Alert archive / Arizona / Maricopa County
Weather alerts in Maricopa County, Arizona, 2011
140 weather alerts in 2011, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Maricopa County and its neighbors
Each county as a circle sized by its count in 2011. Tap one for its archive.
- Alerts
- 140
- Warnings
- 56
- Watches
- 9
- Advisories
- 20
- Busiest month
- July47 alerts
- Busiest day
- September 11, 201119 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
0 of 1 tornado warnings covering Maricopa County in 2011 had a tornado report inside them.
Maricopa County, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 44 | 17 | 61% | 30 | 57% | 15 min |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Phoenix, AZ: tornado warnings | 1 | 0 | 100% | 0 | ||
| NWS Phoenix, AZ: severe thunderstorm warnings | 76 | 26 | 66% | 71 | 63% | 18 min |
| NWS Phoenix, AZ: flash flood warnings | 7 | 1 | 86% | 2 | 50% | 34 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, Mountain Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Apr 26, 4:00 AM MST | Red Flag Warning | PSR | 16 hr |
| Apr 27, 2:42 PM MST | Fire Weather Watch | PSR | 39 hr |
| Apr 28, 4:56 AM MST | Fire Weather Watch | PSR | 10 hr |
| Apr 28, 4:56 AM MST | Red Flag Warning | PSR | 39 hr |
| Apr 28, 2:34 PM MST | Red Flag Warning | PSR | 52 hr |
| May 6, 5:30 AM MST | Fire Weather Watch | PSR | 32 hr |
| May 7, 1:15 PM MST | Red Flag Warning | PSR | 31 hr |
| May 26, 2:40 PM MST | Fire Weather Watch | PSR | 24 hr |
| May 26, 2:40 PM MST | Fire Weather Watch | PSR | 60 hr |
| May 27, 2:32 PM MST | Red Flag Warning | PSR | 29 hr |
| May 28, 2:55 PM MST | Red Flag Warning | PSR | 29 hr |
| Jun 10, 11:20 AM MST | Special Weather Statement | PSR | 40 min |
| Jun 15, 3:06 PM MST | Fire Weather Watch | PSR | 23 hr |
| Jun 16, 4:02 AM MST | Red Flag Warning | PSR | 16 hr |
| Jun 16, 2:25 PM MST | Fire Weather Watch | PSR | 25 hr |
| Jun 16, 2:25 PM MST | Red Flag Warning | PSR | 30 hr |
| Jun 17, 2:55 PM MST | Red Flag Warning | PSR | 28 hr |
| Jun 17, 2:55 PM MST | Red Flag Warning | PSR | 53 hr |
| Jul 2, 6:38 PM MST | Special Weather Statement | PSR | 37 min |
| Jul 3, 1:40 PM MST | Mesoscale Discussion | SPC | 3 hr |
| Jul 3, 3:54 PM MST | Special Weather Statement | PSR | 51 min |
| Jul 3, 4:30 PM MST | Special Weather Statement | PSR | 60 min |
| Jul 3, 5:24 PM MST | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 3, 5:43 PM MST | Special Weather Statement | PSR | 47 min |
| Jul 3, 7:40 PM MST | Severe Thunderstorm Warning | PSR | 65 min |
| Jul 4, 12:57 PM MST | Mesoscale Discussion | SPC | 63 min |
| Jul 4, 7:11 PM MST | Mesoscale Discussion | SPC | 2 hr |
| Jul 4, 7:51 PM MST | Special Weather Statement | PSR | 84 min |
| Jul 4, 11:13 PM MST | Areal Flood Advisory | PSR | 81 min |
| Jul 5, 1:42 PM MST | Mesoscale Discussion | SPC | 63 min |
| Jul 5, 5:36 PM MST | Mesoscale Discussion | SPC | 54 min |
| Jul 5, 5:55 PM MST | Special Weather Statement | PSR | 50 min |
| Jul 5, 6:05 PM MST | Severe Thunderstorm Warning | PSR | 40 min |
| Jul 5, 6:28 PM MST | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 5, 6:56 PM MST | Special Weather Statement | PSR | 49 min |
| Jul 5, 7:21 PM MST | Special Weather Statement | PSR | 84 min |
| Jul 5, 7:24 PM MST | Severe Thunderstorm Warning | PSR | 51 min |
| Jul 5, 7:37 PM MST | Severe Thunderstorm Warning | PSR | 53 min |
| Jul 5, 7:54 PM MST | Severe Thunderstorm Warning | PSR | 51 min |
| Jul 5, 8:21 PM MST | Special Weather Statement | PSR | 54 min |
