Alert archive / Colorado / Jefferson County

Weather alerts in Jefferson County, Colorado, 2023

183 weather alerts in 2023, 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 2023. Tap one for its archive.

Alerts: 183
Warnings: 61
Watches: 36
Advisories: 50
Busiest month: June49 alerts
Busiest day: June 22, 202322 alerts

Over time

By month

Warning verification

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

0 of 3 tornado warnings covering Jefferson County in 2023 had a tornado report inside them.

Jefferson County, 2023

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	3	0	100%	0
Severe thunderstorm warnings	30	20	33%	44	93%	18 min
Flash flood warnings	3	2	33%	1	100%	51 min

Each office's whole area, 2023

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Denver/Boulder, CO: tornado warnings	67	20	70%	79	71%	13 min
NWS Denver/Boulder, CO: severe thunderstorm warnings	467	169	64%	521	75%	18 min
NWS Denver/Boulder, CO: flash flood warnings	80	19	76%	35	74%	74 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 1, 3:06 AM MST	Winter Weather Advisory	BOU	45 hr
Jan 10, 2:06 PM MST	Winter Weather Advisory	BOU	33 hr
Jan 12, 1:15 AM MST	Dense Fog Advisory	BOU	7 hr
Jan 15, 2:52 PM MST	Winter Storm Watch	BOU	22 hr
Jan 16, 12:36 PM MST	Winter Storm Warning	BOU	58 hr
Jan 16, 12:36 PM MST	Winter Weather Advisory	BOU	52 hr
Jan 27, 3:06 AM MST	Winter Weather Advisory	BOU	38 hr
Jan 29, 8:36 AM MST	Winter Weather Advisory	BOU	38 hr
Jan 30, 11:26 AM MST	Winter Weather Advisory	BOU	9 hr
Feb 12, 1:51 PM MST	Winter Storm Watch	BOU	37 hr
Feb 14, 2:59 AM MST	Winter Storm Warning	BOU	45 hr
Feb 14, 2:59 AM MST	Winter Weather Advisory	BOU	45 hr
Feb 18, 2:12 AM MST	High Wind Watch	BOU	25 hr
Feb 19, 3:25 AM MST	High Wind Warning	BOU	57 hr
Feb 20, 2:18 AM MST	Winter Storm Watch	BOU	26 hr
Feb 20, 2:08 PM MST	Winter Storm Warning	BOU	54 hr
Feb 21, 3:50 AM MST	Winter Weather Advisory	BOU	49 hr
Feb 21, 2:53 PM MST	Wind Chill Advisory	BOU	42 hr
Feb 25, 2:08 PM MST	High Wind Watch	BOU	22 hr
Feb 26, 12:04 PM MST	High Wind Warning	BOU	18 hr
Mar 4, 1:53 PM MST	Red Flag Warning	BOU	28 hr
Mar 7, 6:21 AM MST	Winter Weather Advisory	BOU	5 hr
Mar 8, 3:21 PM MST	Red Flag Warning	BOU	25 hr
Mar 9, 2:19 AM MST	Winter Storm Watch	BOU	13 hr
Mar 9, 2:59 PM MST	Winter Storm Warning	BOU	44 hr
Mar 14, 2:56 AM MDT	Winter Weather Advisory	BOU	57 hr
Mar 20, 2:16 PM MDT	Winter Weather Advisory	BOU	58 hr
Mar 29, 3:07 PM MDT	Red Flag Warning	BOU	52 hr
Mar 31, 12:59 PM MDT	Blowing Dust Advisory	BOU	5 hr
Apr 1, 2:31 PM MDT	Red Flag Warning	BOU	29 hr
Apr 2, 3:50 AM MDT	Fire Weather Watch	BOU	24 hr
Apr 3, 3:01 AM MDT	Winter Weather Advisory	BOU	42 hr
Apr 3, 3:36 AM MDT	Red Flag Warning	BOU	16 hr
Apr 10, 2:16 PM MDT	Fire Weather Watch	BOU	24 hr
Apr 11, 2:33 PM MDT	Fire Weather Watch	BOU	24 hr
Apr 11, 2:33 PM MDT	Red Flag Warning	BOU	28 hr
