Alert archive / Montana / Jefferson County
Weather alerts in Jefferson County, Montana, 2019
103 weather alerts in 2019, 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 2019. Tap one for its archive.
- Alerts
- 103
- Warnings
- 36
- Watches
- 8
- Advisories
- 3
- Busiest month
- July43 alerts
- Busiest day
- August 11, 201913 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, 2019
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 22 | 10 | 55% | 12 | 58% | 6 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2019
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Great Falls, MT: tornado warnings | 4 | 1 | 75% | 1 | 100% | 2 min |
| NWS Great Falls, MT: severe thunderstorm warnings | 135 | 58 | 57% | 163 | 66% | 18 min |
| NWS Great Falls, MT: flash flood warnings | 3 | 3 | 0% | 5 | 100% | 29 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, Mountain Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Feb 24, 4:44 PM MST | Mesoscale Discussion | SPC | 6 hr |
| Feb 28, 4:16 PM MST | Special Weather Statement | TFX | 59 min |
| Mar 1, 1:32 PM MST | Special Weather Statement | TFX | 88 min |
| Mar 1, 4:08 PM MST | Special Weather Statement | TFX | 52 min |
| Mar 25, 5:48 PM MDT | Areal Flood Advisory | TFX | 40 hr |
| Mar 27, 9:31 AM MDT | Areal Flood Advisory | TFX | 6 days |
| Apr 2, 2:40 PM MDT | Areal Flood Advisory | TFX | 46 hr |
| Apr 17, 1:46 PM MDT | Special Weather Statement | TFX | 119 min |
| May 26, 4:22 PM MDT | Special Weather Statement | TFX | 53 min |
| Jun 2, 3:42 PM MDT | Special Weather Statement | TFX | 33 min |
| Jun 6, 1:54 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 12, 10:34 PM MDT | Special Weather Statement | TFX | 56 min |
| Jun 26, 1:48 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Jun 26, 2:16 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 26, 6:03 PM MDT | Mesoscale Discussion | SPC | 57 min |
| Jun 27, 12:31 PM MDT | Mesoscale Discussion | SPC | 119 min |
| Jun 27, 1:11 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 27, 1:21 PM MDT | Severe Thunderstorm Warning | TFX | 24 min |
| Jun 27, 1:45 PM MDT | Severe Thunderstorm Warning | TFX | 30 min |
| Jun 27, 2:27 PM MDT | Severe Thunderstorm Warning | TFX | 33 min |
| Jun 27, 2:31 PM MDT | Severe Thunderstorm Warning | TFX | 29 min |
| Jun 27, 2:51 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Jun 27, 2:57 PM MDT | Severe Thunderstorm Warning | TFX | 20 min |
| Jul 2, 6:59 PM MDT | Special Weather Statement | TFX | 31 min |
| Jul 3, 12:22 PM MDT | Special Weather Statement | TFX | 38 min |
| Jul 6, 2:31 PM MDT | Special Weather Statement | TFX | 44 min |
| Jul 6, 3:11 PM MDT | Special Weather Statement | TFX | 34 min |
| Jul 6, 3:52 PM MDT | Mesoscale Discussion | SPC | 113 min |
| Jul 7, 2:58 PM MDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 11, 1:44 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 12, 6:06 PM MDT | Special Weather Statement | TFX | 9 min |
| Jul 12, 6:13 PM MDT | Severe Thunderstorm Warning | TFX | 47 min |
| Jul 12, 6:53 PM MDT | Severe Thunderstorm Warning | TFX | 23 min |
| Jul 12, 7:13 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 12, 7:30 PM MDT | Severe Thunderstorm Warning | TFX | 45 min |
| Jul 12, 7:41 PM MDT | Special Weather Statement | TFX | 19 min |
| Jul 12, 8:09 PM MDT | Special Weather Statement | TFX | 21 min |
| Jul 13, 1:06 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Jul 13, 3:58 PM MDT | Special Weather Statement | TFX | 47 min |
| Jul 14, 2:10 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 14, 4:05 PM MDT | Severe Thunderstorm Warning | TFX | 25 min |
| Jul 14, 6:31 PM MDT | Special Weather Statement | TFX | 29 min |
| Jul 14, 6:55 PM MDT | Special Weather Statement | TFX | 35 min |
| Jul 14, 7:53 PM MDT | Severe Thunderstorm Warning | TFX | 37 min |
| Jul 14, 8:32 PM MDT | Special Weather Statement | TFX | 28 min |
| Jul 16, 6:16 PM MDT | Severe Thunderstorm Warning | TFX | 44 min |
