Alert archive / South Dakota / Day County

Weather alerts in Day County, South Dakota, 2015

116 weather alerts in 2015, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Day County and its neighbors

Each county as a circle sized by its count in 2015. Tap one for its archive.

Alerts: 116
Warnings: 35
Watches: 13
Advisories: 44
Busiest month: July32 alerts
Busiest day: July 18, 201511 alerts

Over time

By month

Warning verification

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

3 of 6 tornado warnings covering Day County in 2015 had a tornado report inside them; 2 of 2 tornado reports fell inside a warning, on average 8 minutes after it went out.

Day County, 2015

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	6	3	50%	2	100%	8 min
Severe thunderstorm warnings	20	18	10%	13	100%	27 min
Flash flood warnings	0			0

Each office's whole area, 2015

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Aberdeen, SD: tornado warnings	19	4	79%	5	80%	9 min
NWS Aberdeen, SD: severe thunderstorm warnings	205	150	27%	308	85%	22 min
NWS Aberdeen, SD: flash flood warnings	9	6	33%	10	100%	68 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 2, 3:54 PM CST	Wind Chill Advisory	ABR	68 hr
Jan 3, 9:56 AM CST	Wind Advisory	ABR	11 hr
Jan 4, 3:01 PM CST	Winter Weather Advisory	ABR	28 hr
Jan 5, 3:17 PM CST	Wind Chill Advisory	ABR	20 hr
Jan 6, 4:06 AM CST	Wind Chill Warning	ABR	32 hr
Jan 7, 4:35 PM CST	Blizzard Watch	ABR	12 hr
Jan 7, 4:35 PM CST	Winter Weather Advisory	ABR	29 hr
Jan 8, 12:25 PM CST	Blizzard Warning	ABR	6 hr
Jan 8, 12:25 PM CST	Winter Weather Advisory	ABR	12 hr
Jan 8, 2:59 PM CST	Wind Chill Advisory	ABR	19 hr
Jan 9, 2:40 PM CST	Wind Chill Advisory	ABR	12 hr
Jan 11, 7:08 PM CST	Wind Chill Advisory	ABR	15 hr
Jan 12, 3:25 PM CST	Wind Chill Advisory	ABR	19 hr
Jan 16, 3:07 PM CST	Wind Advisory	ABR	25 hr
Jan 16, 10:33 PM CST	Freezing Rain Advisory	ABR	7 hr
Feb 7, 3:13 PM CST	Freezing Rain Advisory	ABR	24 hr
Feb 9, 2:15 PM CST	Freezing Rain Advisory	ABR	22 hr
Feb 11, 2:47 AM CST	Wind Chill Advisory	ABR	30 hr
Feb 13, 2:56 PM CST	Wind Chill Advisory	ABR	21 hr
Feb 17, 3:36 AM CST	Wind Chill Advisory	ABR	32 hr
Feb 20, 3:21 PM CST	Wind Chill Advisory	ABR	64 hr
Feb 21, 3:05 AM CST	Wind Chill Warning	ABR	33 hr
Feb 25, 2:55 PM CST	Wind Chill Advisory	ABR	21 hr
Mar 2, 2:31 PM CST	Blizzard Warning	ABR	22 hr
Mar 2, 2:31 PM CST	Winter Weather Advisory	ABR	27 hr
Mar 3, 3:07 PM CST	Wind Chill Advisory	ABR	18 hr
Mar 25, 3:34 AM CDT	Wind Advisory	ABR	14 hr
Mar 28, 4:16 AM CDT	Wind Advisory	ABR	39 hr
Apr 2, 10:56 AM CDT	Wind Advisory	ABR	8 hr
Apr 20, 3:33 AM CDT	Wind Advisory	ABR	15 hr
