Weather alerts in Lyon County, Iowa, 2019

166 weather alerts in 2019, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Lyon County and its neighbors

Each county as a circle sized by its count in 2019. Tap one for its archive.

Alerts: 166
Warnings: 68
Watches: 25
Advisories: 49
Busiest month: July35 alerts
Busiest day: July 17, 201911 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 Lyon County in 2019 had a tornado report inside them; 1 of 2 tornado reports fell inside a warning, on average 0 minutes after it went out.

Lyon County, 2019

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	2	1	50%	2	50%	0 min
Severe thunderstorm warnings	19	15	21%	4	50%	3 min
Flash flood warnings	3	1	67%	0

Each office's whole area, 2019

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Sioux Falls, SD: tornado warnings	37	10	73%	26	50%	7 min
NWS Sioux Falls, SD: severe thunderstorm warnings	172	107	38%	251	88%	18 min
NWS Sioux Falls, SD: flash flood warnings	32	19	41%	26	81%	73 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, Central Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Lasted
Jan 7, 2:44 PM CST	Wind Advisory	FSD	30 hr
Jan 16, 3:00 PM CST	Winter Weather Advisory	FSD	57 hr
Jan 17, 2:29 PM CST	Winter Storm Warning	FSD	34 hr
Jan 18, 11:07 AM CST	Mesoscale Discussion	SPC	3 hr
Jan 18, 2:50 PM CST	Wind Chill Advisory	FSD	19 hr
Jan 21, 3:26 AM CST	Winter Weather Advisory	FSD	35 hr
Jan 23, 2:27 PM CST	Wind Chill Advisory	FSD	43 hr
Jan 23, 2:27 PM CST	Winter Weather Advisory	FSD	20 hr
Jan 26, 2:29 PM CST	Winter Weather Advisory	FSD	46 hr
Jan 27, 3:34 AM CST	Wind Chill Watch	FSD	24 hr
Jan 28, 3:34 AM CST	Wind Chill Warning	FSD	3 days
Jan 28, 3:34 AM CST	Wind Chill Advisory	FSD	35 hr
Jan 28, 3:34 AM CST	Wind Chill Advisory	FSD	3 days
Feb 2, 10:28 PM CST	Dense Fog Advisory	FSD	15 hr
Feb 3, 3:43 AM CST	Winter Weather Advisory	FSD	26 hr
Feb 4, 3:22 AM CST	Wind Chill Advisory	FSD	27 hr
Feb 5, 3:25 PM CST	Winter Weather Advisory	FSD	57 hr
Feb 6, 1:43 PM CST	Blizzard Warning	FSD	34 hr
Feb 7, 3:19 AM CST	Wind Chill Advisory	FSD	54 hr
Feb 12, 10:36 AM CST	Winter Weather Advisory	FSD	10 hr
Feb 14, 3:40 AM CST	Wind Chill Advisory	FSD	29 hr
Feb 15, 2:55 PM CST	Winter Weather Advisory	FSD	51 hr
Feb 19, 4:07 AM CST	Winter Storm Warning	FSD	35 hr
Feb 22, 3:26 PM CST	Blizzard Warning	FSD	51 hr
Feb 24, 2:53 PM CST	Wind Chill Advisory	FSD	17 hr
Mar 2, 3:59 AM CST	Wind Chill Advisory	FSD	56 hr
Mar 7, 3:38 AM CST	Winter Storm Watch	FSD	36 hr
Mar 8, 3:16 PM CST	Winter Weather Advisory	FSD	38 hr
Mar 9, 5:05 AM CST	Mesoscale Discussion	SPC	5 hr
Mar 11, 3:03 PM CDT	Winter Storm Watch	FSD	49 hr
