Alert archive / Illinois / LaSalle County

Weather alerts in LaSalle County, Illinois, 2015

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

LaSalle County and its neighbors

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

Alerts: 206
Warnings: 62
Watches: 31
Advisories: 68
Busiest month: June68 alerts
Busiest day: June 23, 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 5 tornado warnings covering LaSalle County in 2015 had a tornado report inside them; 5 of 5 tornado reports fell inside a warning, on average 20 minutes after it went out.

LaSalle County, 2015

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	5	3	40%	5	100%	20 min
Severe thunderstorm warnings	15	7	53%	25	48%	22 min
Flash flood warnings	8	4	50%	6	100%	40 min

Each office's whole area, 2015

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Chicago, IL: tornado warnings	36	22	39%	69	83%	15 min
NWS Chicago, IL: severe thunderstorm warnings	147	73	50%	252	71%	20 min
NWS Chicago, IL: flash flood warnings	46	20	57%	44	84%	87 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, 3:33 PM CST	Winter Weather Advisory	LOT	23 hr
Jan 4, 3:29 AM CST	Wind Chill Advisory	LOT	33 hr
Jan 4, 3:29 AM CST	Winter Storm Watch	LOT	23 hr
Jan 5, 2:49 AM CST	Winter Weather Advisory	LOT	25 hr
Jan 5, 6:29 PM CST	Mesoscale Discussion	SPC	5 hr
Jan 6, 3:43 AM CST	Wind Chill Warning	LOT	31 hr
Jan 7, 10:52 AM CST	Wind Chill Advisory	LOT	25 hr
Jan 8, 4:03 AM CST	Winter Weather Advisory	LOT	23 hr
Jan 8, 5:38 PM CST	Wind Chill Advisory	LOT	16 hr
Jan 9, 3:15 AM CST	Wind Chill Advisory	LOT	30 hr
Jan 26, 4:44 PM CST	Freezing Rain Advisory	LOT	13 hr
Jan 30, 10:37 AM CST	Winter Storm Watch	LOT	16 hr
Jan 31, 2:46 AM CST	Winter Storm Warning	LOT	45 hr
Jan 31, 10:13 PM CST	Mesoscale Discussion	SPC	6 hr
Feb 1, 4:08 AM CST	Blizzard Warning	LOT	23 hr
Feb 1, 7:43 AM CST	Mesoscale Discussion	SPC	6 hr
Feb 4, 3:05 AM CST	Winter Weather Advisory	LOT	14 hr
Feb 14, 3:52 AM CST	Wind Chill Advisory	LOT	29 hr
Feb 18, 3:50 AM CST	Wind Chill Advisory	LOT	32 hr
Feb 19, 2:58 PM CST	Wind Chill Advisory	LOT	15 hr
Feb 22, 3:44 AM CST	Wind Chill Advisory	LOT	29 hr
Feb 26, 3:03 PM CST	Wind Chill Advisory	LOT	18 hr
Mar 2, 11:44 AM CST	Winter Weather Advisory	LOT	24 hr
Mar 10, 1:05 AM CDT	Dense Fog Advisory	LOT	12 hr
Mar 10, 9:55 AM CDT	River Flood Warning	LOT	39 hr
Mar 10, 11:43 AM CDT	River Flood Advisory	LOT	3 days
Mar 10, 11:43 AM CDT	River Flood Advisory	LOT	4 days
Mar 10, 7:05 PM CDT	Dense Fog Advisory	LOT	14 hr
