Alert archive / Illinois / LaSalle County

Weather alerts in LaSalle County, Illinois, 2008

233 weather alerts in 2008, 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 2008. Tap one for its archive.

Alerts: 233
Warnings: 85
Watches: 45
Advisories: 54
Busiest month: June51 alerts
Busiest day: September 13, 200816 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 3 tornado warnings covering LaSalle County in 2008 had a tornado report inside them; 1 of 1 tornado reports fell inside a warning, on average 21 minutes after it went out.

LaSalle County, 2008

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	3	2	33%	1	100%	21 min
Severe thunderstorm warnings	36	20	44%	28	57%	31 min
Flash flood warnings	12	9	25%	2	50%	252 min

Each office's whole area, 2008

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Chicago, IL: tornado warnings	37	14	62%	75	80%	24 min
NWS Chicago, IL: severe thunderstorm warnings	180	80	56%	370	75%	31 min
NWS Chicago, IL: flash flood warnings	38	15	61%	78	51%	180 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 1, 1:25 PM CST	Snow and Blowing Snow Advisory	LOT	7 hr
Jan 1, 11:25 PM CST	Wind Chill Advisory	LOT	9 hr
Jan 5, 9:29 PM CST	Dense Fog Advisory	LOT	15 hr
Jan 6, 1:42 PM CST	Flood Watch	LOT	50 hr
Jan 7, 10:07 AM CST	River Flood Watch	LOT	24 hr
Jan 7, 10:59 AM CST	River Flood Watch	LOT	24 hr
Jan 7, 1:47 PM CST	Mesoscale Discussion	SPC	58 min
Jan 7, 2:35 PM CST	Tornado Watch	SPC	6 hr
Jan 7, 4:36 PM CST	Severe Thunderstorm Warning	LOT	39 min
Jan 7, 5:29 PM CST	Severe Thunderstorm Warning	LOT	61 min
Jan 8, 4:31 AM CST	River Flood Warning	LOT	5 days
Jan 8, 4:31 AM CST	River Flood Warning	LOT	16 days
Jan 17, 9:15 AM CST	Wind Chill Advisory	LOT	3 days
Jan 22, 5:08 AM CST	Blowing Snow Advisory	LOT	5 hr
Jan 23, 3:50 AM CST	Wind Chill Advisory	LOT	32 hr
Jan 28, 7:44 PM CST	River Flood Advisory	LOT	27 hr
Jan 28, 9:41 PM CST	Winter Storm Warning	LOT	26 hr
Jan 29, 9:22 PM CST	Wind Chill Advisory	LOT	13 hr
Jan 29, 9:22 PM CST	Wind Advisory	LOT	6 hr
Jan 31, 4:28 AM CST	Snow Advisory	LOT	28 hr
Jan 31, 4:28 AM CST	Winter Storm Warning	LOT	32 hr
Feb 3, 3:09 PM CST	Winter Weather Advisory	LOT	10 hr
Feb 3, 4:42 PM CST	Mesoscale Discussion	SPC	4 hr
Feb 4, 4:03 AM CST	Winter Storm Watch	LOT	24 hr
Feb 4, 6:49 AM CST	Dense Fog Advisory	LOT	21 hr
Feb 4, 8:08 AM CST	Severe Thunderstorm Warning	LOT	35 min
Feb 4, 8:44 PM CST	River Flood Warning	LOT	21 days
Feb 5, 4:27 AM CST	Winter Storm Warning	LOT	42 hr
Feb 5, 4:27 AM CST	Winter Weather Advisory	LOT	38 hr
Feb 5, 9:18 AM CST	River Flood Warning	LOT	3 days
Feb 5, 11:15 AM CST	Flood Watch	LOT	26 hr
Feb 6, 6:07 AM CST	Mesoscale Discussion	SPC	6 hr
Feb 9, 4:24 AM CST	Wind Chill Advisory	LOT	44 hr
Feb 10, 3:41 PM CST	Snow Advisory	LOT	37 hr
