Weather alerts in Valley County, Montana, 2020

213 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Valley County and its neighbors

Each county as a circle sized by its count in 2020. Tap one for its archive.

Alerts: 213
Warnings: 71
Watches: 17
Advisories: 79
Busiest month: July45 alerts
Busiest day: May 21, 202010 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 Valley County in 2020 had a tornado report inside them; 1 of 1 tornado reports fell inside a warning, on average 0 minutes after it went out.

Valley County, 2020

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	2	1	50%	1	100%	0 min
Severe thunderstorm warnings	28	17	39%	54	89%	31 min
Flash flood warnings	0			0

Each office's whole area, 2020

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Glasgow, MT: tornado warnings	3	2	33%	2	100%	0 min
NWS Glasgow, MT: severe thunderstorm warnings	79	46	42%	174	74%	25 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, 2:07 PM MST	High Wind Watch	GGW	25 hr
Jan 3, 2:55 PM MST	High Wind Warning	GGW	36 hr
Jan 12, 3:00 AM MST	Winter Weather Advisory	GGW	41 hr
Jan 13, 2:19 PM MST	Wind Chill Advisory	GGW	6 days
Jan 14, 1:31 PM MST	Wind Chill Warning	GGW	46 hr
Jan 14, 1:31 PM MST	Wind Chill Advisory	GGW	19 hr
Jan 17, 4:35 PM MST	Wind Chill Warning	GGW	19 hr
Jan 17, 4:35 PM MST	Wind Chill Advisory	GGW	42 hr
Jan 19, 2:16 PM MST	Wind Chill Advisory	GGW	18 hr
Jan 27, 10:47 AM MST	Dense Fog Advisory	GGW	10 hr
Jan 31, 3:14 AM MST	Red Flag Warning	GGW	43 hr
Feb 7, 2:07 PM MST	Winter Weather Advisory	GGW	31 hr
Feb 11, 3:06 AM MST	Winter Weather Advisory	GGW	30 hr
Feb 12, 3:17 AM MST	Wind Chill Advisory	GGW	31 hr
Feb 17, 1:30 PM MST	Wind Chill Advisory	GGW	21 hr
Feb 18, 1:45 PM MST	Wind Chill Advisory	GGW	21 hr
Feb 23, 2:53 AM MST	Winter Weather Advisory	GGW	48 hr
Mar 1, 6:35 PM MST	Areal Flood Advisory	GGW	42 hr
Mar 1, 9:06 PM MST	River Flood Warning	GGW	50 hr
Mar 2, 2:06 PM MST	Red Flag Warning	GGW	52 hr
Mar 2, 2:06 PM MST	High Wind Watch	GGW	13 hr
Mar 2, 2:06 PM MST	High Wind Warning	GGW	52 hr
Mar 4, 2:20 PM MST	River Flood Warning	GGW	24 hr
Mar 5, 7:57 AM MST	Areal Flood Advisory	GGW	8 days
Mar 5, 9:29 PM MST	River Flood Warning	GGW	32 hr
Mar 6, 9:45 AM MST	River Flood Warning	GGW	6 days
Mar 7, 1:11 PM MST	River Flood Warning	GGW	58 hr
Mar 7, 1:11 PM MST	River Flood Warning	GGW	5 days
Mar 11, 2:43 PM MDT	Winter Storm Watch	GGW	37 hr
Mar 13, 3:27 AM MDT	Winter Storm Warning	GGW	59 hr
Mar 29, 12:19 PM MDT	Areal Flood Advisory	GGW	60 hr
Mar 31, 3:21 AM MDT	Winter Weather Advisory	GGW	39 hr