Mar 11, 11:40 AM CDT	River Flood Warning	LOT	58 hr
Mar 22, 3:19 PM CDT	Winter Weather Advisory	LOT	21 hr
Apr 4, 4:34 PM CDT	Fire Weather Watch	LOT	12 hr
Apr 9, 1:48 PM CDT	Tornado Watch	SPC	9 hr
Apr 9, 3:12 PM CDT	Mesoscale Discussion	SPC	93 min
Apr 9, 6:04 PM CDT	Mesoscale Discussion	SPC	86 min
Apr 9, 7:51 PM CDT	Tornado Warning	LOT	39 min
Apr 9, 8:21 PM CDT	Severe Thunderstorm Warning	LOT	24 min
Apr 9, 8:40 PM CDT	Severe Thunderstorm Warning	LOT	35 min
Apr 9, 10:27 PM CDT	Wind Advisory	LOT	6 hr
Apr 10, 2:17 PM CDT	Wind Advisory	LOT	5 hr
Apr 15, 10:47 AM CDT	Red Flag Warning	LOT	8 hr
Apr 21, 3:16 AM CDT	Wind Advisory	LOT	16 hr
Apr 22, 3:25 PM CDT	Freeze Warning	LOT	17 hr
Apr 23, 4:22 PM CDT	Frost Advisory	LOT	16 hr
May 8, 12:59 PM CDT	Mesoscale Discussion	SPC	3 hr
May 8, 2:09 PM CDT	Special Weather Statement	LOT	36 min
May 8, 9:21 PM CDT	River Flood Advisory	LOT	5 days
May 8, 9:25 PM CDT	River Flood Watch	LOT	5 days
May 9, 11:12 AM CDT	River Flood Advisory	LOT	64 hr
May 10, 11:22 AM CDT	River Flood Advisory	LOT	5 days
May 10, 11:26 AM CDT	River Flood Watch	LOT	5 days
May 10, 1:52 PM CDT	River Flood Warning	LOT	5 days
May 24, 3:34 PM CDT	Mesoscale Discussion	SPC	56 min
May 24, 5:34 PM CDT	Tornado Watch	SPC	7 hr
May 24, 6:41 PM CDT	Mesoscale Discussion	SPC	94 min
Jun 7, 2:36 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jun 7, 5:34 PM CDT	Mesoscale Discussion	SPC	86 min
Jun 7, 8:31 PM CDT	Areal Flood Advisory	LOT	4 hr
Jun 7, 11:10 PM CDT	Areal Flood Advisory	LOT	11 hr
Jun 8, 12:00 PM CDT	River Flood Warning	LOT	34 hr
Jun 8, 3:32 PM CDT	Mesoscale Discussion	SPC	88 min
Jun 9, 4:16 AM CDT	River Flood Advisory	LOT	44 hr
Jun 9, 11:41 AM CDT	River Flood Advisory	LOT	3 days
Jun 10, 7:29 AM CDT	Special Weather Statement	LOT	61 min
Jun 10, 8:19 AM CDT	Special Weather Statement	LOT	41 min
Jun 10, 3:51 PM CDT	Mesoscale Discussion	SPC	114 min
Jun 10, 5:42 PM CDT	Special Weather Statement	LOT	33 min
Jun 11, 11:13 AM CDT	River Flood Warning	LOT	46 days
Jun 11, 11:21 AM CDT	River Flood Advisory	LOT	68 hr
Jun 11, 2:06 PM CDT	Flash Flood Watch	LOT	20 hr
Jun 11, 3:52 PM CDT	Mesoscale Discussion	SPC	113 min
Jun 11, 5:49 PM CDT	Tornado Watch	SPC	2 hr
Jun 11, 7:53 PM CDT	Mesoscale Discussion	SPC	67 min
Jun 13, 2:42 PM CDT	Mesoscale Discussion	SPC	2 hr
Jun 13, 4:32 PM CDT	Severe Thunderstorm Warning	LOT	43 min
Jun 13, 4:35 PM CDT	Severe Thunderstorm Watch	SPC	2 hr
Jun 13, 5:11 PM CDT	Severe Thunderstorm Warning	LOT	49 min
