Alert archive / Arizona / Maricopa County

Weather alerts in Maricopa County, Arizona, 2020

228 weather alerts in 2020, 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 2020. Tap one for its archive.

Alerts: 228
Warnings: 92
Watches: 20
Advisories: 54
Busiest month: August103 alerts
Busiest day: August 21, 202026 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 reports fell inside a warning.

Maricopa County, 2020

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	0			1	0%
Severe thunderstorm warnings	29	10	66%	34	71%	13 min
Flash flood warnings	27	12	56%	15	100%	108 min

Each office's whole area, 2020

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Phoenix, AZ: tornado warnings	0			1	0%
NWS Phoenix, AZ: severe thunderstorm warnings	43	13	70%	41	71%	15 min
NWS Phoenix, AZ: flash flood warnings	47	15	68%	23	87%	100 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
Jan 17, 7:23 AM MST	Dense Fog Advisory	PSR	97 min
Jan 17, 9:48 AM MST	Dense Fog Advisory	PSR	2 hr
Jan 21, 8:54 PM MST	Dense Fog Advisory	PSR	14 hr
Feb 2, 2:20 AM MST	Freeze Watch	PSR	26 hr
Feb 2, 2:20 AM MST	Freeze Watch	PSR	26 hr
Feb 3, 4:18 AM MST	Freeze Warning	PSR	29 hr
Feb 3, 4:18 AM MST	Freeze Warning	PSR	53 hr
Feb 10, 7:02 PM MST	Areal Flood Advisory	PSR	3 hr
Feb 11, 3:08 AM MST	Areal Flood Advisory	PSR	5 hr
Feb 11, 3:18 AM MST	Areal Flood Advisory	PSR	3 hr
Feb 21, 2:34 AM MST	Flash Flood Watch	PSR	42 hr
Feb 22, 10:17 AM MST	Areal Flood Advisory	PSR	3 hr
Feb 22, 3:43 PM MST	Areal Flood Advisory	PSR	3 hr
Feb 23, 1:27 AM MST	Areal Flood Advisory	PSR	4 hr
Feb 23, 3:10 PM MST	Areal Flood Warning	PSR	6 hr
Feb 23, 3:46 PM MST	Areal Flood Advisory	PSR	3 hr
Feb 23, 6:09 PM MST	Areal Flood Advisory	PSR	10 hr
Mar 11, 3:59 AM MST	Flash Flood Watch	PSR	64 hr
Mar 12, 7:30 AM MST	Areal Flood Advisory	PSR	3 hr
Mar 12, 8:07 AM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Mar 12, 2:00 PM MST	Special Weather Statement	PSR	45 min
Mar 12, 2:04 PM MST	Special Weather Statement	PSR	41 min
Mar 12, 2:12 PM MST	Severe Thunderstorm Warning	PSR	33 min
Mar 12, 2:44 PM MST	Special Weather Statement	PSR	46 min
Mar 12, 2:46 PM MST	Special Weather Statement	PSR	44 min
Mar 12, 4:06 PM MST	Mesoscale Discussion	SPC	84 min
Mar 12, 4:16 PM MST	Flash Flood Warning Considerable damage threat	PSR	3 hr
Mar 12, 9:10 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Mar 12, 9:30 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Mar 12, 9:53 PM MST	Flash Flood Warning Considerable damage threat	PSR	7 hr
Mar 12, 10:35 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Mar 13, 12:58 AM MST	Flash Flood Warning Considerable damage threat	PSR	7 hr
Mar 13, 8:18 AM MST	River Flood Warning	PSR	5 hr
Mar 13, 11:02 AM MST	Special Weather Statement	PSR	43 min
Mar 13, 11:35 AM MST	Special Weather Statement	PSR	40 min
