Alert archive / South Dakota / Gregory County

Weather alerts in Gregory County, South Dakota, 2019

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

Gregory County and its neighbors

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

Alerts: 150
Warnings: 58
Watches: 22
Advisories: 34
Busiest month: August36 alerts
Busiest day: June 30, 20198 alerts

Over time

By month

Warning verification

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

2 of 9 tornado warnings covering Gregory County in 2019 had a tornado report inside them; 2 of 3 tornado reports fell inside a warning, on average 3 minutes after it went out.

Gregory County, 2019

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	9	2	78%	3	67%	3 min
Severe thunderstorm warnings	31	22	29%	15	80%	14 min
Flash flood warnings	2	2	0%	1	100%	68 min

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 21, 3:26 AM CST	Winter Weather Advisory	FSD	35 hr
Jan 26, 2:21 PM CST	High Wind Watch	FSD	13 hr
Jan 27, 3:34 AM CST	Wind Chill Watch	FSD	24 hr
Jan 27, 3:48 AM CST	High Wind Warning	FSD	26 hr
Jan 27, 3:48 AM CST	Wind Advisory	FSD	32 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 5, 3:25 PM CST	Winter Weather Advisory	FSD	57 hr
Feb 7, 3:19 AM CST	Wind Chill Advisory	FSD	54 hr
Feb 15, 2:55 PM CST	Winter Weather Advisory	FSD	51 hr
Feb 21, 3:52 AM CST	Winter Weather Advisory	FSD	3 days
Mar 2, 3:59 AM CST	Wind Chill Advisory	FSD	56 hr
Mar 2, 3:19 PM CST	Wind Chill Warning	FSD	21 hr
Mar 6, 3:04 AM CST	Winter Weather Advisory	FSD	37 hr
Mar 7, 3:38 AM CST	Winter Storm Watch	FSD	36 hr
Mar 8, 3:10 AM CST	Winter Storm Warning	FSD	45 hr
Mar 8, 3:16 PM CST	Winter Weather Advisory	FSD	38 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, 3:21 PM CDT	Winter Storm Warning	FSD	42 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, 9:28 PM CDT	Areal Flood Warning	FSD	9 hr
Mar 14, 8:51 AM CDT	Blizzard Warning	FSD	6 hr
Apr 8, 3:46 AM CDT	Winter Storm Watch	FSD	57 hr
Apr 9, 3:52 AM CDT	Blizzard Warning	FSD	3 days
Apr 11, 2:34 AM CDT	Mesoscale Discussion	SPC	6 hr
Apr 11, 8:28 PM CDT	Winter Weather Advisory	FSD	17 hr
May 9, 3:38 AM CDT	Frost Advisory	FSD	28 hr
May 13, 9:33 PM CDT	Special Weather Statement	FSD	42 min
May 17, 4:38 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
May 17, 7:53 PM CDT	Mesoscale Discussion	SPC	2 hr
May 20, 2:58 PM CDT	Wind Advisory	FSD	32 hr
May 26, 7:28 PM CDT	Special Weather Statement	LBF	47 min
May 31, 3:45 PM CDT	Mesoscale Discussion	SPC	2 hr
Jun 8, 2:18 PM CDT	Mesoscale Discussion	SPC	87 min
Jun 8, 3:47 PM CDT	Mesoscale Discussion	SPC	88 min
Jun 19, 6:31 PM CDT	Severe Thunderstorm Warning	FSD	31 min
Jun 19, 7:58 PM CDT	Special Weather Statement	LBF	32 min
Jun 19, 8:16 PM CDT	Mesoscale Discussion	SPC	89 min
Jun 19, 8:28 PM CDT	Special Weather Statement	LBF	32 min
Jun 27, 3:15 PM CDT	Heat Advisory	FSD	29 hr
Jun 28, 2:02 PM CDT	Heat Advisory	FSD	31 hr
Jun 29, 3:18 PM CDT	Heat Advisory	FSD	30 hr
