Alert archive / North Dakota / Slope County

Weather alerts in Slope County, North Dakota, 2020

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

Slope County and its neighbors

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

Alerts: 136
Warnings: 34
Watches: 24
Advisories: 44
Busiest month: July35 alerts
Busiest day: July 5, 20205 alerts

Over time

By month

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

Slope County, 2020

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	0			0
Severe thunderstorm warnings	19	12	37%	3	100%	41 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 Bismarck, ND: tornado warnings	18	4	78%	13	31%	6 min
NWS Bismarck, ND: severe thunderstorm warnings	291	171	41%	339	83%	25 min
NWS Bismarck, ND: flash flood warnings	1	0	100%	0

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 3, 1:50 PM MST	High Wind Watch	BIS	24 hr
Jan 4, 1:45 PM MST	Wind Advisory	BIS	21 hr
Jan 6, 1:27 AM MST	Wind Advisory	BIS	16 hr
Jan 14, 1:40 PM MST	Wind Chill Advisory	BIS	48 hr
Jan 14, 5:00 PM MST	Wind Chill Advisory	BIS	45 hr
Jan 17, 3:05 AM MST	Wind Chill Advisory	BIS	56 hr
Jan 17, 3:06 AM MST	Wind Advisory	BIS	15 hr
Jan 23, 5:14 PM MST	Dense Fog Advisory	BIS	21 hr
Feb 1, 1:49 AM MST	Wind Advisory	BIS	27 hr
Feb 7, 2:03 PM MST	Winter Weather Advisory	BIS	37 hr
Feb 12, 2:12 AM MST	Wind Chill Advisory	BIS	33 hr
Feb 23, 1:24 PM MST	Winter Weather Advisory	BIS	40 hr
Feb 29, 1:37 PM MST	Wind Advisory	BIS	27 hr
Mar 2, 2:08 PM MST	Wind Advisory	BIS	27 hr
Mar 3, 1:35 AM MST	High Wind Warning	BIS	16 hr
Mar 4, 12:48 PM MST	Wind Advisory	BIS	5 hr
Mar 4, 1:39 PM MST	Special Weather Statement	BIS	36 min
Mar 18, 8:18 PM MDT	Winter Weather Advisory	BIS	14 hr
Apr 8, 2:00 AM MDT	Wind Advisory	BIS	17 hr
Apr 20, 8:48 AM MDT	Wind Advisory	BIS	9 hr
Apr 20, 12:09 PM MDT	Red Flag Warning	BIS	6 hr
Apr 21, 5:33 AM MDT	Red Flag Warning	BIS	14 hr
Apr 27, 1:34 PM MDT	Fire Weather Watch	BIS	14 hr
Apr 27, 1:34 PM MDT	Wind Advisory	BIS	30 hr
Apr 28, 9:13 AM MDT	High Wind Warning	BIS	11 hr
Apr 30, 1:03 PM MDT	Fire Weather Watch	BIS	11 hr
May 3, 2:10 PM MDT	Mesoscale Discussion	SPC	2 hr
May 3, 7:57 PM MDT	Special Weather Statement	BIS	33 min
May 8, 1:14 PM MDT	Wind Advisory	BIS	29 hr
May 9, 8:54 AM MDT	High Wind Warning	BIS	5 hr
May 18, 8:11 AM MDT	Wind Advisory	BIS	12 hr
May 20, 8:50 AM MDT	Wind Advisory	BIS	11 hr
May 31, 2:35 PM MDT	Mesoscale Discussion	SPC	115 min
May 31, 4:07 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
May 31, 7:38 PM MDT	Mesoscale Discussion	SPC	97 min
Jun 2, 3:56 AM MDT	Mesoscale Discussion	SPC	3 hr
Jun 6, 9:05 AM MDT	Wind Advisory	BIS	10 hr
Jun 6, 4:49 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 6, 7:40 PM MDT	Severe Thunderstorm Warning	BIS	65 min
Jun 6, 8:47 PM MDT	Severe Thunderstorm Warning	BIS	58 min