Mar 31, 3:41 PM MDT	River Flood Warning	GGW	41 hr
Mar 31, 3:47 PM MDT	River Flood Warning	GGW	41 hr
Apr 17, 3:19 AM MDT	Lake Wind Advisory	GGW	17 hr
Apr 18, 1:52 PM MDT	Lake Wind Advisory	GGW	30 hr
Apr 19, 3:11 AM MDT	Red Flag Warning	GGW	18 hr
Apr 20, 3:20 AM MDT	Lake Wind Advisory	GGW	16 hr
Apr 21, 10:28 AM MDT	Red Flag Warning	GGW	11 hr
Apr 25, 3:05 PM MDT	Fire Weather Watch	GGW	11 hr
Apr 26, 2:28 AM MDT	Lake Wind Advisory	GGW	18 hr
Apr 26, 2:33 AM MDT	Red Flag Warning	GGW	17 hr
Apr 27, 3:04 AM MDT	Fire Weather Watch	GGW	24 hr
Apr 27, 2:41 PM MDT	Lake Wind Advisory	GGW	30 hr
Apr 27, 8:28 PM MDT	Special Weather Statement	GGW	62 min
Apr 27, 8:47 PM MDT	Special Weather Statement	GGW	58 min
Apr 28, 3:13 AM MDT	Red Flag Warning	GGW	18 hr
May 1, 2:56 AM MDT	Lake Wind Advisory	GGW	18 hr
May 3, 3:12 AM MDT	Lake Wind Advisory	GGW	18 hr
May 3, 4:16 PM MDT	Special Weather Statement	GGW	59 min
May 3, 5:01 PM MDT	Special Weather Statement	GGW	59 min
May 6, 3:01 AM MDT	Lake Wind Advisory	GGW	20 hr
May 8, 4:43 PM MDT	Lake Wind Advisory	GGW	13 hr
May 11, 2:38 PM MDT	Lake Wind Advisory	GGW	29 hr
May 16, 2:36 PM MDT	Lake Wind Advisory	GGW	29 hr
May 20, 1:43 PM MDT	Mesoscale Discussion	SPC	92 min
May 20, 3:11 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
May 20, 6:27 PM MDT	Mesoscale Discussion	SPC	93 min
May 20, 8:18 PM MDT	Severe Thunderstorm Warning	GGW	57 min
May 20, 8:44 PM MDT	Severe Thunderstorm Warning	GGW	76 min
May 20, 9:10 PM MDT	Mesoscale Discussion	SPC	95 min
May 20, 9:17 PM MDT	Tornado Warning	GGW	13 min
May 20, 9:33 PM MDT	Severe Thunderstorm Warning	GGW	57 min
May 20, 10:02 PM MDT	Areal Flood Advisory	GGW	3 hr
May 20, 11:09 PM MDT	Special Weather Statement	GGW	81 min
May 21, 3:04 PM MDT	Special Weather Statement	GGW	26 min
May 21, 3:36 PM MDT	Special Weather Statement	GGW	39 min
May 29, 2:23 PM MDT	Lake Wind Advisory	GGW	54 hr
May 31, 2:29 PM MDT	Mesoscale Discussion	SPC	2 hr
Jun 2, 2:02 PM MDT	Lake Wind Advisory	GGW	29 hr
Jun 5, 10:57 AM MDT	Lake Wind Advisory	GGW	52 hr
Jun 6, 1:03 AM MDT	Special Weather Statement	GGW	57 min
Jun 6, 1:42 AM MDT	Special Weather Statement	GGW	48 min
Jun 6, 2:08 AM MDT	Severe Thunderstorm Warning	GGW	53 min
Jun 6, 4:49 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 8, 5:30 PM MDT	Special Weather Statement	GGW	45 min
Jun 12, 12:41 PM MDT	Lake Wind Advisory	GGW	32 hr
Jun 13, 5:19 PM MDT	Mesoscale Discussion	SPC	116 min
Jun 13, 5:53 PM MDT	Severe Thunderstorm Warning	GGW	67 min
Jun 13, 6:58 PM MDT	Severe Thunderstorm Warning	GGW	62 min
