Weather alerts in Linn County, Iowa, 2009

158 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Linn County and its neighbors

Each county as a circle sized by its count in 2009. Tap one for its archive.

Alerts: 158
Warnings: 47
Watches: 28
Advisories: 30
Busiest month: June33 alerts
Busiest day: April 26, 200910 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 2 tornado warnings covering Linn County in 2009 had a tornado report inside them; 4 of 4 tornado reports fell inside a warning, on average 4 minutes after it went out.

Linn County, 2009

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	2	2	0%	4	100%	4 min
Severe thunderstorm warnings	21	15	29%	25	96%	49 min
Flash flood warnings	7	6	14%	8	75%	66 min

Each office's whole area, 2009

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Quad Cities, IA: tornado warnings	17	6	65%	18	78%	11 min
NWS Quad Cities, IA: severe thunderstorm warnings	117	90	23%	347	88%	33 min
NWS Quad Cities, IA: flash flood warnings	49	37	24%	86	84%	91 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 3, 3:24 AM CST	Winter Weather Advisory	DVN	26 hr
Jan 8, 3:11 PM CST	Winter Weather Advisory	DVN	48 hr
Jan 10, 3:04 AM CST	Winter Storm Warning	DVN	9 hr
Jan 11, 3:24 PM CST	Winter Storm Watch	DVN	12 hr
Jan 12, 3:24 AM CST	Blizzard Watch	DVN	10 hr
Jan 12, 3:24 AM CST	Winter Weather Advisory	DVN	23 hr
Jan 12, 1:06 PM CST	Blizzard Warning	DVN	11 hr
Jan 12, 6:27 PM CST	Mesoscale Discussion	SPC	4 hr
Jan 13, 2:45 AM CST	Wind Chill Advisory	DVN	12 hr
Jan 13, 3:15 AM CST	Winter Weather Advisory	DVN	36 hr
Jan 13, 6:12 PM CST	Mesoscale Discussion	SPC	4 hr
Jan 13, 11:38 PM CST	Mesoscale Discussion	SPC	4 hr
Jan 14, 3:45 AM CST	Wind Chill Warning	DVN	56 hr
Jan 17, 4:48 PM CST	Winter Weather Advisory	DVN	7 hr
Jan 23, 4:04 AM CST	Wind Chill Advisory	DVN	32 hr
Feb 2, 3:16 PM CST	Wind Chill Advisory	DVN	19 hr
Feb 20, 4:17 AM CST	Winter Weather Advisory	DVN	35 hr
Mar 6, 11:21 AM CST	Flash Flood Watch	DVN	51 hr
Mar 8, 5:38 AM CDT	Areal Flood Warning	DVN	15 hr
Mar 9, 11:44 AM CDT	River Flood Warning	DVN	58 hr
Mar 10, 4:22 AM CDT	Wind Advisory	DVN	27 hr
Mar 10, 9:25 AM CDT	Dense Fog Advisory	DVN	4 hr
Mar 23, 3:39 PM CDT	Wind Advisory	DVN	4 hr
Mar 28, 3:33 AM CDT	Winter Storm Warning	DVN	24 hr
Mar 28, 3:33 AM CDT	Winter Weather Advisory	DVN	24 hr
Apr 4, 4:00 AM CDT	Winter Storm Watch	DVN	12 hr
Apr 4, 3:43 PM CDT	Winter Storm Warning	DVN	28 hr
Apr 21, 11:03 AM CDT	Wind Advisory	DVN	8 hr
Apr 23, 11:42 PM CDT	Dense Fog Advisory	DVN	8 hr
Apr 25, 5:32 PM CDT	Mesoscale Discussion	SPC	73 min
Apr 25, 9:32 PM CDT	Special Weather Statement	DVN	58 min
Apr 26, 2:20 AM CDT	Special Weather Statement	DVN	3 hr
Apr 26, 3:04 AM CDT	Flash Flood Watch	DVN	24 hr
Apr 26, 9:49 AM CDT	River Flood Warning	DVN	5 days
Apr 26, 4:14 PM CDT	Special Weather Statement	DVN	61 min
Apr 26, 4:41 PM CDT	Severe Thunderstorm Warning	DVN	23 min
Apr 26, 4:52 PM CDT	Tornado Warning	DVN	23 min
Apr 26, 5:02 PM CDT	Tornado Watch	SPC	6 hr
Apr 26, 5:12 PM CDT	Tornado Warning	DVN	48 min
Apr 26, 6:14 PM CDT	Mesoscale Discussion	SPC	61 min
Apr 26, 8:21 PM CDT	Mesoscale Discussion	SPC	54 min
Apr 26, 8:23 PM CDT	Special Weather Statement	DVN	52 min
Apr 26, 11:15 PM CDT	Mesoscale Discussion	SPC	60 min
Apr 26, 11:38 PM CDT	Areal Flood Warning	DVN	10 hr
May 8, 1:05 PM CDT	Mesoscale Discussion	SPC	85 min