Feb 15, 3:13 PM CST	Flood Watch	LOT	48 hr
Feb 17, 10:11 AM CST	River Flood Warning	LOT	33 hr
Feb 17, 10:11 AM CST	River Flood Warning	LOT	34 hr
Feb 18, 8:45 PM CST	River Flood Warning	LOT	13 hr
Feb 19, 2:52 PM CST	Wind Chill Advisory	LOT	20 hr
Feb 24, 3:17 AM CST	Winter Storm Watch	LOT	24 hr
Feb 25, 3:45 AM CST	Winter Storm Warning	LOT	24 hr
Mar 2, 12:37 PM CST	River Flood Advisory	LOT	19 hr
Mar 2, 6:34 PM CST	Flash Flood Watch	LOT	16 hr
Mar 2, 8:39 PM CST	River Flood Warning	LOT	55 hr
Mar 2, 8:39 PM CST	River Flood Warning	LOT	7 days
Mar 17, 11:59 AM CDT	River Flood Watch	LOT	24 hr
Mar 18, 8:44 AM CDT	Dense Fog Advisory	LOT	5 hr
Mar 21, 11:50 AM CDT	River Flood Advisory	LOT	9 hr
Mar 30, 2:58 AM CDT	Flood Watch	LOT	42 hr
Mar 31, 8:53 AM CDT	Mesoscale Discussion	SPC	2 hr
Mar 31, 5:47 PM CDT	Wind Advisory	LOT	2 hr
Apr 1, 10:49 AM CDT	River Flood Advisory	LOT	66 hr
Apr 9, 4:19 AM CDT	Flash Flood Watch	LOT	46 hr
Apr 9, 9:43 PM CDT	River Flood Watch	LOT	32 hr
Apr 9, 10:01 PM CDT	River Flood Watch	LOT	37 hr
Apr 10, 2:11 PM CDT	Wind Advisory	LOT	5 hr
Apr 11, 5:55 AM CDT	River Flood Warning	LOT	22 hr
Apr 11, 10:05 AM CDT	Wind Advisory	LOT	10 hr
Apr 11, 10:53 AM CDT	River Flood Warning	LOT	6 days
Apr 13, 9:22 PM CDT	River Flood Advisory	LOT	12 hr
Apr 17, 9:00 PM CDT	River Flood Advisory	LOT	48 hr
Apr 19, 7:03 PM CDT	Dense Fog Advisory	LOT	14 hr
Apr 25, 1:27 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Apr 25, 3:41 PM CDT	Tornado Watch	SPC	4 hr
Apr 25, 4:17 PM CDT	Severe Thunderstorm Warning	LOT	58 min
Apr 25, 5:37 PM CDT	Severe Thunderstorm Warning	LOT	15 min
Apr 28, 4:03 AM CDT	Freeze Warning	LOT	27 hr
May 2, 3:05 PM CDT	Mesoscale Discussion	SPC	115 min
May 11, 3:36 AM CDT	Wind Advisory	LOT	17 hr
May 11, 5:33 AM CDT	Areal Flood Advisory	LOT	28 days
May 12, 11:04 AM CDT	River Flood Advisory	LOT	33 hr
May 13, 5:45 PM CDT	Mesoscale Discussion	SPC	60 min
May 13, 7:11 PM CDT	Mesoscale Discussion	SPC	2 hr
May 25, 7:54 PM CDT	Tornado Watch	SPC	6 hr
May 25, 10:59 PM CDT	Mesoscale Discussion	SPC	61 min
May 26, 1:16 AM CDT	Severe Thunderstorm Warning	LOT	59 min
May 26, 2:01 AM CDT	Areal Flood Advisory	LOT	18 days
May 30, 7:56 AM CDT	Tornado Watch	SPC	6 hr
May 30, 10:13 AM CDT	Mesoscale Discussion	SPC	62 min
May 30, 4:29 PM CDT	Mesoscale Discussion	SPC	61 min
May 31, 10:57 PM CDT	Severe Thunderstorm Warning	LOT	33 min
Jun 3, 10:05 AM CDT	Mesoscale Discussion	SPC	85 min
Jun 4, 5:51 PM CDT	Mesoscale Discussion	SPC	84 min
Jun 4, 7:02 PM CDT	Tornado Watch	SPC	8 hr
Jun 4, 9:03 PM CDT	Tornado Warning	LOT	31 min
Jun 4, 10:34 PM CDT	Severe Thunderstorm Warning	LOT	23 min
Jun 5, 9:30 AM CDT	Mesoscale Discussion	SPC	90 min
Jun 5, 10:45 AM CDT	River Flood Warning	LOT	54 hr
Jun 6, 5:14 AM CDT	Mesoscale Discussion	SPC	61 min