Mar 11, 3:13 PM CDT	Flood Watch	FSD	72 hr
Mar 12, 3:26 PM CDT	River Flood Watch	FSD	4 days
Mar 12, 3:26 PM CDT	River Flood Watch	FSD	5 days
Mar 12, 3:26 PM CDT	River Flood Watch	FSD	5 days
Mar 12, 3:26 PM CDT	River Flood Watch	FSD	5 days
Mar 12, 5:41 PM CDT	Dense Fog Advisory	FSD	19 hr
Mar 13, 11:04 AM CDT	River Flood Warning	FSD	14 days
Mar 13, 11:04 AM CDT	River Flood Warning	FSD	8 days
Mar 13, 11:04 AM CDT	River Flood Warning	FSD	4 days
Mar 13, 12:55 PM CDT	Areal Flood Warning	FSD	12 hr
Mar 13, 4:03 PM CDT	Winter Weather Advisory	FSD	27 hr
Mar 13, 4:06 PM CDT	Wind Advisory	FSD	36 hr
Mar 13, 6:42 PM CDT	Dense Fog Advisory	FSD	12 hr
Mar 13, 7:28 PM CDT	River Flood Warning	FSD	92 days
Mar 14, 2:18 AM CDT	Areal Flood Warning	FSD	18 hr
Mar 14, 8:54 PM CDT	Areal Flood Warning	FSD	12 hr
Mar 15, 9:46 PM CDT	River Flood Warning	FSD	82 days
Mar 18, 2:27 PM CDT	River Flood Warning	FSD	50 days
Mar 18, 2:27 PM CDT	River Flood Warning	FSD	21 days
Apr 4, 10:24 PM CDT	Dense Fog Advisory	FSD	12 hr
Apr 6, 9:35 AM CDT	River Flood Warning	FSD	14 days
Apr 8, 3:46 AM CDT	Winter Storm Watch	FSD	57 hr
Apr 9, 10:41 AM CDT	River Flood Warning	FSD	9 days
Apr 9, 10:41 AM CDT	River Flood Warning	FSD	10 days
Apr 10, 12:37 PM CDT	Ice Storm Warning	FSD	27 hr
Apr 11, 2:34 AM CDT	Mesoscale Discussion	SPC	6 hr
Apr 26, 8:45 AM CDT	River Flood Warning	FSD	4 days
Apr 27, 5:14 AM CDT	Mesoscale Discussion	SPC	6 hr
May 4, 3:44 AM CDT	Dense Fog Advisory	FSD	5 hr
May 8, 9:39 AM CDT	River Flood Warning	FSD	27 days
May 8, 9:39 AM CDT	River Flood Warning	FSD	4 days
May 9, 3:38 AM CDT	Frost Advisory	FSD	28 hr
May 14, 7:12 PM CDT	Severe Thunderstorm Warning	FSD	33 min
May 20, 2:58 PM CDT	Wind Advisory	FSD	32 hr
May 27, 8:27 AM CDT	River Flood Warning	FSD	5 days
May 27, 2:58 PM CDT	River Flood Warning	FSD	68 hr
Jun 11, 5:36 PM CDT	Severe Thunderstorm Warning	FSD	24 min
Jun 15, 12:30 PM CDT	Mesoscale Discussion	SPC	2 hr
Jun 15, 1:20 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Jun 16, 2:21 AM CDT	Dense Fog Advisory	FSD	8 hr
Jun 24, 2:51 PM CDT	Severe Thunderstorm Warning	FSD	39 min
Jun 27, 4:01 AM CDT	Severe Thunderstorm Watch	SPC	9 hr
Jun 27, 8:18 AM CDT	Flash Flood Warning	FSD	117 min
Jun 27, 8:22 AM CDT	Severe Thunderstorm Warning	FSD	23 min
Jun 27, 8:30 AM CDT	Severe Thunderstorm Warning	FSD	30 min
Jun 27, 8:40 AM CDT	Severe Thunderstorm Warning	FSD	50 min
Jun 27, 8:46 AM CDT	Mesoscale Discussion	SPC	89 min
Jun 27, 9:14 AM CDT	Flash Flood Warning	FSD	3 hr
Jun 27, 12:36 PM CDT	River Flood Warning	FSD	32 hr
Jun 27, 2:26 PM CDT	River Flood Warning	FSD	7 hr
