3:06 AM CDT | Dense Fog Advisory | DMX | 7 hr |
| Oct 11, 10:11 AM CDT | Dense Fog Advisory | DMX | 65 min |
| Oct 20, 3:42 AM CDT | Freeze Warning | DMX | 29 hr |
| Nov 8, 3:42 AM CST | Winter Weather Advisory | DMX | 29 hr |
| Nov 15, 3:25 AM CST | Wind Advisory | DMX | 14 hr |
| Nov 25, 3:31 PM CST | Wind Advisory | DMX | 29 hr |
| Dec 14, 3:16 PM CST | Dense Fog Advisory | DMX | 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 | 22 |
| Tornado Warning | 2 |
| Severe Thunderstorm Watch | 9 |
| Tornado Watch | 5 |
| Mesoscale Discussion | 23 |
| Flooding | |
| Flash Flood Warning | 1 |
| Flash Flood Watch | 2 |
| Winter | |
| Blizzard Warning | 1 |
| Winter Storm Warning | 1 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 6 |
| Heat | |
| Excessive Heat Warning | 1 |
| Excessive Heat Watch | 2 |
| Heat Advisory | 4 |
| Cold | |
| Freeze Warning | 1 |
| Frost Advisory | 5 |
| Wind Chill Advisory | 4 |
| Wind and dust | |
| High Wind Warning | 1 |
| Wind Advisory | 8 |
| Fog and smoke | |
| Dense Fog Advisory | 5 |
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.