Jun 7, 2:59 PM MDT	Mesoscale Discussion	SPC	2 hr
Jun 7, 7:50 PM MDT	Special Weather Statement	BIS	25 min
Jun 13, 2:48 AM MDT	Wind Advisory	BIS	18 hr
Jun 14, 1:20 PM MDT	Mesoscale Discussion	SPC	115 min
Jun 14, 2:20 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jun 14, 5:19 PM MDT	Mesoscale Discussion	SPC	116 min
Jun 14, 5:40 PM MDT	Severe Thunderstorm Warning	BIS	50 min
Jun 29, 2:44 PM MDT	Mesoscale Discussion	SPC	2 hr
Jun 29, 3:56 PM MDT	Tornado Watch	SPC	8 hr
Jun 29, 6:43 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 2, 1:15 PM MDT	Severe Thunderstorm Watch	SPC	9 hr
Jul 2, 5:23 PM MDT	Severe Thunderstorm Warning	BIS	35 min
Jul 3, 2:47 PM MDT	Mesoscale Discussion	SPC	118 min
Jul 3, 5:30 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jul 3, 7:22 PM MDT	Mesoscale Discussion	SPC	113 min
Jul 3, 8:04 PM MDT	Special Weather Statement	BIS	41 min
Jul 3, 8:46 PM MDT	Special Weather Statement	BIS	29 min
Jul 4, 12:09 AM MDT	Special Weather Statement	BIS	36 min
Jul 4, 8:46 PM MDT	Mesoscale Discussion	SPC	119 min
Jul 4, 9:13 PM MDT	Severe Thunderstorm Warning	BIS	62 min
Jul 4, 9:42 PM MDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 4, 10:09 PM MDT	Severe Thunderstorm Warning	BIS	51 min
Jul 5, 2:24 PM MDT	Severe Thunderstorm Warning	BIS	39 min
Jul 6, 1:50 PM MDT	Mesoscale Discussion	SPC	115 min
Jul 6, 2:45 PM MDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 7, 6:35 PM MDT	Mesoscale Discussion	SPC	55 min
Jul 7, 6:59 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 7, 7:33 PM MDT	Severe Thunderstorm Warning	BIS	57 min
Jul 7, 8:29 PM MDT	Severe Thunderstorm Warning	BIS	61 min
Jul 10, 12:26 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 10, 1:08 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jul 10, 2:04 PM MDT	Severe Thunderstorm Warning	BIS	56 min
Jul 10, 2:43 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 10, 2:48 PM MDT	Severe Thunderstorm Warning	BIS	57 min
Jul 12, 6:06 PM MDT	Mesoscale Discussion	SPC	114 min
Jul 12, 9:34 PM MDT	Severe Thunderstorm Warning	BIS	34 min
Jul 23, 1:59 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 23, 2:27 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 23, 4:07 PM MDT	Severe Thunderstorm Warning	BIS	53 min
Jul 23, 4:53 PM MDT	Severe Thunderstorm Warning	BIS	40 min
Jul 23, 4:54 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 30, 2:43 PM MDT	Special Weather Statement	BIS	32 min
Jul 30, 3:25 PM MDT	Severe Thunderstorm Warning	BIS	35 min
Jul 31, 12:37 PM MDT	Special Weather Statement	BIS	38 min
Jul 31, 1:14 PM MDT	Special Weather Statement	BIS	46 min
Aug 8, 8:41 PM MDT	Special Weather Statement	BIS	34 min
Aug 11, 5:50 PM MDT	Severe Thunderstorm Warning	BIS	25 min
Aug 11, 5:59 PM MDT	Mesoscale Discussion	SPC	2 hr