Jun 13, 7:58 PM MDT	Special Weather Statement	GGW	62 min
Jun 27, 6:07 PM MDT	Mesoscale Discussion	SPC	113 min
Jun 27, 6:22 PM MDT	Special Weather Statement	GGW	53 min
Jun 27, 7:05 PM MDT	Special Weather Statement	GGW	55 min
Jun 27, 7:56 PM MDT	Special Weather Statement	GGW	64 min
Jun 27, 8:04 PM MDT	Severe Thunderstorm Warning	GGW	26 min
Jun 27, 8:55 PM MDT	Severe Thunderstorm Warning	GGW	29 min
Jun 29, 3:31 PM MDT	Areal Flood Advisory	GGW	3 hr
Jun 30, 10:23 PM MDT	Special Weather Statement	GGW	52 min
Jul 1, 4:27 PM MDT	Special Weather Statement	GGW	48 min
Jul 1, 6:22 PM MDT	Special Weather Statement	GGW	53 min
Jul 3, 2:47 PM MDT	Mesoscale Discussion	SPC	118 min
Jul 3, 2:51 PM MDT	Lake Wind Advisory	GGW	7 hr
Jul 3, 5:30 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jul 4, 5:39 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 4, 6:50 PM MDT	Mesoscale Discussion	SPC	55 min
Jul 4, 7:58 PM MDT	Severe Thunderstorm Warning	GGW	62 min
Jul 4, 8:31 PM MDT	Severe Thunderstorm Warning	GGW	37 min
Jul 4, 8:41 PM MDT	Special Weather Statement	GGW	64 min
Jul 4, 8:46 PM MDT	Mesoscale Discussion	SPC	119 min
Jul 4, 8:52 PM MDT	Severe Thunderstorm Warning	GGW	53 min
Jul 4, 9:12 PM MDT	Severe Thunderstorm Warning	GGW	36 min
Jul 4, 9:33 PM MDT	Severe Thunderstorm Warning	GGW	57 min
Jul 4, 9:52 PM MDT	Areal Flood Advisory	GGW	2 hr
Jul 6, 3:24 PM MDT	Special Weather Statement	GGW	51 min
Jul 6, 4:19 PM MDT	Special Weather Statement	GGW	56 min
Jul 6, 4:29 PM MDT	Severe Thunderstorm Warning	GGW	61 min
Jul 7, 9:52 AM MDT	Lake Wind Advisory	GGW	11 hr
Jul 7, 12:47 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 7, 1:14 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jul 7, 4:46 PM MDT	Severe Thunderstorm Warning	GGW	59 min
Jul 7, 4:53 PM MDT	Tornado Warning	GGW	23 min
Jul 7, 5:12 PM MDT	Severe Thunderstorm Warning	GGW	63 min
Jul 7, 5:13 PM MDT	Mesoscale Discussion	SPC	92 min
Jul 7, 5:25 PM MDT	Severe Thunderstorm Warning	GGW	65 min
Jul 7, 6:13 PM MDT	Severe Thunderstorm Warning	GGW	62 min
Jul 7, 6:27 PM MDT	Severe Thunderstorm Warning	GGW	63 min
Jul 8, 2:21 AM MDT	Lake Wind Advisory	GGW	22 hr
Jul 10, 2:41 PM MDT	Lake Wind Advisory	GGW	3 hr
Jul 12, 8:07 AM MDT	Lake Wind Advisory	GGW	12 hr
Jul 13, 2:53 AM MDT	Lake Wind Advisory	GGW	16 hr
Jul 14, 5:01 AM MDT	Lake Wind Advisory	GGW	15 hr
Jul 17, 5:40 PM MDT	Special Weather Statement	GGW	50 min
Jul 19, 9:38 PM MDT	Special Weather Statement	GGW	52 min
Jul 23, 2:02 AM MDT	Special Weather Statement	GGW	58 min