| Jul 16, 7:40 PM MDT | Severe Thunderstorm Warning | TFX | 50 min |
| Jul 16, 8:35 PM MDT | Special Weather Statement | TFX | 25 min |
| Jul 16, 8:48 PM MDT | Severe Thunderstorm Warning | TFX | 27 min |
| Jul 16, 9:15 PM MDT | Special Weather Statement | TFX | 30 min |
| Jul 16, 10:36 PM MDT | Special Weather Statement | TFX | 39 min |
| Jul 16, 11:14 PM MDT | Special Weather Statement | TFX | 46 min |
| Jul 23, 12:46 PM MDT | Fire Weather Watch | TFX | 14 hr |
| Jul 23, 4:13 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 24, 2:39 AM MDT | Red Flag Warning | TFX | 42 hr |
| Jul 26, 1:34 PM MDT | Red Flag Warning | TFX | 31 hr |
| Jul 26, 2:33 PM MDT | Red Flag Warning | MSO | 29 hr |
| Jul 28, 8:54 AM MDT | Red Flag Warning | TFX | 39 hr |
| Jul 28, 2:12 PM MDT | Red Flag Warning | MSO | 31 hr |
| Jul 29, 2:07 PM MDT | Red Flag Warning | TFX | 31 hr |
| Jul 29, 5:40 PM MDT | Special Weather Statement | TFX | 35 min |
| Jul 29, 6:30 PM MDT | Special Weather Statement | TFX | 45 min |
| Jul 30, 5:13 AM MDT | Red Flag Warning | MSO | 16 hr |
| Jul 30, 5:11 PM MDT | Severe Thunderstorm Warning | TFX | 45 min |
| Jul 31, 3:05 AM MDT | Red Flag Warning | TFX | 18 hr |
| Jul 31, 4:47 AM MDT | Red Flag Warning | MSO | 16 hr |
| Aug 1, 2:15 PM MDT | Red Flag Warning | TFX | 33 hr |
| Aug 1, 2:31 PM MDT | Red Flag Warning | MSO | 32 hr |
| Aug 1, 6:50 PM MDT | Special Weather Statement | TFX | 40 min |
| Aug 7, 2:29 PM MDT | Fire Weather Watch | MSO | 13 hr |
| Aug 8, 3:12 AM MDT | Red Flag Warning | MSO | 18 hr |
| Aug 10, 11:41 AM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 10, 1:36 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 10, 4:17 PM MDT | Special Weather Statement | TFX | 43 min |
| Aug 10, 4:24 PM MDT | Severe Thunderstorm Warning | TFX | 36 min |
| Aug 10, 4:53 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 10, 5:01 PM MDT | Special Weather Statement | TFX | 44 min |
| Aug 10, 5:16 PM MDT | Severe Thunderstorm Warning | TFX | 29 min |
| Aug 10, 5:25 PM MDT | Severe Thunderstorm Warning | TFX | 35 min |
| Aug 10, 5:48 PM MDT | Severe Thunderstorm Warning | TFX | 27 min |
| Aug 10, 6:14 PM MDT | Severe Thunderstorm Warning | TFX | 31 min |
| Aug 10, 7:42 PM MDT | Special Weather Statement | TFX | 33 min |
| Aug 10, 7:58 PM MDT | Severe Thunderstorm Warning | TFX | 18 min |
| Aug 10, 8:34 PM MDT | Mesoscale Discussion | SPC | 86 min |
| Aug 11, 7:45 AM MDT | Special Weather Statement | TFX | 30 min |
| Aug 11, 8:13 AM MDT | Severe Thunderstorm Warning | TFX | 32 min |
| Aug 11, 11:33 AM MDT | Mesoscale Discussion | SPC | 87 min |
| Aug 11, 12:11 PM MDT | Special Weather Statement | TFX | 19 min |
| Aug 11, 12:27 PM MDT | Special Weather Statement | TFX | 18 min |
| Aug 11, 12:34 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 11, 12:44 PM MDT | Special Weather Statement | TFX | 31 min |
| Aug 11, 2:43 PM MDT | Mesoscale Discussion | SPC | 92 min |
| Aug 11, 3:17 PM MDT | Severe Thunderstorm Warning | TFX | 28 min |
| Aug 21, 5:14 PM MDT | Special Weather Statement | MSO | 31 min |
| Sep 2, 3:03 PM MDT | Fire Weather Watch | TFX | 19 hr |
| Sep 3, 10:08 AM MDT | Red Flag Warning | TFX | 34 hr |
| Sep 3, 1:44 PM MDT | Red Flag Warning | MSO | 30 hr |
| Sep 6, 4:29 PM MDT | Special Weather Statement | TFX | 46 min |
| Sep 6, 5:22 PM MDT | Special Weather Statement | TFX | 23 min |
| Sep 6, 5:45 PM MDT | Special Weather Statement | TFX | 45 min |
| Oct 22, 2:50 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 22, 7:41 PM MDT | Special Weather Statement | TFX | 34 min |
| Nov 10, 6:32 PM MST | Special Weather Statement | TFX | 88 min |
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 |
| Severe Thunderstorm Watch | 5 |
| Mesoscale Discussion | 18 |
| Special Weather Statement | 38 |
| Flooding | |
| Areal Flood Advisory | 3 |
| Fire | |
| Red Flag Warning | 14 |
| Fire Weather Watch | 3 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20182020
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.