Mar 13, 11:37 AM MST	Special Weather Statement	PSR	38 min
Mar 13, 11:49 AM MST	Special Weather Statement	PSR	41 min
Mar 13, 12:20 PM MST	Special Weather Statement	PSR	40 min
Mar 13, 12:27 PM MST	Areal Flood Warning	PSR	36 hr
Mar 13, 12:30 PM MST	Special Weather Statement	PSR	45 min
Mar 13, 2:08 PM MST	Special Weather Statement	PSR	52 min
Mar 13, 2:58 PM MST	Special Weather Statement	PSR	32 min
Mar 13, 3:27 PM MST	Special Weather Statement	PSR	33 min
Mar 13, 3:31 PM MST	Flash Flood Warning	PSR	3 hr
Mar 17, 1:27 PM MST	Winter Weather Advisory	PSR	41 hr
Mar 18, 1:17 PM MST	Mesoscale Discussion	SPC	2 hr
Mar 18, 2:46 PM MST	Special Weather Statement	PSR	29 min
Mar 18, 4:04 PM MST	Special Weather Statement	PSR	56 min
Mar 18, 4:26 PM MST	Severe Thunderstorm Warning	PSR	12 min
Mar 18, 4:37 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Mar 18, 4:42 PM MST	Areal Flood Advisory	PSR	3 hr
Mar 18, 6:32 PM MST	Special Weather Statement	PSR	43 min
Mar 19, 5:33 AM MST	Areal Flood Warning	PSR	12 hr
Mar 19, 8:30 AM MST	Areal Flood Warning	PSR	6 hr
Mar 20, 3:06 AM MST	Areal Flood Warning	PSR	10 days
Mar 23, 1:16 PM MST	Areal Flood Warning	PSR	4 days
Apr 23, 1:37 PM MST	Excessive Heat Watch	PSR	24 hr
Apr 24, 1:32 PM MST	Excessive Heat Warning	PSR	71 hr
Apr 25, 1:37 PM MST	Excessive Heat Watch	PSR	38 hr
Apr 27, 3:44 AM MST	Excessive Heat Warning	PSR	4 days
May 4, 1:55 PM MST	Excessive Heat Watch	PSR	13 hr
May 5, 2:36 AM MST	Excessive Heat Warning	PSR	65 hr
May 10, 3:35 AM MST	Special Weather Statement	PSR	25 min
May 10, 8:31 AM MST	Special Weather Statement	PSR	29 min
May 10, 4:33 PM MST	Special Weather Statement	PSR	42 min
May 22, 3:32 AM MST	Excessive Heat Watch	PSR	47 hr
May 24, 2:55 AM MST	Excessive Heat Warning	PSR	8 days
May 30, 5:48 PM MST	Dust Storm Advisory	PSR	57 min
May 30, 6:55 PM MST	Dust Storm Warning	PSR	65 min
Jun 1, 2:36 AM MST	Excessive Heat Watch	PSR	23 hr
Jun 1, 7:20 PM MST	Dust Storm Advisory	PSR	25 min
Jun 2, 2:04 AM MST	Excessive Heat Warning	PSR	66 hr
Jun 26, 3:54 AM MST	Fire Weather Watch	PSR	23 hr
Jun 26, 3:54 AM MST	Fire Weather Watch	PSR	23 hr
Jun 27, 2:52 AM MST	Red Flag Warning	PSR	41 hr
Jun 27, 2:52 AM MST	Red Flag Warning	PSR	65 hr
Jul 6, 2:31 PM MST	Excessive Heat Watch	PSR	48 hr
Jul 8, 2:19 PM MST	Excessive Heat Warning	PSR	5 days
Jul 17, 12:41 PM MST	Excessive Heat Watch	PSR	15 hr
Jul 18, 3:32 AM MST	Excessive Heat Warning	PSR	40 hr
Jul 21, 7:49 PM MST	Severe Thunderstorm Warning	PSR	26 min
Jul 21, 8:13 PM MST	Special Weather Statement	PSR	32 min
Jul 21, 8:18 PM MST	Dust Storm Advisory	PSR	31 min
Jul 22, 1:24 PM MST	Flash Flood Watch	PSR	31 hr
Jul 22, 8:50 PM MST	Special Weather Statement	PSR	40 min
Jul 22, 9:39 PM MST	Areal Flood Advisory	PSR	3 hr
Jul 23, 1:34 AM MST	Special Weather Statement	PSR	41 min
Jul 23, 3:57 AM MST	Special Weather Statement	PSR	33 min
