Alert archive / Montana / Yellowstone County
Weather alerts in Yellowstone County, Montana, 2018
132 weather alerts in 2018, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Yellowstone County and its neighbors
Each county as a circle sized by its count in 2018. Tap one for its archive.
- Alerts
- 132
- Warnings
- 24
- Watches
- 6
- Advisories
- 10
- Busiest month
- June30 alerts
- Busiest day
- May 23, 201810 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Yellowstone County, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 20 | 12 | 40% | 23 | 65% | 17 min |
| Flash flood warnings | 1 | 1 | 0% | 1 | 100% | 6 min |
Each office's whole area, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Billings, MT: tornado warnings | 2 | 2 | 0% | 5 | 60% | 23 min |
| NWS Billings, MT: severe thunderstorm warnings | 176 | 84 | 52% | 213 | 73% | 23 min |
| NWS Billings, MT: flash flood warnings | 8 | 6 | 25% | 7 | 86% | 44 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 |
|---|---|---|---|
| Jan 2, 6:44 AM MST | Special Weather Statement | BYZ | 2 hr |
| Jan 14, 1:54 PM MST | Special Weather Statement | BYZ | 81 min |
| Jan 14, 3:29 PM MST | Special Weather Statement | BYZ | 106 min |
| Jan 14, 6:57 PM MST | Special Weather Statement | BYZ | 18 min |
| Jan 14, 7:19 PM MST | Special Weather Statement | BYZ | 3 hr |
| Jan 19, 4:59 AM MST | Special Weather Statement | BYZ | 3 hr |
| Jan 31, 2:01 PM MST | Special Weather Statement | BYZ | 119 min |
| Jan 31, 3:49 PM MST | Special Weather Statement | BYZ | 116 min |
| Feb 6, 4:55 PM MST | Special Weather Statement | BYZ | 65 min |
| Feb 6, 5:14 PM MST | Special Weather Statement | BYZ | 46 min |
| Feb 17, 9:42 PM MST | Special Weather Statement | BYZ | 3 hr |
| Mar 9, 7:01 PM MST | Special Weather Statement | BYZ | 59 min |
| Mar 28, 12:56 PM MDT | Special Weather Statement | BYZ | 49 min |
| Apr 7, 10:18 PM MDT | Special Weather Statement | BYZ | 117 min |
| May 6, 7:54 PM MDT | Special Weather Statement | BYZ | 36 min |
| May 7, 1:52 PM MDT | Special Weather Statement | BYZ | 38 min |
| May 7, 2:04 PM MDT | Severe Thunderstorm Warning | BYZ | 56 min |
| May 7, 2:49 PM MDT | Mesoscale Discussion | SPC | 116 min |
| May 7, 3:00 PM MDT | Severe Thunderstorm Warning | BYZ | 60 min |
| May 10, 10:42 PM MDT | Special Weather Statement | BYZ | 48 min |
| May 17, 4:05 PM MDT | Special Weather Statement | BYZ | 40 min |
| May 17, 5:12 PM MDT | Areal Flood Advisory | BYZ | 3 hr |
| May 22, 12:40 PM MDT | Flood Watch | BYZ | 35 hr |
| May 22, 6:07 PM MDT | Special Weather Statement | BYZ | 38 min |
| May 22, 8:43 PM MDT | Areal Flood Advisory | BYZ | 3 hr |
| May 23, 5:00 AM MDT | Areal Flood Advisory | BYZ | 7 hr |
| May 23, 12:14 PM MDT | River Flood Watch | BYZ | 3 days |
| May 23, 1:25 PM MDT | Special Weather Statement | BYZ | 50 min |
| May 23, 3:31 PM MDT | Special Weather Statement | BYZ | 44 min |
| May 23, 3:49 PM MDT | Severe Thunderstorm Warning | BYZ | 56 min |
| May 23, 3:58 PM MDT | Special Weather Statement | BYZ | 47 min |
| May 23, 4:12 PM MDT | Severe Thunderstorm Warning | BYZ | 48 min |
| May 23, 4:29 PM MDT | Severe Thunderstorm Warning | BYZ | 61 min |
| May 23, 6:12 PM MDT | Severe Thunderstorm Warning | BYZ | 63 min |