Jun 6, 10:50 AM CDT	Mesoscale Discussion	SPC	85 min
Jun 6, 1:05 PM CDT	Tornado Watch	SPC	5 hr
Jun 6, 3:39 PM CDT	Wind Advisory	LOT	4 hr
Jun 7, 2:01 PM CDT	Tornado Watch	SPC	6 hr
Jun 7, 3:38 PM CDT	Tornado Warning	LOT	41 min
Jun 7, 3:48 PM CDT	Tornado Warning	LOT	57 min
Jun 8, 9:47 AM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jun 8, 11:30 AM CDT	Severe Thunderstorm Warning	LOT	60 min
Jun 8, 12:31 PM CDT	Severe Thunderstorm Warning	LOT	44 min
Jun 8, 2:04 PM CDT	Mesoscale Discussion	SPC	116 min
Jun 8, 3:59 PM CDT	Flash Flood Watch	LOT	35 hr
Jun 8, 7:52 PM CDT	Mesoscale Discussion	SPC	53 min
Jun 8, 8:03 PM CDT	Tornado Watch	SPC	5 hr
Jun 8, 10:01 PM CDT	Mesoscale Discussion	SPC	59 min
Jun 8, 10:58 PM CDT	Severe Thunderstorm Warning	LOT	17 min
Jun 9, 12:02 PM CDT	River Flood Warning	LOT	34 hr
Jun 12, 3:52 AM CDT	Flash Flood Watch	LOT	34 hr
Jun 12, 12:37 PM CDT	Mesoscale Discussion	SPC	113 min
Jun 12, 1:04 PM CDT	Tornado Watch	SPC	7 hr
Jun 12, 3:45 PM CDT	Mesoscale Discussion	SPC	90 min
Jun 12, 6:49 PM CDT	Mesoscale Discussion	SPC	86 min
Jun 12, 7:48 PM CDT	Tornado Watch	SPC	6 hr
Jun 12, 11:15 PM CDT	Mesoscale Discussion	SPC	90 min
Jun 12, 11:37 PM CDT	Severe Thunderstorm Warning	LOT	53 min
Jun 12, 11:59 PM CDT	Severe Thunderstorm Warning	LOT	61 min
Jun 13, 1:36 AM CDT	Mesoscale Discussion	SPC	54 min
Jun 13, 1:57 AM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 14, 5:17 PM CDT	Mesoscale Discussion	SPC	88 min
Jun 15, 5:10 AM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jun 15, 6:49 AM CDT	Severe Thunderstorm Warning	LOT	41 min
Jun 15, 11:42 AM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 15, 2:23 PM CDT	Severe Thunderstorm Warning	LOT	67 min
Jun 15, 2:51 PM CDT	Severe Thunderstorm Warning	LOT	39 min
Jun 15, 3:01 PM CDT	Severe Thunderstorm Warning	LOT	59 min
Jun 15, 3:17 PM CDT	Flash Flood Warning	LOT	3 hr
Jun 27, 11:55 AM CDT	Mesoscale Discussion	SPC	3 hr
Jun 27, 12:30 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Jun 27, 8:56 PM CDT	Mesoscale Discussion	SPC	94 min
Jun 28, 10:44 AM CDT	Mesoscale Discussion	SPC	2 hr
Jun 28, 2:21 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 28, 3:34 PM CDT	Severe Thunderstorm Warning	LOT	26 min
Jun 28, 3:55 PM CDT	Severe Thunderstorm Warning	LOT	35 min
Jul 2, 9:42 AM CDT	Mesoscale Discussion	SPC	2 hr
Jul 2, 1:55 PM CDT	Mesoscale Discussion	SPC	95 min
Jul 2, 3:08 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 2, 7:03 PM CDT	Mesoscale Discussion	SPC	57 min
Jul 7, 10:21 PM CDT	Mesoscale Discussion	SPC	84 min
Jul 10, 12:55 PM CDT	Mesoscale Discussion	SPC	95 min
Jul 10, 1:18 PM CDT	Severe Thunderstorm Watch	SPC	10 hr
Jul 10, 1:30 PM CDT	Severe Thunderstorm Warning	LOT	60 min
Jul 10, 2:31 PM CDT	Severe Thunderstorm Warning	LOT	59 min