May 10, 3:44 PM CDT	Severe Thunderstorm Warning	ABR	46 min
May 10, 3:44 PM CDT	Severe Thunderstorm Warning	ABR	46 min
May 11, 3:27 PM CDT	Frost Advisory	ABR	17 hr
May 16, 2:10 PM CDT	Mesoscale Discussion	SPC	95 min
May 17, 3:44 AM CDT	Wind Advisory	ABR	27 hr
May 18, 3:50 AM CDT	Freeze Warning	ABR	28 hr
Jun 6, 3:05 PM CDT	Mesoscale Discussion	SPC	85 min
Jun 6, 5:05 PM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 7, 2:34 PM CDT	Special Weather Statement	ABR	26 min
Jun 14, 7:34 AM CDT	Mesoscale Discussion	SPC	2 hr
Jun 19, 4:02 PM CDT	Flash Flood Watch	ABR	11 hr
Jun 21, 10:41 PM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 21, 11:25 PM CDT	Mesoscale Discussion	SPC	95 min
Jun 22, 12:37 AM CDT	Severe Thunderstorm Warning	ABR	38 min
Jun 22, 1:30 AM CDT	Severe Thunderstorm Warning	ABR	45 min
Jun 22, 2:13 AM CDT	Severe Thunderstorm Warning	ABR	47 min
Jun 22, 2:22 AM CDT	Severe Thunderstorm Warning	ABR	53 min
Jun 22, 3:16 AM CDT	Mesoscale Discussion	SPC	89 min
Jun 22, 3:31 AM CDT	Severe Thunderstorm Warning	ABR	44 min
Jun 27, 4:45 PM CDT	Mesoscale Discussion	SPC	90 min
Jun 27, 5:11 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 5, 1:19 PM CDT	Mesoscale Discussion	SPC	86 min
Jul 11, 4:05 AM CDT	Heat Advisory	ABR	39 hr
Jul 11, 5:40 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 11, 9:04 PM CDT	Mesoscale Discussion	SPC	86 min
Jul 16, 2:05 PM CDT	Mesoscale Discussion	SPC	115 min
Jul 16, 3:14 PM CDT	Severe Thunderstorm Warning	ABR	61 min
Jul 17, 1:10 PM CDT	Mesoscale Discussion	SPC	2 hr
Jul 17, 3:43 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 17, 6:02 PM CDT	Mesoscale Discussion	SPC	118 min
Jul 17, 6:18 PM CDT	Severe Thunderstorm Warning	ABR	57 min
Jul 17, 6:24 PM CDT	Severe Thunderstorm Warning	ABR	66 min
Jul 17, 7:02 PM CDT	Severe Thunderstorm Warning	ABR	28 min
Jul 17, 7:05 PM CDT	Tornado Warning	ABR	25 min
Jul 17, 7:17 PM CDT	Tornado Warning	ABR	28 min
Jul 17, 7:25 PM CDT	Tornado Warning Tornado observed	ABR	32 min
Jul 17, 7:28 PM CDT	Severe Thunderstorm Warning	ABR	62 min
Jul 17, 7:41 PM CDT	Tornado Warning Tornado observed	ABR	49 min
Jul 17, 7:44 PM CDT	Severe Thunderstorm Warning	ABR	61 min
Jul 17, 7:45 PM CDT	Tornado Warning Tornado observedConsiderable damage threat	ABR	45 min
Jul 17, 7:55 PM CDT	Severe Thunderstorm Warning	ABR	50 min
Jul 17, 8:21 PM CDT	Tornado Warning	ABR	54 min
Jul 17, 9:55 PM CDT	Mesoscale Discussion	SPC	65 min
Jul 23, 10:02 PM CDT	Severe Thunderstorm Warning	ABR	58 min
Jul 23, 10:28 PM CDT	Mesoscale Discussion	SPC	32 min
Jul 24, 12:41 AM CDT	Mesoscale Discussion	SPC	2 hr
Jul 25, 4:03 PM CDT	Tornado Watch	SPC	7 hr