| May 26, 11:28 AM MDT | River Flood Warning | BYZ | 3 days |
| May 26, 2:21 PM MDT | Mesoscale Discussion | SPC | 114 min |
| May 26, 6:32 PM MDT | Special Weather Statement | BYZ | 28 min |
| May 28, 12:19 PM MDT | Special Weather Statement | BYZ | 26 min |
| May 28, 12:35 PM MDT | Areal Flood Advisory | BYZ | 3 hr |
| May 28, 3:30 PM MDT | Areal Flood Advisory | BYZ | 4 hr |
| May 31, 1:50 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 31, 5:07 PM MDT | Areal Flood Advisory | BYZ | 48 min |
| May 31, 5:27 PM MDT | Mesoscale Discussion | SPC | 93 min |
| May 31, 8:18 PM MDT | Mesoscale Discussion | SPC | 57 min |
| May 31, 10:54 PM MDT | Special Weather Statement | BYZ | 36 min |
| May 31, 11:19 PM MDT | Areal Flood Warning | BYZ | 75 min |
| May 31, 11:33 PM MDT | Special Weather Statement | BYZ | 42 min |
| Jun 1, 7:41 AM MDT | Areal Flood Advisory | BYZ | 3 hr |
| Jun 1, 8:08 AM MDT | Special Weather Statement | BYZ | 22 min |
| Jun 1, 9:36 AM MDT | Special Weather Statement | BYZ | 39 min |
| Jun 1, 6:07 PM MDT | Special Weather Statement | BYZ | 23 min |
| Jun 4, 1:47 PM MDT | Mesoscale Discussion | SPC | 118 min |
| Jun 4, 7:02 PM MDT | Severe Thunderstorm Warning | BYZ | 34 min |
| Jun 7, 3:10 PM MDT | Special Weather Statement | BYZ | 65 min |
| Jun 7, 3:59 PM MDT | Special Weather Statement | BYZ | 61 min |
| Jun 7, 5:27 PM MDT | Severe Thunderstorm Warning | BYZ | 48 min |
| Jun 7, 11:10 PM MDT | Special Weather Statement | BYZ | 35 min |
| Jun 16, 6:25 PM MDT | Special Weather Statement | BYZ | 50 min |
| Jun 18, 11:49 AM MDT | Special Weather Statement | BYZ | 41 min |
| Jun 18, 6:21 PM MDT | Special Weather Statement | BYZ | 69 min |
| Jun 19, 8:13 PM MDT | Areal Flood Advisory | BYZ | 10 hr |
| Jun 19, 9:26 PM MDT | Special Weather Statement | BYZ | 64 min |
| Jun 19, 10:25 PM MDT | Areal Flood Advisory | BYZ | 3 hr |
| Jun 21, 2:28 PM MDT | Mesoscale Discussion | SPC | 92 min |
| Jun 21, 5:29 PM MDT | Special Weather Statement | BYZ | 46 min |
| Jun 21, 6:16 PM MDT | Special Weather Statement | BYZ | 44 min |
| Jun 22, 2:22 PM MDT | Areal Flood Advisory | BYZ | 3 hr |
| Jun 25, 5:29 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 26, 4:48 PM MDT | Special Weather Statement | BYZ | 42 min |
| Jun 26, 4:51 PM MDT | Severe Thunderstorm Warning | BYZ | 54 min |
| Jun 26, 5:34 PM MDT | Special Weather Statement | BYZ | 41 min |
| Jun 28, 7:08 PM MDT | Special Weather Statement | BYZ | 22 min |
| Jun 29, 7:07 PM MDT | Special Weather Statement | BYZ | 38 min |
| Jul 2, 5:58 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 2, 6:57 PM MDT | Severe Thunderstorm Warning | BYZ | 63 min |
| Jul 2, 6:59 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 2, 7:13 PM MDT | Special Weather Statement | BYZ | 47 min |
| Jul 2, 7:25 PM MDT | Severe Thunderstorm Warning | BYZ | 65 min |
| Jul 2, 7:55 PM MDT | Severe Thunderstorm Warning | BYZ | 65 min |
| Jul 2, 8:44 PM MDT | Severe Thunderstorm Warning | BYZ | 61 min |
| Jul 2, 8:50 PM MDT | Mesoscale Discussion | SPC | 115 min |
| Jul 3, 5:46 PM MDT | Special Weather Statement | BYZ | 59 min |
| Jul 3, 6:45 PM MDT | Special Weather Statement | BYZ | 45 min |
| Jul 10, 1:50 PM MDT | Mesoscale Discussion | SPC | 115 min |