Jul 23, 5:46 PM MDT	Severe Thunderstorm Warning	GGW	44 min
Jul 25, 1:18 AM MDT	Severe Thunderstorm Warning	GGW	57 min
Jul 25, 2:12 AM MDT	Special Weather Statement	GGW	48 min
Jul 25, 2:45 AM MDT	Lake Wind Advisory	GGW	17 hr
Jul 30, 5:59 PM MDT	Special Weather Statement	GGW	46 min
Jul 30, 9:32 PM MDT	Special Weather Statement	GGW	43 min
Jul 30, 10:09 PM MDT	Special Weather Statement	GGW	51 min
Jul 31, 6:52 AM MDT	Special Weather Statement	GGW	53 min
Aug 3, 3:05 AM MDT	Lake Wind Advisory	GGW	14 hr
Aug 3, 5:00 PM MDT	Special Weather Statement	GGW	45 min
Aug 5, 2:40 PM MDT	Fire Weather Watch	GGW	24 hr
Aug 6, 3:08 PM MDT	Red Flag Warning	GGW	30 hr
Aug 6, 3:24 PM MDT	Lake Wind Advisory	GGW	29 hr
Aug 6, 8:07 PM MDT	Severe Thunderstorm Warning	GGW	38 min
Aug 6, 8:37 PM MDT	Special Weather Statement	GGW	53 min
Aug 6, 10:18 PM MDT	Special Weather Statement	GGW	57 min
Aug 8, 2:32 PM MDT	Lake Wind Advisory	GGW	30 hr
Aug 11, 12:41 PM MDT	Red Flag Warning	GGW	32 hr
Aug 16, 2:08 PM MDT	Heat Advisory	GGW	53 hr
Aug 17, 10:14 AM MDT	Red Flag Warning	GGW	11 hr
Aug 17, 2:44 PM MDT	Red Flag Warning	GGW	29 hr
Aug 19, 3:18 AM MDT	Heat Advisory	GGW	17 hr
Aug 20, 9:47 AM MDT	Red Flag Warning	GGW	17 hr
Aug 20, 8:15 PM MDT	Special Weather Statement	GGW	60 min
Aug 20, 8:49 PM MDT	Severe Thunderstorm Warning	GGW	56 min
Aug 20, 9:43 PM MDT	Severe Thunderstorm Warning	GGW	62 min
Aug 20, 10:43 PM MDT	Severe Thunderstorm Warning	GGW	62 min
Aug 25, 2:53 PM MDT	Fire Weather Watch	GGW	24 hr
Aug 26, 2:40 PM MDT	Red Flag Warning	GGW	31 hr
Aug 27, 10:10 AM MDT	Lake Wind Advisory	GGW	17 hr
Aug 27, 3:33 PM MDT	Special Weather Statement	GGW	57 min
Aug 27, 4:03 PM MDT	Severe Thunderstorm Warning	GGW	28 min
Aug 27, 4:07 PM MDT	Special Weather Statement	GGW	53 min
Aug 29, 3:48 PM MDT	Lake Wind Advisory	GGW	31 hr
Aug 30, 9:48 AM MDT	Red Flag Warning	GGW	10 hr
Aug 31, 3:18 AM MDT	Red Flag Warning	GGW	66 hr
Aug 31, 2:23 PM MDT	Lake Wind Advisory	GGW	43 hr
Sep 2, 9:44 AM MDT	High Wind Warning	GGW	10 hr
Sep 4, 11:21 AM MDT	Red Flag Warning	GGW	34 hr
Sep 5, 9:07 PM MDT	Lake Wind Advisory	GGW	23 hr
Sep 6, 8:05 PM MDT	Lake Wind Advisory	GGW	25 hr
Sep 12, 2:34 AM MDT	Fire Weather Watch	GGW	24 hr
Sep 13, 2:34 AM MDT	Red Flag Warning	GGW	40 hr
Sep 19, 8:13 PM MDT	Lake Wind Advisory	GGW	25 hr
Sep 22, 2:07 PM MDT	Fire Weather Watch	GGW	24 hr
Sep 23, 2:17 PM MDT	Red Flag Warning	GGW	31 hr
Sep 23, 2:25 PM MDT	Lake Wind Advisory	GGW	31 hr
Sep 25, 2:39 PM MDT	Lake Wind Advisory	GGW	13 hr
Sep 25, 2:43 PM MDT	Lake Wind Advisory	GGW	54 hr
Sep 30, 2:44 AM MDT	Lake Wind Advisory	GGW	17 hr