Aug 11, 6:04 PM MDT	Areal Flood Advisory	BIS	6 hr
Aug 11, 6:14 PM MDT	Severe Thunderstorm Warning	BIS	31 min
Aug 11, 6:38 PM MDT	Severe Thunderstorm Watch	SPC	7 hr
Aug 13, 10:28 PM MDT	Mesoscale Discussion	SPC	2 hr
Aug 13, 10:50 PM MDT	Severe Thunderstorm Warning	BIS	55 min
Aug 13, 11:43 PM MDT	Severe Thunderstorm Warning	BIS	62 min
Aug 27, 4:52 PM MDT	Mesoscale Discussion	SPC	83 min
Aug 27, 5:31 PM MDT	Severe Thunderstorm Watch	SPC	7 hr
Aug 27, 8:20 PM MDT	Mesoscale Discussion	SPC	85 min
Aug 27, 8:56 PM MDT	Special Weather Statement	BIS	34 min
Aug 31, 2:56 AM MDT	Fire Weather Watch	BIS	11 hr
Aug 31, 1:29 PM MDT	Red Flag Warning	BIS	30 hr
Sep 1, 4:16 AM MDT	Wind Advisory	BIS	15 hr
Sep 1, 4:56 AM MDT	Fire Weather Watch	BIS	8 hr
Sep 1, 1:23 PM MDT	Red Flag Warning	BIS	32 hr
Sep 1, 1:44 PM MDT	Wind Advisory	BIS	33 hr
Sep 2, 6:07 PM MDT	High Wind Warning	BIS	5 hr
Sep 4, 2:10 PM MDT	Red Flag Warning	BIS	28 hr
Sep 6, 2:00 AM MDT	Freeze Watch	BIS	24 hr
Sep 7, 1:51 AM MDT	Freeze Watch	BIS	36 hr
Sep 7, 1:51 AM MDT	Freeze Warning	BIS	30 hr
Sep 8, 1:32 PM MDT	Freeze Warning	BIS	18 hr
Sep 25, 1:53 PM MDT	Red Flag Warning	BIS	30 hr
Sep 25, 2:15 PM MDT	Wind Advisory	BIS	30 hr
Sep 27, 2:11 AM MDT	Wind Advisory	BIS	17 hr
Sep 29, 1:20 PM MDT	Wind Advisory	BIS	30 hr
Oct 10, 2:24 AM MDT	Red Flag Warning	BIS	17 hr
Oct 11, 9:05 AM MDT	Wind Advisory	BIS	9 hr
Oct 12, 9:01 AM MDT	Wind Advisory	BIS	12 hr
Oct 13, 1:23 PM MDT	Wind Advisory	BIS	29 hr
Oct 13, 8:04 PM MDT	High Wind Warning	BIS	19 hr
Oct 20, 1:53 PM MDT	Winter Storm Watch	BIS	24 hr
Oct 21, 2:02 PM MDT	Winter Weather Advisory	BIS	27 hr
Oct 23, 2:16 AM MDT	Winter Storm Watch	BIS	12 hr
Oct 23, 1:53 PM MDT	Winter Weather Advisory	BIS	36 hr
Oct 30, 3:04 AM MDT	High Wind Watch	BIS	10 hr
Oct 30, 1:13 PM MDT	Wind Advisory	BIS	31 hr
Nov 7, 3:47 AM MST	Dense Fog Advisory	BIS	10 hr
Nov 7, 1:34 PM MST	Wind Advisory	BIS	33 hr
Nov 7, 8:07 PM MST	Dense Fog Advisory	BIS	17 hr
Nov 11, 11:37 AM MST	Wind Advisory	BIS	6 hr
Nov 13, 1:18 PM MST	Wind Advisory	BIS	31 hr
Dec 1, 1:36 AM MST	Wind Advisory	BIS	15 hr
Dec 11, 1:02 AM MST	Dense Fog Advisory	BIS	12 hr
Dec 11, 7:25 PM MST	Dense Fog Advisory	BIS	16 hr
Dec 20, 3:11 AM MST	Wind Advisory	BIS	16 hr
Dec 21, 2:43 PM MST	High Wind Watch	BIS	24 hr
Dec 22, 3:20 AM MST	High Wind Warning	BIS	32 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	19
Severe Thunderstorm Watch	12
Tornado Watch	1
Mesoscale Discussion	23
Special Weather Statement	11
Flooding
Areal Flood Advisory	1
Winter
Winter Storm Watch	2
Winter Weather Advisory	5
Cold
Freeze Warning	2
Freeze Watch	2
Wind Chill Advisory	4
Wind and dust
High Wind Warning	6
High Wind Watch	3
Wind Advisory	29
Fire
Red Flag Warning	7
Fire Weather Watch	4
Fog and smoke
Dense Fog Advisory	5

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.