Alert archive / Iowa / Jefferson County
Weather alerts in Jefferson County, Iowa, 2009
129 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Jefferson County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 129
- Warnings
- 25
- Watches
- 27
- Advisories
- 29
- Busiest month
- June36 alerts
- Busiest day
- June 8, 20096 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Jefferson County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 13 | 9 | 31% | 5 | 60% | 25 min |
| Flash flood warnings | 4 | 1 | 75% | 0 |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Quad Cities, IA: tornado warnings | 17 | 6 | 65% | 18 | 78% | 11 min |
| NWS Quad Cities, IA: severe thunderstorm warnings | 117 | 90 | 23% | 347 | 88% | 33 min |
| NWS Quad Cities, IA: flash flood warnings | 49 | 37 | 24% | 86 | 84% | 91 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 PM CST | Dense Fog Advisory | DVN | 10 hr |
| Jan 12, 3:24 AM CST | Blizzard Watch | DVN | 10 hr |
| Jan 12, 3:24 AM CST | Winter Weather Advisory | DVN | 23 hr |
| Jan 12, 6:27 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Jan 13, 2:45 AM CST | Wind Chill Advisory | DVN | 12 hr |
| Jan 13, 3:15 AM CST | Winter Weather Advisory | DVN | 36 hr |
| Jan 13, 6:12 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Jan 13, 11:38 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Jan 14, 3:45 AM CST | Wind Chill Warning | DVN | 56 hr |
| Jan 14, 3:45 AM CST | Wind Chill Advisory | DVN | 11 hr |
| Jan 17, 4:48 PM CST | Winter Weather Advisory | DVN | 7 hr |
| Feb 2, 3:16 PM CST | Wind Chill Advisory | DVN | 19 hr |
| Feb 20, 4:17 AM CST | Winter Weather Advisory | DVN | 35 hr |
| Feb 26, 9:26 AM CST | Mesoscale Discussion | SPC | 2 hr |
| Feb 26, 10:09 AM CST | Dense Fog Advisory | DVN | 4 hr |
| Mar 6, 11:21 AM CST | Flash Flood Watch | DVN | 51 hr |
| Mar 7, 6:51 PM CST | Severe Thunderstorm Warning | DVN | 39 min |
| Mar 7, 8:10 PM CST | Severe Thunderstorm Warning | DVN | 35 min |
| Mar 7, 8:34 PM CST | Severe Thunderstorm Warning | DVN | 23 min |
| Mar 7, 9:31 PM CST | Severe Thunderstorm Warning | DVN | 44 min |
| Mar 8, 5:38 AM CDT | Areal Flood Warning | DVN | 15 hr |
| Mar 9, 4:19 AM CDT | Flash Flood Watch | DVN | 32 hr |
| Mar 9, 11:45 PM CDT | Areal Flood Warning | DVN | 12 hr |
| Mar 10, 4:22 AM CDT | Wind Advisory | DVN | 27 hr |
| Mar 10, 9:25 AM CDT | Dense Fog Advisory | DVN | 4 hr |
| Mar 23, 3:39 PM CDT | Wind Advisory | DVN | 4 hr |
| Mar 27, 11:32 AM CDT | Winter Storm Watch | DVN | 16 hr |
| Mar 28, 3:33 AM CDT | Winter Storm Warning | DVN | 24 hr |
| Apr 21, 11:03 AM CDT | Wind Advisory | DVN | 8 hr |
| Apr 23, 11:42 PM CDT | Dense Fog Advisory | DVN | 8 hr |
| Apr 25, 5:32 PM CDT | Mesoscale Discussion | SPC | 73 min |
| Apr 25, 8:25 PM CDT | Special Weather Statement | DVN | 50 min |
| Apr 26, 3:04 AM CDT | Flash Flood Watch | DVN | 24 hr |
| Apr 26, 6:14 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Apr 26, 8:21 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Apr 26, 11:15 PM CDT | Mesoscale Discussion | SPC | 60 min |
| May 8, 1:05 PM CDT | Mesoscale Discussion | SPC | 85 min |
| May 8, 5:47 PM CDT | Mesoscale Discussion | SPC | 58 min |