| Jul 5, 8:45 PM MST | Areal Flood Advisory | PSR | 2 hr |
| Jul 5, 9:12 PM MST | Areal Flood Advisory | PSR | 2 hr |
| Jul 9, 6:33 PM MST | Special Weather Statement | PSR | 42 min |
| Jul 9, 6:47 PM MST | Severe Thunderstorm Warning | PSR | 35 min |
| Jul 9, 8:09 PM MST | Areal Flood Advisory | PSR | 111 min |
| Jul 10, 2:22 PM MST | Severe Thunderstorm Warning | PSR | 53 min |
| Jul 10, 3:01 PM MST | Special Weather Statement | PSR | 59 min |
| Jul 10, 4:32 PM MST | Special Weather Statement | PSR | 43 min |
| Jul 11, 3:10 AM MST | Special Weather Statement | PSR | 50 min |
| Jul 11, 3:45 AM MST | Areal Flood Advisory | PSR | 2 hr |
| Jul 11, 7:47 PM MST | Special Weather Statement | PSR | 58 min |
| Jul 11, 11:03 PM MST | Special Weather Statement | PSR | 57 min |
| Jul 18, 5:54 PM MST | Special Weather Statement | PSR | 51 min |
| Jul 18, 6:06 PM MST | Severe Thunderstorm Warning | PSR | 39 min |
| Jul 18, 6:29 PM MST | Special Weather Statement | PSR | 46 min |
| Jul 18, 6:45 PM MST | Areal Flood Advisory | PSR | 92 min |
| Jul 24, 6:07 PM MST | Mesoscale Discussion | SPC | 83 min |
| Jul 24, 8:43 PM MST | Severe Thunderstorm Warning | PSR | 62 min |
| Jul 24, 8:57 PM MST | Areal Flood Advisory | PSR | 108 min |
| Jul 24, 9:47 PM MST | Special Weather Statement | PSR | 58 min |
| Jul 24, 9:56 PM MST | Areal Flood Advisory | PSR | 109 min |
| Jul 24, 10:29 PM MST | Severe Thunderstorm Warning | PSR | 38 min |
| Jul 24, 11:02 PM MST | Special Weather Statement | PSR | 43 min |
| Jul 30, 7:05 PM MST | Areal Flood Advisory | PSR | 115 min |
| Jul 30, 7:45 PM MST | Severe Thunderstorm Warning | PSR | 45 min |
| Jul 31, 7:09 PM MST | Severe Thunderstorm Warning | PSR | 51 min |
| Jul 31, 7:17 PM MST | Severe Thunderstorm Warning | PSR | 43 min |
| Jul 31, 7:22 PM MST | Areal Flood Advisory | PSR | 113 min |
| Jul 31, 8:41 PM MST | Special Weather Statement | PSR | 64 min |
| Jul 31, 9:07 PM MST | Special Weather Statement | PSR | 53 min |
| Jul 31, 9:17 PM MST | Areal Flood Advisory | PSR | 118 min |
| Aug 2, 6:59 PM MST | Severe Thunderstorm Warning | PSR | 46 min |
| Aug 2, 7:23 PM MST | Special Weather Statement | PSR | 52 min |
| Aug 2, 9:00 PM MST | Special Weather Statement | PSR | 45 min |
| Aug 3, 4:46 PM MST | Special Weather Statement | PSR | 44 min |
| Aug 3, 5:07 PM MST | Special Weather Statement | PSR | 38 min |
| Aug 3, 5:39 PM MST | Severe Thunderstorm Warning | PSR | 66 min |
| Aug 3, 5:45 PM MST | Special Weather Statement | PSR | 45 min |
| Aug 3, 5:58 PM MST | Areal Flood Advisory | PSR | 2 hr |
| Aug 3, 6:13 PM MST | Special Weather Statement | PSR | 47 min |
| Aug 3, 6:50 PM MST | Severe Thunderstorm Warning | PSR | 40 min |
| Aug 3, 7:33 PM MST | Special Weather Statement | PSR | 42 min |
| Aug 3, 8:04 PM MST | Special Weather Statement | PSR | 41 min |
| Aug 3, 8:29 PM MST | Severe Thunderstorm Warning | PSR | 46 min |
| Aug 3, 8:31 PM MST | Areal Flood Advisory | PSR | 119 min |
| Aug 3, 9:06 PM MST | Special Weather Statement | PSR | 39 min |
| Aug 3, 9:48 PM MST | Special Weather Statement | PSR | 42 min |
| Aug 3, 10:11 PM MST | Severe Thunderstorm Warning | PSR | 30 min |
| Aug 12, 10:08 PM MST | Areal Flood Advisory | PSR | 56 min |
| Aug 18, 4:54 PM MST | Severe Thunderstorm Warning | PSR | 51 min |
| Aug 18, 6:12 PM MST | Severe Thunderstorm Warning | PSR | 48 min |
| Aug 18, 7:16 PM MST | Areal Flood Advisory | PSR | 3 hr |
| Aug 26, 3:07 PM MST | Severe Thunderstorm Warning | PSR | 26 min |