Jun 28, 1:42 PM CDT	River Flood Warning	FSD	25 hr
Jun 28, 2:02 PM CDT	Heat Advisory	FSD	31 hr
Jun 29, 11:59 AM CDT	Excessive Heat Warning	FSD	9 hr
Jun 29, 3:18 PM CDT	Heat Advisory	FSD	30 hr
Jul 1, 1:31 PM CDT	Mesoscale Discussion	SPC	119 min
Jul 1, 3:14 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 1, 4:16 PM CDT	Flash Flood Watch	FSD	9 hr
Jul 1, 5:09 PM CDT	Mesoscale Discussion	SPC	2 hr
Jul 1, 11:01 PM CDT	River Flood Warning	FSD	3 days
Jul 4, 2:52 AM CDT	Severe Thunderstorm Warning	FSD	53 min
Jul 9, 10:40 AM CDT	River Flood Warning	FSD	21 days
Jul 10, 6:19 AM CDT	River Flood Warning	FSD	19 hr
Jul 12, 10:05 AM CDT	Mesoscale Discussion	SPC	85 min
Jul 13, 2:12 PM CDT	Mesoscale Discussion	SPC	2 hr
Jul 14, 3:33 PM CDT	Heat Advisory	FSD	29 hr
Jul 15, 3:12 PM CDT	Mesoscale Discussion	SPC	93 min
Jul 15, 3:38 PM CDT	Excessive Heat Watch	FSD	50 hr
Jul 17, 4:07 AM CDT	Excessive Heat Warning	FSD	66 hr
Jul 17, 4:14 AM CDT	Mesoscale Discussion	SPC	91 min
Jul 17, 4:48 AM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 17, 6:17 AM CDT	Severe Thunderstorm Warning	FSD	58 min
Jul 17, 6:54 AM CDT	Severe Thunderstorm Warning	FSD	66 min
Jul 17, 7:27 AM CDT	Severe Thunderstorm Warning	FSD	48 min
Jul 17, 9:02 AM CDT	River Flood Warning	FSD	67 hr
Jul 17, 9:09 AM CDT	Mesoscale Discussion	SPC	96 min
Jul 17, 9:56 AM CDT	River Flood Warning	FSD	21 days
Jul 17, 10:52 AM CDT	River Flood Warning	FSD	53 hr
Jul 17, 5:19 PM CDT	Heat Advisory	FSD	28 hr
Jul 18, 4:54 PM CDT	Mesoscale Discussion	SPC	66 min
Jul 18, 5:30 PM CDT	Tornado Watch	SPC	4 hr
Jul 20, 5:02 AM CDT	Mesoscale Discussion	SPC	88 min
Jul 20, 5:51 AM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 20, 7:40 AM CDT	Mesoscale Discussion	SPC	95 min
Jul 20, 8:15 AM CDT	Severe Thunderstorm Warning	FSD	30 min
Jul 20, 8:39 AM CDT	Severe Thunderstorm Warning	FSD	36 min
Jul 20, 9:02 AM CDT	Severe Thunderstorm Warning	FSD	43 min
Jul 20, 9:46 AM CDT	River Flood Warning	FSD	25 hr
Jul 28, 7:27 PM CDT	Severe Thunderstorm Watch	SPC	4 hr
Jul 28, 8:38 PM CDT	Severe Thunderstorm Warning	FSD	37 min
Aug 11, 2:21 AM CDT	Dense Fog Advisory	FSD	7 hr
Aug 15, 7:48 PM CDT	Mesoscale Discussion	SPC	117 min
Aug 15, 7:52 PM CDT	Severe Thunderstorm Warning	FSD	53 min
Aug 17, 5:12 PM CDT	Mesoscale Discussion	SPC	2 hr
Aug 17, 6:14 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Aug 17, 8:26 PM CDT	Mesoscale Discussion	SPC	94 min
Aug 17, 10:32 PM CDT	Mesoscale Discussion	SPC	88 min
Aug 17, 10:41 PM CDT	Tornado Warning	FSD	9 min
Aug 17, 10:46 PM CDT	Severe Thunderstorm Warning	FSD	44 min
Aug 19, 11:05 PM CDT	Mesoscale Discussion	SPC	115 min