Jul 23, 11:46 AM MST	Special Weather Statement	PSR	44 min
Jul 23, 12:08 PM MST	Severe Thunderstorm Warning	PSR	37 min
Jul 23, 12:27 PM MST	Special Weather Statement	PSR	48 min
Jul 23, 12:32 PM MST	Severe Thunderstorm Warning	PSR	28 min
Jul 23, 12:47 PM MST	Special Weather Statement	PSR	43 min
Jul 23, 12:56 PM MST	Special Weather Statement	PSR	49 min
Jul 23, 1:33 PM MST	Special Weather Statement	PSR	42 min
Jul 23, 2:50 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Jul 23, 11:09 PM MST	Areal Flood Advisory	PSR	3 hr
Jul 23, 11:59 PM MST	Flash Flood Warning Considerable damage threat	PSR	2 hr
Jul 24, 3:49 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Jul 24, 4:58 PM MST	Special Weather Statement	PSR	47 min
Jul 24, 5:52 PM MST	Special Weather Statement	PSR	23 min
Jul 24, 6:23 PM MST	Special Weather Statement	PSR	37 min
Jul 24, 7:00 PM MST	Special Weather Statement	PSR	30 min
Jul 24, 7:20 PM MST	Areal Flood Advisory	PSR	3 hr
Jul 24, 8:04 PM MST	Areal Flood Advisory	PSR	3 hr
Jul 27, 1:17 AM MST	Excessive Heat Watch	PSR	26 hr
Jul 27, 6:48 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Jul 28, 2:57 AM MST	Excessive Heat Warning	PSR	8 days
Jul 28, 2:57 AM MST	Heat Advisory	PSR	5 days
Aug 2, 1:52 AM MST	Excessive Heat Warning	PSR	66 hr
Aug 6, 2:14 AM MST	Excessive Heat Watch	PSR	35 hr
Aug 7, 1:13 PM MST	Excessive Heat Warning	PSR	3 days
Aug 10, 2:20 AM MST	Excessive Heat Watch	PSR	35 hr
Aug 11, 1:27 PM MST	Excessive Heat Warning	PSR	9 days
Aug 11, 1:27 PM MST	Heat Advisory	PSR	9 days
Aug 11, 6:35 PM MST	Dust Storm Advisory	PSR	55 min
Aug 11, 7:08 PM MST	Dust Storm Advisory	PSR	67 min
Aug 11, 7:38 PM MST	Dust Storm Advisory	PSR	67 min
Aug 13, 4:53 PM MST	Special Weather Statement	PSR	22 min
Aug 13, 5:21 PM MST	Dust Storm Advisory	PSR	39 min
Aug 13, 5:57 PM MST	Special Weather Statement	PSR	33 min
Aug 16, 10:36 AM MST	Blowing Dust Advisory	PSR	11 hr
Aug 16, 1:21 PM MST	Mesoscale Discussion	SPC	114 min
Aug 16, 5:35 PM MST	Severe Thunderstorm Warning	PSR	25 min
Aug 16, 5:47 PM MST	Dust Storm Advisory	PSR	58 min
Aug 16, 5:57 PM MST	Special Weather Statement	PSR	33 min
Aug 16, 6:03 PM MST	Dust Storm Warning	PSR	87 min
Aug 16, 6:13 PM MST	Special Weather Statement	PSR	32 min
Aug 16, 6:28 PM MST	Special Weather Statement	PSR	32 min
Aug 16, 6:43 PM MST	Dust Storm Advisory	PSR	62 min
Aug 16, 7:29 PM MST	Dust Storm Warning	PSR	61 min
Aug 16, 8:03 PM MST	Dust Storm Advisory	PSR	57 min
Aug 16, 8:30 PM MST	Dust Storm Warning	PSR	60 min
Aug 16, 8:31 PM MST	Areal Flood Advisory	PSR	3 hr
Aug 17, 4:48 PM MST	Mesoscale Discussion	SPC	87 min
Aug 17, 5:45 PM MST	Severe Thunderstorm Warning	PSR	30 min
Aug 17, 6:09 PM MST	Dust Storm Advisory	PSR	51 min
Aug 17, 6:16 PM MST	Severe Thunderstorm Warning	PSR	29 min
Aug 17, 6:45 PM MST	Severe Thunderstorm Warning	PSR	45 min
Aug 17, 7:11 PM MST	Dust Storm Warning	PSR	64 min
