Alert archive / North Dakota / Nelson County
Weather alerts in Nelson County, North Dakota, 2017
101 weather alerts in 2017, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Nelson County and its neighbors
Each county as a circle sized by its count in 2017. Tap one for its archive.
- Alerts
- 101
- Warnings
- 21
- Watches
- 11
- Advisories
- 45
- Busiest month
- June20 alerts
- Busiest day
- June 10, 201710 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 Nelson County in 2017 had a tornado report inside them; 0 of 5 tornado reports fell inside a warning.
Nelson County, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 4 | 2 | 50% | 5 | 0% | |
| Severe thunderstorm warnings | 6 | 5 | 17% | 7 | 57% | 5 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 Grand Forks, ND: tornado warnings | 39 | 24 | 38% | 67 | 67% | 15 min |
| NWS Grand Forks, ND: severe thunderstorm warnings | 148 | 137 | 7% | 435 | 76% | 26 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 1, 3:27 PM CST | Winter Weather Advisory | FGF | 45 hr |
| Jan 2, 4:14 AM CST | Winter Storm Warning | FGF | 32 hr |
| Jan 3, 2:18 PM CST | Wind Chill Advisory | FGF | 70 hr |
| Jan 6, 2:54 PM CST | Wind Chill Advisory | FGF | 21 hr |
| Jan 7, 3:30 PM CST | Wind Chill Advisory | FGF | 18 hr |
| Jan 8, 3:30 PM CST | Wind Chill Advisory | FGF | 12 hr |
| Jan 10, 2:55 PM CST | Wind Chill Advisory | FGF | 45 hr |
| Jan 11, 3:33 PM CST | Winter Weather Advisory | FGF | 23 hr |
| Jan 12, 9:35 AM CST | Blizzard Warning | FGF | 3 hr |
| Jan 12, 2:49 PM CST | Wind Chill Warning | FGF | 21 hr |
| Jan 20, 6:03 PM CST | Dense Fog Advisory | FGF | 18 hr |
| Jan 21, 5:53 PM CST | Dense Fog Advisory | FGF | 18 hr |
| Jan 30, 4:14 AM CST | Wind Advisory | FGF | 15 hr |
| Feb 6, 3:11 PM CST | Winter Weather Advisory | FGF | 22 hr |
| Feb 7, 2:22 PM CST | Wind Chill Advisory | FGF | 43 hr |
| Feb 20, 12:46 AM CST | Dense Fog Advisory | FGF | 8 hr |
| Feb 21, 6:43 PM CST | Dense Fog Advisory | FGF | 8 hr |
| Mar 6, 6:34 AM CST | Dense Fog Advisory | FGF | 4 hr |
| Mar 6, 11:19 AM CST | Dense Fog Advisory | FGF | 4 hr |
| Mar 6, 3:33 PM CST | Wind Advisory | FGF | 41 hr |
| Mar 7, 3:40 AM CST | High Wind Warning | FGF | 17 hr |
| Mar 7, 6:14 PM CST | Wind Advisory | FGF | 15 hr |
| Mar 9, 3:34 AM CST | Wind Chill Advisory | FGF | 29 hr |
| Mar 26, 11:49 PM CDT | Dense Fog Advisory | FGF | 14 hr |
| Mar 27, 8:46 PM CDT | Dense Fog Advisory | FGF | 15 hr |
| Apr 21, 5:14 AM CDT | Dense Fog Advisory | FGF | 5 hr |
| Apr 24, 3:51 AM CDT | Winter Weather Advisory | FGF | 12 hr |
| May 17, 3:41 PM CDT | Frost Advisory | FGF | 17 hr |
| May 18, 3:11 PM CDT | Frost Advisory | FGF | 17 hr |
| Jun 2, 3:39 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 9, 3:26 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 9, 4:58 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 9, 7:08 PM CDT | Mesoscale Discussion | SPC | 67 min |
| Jun 9, 8:15 PM CDT | Tornado Warning | FGF | 45 min |
| Jun 9, 8:16 PM CDT | Tornado Warning | FGF | 44 min |
| Jun 9, 8:38 PM CDT | Severe Thunderstorm Warning | FGF | 38 min |
| Jun 9, 8:58 PM CDT | Tornado Warning | FGF | 15 min |
| Jun 9, 9:30 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Jun 10, 4:08 AM CDT | Severe Thunderstorm Warning | FGF | 37 min |
| Jun 10, 5:40 AM CDT | Severe Thunderstorm Warning | FGF | 50 min |
| Jun 10, 6:07 AM CDT | Severe Thunderstorm Warning | FGF | 38 min |
| Jun 10, 6:49 AM CDT | Special Weather Statement | FGF | 41 min |