Jun 13, 5:44 PM CDT	Flash Flood Warning	LOT	6 hr
Jun 13, 9:38 PM CDT	River Flood Warning	LOT	18 days
Jun 13, 10:08 PM CDT	Areal Flood Advisory	LOT	3 hr
Jun 13, 11:42 PM CDT	Areal Flood Warning	LOT	12 hr
Jun 14, 8:17 AM CDT	River Flood Advisory	LOT	40 hr
Jun 14, 6:54 PM CDT	Areal Flood Advisory	LOT	4 hr
Jun 15, 4:10 AM CDT	Flash Flood Watch	LOT	24 hr
Jun 15, 10:13 AM CDT	River Flood Advisory	LOT	62 hr
Jun 15, 10:32 AM CDT	Flash Flood Warning	LOT	6 hr
Jun 15, 4:41 PM CDT	Areal Flood Warning	LOT	18 hr
Jun 15, 5:39 PM CDT	Severe Thunderstorm Warning	LOT	21 min
Jun 15, 6:09 PM CDT	Flash Flood Warning	LOT	4 hr
Jun 15, 8:44 PM CDT	River Flood Warning	LOT	3 days
Jun 15, 10:29 PM CDT	Areal Flood Warning	LOT	12 hr
Jun 20, 6:55 PM CDT	Severe Thunderstorm Warning	LOT	35 min
Jun 20, 9:47 PM CDT	Special Weather Statement	LOT	43 min
Jun 20, 9:57 PM CDT	Severe Thunderstorm Warning	LOT	33 min
Jun 20, 10:15 PM CDT	Flash Flood Warning	LOT	6 hr
Jun 22, 9:14 AM CDT	Mesoscale Discussion	SPC	61 min
Jun 22, 9:39 AM CDT	Severe Thunderstorm Watch	SPC	3 hr
Jun 22, 11:00 AM CDT	Mesoscale Discussion	SPC	2 hr
Jun 22, 11:14 AM CDT	Severe Thunderstorm Warning	LOT	46 min
Jun 22, 11:52 AM CDT	Special Weather Statement	LOT	23 min
Jun 22, 1:22 PM CDT	Mesoscale Discussion	SPC	113 min
Jun 22, 3:56 PM CDT	Tornado Watch	SPC	9 hr
Jun 22, 6:08 PM CDT	Mesoscale Discussion	SPC	67 min
Jun 22, 7:30 PM CDT	Flash Flood Warning	LOT	6 hr
Jun 22, 8:03 PM CDT	Tornado Warning	LOT	42 min
Jun 22, 8:16 PM CDT	Mesoscale Discussion	SPC	59 min
Jun 22, 8:38 PM CDT	Tornado Warning Tornado observed	LOT	37 min
Jun 22, 8:59 PM CDT	Flash Flood Warning	LOT	3 hr
Jun 22, 9:06 PM CDT	Tornado Warning Tornado observed	LOT	39 min
Jun 22, 10:37 PM CDT	Severe Thunderstorm Warning	LOT	53 min
Jun 22, 11:34 PM CDT	River Flood Warning	LOT	46 hr
Jun 22, 11:50 PM CDT	Areal Flood Warning	LOT	6 hr
Jun 23, 4:54 AM CDT	Areal Flood Warning	LOT	30 hr
Jun 23, 3:08 PM CDT	Flash Flood Watch	LOT	44 hr
Jun 24, 11:15 AM CDT	River Flood Warning	LOT	64 hr
Jun 24, 9:26 PM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 26, 1:17 PM CDT	Areal Flood Advisory	LOT	6 hr
Jun 26, 2:08 PM CDT	Areal Flood Warning	LOT	21 hr
Jun 28, 6:25 PM CDT	Areal Flood Advisory	LOT	6 hr
Jun 29, 5:30 PM CDT	Tornado Warning	LOT	23 min
Jun 29, 5:45 PM CDT	Areal Flood Advisory	LOT	4 hr
Jun 29, 6:21 PM CDT	Special Weather Statement	LOT	54 min
Jun 29, 6:25 PM CDT	Flash Flood Warning	LOT	5 hr
Jul 6, 10:32 PM CDT	Areal Flood Advisory	LOT	3 hr
Jul 9, 9:33 AM CDT	River Flood Warning	LOT	49 hr