Jul 25, 6:46 PM CDT	Severe Thunderstorm Warning	ABR	59 min
Jul 27, 9:41 PM CDT	Mesoscale Discussion	SPC	3 hr
Jul 27, 10:49 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 28, 1:23 AM CDT	Severe Thunderstorm Warning	ABR	56 min
Jul 28, 1:57 AM CDT	Mesoscale Discussion	SPC	2 hr
Jul 29, 3:00 AM CDT	Wind Advisory	ABR	8 hr
Aug 1, 3:13 PM CDT	Mesoscale Discussion	SPC	62 min
Aug 1, 6:04 PM CDT	Severe Thunderstorm Watch	SPC	3 hr
Aug 6, 1:30 AM CDT	Severe Thunderstorm Warning	ABR	60 min
Aug 6, 2:28 AM CDT	Special Weather Statement	ABR	62 min
Aug 6, 11:07 AM CDT	Flash Flood Watch	ABR	7 hr
Aug 7, 5:42 PM CDT	Mesoscale Discussion	SPC	63 min
Aug 9, 5:17 AM CDT	Severe Thunderstorm Warning	ABR	24 min
Aug 9, 7:31 AM CDT	Severe Thunderstorm Warning	ABR	21 min
Aug 9, 4:03 PM CDT	Mesoscale Discussion	SPC	117 min
Aug 14, 2:58 PM CDT	Heat Advisory	ABR	30 hr
Aug 15, 6:41 PM CDT	Mesoscale Discussion	SPC	94 min
Aug 21, 3:11 PM CDT	Wind Advisory	ABR	43 hr
Sep 24, 8:50 AM CDT	Dense Fog Advisory	ABR	3 hr
Oct 8, 2:51 PM CDT	Frost Advisory	ABR	18 hr
Oct 11, 3:26 PM CDT	High Wind Warning	ABR	21 hr
Oct 11, 3:26 PM CDT	Wind Advisory	ABR	24 hr
Oct 15, 3:31 AM CDT	Freeze Warning	ABR	30 hr
Oct 28, 3:33 AM CDT	Wind Advisory	ABR	15 hr
Oct 31, 3:31 AM CDT	Wind Advisory	ABR	15 hr
Nov 10, 2:57 PM CST	High Wind Watch	ABR	24 hr
Nov 11, 3:13 PM CST	Wind Advisory	ABR	26 hr
Nov 18, 3:50 AM CST	Wind Advisory	ABR	38 hr
Nov 29, 3:18 PM CST	Winter Storm Warning	ABR	42 hr
Nov 29, 3:18 PM CST	Winter Weather Advisory	ABR	48 hr
Nov 30, 12:03 PM CST	Mesoscale Discussion	SPC	6 hr
Dec 4, 11:11 AM CST	Wind Advisory	ABR	16 hr
Dec 14, 3:42 AM CST	Winter Storm Watch	ABR	24 hr
Dec 14, 2:45 PM CST	Winter Storm Warning	ABR	45 hr
Dec 15, 4:55 PM CST	Mesoscale Discussion	SPC	6 hr
Dec 15, 10:22 PM CST	Winter Weather Advisory	ABR	20 hr
Dec 21, 6:32 AM CST	Dense Fog Advisory	ABR	5 hr
Dec 25, 3:35 AM CST	Winter Weather Advisory	ABR	35 hr
Dec 28, 2:47 AM CST	Winter Weather Advisory	ABR	24 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	20
Tornado Warning	6
Severe Thunderstorm Watch	7
Tornado Watch	1
Mesoscale Discussion	22
Special Weather Statement	2
Flooding
Flash Flood Watch	2
Winter
Blizzard Warning	2
Winter Storm Warning	2
Blizzard Watch	1
Winter Storm Watch	1
Freezing Rain Advisory	3
Winter Weather Advisory	8
Heat
Heat Advisory	2
Cold
Freeze Warning	2
Wind Chill Warning	2
Frost Advisory	2
Wind Chill Advisory	12
Wind and dust
High Wind Warning	1
High Wind Watch	1
Wind Advisory	15
Fog and smoke
Dense Fog Advisory	2

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2014 2016

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.