| Jun 13, 5:43 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 13, 5:56 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 19, 1:42 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 22, 2:45 PM CDT | Wind Advisory | FGF | 7 hr |
| Jun 28, 12:14 AM CDT | Special Weather Statement | FGF | 61 min |
| Jun 29, 4:36 AM CDT | Dense Fog Advisory | FGF | 4 hr |
| Jun 29, 2:41 PM CDT | Special Weather Statement | FGF | 34 min |
| Jul 4, 3:33 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 4, 6:03 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 5, 5:52 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 5, 9:51 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Jul 5, 10:12 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 11, 3:48 PM CDT | Mesoscale Discussion | SPC | 87 min |
| Jul 11, 4:48 PM CDT | Tornado Watch | SPC | 6 hr |
| Jul 11, 5:09 PM CDT | Severe Thunderstorm Warning | FGF | 66 min |
| Jul 14, 3:03 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Jul 19, 7:01 AM CDT | Mesoscale Discussion | SPC | 119 min |
| Jul 21, 9:42 AM CDT | Mesoscale Discussion | SPC | 93 min |
| Jul 21, 2:20 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 21, 3:07 PM CDT | Severe Thunderstorm Watch | SPC | 10 hr |
| Jul 21, 3:53 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Jul 21, 10:34 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jul 22, 12:36 AM CDT | Special Weather Statement | FGF | 24 min |
| Jul 31, 3:43 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 1, 5:40 PM CDT | Tornado Warning | FGF | 35 min |
| Sep 1, 6:12 PM CDT | Severe Thunderstorm Warning | FGF | 33 min |
| Sep 19, 1:51 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Sep 19, 3:37 PM CDT | Tornado Watch | SPC | 8 hr |
| Sep 19, 6:36 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Sep 19, 8:56 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 4, 3:06 PM CDT | Frost Advisory | FGF | 18 hr |
| Oct 5, 2:51 PM CDT | Frost Advisory | FGF | 18 hr |
| Oct 8, 3:23 PM CDT | Freeze Warning | FGF | 18 hr |
| Oct 9, 3:01 AM CDT | Freeze Warning | FGF | 30 hr |
| Oct 17, 2:23 PM CDT | Wind Advisory | FGF | 29 hr |
| Oct 17, 2:32 PM CDT | Fire Weather Watch | FGF | 13 hr |
| Oct 18, 3:41 AM CDT | Red Flag Warning | FGF | 15 hr |
| Oct 24, 3:32 PM CDT | Winter Storm Watch | FGF | 37 hr |
| Oct 25, 3:15 PM CDT | High Wind Warning | FGF | 31 hr |
| Oct 30, 3:52 AM CDT | Wind Advisory | FGF | 13 hr |
| Nov 3, 3:30 AM CDT | Winter Weather Advisory | FGF | 43 hr |
| Nov 10, 10:55 AM CST | Wind Advisory | FGF | 4 hr |
| Nov 16, 7:55 PM CST | Winter Weather Advisory | FGF | 10 hr |
| Nov 17, 3:02 AM CST | Winter Weather Advisory | FGF | 2 hr |
| Nov 20, 10:59 AM CST | Wind Advisory | FGF | 19 hr |
| Nov 28, 3:23 AM CST | Wind Advisory | FGF | 15 hr |
| Nov 29, 3:07 AM CST | Wind Advisory | FGF | 14 hr |
| Nov 29, 5:03 PM CST | Wind Advisory | FGF | 7 hr |
| Dec 3, 3:54 AM CST | Winter Storm Watch | FGF | 24 hr |
| Dec 3, 3:14 PM CST | Blizzard Warning | FGF | 28 hr |
| Dec 4, 4:14 AM CST | Winter Weather Advisory | FGF | 14 hr |
| Dec 12, 3:02 PM CST | Winter Weather Advisory | FGF | 21 hr |
| Dec 13, 2:03 AM CST | Wind Advisory | FGF | 10 hr |
| Dec 19, 2:14 PM CST | Winter Weather Advisory | FGF | 38 hr |
| Dec 23, 9:41 PM CST | Wind Chill Watch | FGF | 13 hr |
| Dec 24, 10:55 AM CST | Wind Chill Warning | FGF | 49 hr |
| Dec 24, 10:55 AM CST | Wind Chill Advisory | FGF | 3 days |
| Dec 28, 3:42 PM CST | Wind Chill Advisory | FGF | 26 hr |
| Dec 29, 2:37 AM CST | Wind Chill Warning | FGF | 3 days |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
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.