May 8, 5:23 PM CDT	Special Weather Statement	DVN	52 min
May 8, 5:47 PM CDT	Mesoscale Discussion	SPC	58 min
May 8, 5:57 PM CDT	Severe Thunderstorm Warning	DVN	63 min
May 8, 6:10 PM CDT	Severe Thunderstorm Watch	SPC	4 hr
May 13, 5:47 PM CDT	Mesoscale Discussion	SPC	88 min
May 13, 6:19 PM CDT	Special Weather Statement	DVN	86 min
May 14, 3:19 PM CDT	Flash Flood Watch	DVN	31 hr
May 16, 3:53 AM CDT	Frost Advisory	DVN	28 hr
Jun 7, 4:30 AM CDT	Severe Thunderstorm Warning	DVN	45 min
Jun 7, 4:45 AM CDT	Mesoscale Discussion	SPC	30 min
Jun 7, 8:49 PM CDT	Mesoscale Discussion	SPC	56 min
Jun 7, 9:47 PM CDT	Severe Thunderstorm Warning	DVN	32 min
Jun 17, 4:30 AM CDT	Dense Fog Advisory	DVN	4 hr
Jun 17, 11:53 PM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 18, 9:42 AM CDT	Mesoscale Discussion	SPC	93 min
Jun 18, 10:11 AM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 18, 10:37 AM CDT	Severe Thunderstorm Warning	DVN	53 min
Jun 18, 1:17 PM CDT	Mesoscale Discussion	SPC	88 min
Jun 19, 6:58 AM CDT	Mesoscale Discussion	SPC	62 min
Jun 19, 7:00 AM CDT	Severe Thunderstorm Warning	DVN	60 min
Jun 19, 7:14 AM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 19, 7:45 AM CDT	Severe Thunderstorm Warning	DVN	60 min
Jun 19, 12:37 PM CDT	Mesoscale Discussion	SPC	83 min
Jun 19, 1:54 PM CDT	Mesoscale Discussion	SPC	96 min
Jun 19, 2:24 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Jun 19, 4:36 PM CDT	Flash Flood Warning	DVN	3 hr
Jun 21, 3:17 PM CDT	Tornado Watch	SPC	8 hr
Jun 21, 6:51 PM CDT	Mesoscale Discussion	SPC	84 min
Jun 21, 8:37 PM CDT	Flash Flood Warning	DVN	6 hr
Jun 21, 9:06 PM CDT	Mesoscale Discussion	SPC	54 min
Jun 22, 3:25 PM CDT	Heat Advisory	DVN	29 hr
Jun 23, 3:21 PM CDT	Mesoscale Discussion	SPC	54 min
Jun 23, 3:28 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 23, 4:18 PM CDT	Severe Thunderstorm Warning	DVN	87 min
Jun 23, 5:39 PM CDT	Severe Thunderstorm Warning	DVN	51 min
Jun 25, 12:14 PM CDT	Mesoscale Discussion	SPC	61 min
Jun 25, 12:48 PM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 25, 2:56 PM CDT	Mesoscale Discussion	SPC	64 min
Jun 25, 5:36 PM CDT	Mesoscale Discussion	SPC	84 min
Jun 27, 1:19 PM CDT	Mesoscale Discussion	SPC	56 min
Jun 27, 2:41 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 7, 4:42 PM CDT	Special Weather Statement	DVN	108 min
Jul 10, 1:36 AM CDT	Mesoscale Discussion	SPC	24 min
Jul 10, 4:05 AM CDT	Severe Thunderstorm Warning	DVN	55 min
Jul 10, 5:00 AM CDT	Severe Thunderstorm Warning	DVN	60 min
Jul 10, 6:31 AM CDT	Special Weather Statement	DVN	74 min
Jul 10, 8:51 AM CDT	Severe Thunderstorm Warning	DVN	54 min
Jul 10, 9:57 AM CDT	Special Weather Statement	DVN	63 min
Jul 10, 10:24 AM CDT	Special Weather Statement	DVN	66 min
Jul 10, 11:46 AM CDT	Flash Flood Warning	DVN	8 hr
Jul 10, 11:52 AM CDT	Special Weather Statement	DVN	53 min
Jul 10, 10:52 PM CDT	Severe Thunderstorm Warning	DVN	53 min
Jul 15, 5:06 AM CDT	Special Weather Statement	DVN	69 min
Jul 15, 5:50 AM CDT	Special Weather Statement	DVN	85 min
Jul 15, 7:02 AM CDT	Special Weather Statement	DVN	58 min
Jul 15, 7:50 AM CDT	Special Weather Statement	DVN	55 min
Jul 24, 10:32 AM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 24, 1:12 PM CDT	Tornado Watch	SPC	4 hr
Jul 24, 3:52 PM CDT	Mesoscale Discussion	SPC	83 min
Jul 24, 5:02 PM CDT	Tornado Watch	SPC	6 hr
Jul 24, 7:20 PM CDT	Mesoscale Discussion	SPC	85 min