Jun 30, 4:23 PM CDT	Tornado Warning	FSD	37 min
Jun 30, 4:51 PM CDT	Mesoscale Discussion	SPC	114 min
Jun 30, 5:02 PM CDT	Tornado Warning Tornado observed	FSD	28 min
Jun 30, 5:17 PM CDT	Severe Thunderstorm Warning	FSD	43 min
Jun 30, 5:19 PM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 30, 5:27 PM CDT	Tornado Warning	FSD	33 min
Jun 30, 5:58 PM CDT	Severe Thunderstorm Warning	FSD	47 min
Jun 30, 6:10 PM CDT	Tornado Warning	FSD	35 min
Jun 30, 7:30 PM CDT	Mesoscale Discussion	SPC	90 min
Jun 30, 9:40 PM CDT	Mesoscale Discussion	SPC	65 min
Jul 3, 5:10 PM CDT	Mesoscale Discussion	SPC	2 hr
Jul 3, 7:09 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 3, 10:13 PM CDT	Mesoscale Discussion	SPC	92 min
Jul 3, 10:14 PM CDT	Severe Thunderstorm Warning	FSD	46 min
Jul 3, 10:52 PM CDT	Severe Thunderstorm Warning	FSD	53 min
Jul 4, 11:32 PM CDT	Severe Thunderstorm Watch	SPC	4 hr
Jul 5, 1:43 AM CDT	Mesoscale Discussion	SPC	2 hr
Jul 9, 8:08 PM CDT	Severe Thunderstorm Warning	FSD	52 min
Jul 14, 2:56 AM CDT	Heat Advisory	FSD	18 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 15, 10:14 PM CDT	Mesoscale Discussion	SPC	91 min
Jul 16, 11:34 PM CDT	Mesoscale Discussion	SPC	86 min
Jul 17, 4:07 AM CDT	Heat Advisory	FSD	9 hr
Jul 17, 4:09 AM CDT	Severe Thunderstorm Warning	FSD	51 min
Jul 17, 4:14 AM CDT	Mesoscale Discussion	SPC	91 min
Jul 17, 4:32 AM CDT	Severe Thunderstorm Warning	FSD	28 min
Jul 17, 4:51 AM CDT	Severe Thunderstorm Warning	FSD	39 min
Jul 17, 5:19 PM CDT	Heat Advisory	FSD	28 hr
Jul 18, 4:09 PM CDT	Heat Advisory	FSD	28 hr
Jul 20, 5:02 AM CDT	Mesoscale Discussion	SPC	88 min
Jul 28, 7:27 PM CDT	Severe Thunderstorm Watch	SPC	4 hr
Jul 28, 8:51 PM CDT	Severe Thunderstorm Warning	FSD	39 min
Jul 28, 8:54 PM CDT	Tornado Warning Tornado observed	FSD	21 min
Aug 2, 10:44 AM CDT	Areal Flood Warning	FSD	6 hr
Aug 6, 6:19 PM CDT	Mesoscale Discussion	SPC	116 min
Aug 6, 8:19 PM CDT	Severe Thunderstorm Watch	SPC	9 hr
Aug 6, 8:52 PM CDT	Severe Thunderstorm Warning	FSD	53 min
Aug 6, 9:38 PM CDT	Severe Thunderstorm Warning	FSD	67 min
Aug 6, 10:04 PM CDT	Severe Thunderstorm Warning	FSD	41 min
Aug 6, 10:24 PM CDT	Mesoscale Discussion	SPC	2 hr
Aug 6, 10:33 PM CDT	Severe Thunderstorm Warning	FSD	42 min
Aug 7, 10:51 PM CDT	Severe Thunderstorm Warning	FSD	24 min
Aug 7, 11:13 PM CDT	Mesoscale Discussion	SPC	92 min
Aug 9, 1:47 PM CDT	Mesoscale Discussion	SPC	88 min
Aug 9, 2:09 PM CDT	Tornado Watch	SPC	7 hr
Aug 9, 6:03 PM CDT	Mesoscale Discussion	SPC	57 min
Aug 9, 6:27 PM CDT	Severe Thunderstorm Warning	FSD	33 min
Aug 9, 6:57 PM CDT	Severe Thunderstorm Warning	FSD	48 min
Aug 9, 6:59 PM CDT	Mesoscale Discussion	SPC	2 hr
Aug 9, 7:03 PM CDT	Tornado Warning	FSD	27 min
Aug 9, 7:29 PM CDT	Tornado Warning	FSD	16 min
Aug 9, 7:38 PM CDT	Severe Thunderstorm Warning	FSD	52 min
Aug 9, 7:47 PM CDT	Tornado Warning	FSD	28 min
Aug 9, 7:52 PM CDT	Flash Flood Warning	FSD	6 hr
Aug 9, 8:16 PM CDT	Severe Thunderstorm Warning	FSD	29 min
Aug 15, 1:18 PM CDT	Mesoscale Discussion	SPC	87 min