Aug 19, 11:56 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Aug 20, 3:08 AM CDT	Mesoscale Discussion	SPC	97 min
Sep 10, 3:22 PM CDT	Flash Flood Watch	FSD	16 hr
Sep 10, 8:33 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Sep 10, 11:13 PM CDT	Severe Thunderstorm Warning	FSD	47 min
Sep 10, 11:27 PM CDT	Tornado Warning	FSD	33 min
Sep 10, 11:31 PM CDT	Mesoscale Discussion	SPC	89 min
Sep 10, 11:59 PM CDT	Severe Thunderstorm Warning	FSD	46 min
Sep 11, 12:44 AM CDT	Severe Thunderstorm Warning	FSD	46 min
Sep 11, 1:03 AM CDT	Flash Flood Warning	FSD	6 hr
Sep 11, 4:07 AM CDT	Flash Flood Watch	FSD	26 hr
Sep 11, 8:01 AM CDT	River Flood Warning	FSD	29 days
Sep 11, 9:10 AM CDT	River Flood Warning	FSD	14 days
Sep 12, 7:14 AM CDT	River Flood Warning	FSD	21 days
Sep 12, 7:14 AM CDT	River Flood Warning	FSD	4 days
Sep 12, 9:15 AM CDT	River Flood Warning	FSD	60 hr
Sep 13, 1:36 AM CDT	River Flood Warning	FSD	3 days
Sep 15, 3:19 AM CDT	Dense Fog Advisory	FSD	9 hr
Sep 24, 4:43 PM CDT	Tornado Watch	SPC	7 hr
Oct 3, 3:19 PM CDT	Frost Advisory	FSD	18 hr
Oct 4, 3:31 PM CDT	Wind Advisory	FSD	27 hr
Oct 12, 9:55 AM CDT	Wind Advisory	FSD	9 hr
Oct 20, 9:20 PM CDT	Wind Advisory	FSD	43 hr
Oct 21, 4:03 AM CDT	High Wind Warning	FSD	24 hr
Oct 21, 11:40 AM CDT	Wind Advisory	FSD	4 hr
Nov 5, 1:03 PM CST	Winter Weather Advisory	FSD	17 hr
Nov 24, 2:01 PM CST	Winter Storm Watch	FSD	25 hr
Nov 25, 4:05 AM CST	Winter Storm Warning	FSD	56 hr
Nov 26, 5:23 PM CST	Mesoscale Discussion	SPC	6 hr
Nov 27, 5:56 PM CST	Winter Weather Advisory	FSD	4 days
Dec 8, 12:21 PM CST	Dense Fog Advisory	FSD	15 hr
Dec 8, 5:30 PM CST	Dense Fog Advisory	FSD	10 hr
Dec 13, 9:07 AM CST	Dense Fog Advisory	FSD	7 hr
Dec 17, 1:48 AM CST	Dense Fog Advisory	FSD	4 hr
Dec 24, 2:24 PM CST	Dense Fog Advisory	FSD	34 hr
Dec 25, 4:54 AM CST	Winter Weather Advisory	FSD	22 hr
Dec 27, 3:18 PM CST	Winter Weather Advisory	FSD	3 days

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
Tornado Warning	2
Severe Thunderstorm Watch	9
Tornado Watch	2
Mesoscale Discussion	24
Flooding
Areal Flood Warning	3
Flash Flood Warning	3
River Flood Warning	31
Flash Flood Watch	3
Flood Watch	1
River Flood Watch	4
Winter
Blizzard Warning	2
Ice Storm Warning	1
Winter Storm Warning	3
Winter Storm Watch	4
Winter Weather Advisory	14
Heat
Excessive Heat Warning	2
Excessive Heat Watch	1
Heat Advisory	4
Cold
Wind Chill Warning	1
Wind Chill Watch	1
Frost Advisory	2
Wind Chill Advisory	9
Wind and dust
High Wind Warning	1
Wind Advisory	7
Fog and smoke
Dense Fog Advisory	13

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2018 2020

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.