Jul 10, 9:03 AM CDT	River Flood Advisory	LOT	24 hr
Jul 10, 10:02 AM CDT	River Flood Advisory	LOT	3 days
Jul 11, 10:49 PM CDT	River Flood Warning	LOT	70 hr
Jul 12, 2:19 PM CDT	Flash Flood Watch	LOT	33 hr
Jul 13, 4:14 AM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 13, 4:18 AM CDT	Heat Advisory	LOT	15 hr
Jul 13, 7:19 AM CDT	Mesoscale Discussion	SPC	86 min
Jul 13, 7:55 AM CDT	Areal Flood Advisory	LOT	6 hr
Jul 13, 12:07 PM CDT	River Flood Warning	LOT	3 days
Jul 13, 3:21 PM CDT	Mesoscale Discussion	SPC	84 min
Jul 13, 4:01 PM CDT	Tornado Watch	SPC	7 hr
Jul 13, 4:59 PM CDT	Severe Thunderstorm Warning	LOT	61 min
Jul 13, 5:37 PM CDT	Severe Thunderstorm Warning	LOT	53 min
Jul 13, 6:03 PM CDT	Areal Flood Advisory	LOT	4 hr
Jul 13, 6:59 PM CDT	Mesoscale Discussion	SPC	91 min
Jul 13, 8:26 PM CDT	Areal Flood Advisory	LOT	5 hr
Jul 16, 4:55 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 16, 7:58 PM CDT	Mesoscale Discussion	SPC	92 min
Jul 17, 10:45 AM CDT	Heat Advisory	LOT	33 hr
Jul 18, 12:31 PM CDT	Mesoscale Discussion	SPC	119 min
Jul 18, 1:31 PM CDT	Tornado Watch	SPC	5 hr
Jul 18, 1:56 PM CDT	Flash Flood Watch	LOT	5 hr
Jul 25, 4:52 PM CDT	Mesoscale Discussion	SPC	2 hr
Jul 29, 12:29 AM CDT	Special Weather Statement	LOT	46 min
Jul 29, 1:14 AM CDT	Areal Flood Advisory	LOT	3 hr
Aug 2, 8:30 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Aug 10, 4:47 AM CDT	Dense Fog Advisory	LOT	5 hr
Aug 15, 1:43 PM CDT	Mesoscale Discussion	SPC	2 hr
Aug 18, 12:49 PM CDT	Mesoscale Discussion	SPC	116 min
Aug 18, 1:35 PM CDT	Tornado Watch	SPC	8 hr
Aug 18, 3:53 PM CDT	Mesoscale Discussion	SPC	2 hr
Aug 18, 6:19 PM CDT	Severe Thunderstorm Warning	LOT	56 min
Sep 8, 9:52 AM CDT	Mesoscale Discussion	SPC	113 min
Sep 10, 12:47 PM CDT	Mesoscale Discussion	SPC	58 min
Sep 17, 1:49 PM CDT	Mesoscale Discussion	SPC	116 min
Sep 18, 3:43 AM CDT	Flash Flood Watch	LOT	23 hr
Sep 18, 6:27 PM CDT	Flash Flood Warning	LOT	6 hr
Sep 18, 11:34 PM CDT	Special Weather Statement	LOT	26 min
Oct 15, 3:43 AM CDT	Freeze Watch	LOT	24 hr
Oct 16, 3:13 AM CDT	Freeze Warning	LOT	30 hr
Oct 19, 3:23 AM CDT	Red Flag Warning	LOT	16 hr
Nov 3, 3:43 AM CST	Dense Fog Advisory	LOT	6 hr
Nov 3, 7:08 PM CST	Dense Fog Advisory	LOT	15 hr
Nov 10, 2:51 PM CST	Wind Advisory	LOT	51 hr
Nov 11, 5:46 PM CST	Mesoscale Discussion	SPC	59 min
Nov 11, 6:16 PM CST	Severe Thunderstorm Watch	SPC	4 hr
Nov 11, 7:00 PM CST	Special Weather Statement	LOT	60 min
Nov 11, 7:31 PM CST	Severe Thunderstorm Warning	LOT	59 min