| May 8, 6:10 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| May 13, 2:39 PM CDT | Tornado Watch | SPC | 7 hr |
| May 13, 5:47 PM CDT | Mesoscale Discussion | SPC | 88 min |
| May 13, 7:05 PM CDT | Mesoscale Discussion | SPC | 85 min |
| May 14, 3:19 PM CDT | Flash Flood Watch | DVN | 31 hr |
| May 15, 9:52 AM CDT | Flash Flood Warning | DVN | 6 hr |
| May 15, 3:32 PM CDT | Areal Flood Warning | DVN | 16 hr |
| Jun 1, 3:29 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 1, 5:25 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 1, 9:27 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Jun 7, 4:45 AM CDT | Mesoscale Discussion | SPC | 30 min |
| Jun 7, 5:31 PM CDT | Mesoscale Discussion | SPC | 59 min |
| Jun 7, 8:49 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jun 7, 9:58 PM CDT | Special Weather Statement | DVN | 62 min |
| Jun 7, 10:26 PM CDT | Severe Thunderstorm Warning | DVN | 64 min |
| Jun 7, 11:09 PM CDT | Severe Thunderstorm Warning | DVN | 51 min |
| Jun 7, 11:09 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 8, 3:25 AM CDT | Mesoscale Discussion | SPC | 65 min |
| Jun 17, 4:30 AM CDT | Dense Fog Advisory | DVN | 4 hr |
| Jun 17, 11:53 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 18, 1:01 AM CDT | Mesoscale Discussion | SPC | 89 min |
| Jun 18, 1:47 AM CDT | Severe Thunderstorm Warning | DVN | 58 min |
| Jun 18, 2:48 AM CDT | Severe Thunderstorm Warning | DVN | 42 min |
| Jun 18, 3:20 AM CDT | Mesoscale Discussion | SPC | 85 min |
| Jun 19, 7:14 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 19, 12:37 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Jun 19, 1:54 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Jun 19, 2:24 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 19, 4:24 PM CDT | Severe Thunderstorm Warning | DVN | 54 min |
| Jun 22, 1:29 AM CDT | Special Weather Statement | DVN | 61 min |
| Jun 22, 1:55 AM CDT | Severe Thunderstorm Warning | DVN | 50 min |
| Jun 22, 2:45 AM CDT | Severe Thunderstorm Warning | DVN | 60 min |
| Jun 22, 12:07 PM CDT | Heat Advisory | DVN | 7 hr |
| Jun 22, 3:25 PM CDT | Heat Advisory | DVN | 29 hr |
| Jun 23, 3:21 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Jun 23, 5:19 PM CDT | Severe Thunderstorm Warning | DVN | 71 min |
| Jun 23, 5:52 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jun 23, 6:06 PM CDT | Severe Thunderstorm Warning | DVN | 69 min |
| Jun 24, 3:57 AM CDT | Heat Advisory | DVN | 11 hr |
| Jun 25, 10:40 AM CDT | Heat Advisory | DVN | 9 hr |
| Jun 25, 12:48 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 27, 1:19 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jun 27, 2:41 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 7, 4:25 PM CDT | Special Weather Statement | DVN | 50 min |
| Jul 7, 4:42 PM CDT | Special Weather Statement | DVN | 108 min |
| Jul 7, 6:06 PM CDT | Special Weather Statement | DVN | 114 min |
| Jul 15, 12:50 AM CDT | Mesoscale Discussion | SPC | 85 min |
| Jul 15, 1:18 AM CDT | Special Weather Statement | DVN | 3 hr |
| Jul 15, 2:15 AM CDT | Flash Flood Warning | DVN | 5 hr |
| Jul 15, 5:06 AM CDT | Special Weather Statement | DVN | 69 min |
| Jul 15, 5:50 AM CDT | Special Weather Statement | DVN | 85 min |