Aug 17, 7:14 PM MST	Severe Thunderstorm Warning	PSR	31 min
Aug 17, 7:32 PM MST	Dust Storm Advisory	PSR	58 min
Aug 17, 7:40 PM MST	Severe Thunderstorm Warning	PSR	54 min
Aug 17, 7:57 PM MST	Severe Thunderstorm Warning	PSR	33 min
Aug 17, 8:08 PM MST	Special Weather Statement	PSR	67 min
Aug 17, 8:24 PM MST	Dust Storm Advisory	PSR	6 min
Aug 17, 8:29 PM MST	Dust Storm Warning	PSR	61 min
Aug 18, 1:49 PM MST	Mesoscale Discussion	SPC	116 min
Aug 18, 10:08 PM MST	Special Weather Statement	PSR	37 min
Aug 20, 2:00 AM MST	Areal Flood Advisory	PSR	3 hr
Aug 20, 6:52 PM MST	Severe Thunderstorm Warning	PSR	23 min
Aug 20, 7:01 PM MST	Dust Storm Advisory	PSR	59 min
Aug 20, 7:03 PM MST	Dust Storm Advisory	PSR	57 min
Aug 20, 7:10 PM MST	Areal Flood Advisory	PSR	3 hr
Aug 20, 7:25 PM MST	Special Weather Statement	PSR	35 min
Aug 20, 7:29 PM MST	Severe Thunderstorm Warning	PSR	31 min
Aug 20, 7:35 PM MST	Flash Flood Warning Considerable damage threat	PSR	3 hr
Aug 20, 7:46 PM MST	Severe Thunderstorm Warning	PSR	29 min
Aug 20, 7:53 PM MST	Severe Thunderstorm Warning	PSR	52 min
Aug 20, 7:59 PM MST	Special Weather Statement	PSR	46 min
Aug 20, 8:02 PM MST	Severe Thunderstorm Warning	PSR	28 min
Aug 20, 8:11 PM MST	Severe Thunderstorm Warning	PSR	34 min
Aug 20, 8:15 PM MST	Areal Flood Advisory	PSR	3 hr
Aug 20, 8:20 PM MST	Special Weather Statement	PSR	40 min
Aug 20, 8:27 PM MST	Dust Storm Advisory	PSR	70 min
Aug 20, 8:46 PM MST	Severe Thunderstorm Warning	PSR	29 min
Aug 20, 9:01 PM MST	Areal Flood Advisory	PSR	3 hr
Aug 20, 9:06 PM MST	Special Weather Statement	PSR	24 min
Aug 20, 9:09 PM MST	Severe Thunderstorm Warning	PSR	36 min
Aug 20, 9:29 PM MST	Special Weather Statement	PSR	46 min
Aug 20, 9:48 PM MST	Severe Thunderstorm Warning	PSR	27 min
Aug 20, 10:00 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 20, 10:32 PM MST	Dust Storm Advisory	PSR	88 min
Aug 20, 11:07 PM MST	Areal Flood Advisory	PSR	3 hr
Aug 20, 11:37 PM MST	Flash Flood Warning Considerable damage threat	PSR	5 hr
Aug 21, 3:20 AM MST	Excessive Heat Watch	PSR	47 hr
Aug 22, 7:00 PM MST	Severe Thunderstorm Warning	PSR	45 min
Aug 22, 7:51 PM MST	Severe Thunderstorm Warning	PSR	39 min
Aug 22, 8:02 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 23, 2:25 AM MST	Excessive Heat Warning	PSR	6 days
Aug 24, 9:38 AM MST	Blowing Dust Advisory	PSR	11 hr
Aug 25, 1:00 PM MST	Mesoscale Discussion	SPC	3 hr
Aug 25, 5:35 PM MST	Areal Flood Advisory	PSR	3 hr
Aug 26, 5:19 PM MST	Special Weather Statement	PSR	26 min
Aug 27, 5:47 PM MST	Areal Flood Advisory	PSR	3 hr
Aug 28, 1:24 PM MST	Flash Flood Watch	PSR	58 hr
Aug 29, 8:47 AM MST	Special Weather Statement	PSR	43 min
Aug 29, 9:12 AM MST	Special Weather Statement	PSR	48 min
Aug 29, 10:04 AM MST	Special Weather Statement	PSR	41 min
Aug 29, 10:25 AM MST	Special Weather Statement	PSR	50 min