Oct 2, 3:07 AM MDT	Lake Wind Advisory	GGW	16 hr
Oct 3, 5:21 PM MDT	Red Flag Warning	GGW	27 hr
Oct 4, 2:11 PM MDT	Lake Wind Advisory	GGW	28 hr
Oct 6, 3:30 AM MDT	Red Flag Warning	GGW	17 hr
Oct 7, 1:21 PM MDT	Red Flag Warning	GGW	31 hr
Oct 9, 2:42 AM MDT	Red Flag Warning	GGW	41 hr
Oct 9, 7:38 PM MDT	Lake Wind Advisory	GGW	48 hr
Oct 11, 8:31 AM MDT	Red Flag Warning	GGW	9 hr
Oct 12, 3:09 AM MDT	Lake Wind Advisory	GGW	17 hr
Oct 13, 8:45 AM MDT	Lake Wind Advisory	GGW	33 hr
Oct 15, 2:55 AM MDT	Lake Wind Advisory	GGW	17 hr
Oct 16, 3:01 AM MDT	Winter Weather Advisory	GGW	33 hr
Oct 16, 1:41 PM MDT	Lake Wind Advisory	GGW	28 hr
Oct 20, 1:29 PM MDT	Winter Weather Advisory	GGW	45 hr
Oct 21, 10:27 AM MDT	Winter Storm Warning	GGW	22 hr
Oct 21, 7:06 PM MDT	Special Weather Statement	GGW	84 min
Oct 25, 2:21 PM MDT	Wind Chill Advisory	GGW	20 hr
Oct 29, 2:12 PM MDT	Lake Wind Advisory	GGW	52 hr
Oct 30, 7:08 PM MDT	Severe Thunderstorm Warning	GGW	52 min
Oct 30, 7:43 PM MDT	Severe Thunderstorm Warning	GGW	38 min
Nov 3, 11:31 AM MST	Red Flag Warning	GGW	5 hr
Nov 4, 2:50 AM MST	Lake Wind Advisory	GGW	15 hr
Nov 5, 2:26 PM MST	Winter Storm Watch	GGW	47 hr
Nov 6, 2:45 PM MST	Winter Storm Warning	GGW	69 hr
Nov 10, 2:44 AM MST	Dense Fog Advisory	GGW	6 hr
Nov 10, 1:45 PM MST	Lake Wind Advisory	GGW	27 hr
Nov 13, 1:40 PM MST	Lake Wind Advisory	GGW	29 hr
Nov 18, 2:28 PM MST	Winter Weather Advisory	GGW	21 hr
Nov 24, 8:46 AM MST	Dense Fog Advisory	GGW	3 hr
Nov 26, 3:00 AM MST	Lake Wind Advisory	GGW	14 hr
Nov 27, 1:59 PM MST	Lake Wind Advisory	GGW	30 hr
Dec 10, 11:40 AM MST	Dense Fog Advisory	GGW	44 hr
Dec 12, 1:30 PM MST	Wind Chill Advisory	GGW	20 hr
Dec 13, 2:36 PM MST	Wind Chill Advisory	GGW	18 hr
Dec 18, 12:17 PM MST	High Wind Watch	GGW	39 hr
Dec 20, 2:49 AM MST	High Wind Warning	GGW	15 hr
Dec 21, 12:02 PM MST	High Wind Watch	GGW	15 hr
Dec 22, 3:05 AM MST	High Wind Warning	GGW	20 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	28
Tornado Warning	2
Severe Thunderstorm Watch	5
Mesoscale Discussion	11
Special Weather Statement	35
Flooding
River Flood Warning	8
Areal Flood Advisory	6
Winter
Winter Storm Warning	3
Winter Storm Watch	2
Winter Weather Advisory	8
Heat
Heat Advisory	2
Cold
Wind Chill Warning	2
Wind Chill Advisory	10
Wind and dust
High Wind Warning	5
High Wind Watch	4
Lake Wind Advisory	49
Fire
Red Flag Warning	23
Fire Weather Watch	6
Fog and smoke
Dense Fog Advisory	4

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2019 2021

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.