Jul 24, 7:30 PM CDT	Severe Thunderstorm Warning	DVN	60 min
Jul 24, 7:48 PM CDT	Severe Thunderstorm Warning	DVN	62 min
Jul 24, 7:51 PM CDT	Flash Flood Warning	DVN	6 hr
Jul 24, 8:43 PM CDT	Severe Thunderstorm Warning	DVN	62 min
Aug 8, 1:29 AM CDT	Mesoscale Discussion	SPC	2 hr
Aug 8, 2:43 AM CDT	Heat Advisory	DVN	40 hr
Aug 9, 9:55 AM CDT	Mesoscale Discussion	SPC	35 min
Aug 9, 10:21 AM CDT	Severe Thunderstorm Watch	SPC	8 hr
Aug 9, 11:31 AM CDT	Severe Thunderstorm Warning	DVN	59 min
Aug 9, 12:13 PM CDT	Severe Thunderstorm Warning	DVN	77 min
Aug 9, 1:44 PM CDT	Severe Thunderstorm Warning	DVN	61 min
Aug 9, 3:41 PM CDT	Flash Flood Watch	DVN	11 hr
Aug 9, 5:52 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Aug 9, 7:34 PM CDT	Severe Thunderstorm Warning	DVN	56 min
Aug 9, 8:07 PM CDT	Severe Thunderstorm Warning	DVN	68 min
Aug 17, 6:58 AM CDT	Special Weather Statement	DVN	77 min
Aug 19, 4:49 PM CDT	Tornado Watch	SPC	5 hr
Aug 19, 7:45 PM CDT	Mesoscale Discussion	SPC	90 min
Aug 20, 1:51 PM CDT	Mesoscale Discussion	SPC	114 min
Aug 26, 1:27 AM CDT	Flash Flood Warning	DVN	3 hr
Aug 26, 9:10 AM CDT	Flash Flood Watch	DVN	42 hr
Aug 26, 9:38 AM CDT	Areal Flood Warning	DVN	12 hr
Aug 27, 2:06 AM CDT	Flash Flood Warning	DVN	3 hr
Aug 27, 7:55 AM CDT	Flash Flood Warning	DVN	6 hr
Aug 27, 1:56 PM CDT	Areal Flood Warning	DVN	21 hr
Aug 27, 3:49 PM CDT	River Flood Warning	DVN	37 hr
Aug 28, 6:38 AM CDT	River Flood Warning	DVN	14 hr
Aug 28, 10:52 AM CDT	Areal Flood Warning	DVN	48 hr
Sep 9, 9:22 PM CDT	Dense Fog Advisory	DVN	13 hr
Sep 10, 3:10 PM CDT	Dense Fog Advisory	DVN	18 hr
Sep 23, 4:12 AM CDT	Dense Fog Advisory	DVN	6 hr
Sep 26, 1:46 PM CDT	Special Weather Statement	DVN	59 min
Sep 29, 3:17 AM CDT	Frost Advisory	DVN	24 hr
Oct 9, 4:02 AM CDT	Freeze Warning	DVN	29 hr
Nov 20, 9:28 PM CST	Dense Fog Advisory	DVN	13 hr
Dec 6, 3:14 PM CST	Winter Storm Watch	DVN	25 hr
Dec 7, 3:46 AM CST	Blizzard Watch	DVN	34 hr
Dec 7, 3:45 PM CST	Winter Storm Warning	DVN	50 hr
Dec 8, 11:22 AM CST	Mesoscale Discussion	SPC	5 hr
Dec 8, 1:55 PM CST	Blizzard Warning	DVN	28 hr
Dec 8, 6:00 PM CST	Mesoscale Discussion	SPC	5 hr
Dec 8, 9:38 PM CST	Mesoscale Discussion	SPC	6 hr
Dec 9, 10:22 AM CST	Mesoscale Discussion	SPC	4 hr
Dec 9, 3:41 PM CST	Winter Weather Advisory	DVN	12 hr
Dec 10, 3:16 AM CST	Wind Chill Advisory	DVN	9 hr
Dec 12, 2:52 PM CST	Freezing Rain Advisory	DVN	17 hr
Dec 14, 2:06 AM CST	Winter Weather Advisory	DVN	10 hr
Dec 14, 3:25 PM CST	Wind Chill Advisory	DVN	20 hr
Dec 21, 3:18 PM CST	Winter Storm Watch	DVN	3 days
Dec 22, 3:47 PM CST	Flood Watch	DVN	62 hr
Dec 22, 4:07 PM CST	Winter Weather Advisory	DVN	36 hr
Dec 23, 12:21 PM CST	Mesoscale Discussion	SPC	4 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	21
Tornado Warning	2
Severe Thunderstorm Watch	11
Tornado Watch	5
Mesoscale Discussion	36
Special Weather Statement	17
Flooding
Areal Flood Warning	5
Flash Flood Warning	7
River Flood Warning	4
Flash Flood Watch	5
Flood Watch	1
Winter
Blizzard Warning	2
Winter Storm Warning	4
Blizzard Watch	2
Winter Storm Watch	4
Freezing Rain Advisory	1
Winter Weather Advisory	10
Heat
Heat Advisory	2
Cold
Freeze Warning	1
Wind Chill Warning	1
Frost Advisory	2
Wind Chill Advisory	5
Wind and dust
Wind Advisory	3
Fog and smoke
Dense Fog Advisory	7

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2008 2010

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.