Jul 10, 4:15 PM CDT	Areal Flood Advisory	LOT	4 hr
Jul 10, 4:21 PM CDT	Flash Flood Warning	LOT	6 hr
Jul 10, 5:52 PM CDT	Mesoscale Discussion	SPC	83 min
Jul 10, 9:12 PM CDT	Areal Flood Advisory	LOT	4 hr
Jul 10, 10:21 PM CDT	Areal Flood Warning	LOT	3 hr
Jul 12, 1:52 AM CDT	Mesoscale Discussion	SPC	53 min
Jul 12, 3:31 AM CDT	Severe Thunderstorm Warning	LOT	44 min
Jul 12, 4:15 AM CDT	Severe Thunderstorm Warning	LOT	60 min
Jul 12, 4:39 AM CDT	Severe Thunderstorm Warning	LOT	66 min
Jul 12, 5:05 AM CDT	Severe Thunderstorm Warning	LOT	55 min
Jul 12, 5:44 AM CDT	Areal Flood Advisory	LOT	6 hr
Jul 19, 11:24 PM CDT	Mesoscale Discussion	SPC	96 min
Jul 21, 4:21 AM CDT	Severe Thunderstorm Watch	SPC	8 hr
Jul 21, 6:46 AM CDT	Severe Thunderstorm Warning	LOT	59 min
Jul 29, 7:05 PM CDT	Mesoscale Discussion	SPC	85 min
Jul 29, 8:15 PM CDT	Severe Thunderstorm Warning	LOT	45 min
Jul 31, 7:21 AM CDT	Dense Fog Advisory	LOT	3 hr
Jul 31, 11:59 AM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 31, 1:44 PM CDT	Severe Thunderstorm Warning	LOT	47 min
Jul 31, 1:51 PM CDT	Mesoscale Discussion	SPC	84 min
Jul 31, 3:51 PM CDT	Mesoscale Discussion	SPC	84 min
Aug 3, 3:37 PM CDT	Heat Advisory	LOT	28 hr
Aug 4, 3:51 PM CDT	Mesoscale Discussion	SPC	84 min
Aug 4, 4:48 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Aug 4, 6:45 PM CDT	Mesoscale Discussion	SPC	90 min
Aug 4, 7:18 PM CDT	Severe Thunderstorm Warning	LOT	72 min
Aug 4, 7:33 PM CDT	Severe Thunderstorm Warning	LOT	57 min
Aug 4, 8:26 PM CDT	Severe Thunderstorm Warning	LOT	39 min
Aug 5, 2:55 AM CDT	Severe Thunderstorm Watch	SPC	4 hr
Aug 5, 4:10 AM CDT	Severe Thunderstorm Warning	LOT	50 min
Aug 5, 4:57 AM CDT	Severe Thunderstorm Warning	LOT	63 min
Aug 5, 7:07 AM CDT	Mesoscale Discussion	SPC	53 min
Sep 4, 5:21 PM CDT	Areal Flood Advisory	LOT	6 hr
Sep 12, 2:55 PM CDT	Flood Watch	LOT	49 hr
Sep 12, 9:34 PM CDT	River Flood Advisory	LOT	15 hr
Sep 12, 11:30 PM CDT	Areal Flood Advisory	LOT	6 hr
Sep 12, 11:44 PM CDT	Mesoscale Discussion	SPC	91 min
Sep 13, 1:28 AM CDT	Flash Flood Warning	LOT	6 hr
Sep 13, 1:29 AM CDT	Mesoscale Discussion	SPC	91 min
Sep 13, 1:46 AM CDT	Tornado Watch	SPC	6 hr
Sep 13, 2:12 AM CDT	Flash Flood Warning	LOT	3 hr
Sep 13, 3:28 AM CDT	Mesoscale Discussion	SPC	92 min
Sep 13, 4:29 AM CDT	Severe Thunderstorm Warning	LOT	1 min
Sep 13, 4:33 AM CDT	Flash Flood Warning	LOT	6 hr
Sep 13, 7:26 AM CDT	Flash Flood Warning	LOT	3 hr
Sep 13, 10:29 AM CDT	Flash Flood Warning	LOT	6 hr
Sep 13, 11:21 AM CDT	River Flood Warning	LOT	5 days
Sep 13, 12:16 PM CDT	River Flood Warning	LOT	16 days
Sep 13, 4:30 PM CDT	Areal Flood Warning	LOT	13 hr
Sep 13, 4:48 PM CDT	River Flood Warning	LOT	4 days
Sep 14, 5:02 AM CDT	Flash Flood Warning	LOT	11 hr
Sep 14, 4:08 PM CDT	Areal Flood Warning	LOT	18 hr
Sep 15, 10:50 AM CDT	Areal Flood Warning	LOT	28 hr