| Jul 23, 5:30 PM CDT | Special Weather Statement | DVN | 60 min |
| Jul 23, 6:45 PM CDT | Special Weather Statement | DVN | 60 min |
| Jul 24, 9:22 PM CDT | Mesoscale Discussion | SPC | 53 min |
| Jul 24, 9:51 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 4, 7:11 AM CDT | Mesoscale Discussion | SPC | 94 min |
| Aug 8, 2:43 AM CDT | Heat Advisory | DVN | 40 hr |
| Aug 9, 9:55 AM CDT | Mesoscale Discussion | SPC | 35 min |
| Aug 9, 5:49 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 9, 5:52 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 9, 8:30 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Aug 17, 1:22 AM CDT | Mesoscale Discussion | SPC | 83 min |
| Aug 17, 3:49 AM CDT | Flash Flood Watch | DVN | 11 hr |
| Aug 26, 9:10 AM CDT | Flash Flood Watch | DVN | 42 hr |
| Aug 27, 12:57 AM CDT | Flash Flood Warning | DVN | 6 hr |
| Aug 27, 5:53 PM CDT | Flash Flood Warning | DVN | 6 hr |
| Sep 9, 9:22 PM CDT | Dense Fog Advisory | DVN | 13 hr |
| Sep 10, 3:10 PM CDT | Dense Fog Advisory | DVN | 18 hr |
| Sep 23, 4:12 AM CDT | Dense Fog Advisory | DVN | 6 hr |
| Oct 9, 4:02 AM CDT | Frost Advisory | DVN | 17 hr |
| Oct 9, 4:02 AM CDT | Freeze Watch | DVN | 18 hr |
| Oct 9, 4:02 AM CDT | Freeze Warning | DVN | 29 hr |
| Oct 29, 2:46 PM CDT | Flash Flood Watch | DVN | 13 hr |
| Nov 16, 4:01 AM CST | Flood Watch | DVN | 33 hr |
| Nov 20, 9:28 PM CST | Dense Fog Advisory | DVN | 13 hr |
| Dec 6, 3:14 PM CST | Winter Storm Watch | DVN | 25 hr |
| Dec 7, 3:46 AM CST | Blizzard Watch | DVN | 34 hr |
| Dec 7, 3:45 PM CST | Winter Storm Warning | DVN | 50 hr |
| Dec 8, 11:22 AM CST | Mesoscale Discussion | SPC | 5 hr |
| Dec 8, 1:55 PM CST | Blizzard Warning | DVN | 28 hr |
| Dec 8, 2:31 PM CST | Special Weather Statement | DVN | 3 hr |
| Dec 8, 3:53 PM CST | Special Weather Statement | DVN | 2 hr |
| Dec 8, 6:00 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Dec 8, 9:38 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Dec 9, 10:22 AM CST | Mesoscale Discussion | SPC | 4 hr |
| Dec 9, 3:41 PM CST | Winter Weather Advisory | DVN | 12 hr |
| Dec 10, 3:16 AM CST | Wind Chill Advisory | DVN | 9 hr |
| Dec 14, 3:32 AM CST | Dense Fog Advisory | DVN | 8 hr |
| Dec 21, 3:18 PM CST | Winter Storm Watch | DVN | 3 days |
| Dec 22, 3:47 PM CST | Flood Watch | DVN | 62 hr |
| Dec 27, 2:30 AM CST | Winter Weather Advisory | DVN | 12 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 | 13 |
| Severe Thunderstorm Watch | 11 |
| Tornado Watch | 1 |
| Mesoscale Discussion | 35 |
| Special Weather Statement | 13 |
| Flooding | |
| Areal Flood Warning | 3 |
| Flash Flood Warning | 4 |
| Flash Flood Watch | 7 |
| Flood Watch | 2 |
| Winter | |
| Blizzard Warning | 1 |
| Winter Storm Warning | 2 |
| Blizzard Watch | 2 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 6 |
| Heat | |
| Heat Advisory | 5 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Warning | 1 |
| Freeze Watch | 1 |
| Frost Advisory | 1 |
| Wind Chill Advisory | 4 |
| Wind and dust | |
| Wind Advisory | 3 |
| Fog and smoke | |
| Dense Fog Advisory | 10 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20082010
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.