Apr 12, 2:35 PM MDT	Red Flag Warning	BOU	29 hr
Apr 13, 2:35 PM MDT	Winter Weather Advisory	BOU	39 hr
Apr 16, 5:02 AM MDT	Fire Weather Watch	BOU	34 hr
Apr 17, 2:35 PM MDT	Red Flag Warning	BOU	29 hr
Apr 20, 1:22 PM MDT	Winter Weather Advisory	BOU	46 hr
Apr 23, 1:53 PM MDT	Winter Storm Watch	BOU	24 hr
Apr 24, 1:45 PM MDT	Winter Storm Warning	BOU	39 hr
Apr 27, 3:29 AM MDT	Winter Weather Advisory	BOU	27 hr
May 4, 3:11 PM MDT	Special Weather Statement	BOU	49 min
May 8, 2:24 PM MDT	Red Flag Warning	BOU	29 hr
May 10, 3:08 AM MDT	Flood Watch	BOU	57 hr
May 10, 1:25 PM MDT	Mesoscale Discussion	SPC	2 hr
May 10, 2:15 PM MDT	Tornado Warning	BOU	30 min
May 10, 2:28 PM MDT	Severe Thunderstorm Warning	BOU	47 min
May 10, 2:56 PM MDT	Tornado Warning	BOU	34 min
May 10, 3:30 PM MDT	Tornado Warning	BOU	15 min
May 10, 8:35 PM MDT	Winter Weather Advisory	BOU	6 hr
May 10, 9:02 PM MDT	Winter Storm Watch	BOU	5 hr
May 11, 2:09 AM MDT	Winter Storm Warning	BOU	32 hr
May 11, 10:12 AM MDT	Areal Flood Advisory	BOU	6 hr
May 15, 9:27 AM MDT	Areal Flood Advisory	BOU	11 hr
May 25, 3:30 PM MDT	Special Weather Statement	BOU	45 min
May 26, 11:56 AM MDT	Mesoscale Discussion	SPC	2 hr
May 26, 1:33 PM MDT	Severe Thunderstorm Watch	SPC	7 hr
May 26, 1:44 PM MDT	Special Weather Statement	BOU	46 min
May 26, 2:21 PM MDT	Severe Thunderstorm Warning	BOU	39 min
May 31, 3:03 PM MDT	Severe Thunderstorm Warning	BOU	42 min
Jun 5, 3:29 PM MDT	Areal Flood Advisory	BOU	2 hr
Jun 5, 4:16 PM MDT	Areal Flood Advisory	BOU	2 hr
Jun 7, 2:35 AM MDT	Flash Flood Watch	BOU	17 hr
Jun 7, 3:52 PM MDT	Severe Thunderstorm Warning	BOU	27 min
Jun 8, 7:43 PM MDT	Special Weather Statement	BOU	47 min
Jun 8, 8:38 PM MDT	Areal Flood Advisory	BOU	2 hr
Jun 11, 11:43 AM MDT	Flood Watch	BOU	15 hr
Jun 11, 12:44 PM MDT	Mesoscale Discussion	SPC	61 min
Jun 12, 3:24 AM MDT	Flood Watch	BOU	21 hr
Jun 12, 10:32 AM MDT	Special Weather Statement	BOU	28 min
Jun 12, 10:58 AM MDT	Areal Flood Advisory	BOU	3 hr
Jun 12, 12:48 PM MDT	Areal Flood Advisory	BOU	4 hr
Jun 16, 2:23 AM MDT	Flood Watch	BOU	20 hr
Jun 21, 12:36 PM MDT	Severe Thunderstorm Watch	SPC	9 hr
Jun 21, 2:49 PM MDT	Mesoscale Discussion	SPC	86 min
Jun 21, 5:25 PM MDT	Mesoscale Discussion	SPC	65 min
Jun 21, 5:54 PM MDT	Severe Thunderstorm Warning	BOU	36 min
Jun 21, 7:46 PM MDT	Severe Thunderstorm Warning	BOU	44 min
Jun 21, 7:58 PM MDT	Mesoscale Discussion	SPC	92 min
Jun 21, 8:40 PM MDT	Severe Thunderstorm Warning	BOU	50 min
Jun 21, 8:43 PM MDT	Severe Thunderstorm Warning	BOU	32 min
Jun 21, 9:04 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	26 min
Jun 21, 9:20 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	40 min
Jun 21, 9:28 PM MDT	Areal Flood Advisory	BOU	3 hr
Jun 21, 9:58 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jun 21, 11:35 PM MDT	Severe Thunderstorm Warning	BOU	25 min