Aug 16, 9:57 PM CDT	Severe Thunderstorm Warning	FSD	33 min
Aug 16, 10:28 PM CDT	Severe Thunderstorm Warning	FSD	32 min
Aug 17, 5:12 PM CDT	Mesoscale Discussion	SPC	2 hr
Aug 17, 5:32 PM CDT	Severe Thunderstorm Warning	FSD	43 min
Aug 17, 6:14 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Aug 17, 6:16 PM CDT	Severe Thunderstorm Warning	FSD	44 min
Aug 17, 6:24 PM CDT	Tornado Warning	FSD	36 min
Aug 17, 7:10 PM CDT	Severe Thunderstorm Warning	FSD	50 min
Aug 17, 7:43 PM CDT	Severe Thunderstorm Warning	FSD	47 min
Aug 17, 8:06 PM CDT	Severe Thunderstorm Warning	FSD	39 min
Aug 17, 8:26 PM CDT	Mesoscale Discussion	SPC	94 min
Aug 25, 9:49 PM CDT	Mesoscale Discussion	SPC	116 min
Aug 26, 1:05 AM CDT	Mesoscale Discussion	SPC	55 min
Sep 10, 2:25 PM CDT	Mesoscale Discussion	SPC	2 hr
Sep 10, 6:25 PM CDT	Severe Thunderstorm Watch	SPC	4 hr
Sep 10, 6:26 PM CDT	Severe Thunderstorm Warning	FSD	34 min
Sep 10, 6:56 PM CDT	Severe Thunderstorm Warning	FSD	34 min
Sep 10, 7:24 PM CDT	Severe Thunderstorm Warning	FSD	36 min
Sep 10, 8:01 PM CDT	Severe Thunderstorm Warning	FSD	44 min
Sep 10, 8:07 PM CDT	Mesoscale Discussion	SPC	83 min
Sep 10, 8:33 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Sep 10, 9:13 PM CDT	Severe Thunderstorm Warning	FSD	47 min
Sep 11, 4:07 AM CDT	Flash Flood Watch	FSD	26 hr
Sep 11, 5:43 PM CDT	Mesoscale Discussion	SPC	2 hr
Sep 11, 8:03 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Sep 11, 9:01 PM CDT	Flash Flood Warning	FSD	4 hr
Sep 12, 1:01 AM CDT	Areal Flood Warning	FSD	10 hr
Sep 12, 10:38 AM CDT	Areal Flood Warning	FSD	24 hr
Sep 13, 10:29 AM CDT	Areal Flood Warning	FSD	24 hr
Sep 14, 10:25 AM CDT	Areal Flood Warning	FSD	48 hr
Sep 21, 1:22 AM CDT	Mesoscale Discussion	SPC	83 min
Oct 4, 3:31 PM CDT	Wind Advisory	FSD	27 hr
Oct 10, 3:22 AM CDT	Winter Weather Advisory	FSD	67 hr
Oct 20, 9:20 PM CDT	Wind Advisory	FSD	43 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 27, 5:56 PM CST	Winter Weather Advisory	FSD	4 days
Nov 28, 3:20 AM CST	Winter Storm Watch	FSD	35 hr
Nov 29, 11:52 AM CST	Winter Storm Warning	FSD	48 hr
Nov 29, 11:52 AM CST	Winter Weather Advisory	FSD	18 hr
Nov 30, 6:02 AM CST	Winter Weather Advisory	FSD	6 hr
Dec 24, 2:24 PM CST	Dense Fog Advisory	FSD	34 hr
Dec 26, 3:10 PM CST	Winter Storm Watch	FSD	24 hr
Dec 27, 3:18 PM CST	Winter Storm Warning	FSD	63 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	31
Tornado Warning	9
Severe Thunderstorm Watch	10
Tornado Watch	1
Mesoscale Discussion	32
Special Weather Statement	4
Flooding
Areal Flood Warning	6
Flash Flood Warning	2
Flash Flood Watch	1
Flood Watch	1
Winter
Blizzard Warning	2
Winter Storm Warning	5
Winter Storm Watch	6
Winter Weather Advisory	14
Heat
Excessive Heat Watch	1
Heat Advisory	8
Cold
Wind Chill Warning	2
Wind Chill Watch	1
Frost Advisory	1
Wind Chill Advisory	4
Wind and dust
High Wind Warning	1
High Wind Watch	1
Wind Advisory	6
Fog and smoke
Dense Fog Advisory	1

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.