Nov 11, 7:56 PM CST	Severe Thunderstorm Warning	LOT	34 min
Nov 11, 8:30 PM CST	Severe Thunderstorm Warning	LOT	45 min
Nov 16, 11:52 AM CST	River Flood Advisory	LOT	4 days
Nov 16, 11:52 AM CST	River Flood Advisory	LOT	4 days
Nov 19, 3:46 AM CST	Winter Storm Watch	LOT	24 hr
Nov 20, 3:24 AM CST	Winter Storm Warning	LOT	41 hr
Nov 21, 6:28 AM CST	Mesoscale Discussion	SPC	4 hr
Nov 21, 6:32 AM CST	Mesoscale Discussion	SPC	4 hr
Nov 26, 9:52 AM CST	River Flood Advisory	LOT	4 days
Nov 26, 9:55 AM CST	River Flood Advisory	LOT	4 days
Nov 27, 11:26 AM CST	River Flood Warning	LOT	3 days
Nov 27, 11:36 AM CST	River Flood Advisory	LOT	69 hr
Dec 4, 8:01 PM CST	Dense Fog Advisory	LOT	16 hr
Dec 6, 9:18 PM CST	Dense Fog Advisory	LOT	24 hr
Dec 12, 4:22 AM CST	Dense Fog Advisory	LOT	25 hr
Dec 12, 8:42 PM CST	River Flood Advisory	LOT	4 days
Dec 13, 9:11 PM CST	River Flood Watch	LOT	51 hr
Dec 14, 9:56 AM CST	River Flood Warning	LOT	53 hr
Dec 14, 11:26 AM CST	River Flood Warning	LOT	3 days
Dec 14, 11:32 AM CST	River Flood Advisory	LOT	36 hr
Dec 21, 8:45 PM CST	River Flood Advisory	LOT	5 days
Dec 21, 9:06 PM CST	River Flood Warning	LOT	27 days
Dec 21, 9:10 PM CST	River Flood Advisory	LOT	6 days
Dec 22, 9:35 AM CST	River Flood Watch	LOT	3 days
Dec 23, 10:19 AM CST	River Flood Advisory	LOT	67 hr
Dec 23, 11:30 AM CST	Wind Advisory	LOT	16 hr
Dec 26, 10:31 AM CST	River Flood Warning	LOT	6 days
Dec 26, 10:39 AM CST	River Flood Advisory	LOT	3 days
Dec 26, 11:38 AM CST	River Flood Warning	LOT	8 days
Dec 26, 3:32 PM CST	Winter Storm Watch	LOT	24 hr
Dec 27, 11:12 AM CST	River Flood Warning	LOT	4 days
Dec 27, 3:07 PM CST	Winter Storm Warning	LOT	33 hr
Dec 28, 5:26 AM CST	Mesoscale Discussion	SPC	4 hr
Dec 28, 5:27 PM CST	Areal Flood Advisory	LOT	12 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	15
Tornado Warning	5
Severe Thunderstorm Watch	8
Tornado Watch	7
Mesoscale Discussion	35
Special Weather Statement	10
Flooding
Areal Flood Warning	6
Flash Flood Warning	8
River Flood Warning	19
Flash Flood Watch	6
River Flood Watch	4
Areal Flood Advisory	13
River Flood Advisory	23
Winter
Blizzard Warning	1
Winter Storm Warning	3
Winter Storm Watch	4
Freezing Rain Advisory	1
Winter Weather Advisory	6
Heat
Heat Advisory	2
Cold
Freeze Warning	2
Wind Chill Warning	1
Freeze Watch	1
Frost Advisory	1
Wind Chill Advisory	9
Wind and dust
Wind Advisory	5
Fire
Red Flag Warning	2
Fire Weather Watch	1
Fog and smoke
Dense Fog Advisory	8

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.