Jun 22, 12:50 AM MDT	Areal Flood Advisory	BOU	3 hr
Jun 22, 10:13 AM MDT	Flood Watch	BOU	14 hr
Jun 22, 11:08 AM MDT	Mesoscale Discussion	SPC	2 hr
Jun 22, 12:14 PM MDT	Severe Thunderstorm Watch	SPC	10 hr
Jun 22, 1:40 PM MDT	Severe Thunderstorm Warning	BOU	15 min
Jun 22, 2:15 PM MDT	Severe Thunderstorm Warning	BOU	45 min
Jun 22, 2:37 PM MDT	Mesoscale Discussion	SPC	83 min
Jun 22, 2:45 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	45 min
Jun 22, 3:01 PM MDT	Severe Thunderstorm Warning Destructive damage threat	BOU	44 min
Jun 22, 3:09 PM MDT	Areal Flood Advisory	BOU	3 hr
Jun 22, 3:15 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	45 min
Jun 22, 3:44 PM MDT	Areal Flood Advisory	BOU	3 hr
Jun 22, 5:56 PM MDT	Mesoscale Discussion	SPC	94 min
Jun 22, 8:23 PM MDT	Special Weather Statement	BOU	37 min
Jun 22, 8:25 PM MDT	Severe Thunderstorm Warning	BOU	21 min
Jun 29, 11:40 AM MDT	Mesoscale Discussion	SPC	2 hr
Jun 29, 1:17 PM MDT	Tornado Watch	SPC	8 hr
Jun 29, 3:17 PM MDT	Severe Thunderstorm Warning	BOU	43 min
Jun 29, 3:30 PM MDT	Areal Flood Advisory	BOU	2 hr
Jun 29, 3:52 PM MDT	Severe Thunderstorm Warning	BOU	38 min
Jun 29, 4:07 PM MDT	Flash Flood Warning	BOU	113 min
Jun 29, 5:42 PM MDT	Severe Thunderstorm Warning	BOU	48 min
Jun 30, 2:36 PM MDT	Severe Thunderstorm Warning	BOU	24 min
Jul 4, 1:41 PM MDT	Mesoscale Discussion	SPC	64 min
Jul 4, 2:05 PM MDT	Severe Thunderstorm Watch	SPC	9 hr
Jul 4, 5:14 PM MDT	Mesoscale Discussion	SPC	91 min
Jul 4, 8:03 PM MDT	Areal Flood Advisory	BOU	87 min
Jul 4, 10:11 PM MDT	Special Weather Statement	BOU	49 min
Jul 5, 1:01 PM MDT	Severe Thunderstorm Warning	BOU	29 min
Jul 5, 1:59 PM MDT	Special Weather Statement	BOU	31 min
Jul 5, 9:36 PM MDT	Dense Fog Advisory	BOU	11 hr
Jul 6, 1:37 PM MDT	Mesoscale Discussion	SPC	113 min
Jul 6, 2:51 PM MDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 8, 12:23 PM MDT	Mesoscale Discussion	SPC	97 min
Jul 8, 1:09 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jul 8, 3:33 PM MDT	Severe Thunderstorm Warning	BOU	42 min
Jul 15, 1:17 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 15, 2:17 PM MDT	Heat Advisory	BOU	54 hr
Jul 17, 4:46 PM MDT	Special Weather Statement	BOU	59 min
Jul 18, 3:33 PM MDT	Special Weather Statement	BOU	27 min
Jul 18, 3:47 PM MDT	Special Weather Statement	BOU	43 min
Jul 20, 12:15 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 20, 1:27 PM MDT	Severe Thunderstorm Watch	SPC	9 hr
Jul 20, 3:50 PM MDT	Special Weather Statement	BOU	25 min
Jul 20, 4:01 PM MDT	Severe Thunderstorm Warning	BOU	44 min
Jul 28, 3:29 PM MDT	Severe Thunderstorm Warning	BOU	31 min
Jul 31, 3:11 AM MDT	Flood Watch	BOU	21 hr
Jul 31, 2:37 PM MDT	Flood Watch	BOU	32 hr
Jul 31, 4:54 PM MDT	Flash Flood Warning	BOU	3 hr
Jul 31, 5:24 PM MDT	Areal Flood Advisory	BOU	3 hr
Jul 31, 6:38 PM MDT	Severe Thunderstorm Warning	BOU	37 min