| Jul 10, 2:14 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 10, 4:37 PM MDT | Special Weather Statement | BYZ | 53 min |
| Jul 10, 5:37 PM MDT | Special Weather Statement | BYZ | 53 min |
| Jul 10, 6:32 PM MDT | Mesoscale Discussion | SPC | 118 min |
| Jul 17, 3:39 PM MDT | Special Weather Statement | BYZ | 66 min |
| Jul 17, 4:42 PM MDT | Special Weather Statement | BYZ | 33 min |
| Jul 17, 5:51 PM MDT | Special Weather Statement | BYZ | 54 min |
| Jul 18, 5:16 PM MDT | Special Weather Statement | BYZ | 59 min |
| Jul 21, 8:06 PM MDT | Special Weather Statement | BYZ | 54 min |
| Jul 21, 8:16 PM MDT | Severe Thunderstorm Warning | BYZ | 29 min |
| Jul 26, 2:41 AM MDT | Special Weather Statement | BYZ | 49 min |
| Jul 26, 3:12 AM MDT | Special Weather Statement | BYZ | 48 min |
| Jul 26, 1:10 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 27, 3:45 PM MDT | Severe Thunderstorm Warning | BYZ | 30 min |
| Jul 27, 4:08 PM MDT | Severe Thunderstorm Warning | BYZ | 52 min |
| Jul 27, 4:37 PM MDT | Flash Flood Warning | BYZ | 82 min |
| Jul 27, 4:54 PM MDT | Severe Thunderstorm Warning | BYZ | 66 min |
| Jul 28, 5:33 PM MDT | Special Weather Statement | BYZ | 42 min |
| Jul 28, 6:12 PM MDT | Special Weather Statement | BYZ | 48 min |
| Aug 2, 2:32 PM MDT | Severe Thunderstorm Warning | BYZ | 28 min |
| Aug 2, 2:40 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 2, 2:57 PM MDT | Severe Thunderstorm Warning | BYZ | 48 min |
| Aug 2, 3:42 PM MDT | Special Weather Statement | BYZ | 48 min |
| Aug 2, 7:51 PM MDT | Special Weather Statement | BYZ | 39 min |
| Aug 3, 1:48 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Aug 3, 4:13 PM MDT | Special Weather Statement | BYZ | 47 min |
| Aug 3, 4:51 PM MDT | Severe Thunderstorm Warning | BYZ | 39 min |
| Aug 3, 5:45 PM MDT | Special Weather Statement | BYZ | 30 min |
| Aug 9, 2:50 PM MDT | Fire Weather Watch | BYZ | 37 hr |
| Aug 11, 3:28 AM MDT | Red Flag Warning | BYZ | 42 hr |
| Aug 11, 10:34 PM MDT | Special Weather Statement | BYZ | 56 min |
| Aug 11, 11:29 PM MDT | Special Weather Statement | BYZ | 46 min |
| Aug 14, 10:20 AM MDT | Special Weather Statement | BYZ | 40 min |
| Aug 17, 10:30 PM MDT | Special Weather Statement | BYZ | 60 min |
| Aug 20, 6:37 AM MDT | Special Weather Statement | BYZ | 38 min |
| Aug 20, 7:25 AM MDT | Special Weather Statement | BYZ | 50 min |
| Aug 22, 8:11 AM MDT | Special Weather Statement | BYZ | 2 hr |
| Aug 24, 4:54 PM MDT | Special Weather Statement | BYZ | 36 min |
| Aug 24, 6:47 PM MDT | Special Weather Statement | BYZ | 43 min |
| Aug 24, 7:36 PM MDT | Special Weather Statement | BYZ | 39 min |
| Aug 30, 3:20 PM MDT | Special Weather Statement | BYZ | 40 min |
| Sep 8, 3:56 PM MDT | Special Weather Statement | BYZ | 49 min |
| Sep 20, 4:18 PM MDT | Special Weather Statement | BYZ | 42 min |
| Sep 23, 8:04 AM MDT | Special Weather Statement | BYZ | 4 hr |
| Sep 30, 9:51 AM MDT | Special Weather Statement | BYZ | 54 min |
| Nov 25, 4:48 AM MST | Special Weather Statement | BYZ | 5 hr |
| Dec 3, 9:42 AM MST | Special Weather Statement | BYZ | 108 min |
| Dec 30, 8:48 PM MST | Mesoscale Discussion | SPC | 5 hr |
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 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.