Aug 29, 6:39 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 29, 6:46 PM MST	Special Weather Statement	PSR	44 min
Aug 29, 6:56 PM MST	Dust Storm Advisory	PSR	64 min
Aug 29, 7:16 PM MST	Severe Thunderstorm Warning	PSR	59 min
Aug 29, 7:33 PM MST	Special Weather Statement	PSR	42 min
Aug 29, 7:52 PM MST	Flash Flood Warning Considerable damage threat	PSR	3 hr
Aug 29, 9:40 PM MST	Areal Flood Advisory	PSR	110 min
Aug 30, 12:13 AM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 30, 2:41 PM MST	Special Weather Statement	PSR	49 min
Aug 30, 3:08 PM MST	Severe Thunderstorm Warning	PSR	37 min
Aug 30, 3:37 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 30, 4:08 PM MST	Dust Storm Advisory	PSR	67 min
Aug 30, 5:16 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 30, 5:19 PM MST	Special Weather Statement	PSR	56 min
Aug 30, 5:57 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 30, 6:13 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 30, 6:13 PM MST	Special Weather Statement	PSR	62 min
Aug 30, 6:20 PM MST	Areal Flood Advisory	PSR	22 min
Aug 30, 6:42 PM MST	Flash Flood Warning Considerable damage threat	PSR	3 hr
Aug 30, 7:14 PM MST	Flash Flood Warning Considerable damage threat	PSR	4 hr
Aug 30, 7:16 PM MST	Special Weather Statement	PSR	59 min
Aug 30, 8:28 PM MST	Severe Thunderstorm Warning	PSR	33 min
Sep 1, 2:23 AM MST	Excessive Heat Watch	PSR	35 hr
Sep 1, 5:27 AM MST	Flash Flood Warning Considerable damage threat	PSR	3 hr
Sep 2, 1:33 PM MST	Excessive Heat Warning	PSR	5 days
Sep 6, 2:44 PM MST	Red Flag Warning	PSR	57 hr
Sep 8, 4:33 PM MST	Severe Thunderstorm Warning	PSR	27 min
Sep 8, 4:58 PM MST	Severe Thunderstorm Warning	PSR	32 min
Sep 8, 5:12 PM MST	Special Weather Statement	PSR	33 min
Sep 8, 5:29 PM MST	Severe Thunderstorm Warning	PSR	31 min
Sep 15, 1:57 PM MST	Excessive Heat Warning	PSR	54 hr
Oct 25, 2:22 AM MST	Freeze Warning	PSR	55 hr
Nov 29, 1:35 AM MST	Wind Advisory	PSR	34 hr
Dec 3, 1:44 AM MST	Freeze Warning	PSR	30 hr
Dec 10, 8:10 AM MST	Areal Flood Advisory	PSR	3 hr
Dec 11, 5:05 AM MST	Dense Fog Advisory	PSR	5 hr
Dec 14, 1:41 PM MST	Freeze Warning	PSR	19 hr
Dec 15, 2:04 PM MST	Freeze Warning	PSR	19 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	29
Mesoscale Discussion	6
Special Weather Statement	56
Flooding
Areal Flood Warning	6
Flash Flood Warning	27
River Flood Warning	1
Flash Flood Watch	4
Areal Flood Advisory	25
Winter
Winter Weather Advisory	1
Heat
Excessive Heat Warning	14
Excessive Heat Watch	12
Heat Advisory	2
Cold
Freeze Warning	6
Freeze Watch	2
Wind and dust
Dust Storm Warning	6
Blowing Dust Advisory	2
Dust Storm Advisory	19
Wind Advisory	1
Fire
Red Flag Warning	3
Fire Weather Watch	2
Fog and smoke
Dense Fog Advisory	4

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2019 2021

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.