Aug 1, 2:17 PM MDT	Special Weather Statement	BOU	43 min
Aug 1, 2:24 PM MDT	Severe Thunderstorm Warning	BOU	36 min
Aug 1, 2:58 PM MDT	Severe Thunderstorm Warning	BOU	32 min
Aug 1, 3:23 PM MDT	Flash Flood Warning	BOU	3 hr
Aug 1, 3:27 PM MDT	Severe Thunderstorm Warning	BOU	19 min
Aug 2, 8:18 PM MDT	Severe Thunderstorm Warning	BOU	42 min
Aug 2, 8:36 PM MDT	Mesoscale Discussion	SPC	84 min
Aug 6, 3:25 PM MDT	Mesoscale Discussion	SPC	2 hr
Aug 16, 6:39 PM MDT	Special Weather Statement	BOU	36 min
Aug 18, 4:21 PM MDT	Special Weather Statement	BOU	24 min
Aug 24, 1:53 PM MDT	Flood Watch	BOU	30 hr
Aug 27, 10:22 PM MDT	Areal Flood Advisory	BOU	83 min
Aug 28, 6:59 PM MDT	Special Weather Statement	BOU	46 min
Aug 28, 7:50 PM MDT	Special Weather Statement	BOU	25 min
Sep 3, 2:23 PM MDT	Areal Flood Advisory	BOU	82 min
Sep 10, 2:06 PM MDT	Mesoscale Discussion	SPC	114 min
Sep 14, 3:09 PM MDT	Areal Flood Advisory	BOU	59 min
Sep 14, 3:45 PM MDT	Areal Flood Advisory	BOU	70 min
Oct 6, 2:56 AM MDT	Frost Advisory	BOU	30 hr
Oct 10, 2:48 PM MDT	Winter Weather Advisory	BOU	63 hr
Oct 12, 1:12 PM MDT	Freeze Watch	BOU	15 hr
Oct 13, 4:06 AM MDT	Freeze Warning	BOU	29 hr
Oct 26, 7:17 AM MDT	Dense Fog Advisory	BOU	5 hr
Oct 26, 1:51 PM MDT	Winter Storm Watch	BOU	12 hr
Oct 26, 5:21 PM MDT	Freeze Warning	BOU	19 hr
Oct 27, 1:53 AM MDT	Winter Storm Warning	BOU	58 hr
Oct 27, 2:22 PM MDT	Winter Storm Watch	BOU	6 hr
Nov 7, 1:46 PM MST	Winter Weather Advisory	BOU	34 hr
Nov 22, 1:59 PM MST	Winter Storm Warning	BOU	45 hr
Nov 22, 1:59 PM MST	Winter Weather Advisory	BOU	63 hr
Nov 25, 6:40 AM MST	Winter Weather Advisory	BOU	7 hr
Dec 1, 3:16 AM MST	Winter Storm Warning	BOU	3 days
Dec 1, 1:42 PM MST	Winter Weather Advisory	BOU	63 hr
Dec 1, 1:45 PM MST	High Wind Watch	BOU	23 hr
Dec 2, 12:43 PM MST	High Wind Warning	BOU	25 hr
Dec 5, 2:22 PM MST	High Wind Watch	BOU	23 hr
Dec 6, 1:25 PM MST	High Wind Warning	BOU	28 hr
Dec 7, 3:01 AM MST	Winter Weather Advisory	BOU	50 hr
Dec 9, 3:55 AM MST	High Wind Watch	BOU	9 hr
Dec 9, 1:18 PM MST	High Wind Warning	BOU	28 hr
Dec 12, 5:28 PM MST	Winter Weather Advisory	BOU	16 hr
Dec 14, 4:51 AM MST	Dense Fog Advisory	BOU	5 hr
Dec 22, 8:49 PM MST	Winter Weather Advisory	BOU	38 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	30
Tornado Warning	3
Severe Thunderstorm Watch	8
Tornado Watch	1
Mesoscale Discussion	19
Special Weather Statement	17
Flooding
Flash Flood Warning	3
Flash Flood Watch	1
Flood Watch	8
Areal Flood Advisory	18
Winter
Winter Storm Warning	9
Winter Storm Watch	8
Winter Weather Advisory	24
Heat
Heat Advisory	1
Cold
Freeze Warning	2
Freeze Watch	1
Frost Advisory	1
Wind Chill Advisory	1
Wind and dust
High Wind Warning	5
High Wind Watch	5
Blowing Dust Advisory	1
Fire
Red Flag Warning	9
Fire Weather Watch	4
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 2022 2024

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.