Sep 16, 5:22 AM CDT	Dense Fog Advisory	LOT	4 hr
Sep 26, 5:21 AM CDT	Dense Fog Advisory	LOT	4 hr
Oct 16, 4:00 PM CDT	Frost Advisory	LOT	15 hr
Oct 25, 4:18 AM CDT	Wind Advisory	LOT	40 hr
Oct 26, 3:50 PM CDT	Freeze Warning	LOT	11 hr
Oct 27, 4:05 AM CDT	Freeze Warning	LOT	29 hr
Nov 29, 3:07 PM CST	Winter Weather Advisory	LOT	49 hr
Nov 30, 3:40 AM CST	Winter Storm Warning	LOT	31 hr
Dec 8, 9:31 AM CST	Freezing Rain Advisory	LOT	6 hr
Dec 14, 4:13 PM CST	Winter Weather Advisory	LOT	12 hr
Dec 14, 5:47 PM CST	Mesoscale Discussion	SPC	4 hr
Dec 14, 11:47 PM CST	Mesoscale Discussion	SPC	4 hr
Dec 15, 3:22 PM CST	Winter Weather Advisory	LOT	34 hr
Dec 17, 3:25 AM CST	Winter Storm Watch	LOT	12 hr
Dec 17, 3:29 PM CST	Winter Storm Warning	LOT	43 hr
Dec 18, 10:10 AM CST	River Flood Advisory	LOT	59 hr
Dec 18, 6:46 PM CST	Mesoscale Discussion	SPC	6 hr
Dec 19, 12:45 AM CST	Mesoscale Discussion	SPC	4 hr
Dec 20, 4:17 AM CST	Wind Chill Advisory	LOT	56 hr
Dec 20, 10:57 AM CST	Winter Weather Advisory	LOT	37 hr
Dec 21, 1:24 AM CST	Blizzard Warning	LOT	17 hr
Dec 22, 4:44 AM CST	Winter Storm Watch	LOT	9 hr
Dec 22, 2:03 PM CST	Winter Weather Advisory	LOT	55 hr
Dec 25, 3:40 PM CST	Flash Flood Watch	LOT	47 hr
Dec 25, 3:51 PM CST	Freezing Rain Advisory	LOT	17 hr
Dec 26, 11:21 AM CST	Dense Fog Advisory	LOT	29 hr
Dec 26, 5:27 PM CST	River Flood Warning	LOT	4 days
Dec 26, 6:05 PM CST	River Flood Warning	LOT	8 days
Dec 26, 6:05 PM CST	River Flood Warning	LOT	4 days
Dec 27, 3:57 AM CST	Flash Flood Warning	LOT	6 hr
Dec 27, 9:10 AM CST	Flash Flood Warning	LOT	11 hr
Dec 27, 10:58 AM CST	Tornado Watch	SPC	8 hr
Dec 27, 11:46 AM CST	Mesoscale Discussion	SPC	89 min
Dec 27, 12:16 PM CST	Severe Thunderstorm Warning	LOT	59 min
Dec 27, 12:30 PM CST	Tornado Watch	SPC	4 hr
Dec 27, 12:37 PM CST	Flash Flood Warning	LOT	8 hr
Dec 27, 1:25 PM CST	Severe Thunderstorm Warning	LOT	80 min
Dec 27, 1:51 PM CST	Flash Flood Warning	LOT	6 hr
Dec 27, 6:24 PM CST	Wind Advisory	LOT	14 hr
Dec 27, 8:04 PM CST	Areal Flood Warning	LOT	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	36
Tornado Warning	3
Severe Thunderstorm Watch	13
Tornado Watch	13
Mesoscale Discussion	49
Flooding
Areal Flood Warning	5
Flash Flood Warning	12
River Flood Warning	19
Flash Flood Watch	5
Flood Watch	5
River Flood Watch	5
Areal Flood Advisory	7
River Flood Advisory	9
Winter
Blizzard Warning	1
Winter Storm Warning	6
Winter Storm Watch	4
Blowing Snow Advisory	1
Freezing Rain Advisory	2
Snow Advisory	2
Snow and Blowing Snow Advisory	1
Winter Weather Advisory	7
Heat
Heat Advisory	1
Cold
Freeze Warning	3
Frost Advisory	1
Wind Chill Advisory	7
Wind and dust
Wind Advisory	8
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 2007 2009

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.