| Aug 26, 3:58 PM MST | Special Weather Statement | PSR | 47 min |
| Aug 26, 4:10 PM MST | Severe Thunderstorm Warning | PSR | 43 min |
| Aug 27, 5:01 PM MST | Severe Thunderstorm Warning | PSR | 59 min |
| Aug 27, 6:58 PM MST | Severe Thunderstorm Warning | PSR | 25 min |
| Aug 27, 8:38 PM MST | Severe Thunderstorm Warning | PSR | 52 min |
| Aug 27, 9:18 PM MST | Areal Flood Advisory | PSR | 3 hr |
| Aug 27, 9:38 PM MST | Flash Flood Warning | PSR | 3 hr |
| Sep 9, 1:00 PM MST | Mesoscale Discussion | SPC | 90 min |
| Sep 9, 7:09 PM MST | Severe Thunderstorm Warning | PSR | 36 min |
| Sep 9, 7:47 PM MST | Severe Thunderstorm Warning | PSR | 28 min |
| Sep 9, 8:13 PM MST | Special Weather Statement | PSR | 47 min |
| Sep 9, 8:24 PM MST | Areal Flood Advisory | PSR | 2 hr |
| Sep 9, 10:37 PM MST | Areal Flood Advisory | PSR | 113 min |
| Sep 10, 4:59 PM MST | Severe Thunderstorm Warning | PSR | 31 min |
| Sep 10, 5:34 PM MST | Severe Thunderstorm Warning | PSR | 56 min |
| Sep 10, 5:56 PM MST | Severe Thunderstorm Warning | PSR | 34 min |
| Sep 10, 6:05 PM MST | Tornado Warning | PSR | 15 min |
| Sep 10, 6:30 PM MST | Severe Thunderstorm Warning | PSR | 45 min |
| Sep 10, 7:17 PM MST | Severe Thunderstorm Warning | PSR | 25 min |
| Sep 10, 7:41 PM MST | Areal Flood Advisory | PSR | 2 hr |
| Sep 10, 7:48 PM MST | Severe Thunderstorm Warning | PSR | 27 min |
| Sep 10, 7:56 PM MST | Severe Thunderstorm Warning | PSR | 22 min |
| Sep 10, 8:29 PM MST | Areal Flood Advisory | PSR | 2 hr |
| Sep 10, 8:29 PM MST | Special Weather Statement | PSR | 46 min |
| Sep 11, 1:27 PM MST | Special Weather Statement | PSR | 48 min |
| Sep 11, 2:22 PM MST | Special Weather Statement | PSR | 38 min |
| Sep 11, 2:47 PM MST | Mesoscale Discussion | SPC | 2 hr |
| Sep 11, 3:01 PM MST | Special Weather Statement | PSR | 44 min |
| Sep 11, 3:11 PM MST | Severe Thunderstorm Warning | PSR | 49 min |
| Sep 11, 3:21 PM MST | Special Weather Statement | PSR | 39 min |
| Sep 11, 3:27 PM MST | Special Weather Statement | PSR | 48 min |
| Sep 11, 3:59 PM MST | Severe Thunderstorm Warning | PSR | 21 min |
| Sep 11, 4:13 PM MST | Severe Thunderstorm Warning | PSR | 38 min |
| Sep 11, 6:11 PM MST | Special Weather Statement | PSR | 49 min |
| Sep 11, 6:12 PM MST | Special Weather Statement | PSR | 48 min |
| Sep 12, 1:50 PM MST | Severe Thunderstorm Warning | PSR | 40 min |
| Sep 12, 3:13 PM MST | Severe Thunderstorm Warning | PSR | 32 min |
| Sep 12, 3:47 PM MST | Special Weather Statement | PSR | 43 min |
| Sep 12, 3:55 PM MST | Mesoscale Discussion | SPC | 2 hr |
| Sep 13, 3:42 PM MST | Special Weather Statement | PSR | 48 min |
| Sep 13, 3:56 PM MST | Severe Thunderstorm Warning | PSR | 49 min |
| Sep 13, 4:12 PM MST | Severe Thunderstorm Warning | PSR | 30 min |
| Oct 4, 12:53 PM MST | Mesoscale Discussion | SPC | 2 hr |
| Oct 4, 5:39 PM MST | Severe Thunderstorm Warning | PSR | 41 min |
| Oct 25, 5:52 PM MST | Special Weather Statement | PSR | 38 min |
| Nov 4, 11:58 PM MST | Severe Thunderstorm Warning | PSR | 47 min |
| Nov 5, 12:29 AM MST | Severe Thunderstorm Warning | PSR | 61 min |
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 | 44 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 2 |
| Mesoscale Discussion | 10 |
| Special Weather Statement | 45 |
| Flooding | |
| Flash Flood Warning | 1 |
| Areal Flood Advisory | 20 |
| Fire | |
| Red Flag Warning | 10 |
| Fire Weather Watch | 7 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20102012
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.