Alert archive / Virginia / Fairfax County

Weather alerts in Fairfax County, Virginia, 2018

192 weather alerts in 2018, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Fairfax County and its neighbors

Each county as a circle sized by its count in 2018. Tap one for its archive.

Alerts: 192
Warnings: 83
Watches: 46
Advisories: 33
Busiest month: May36 alerts
Busiest day: May 14, 20189 alerts

Over time

By month

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

1 of 2 tornado warnings covering Fairfax County in 2018 had a tornado report inside them; 1 of 1 tornado reports fell inside a warning, on average 1 minutes after it went out.

Fairfax County, 2018

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	2	1	50%	1	100%	1 min
Severe thunderstorm warnings	20	14	30%	23	65%	23 min
Flash flood warnings	8	6	25%	5	80%	37 min

Each office's whole area, 2018

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Baltimore/Washington: tornado warnings	19	1	95%	4	25%	1 min
NWS Baltimore/Washington: severe thunderstorm warnings	312	208	33%	690	70%	20 min
NWS Baltimore/Washington: flash flood warnings	87	38	56%	129	89%	103 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, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Lasted
Jan 3, 3:34 AM EST	Winter Weather Advisory	LWX	35 hr
Jan 4, 3:36 AM EST	Wind Chill Advisory	LWX	32 hr
Jan 4, 12:47 PM EST	Wind Advisory	LWX	5 hr
Jan 5, 3:45 AM EST	Wind Chill Advisory	LWX	54 hr
Jan 6, 3:55 AM EST	Wind Chill Advisory	LWX	26 hr
Jan 7, 2:46 PM EST	Winter Weather Advisory	LWX	33 hr
Jan 9, 4:32 AM EST	Dense Fog Advisory	LWX	4 hr
Jan 15, 1:47 PM EST	Winter Weather Advisory	LWX	46 hr
Feb 3, 3:00 PM EST	Winter Weather Advisory	LWX	28 hr
Feb 6, 4:02 AM EST	Winter Weather Advisory	LWX	38 hr
Feb 10, 3:38 AM EST	Flood Watch	LWX	36 hr
Feb 16, 9:12 PM EST	Winter Weather Advisory	LWX	31 hr
Feb 23, 8:30 PM EST	Dense Fog Advisory	LWX	15 hr
Feb 25, 10:46 PM EST	Dense Fog Advisory	LWX	6 hr
Feb 28, 2:52 PM EST	High Wind Watch	LWX	21 hr
Mar 1, 4:06 AM EST	High Wind Warning	LWX	45 hr
Mar 1, 10:37 PM EST	Special Weather Statement	LWX	7 hr
Mar 2, 7:57 PM EST	Wind Advisory	LWX	10 hr
Mar 19, 12:06 PM EDT	Winter Storm Watch	LWX	25 hr
Mar 20, 10:00 AM EDT	Special Weather Statement	LWX	15 min
Mar 20, 12:47 PM EDT	Winter Storm Warning	LWX	31 hr
Apr 3, 5:33 PM EDT	Wind Advisory	LWX	25 hr
Apr 11, 1:34 PM EDT	Fire Weather Watch	LWX	14 hr
Apr 12, 3:42 AM EDT	Red Flag Warning	LWX	16 hr
Apr 16, 3:34 AM EDT	Flash Flood Warning	LWX	2 hr
Apr 16, 5:39 AM EDT	Areal Flood Warning	LWX	6 hr
Apr 17, 4:08 AM EDT	Freeze Watch	LWX	9 hr
Apr 17, 1:24 PM EDT	Freeze Warning	LWX	19 hr
Apr 19, 4:27 AM EDT	Freeze Watch	LWX	10 hr
Apr 19, 2:22 PM EDT	Freeze Warning	LWX	18 hr
Apr 27, 7:18 AM EDT	Areal Flood Warning	LWX	4 hr
Apr 28, 5:21 AM EDT	Dense Fog Advisory	LWX	5 hr
Apr 29, 3:15 PM EDT	Frost Advisory	LWX	17 hr
Apr 29, 3:18 PM EDT	Fire Weather Watch	LWX	12 hr
Apr 30, 3:32 AM EDT	Red Flag Warning	LWX	16 hr
May 10, 12:36 PM EDT	Mesoscale Discussion	SPC	114 min
May 10, 1:14 PM EDT	Severe Thunderstorm Watch	SPC	8 hr
May 10, 4:53 PM EDT	Mesoscale Discussion	SPC	67 min
May 12, 2:47 PM EDT	Severe Thunderstorm Watch	SPC	8 hr
May 12, 7:46 PM EDT	Severe Thunderstorm Warning	LWX	22 min
May 13, 7:00 PM EDT	Mesoscale Discussion	SPC	60 min
May 13, 10:12 PM EDT	Severe Thunderstorm Warning	LWX	48 min
May 13, 10:21 PM EDT	Severe Thunderstorm Warning	LWX	39 min
May 14, 11:56 AM EDT	Mesoscale Discussion	SPC	64 min
May 14, 12:29 PM EDT	Severe Thunderstorm Watch	SPC	9 hr
May 14, 3:26 PM EDT	Mesoscale Discussion	SPC	2 hr
May 14, 6:07 PM EDT	Severe Thunderstorm Warning	LWX	53 min
May 14, 6:12 PM EDT	Tornado Warning	LWX	33 min
May 14, 6:56 PM EDT	Flash Flood Warning	LWX	3 hr
May 14, 7:00 PM EDT	Severe Thunderstorm Warning	LWX	30 min
May 15, 4:33 AM EDT	Flash Flood Watch	LWX	20 hr
May 15, 5:43 PM EDT	Mesoscale Discussion	SPC	92 min
May 15, 5:54 PM EDT	Severe Thunderstorm Watch	SPC	4 hr
May 15, 8:34 PM EDT	Severe Thunderstorm Warning	LWX	41 min
May 15, 8:41 PM EDT	Mesoscale Discussion	SPC	94 min
May 15, 9:09 PM EDT	Areal Flood Warning	LWX	111 min
May 16, 1:40 PM EDT	Flood Watch	LWX	3 days
May 17, 3:44 PM EDT	River Flood Warning	LWX	3 days
May 19, 1:37 AM EDT	Areal Flood Warning	LWX	15 hr
May 22, 1:52 PM EDT	Mesoscale Discussion	SPC	113 min
May 22, 2:33 PM EDT	Severe Thunderstorm Watch	SPC	6 hr
May 22, 3:25 PM EDT	Severe Thunderstorm Warning	LWX	50 min
May 22, 4:43 PM EDT	Areal Flood Warning	LWX	4 hr
May 22, 4:48 PM EDT	Severe Thunderstorm Warning	LWX	42 min
May 22, 4:50 PM EDT	Mesoscale Discussion	SPC	115 min
May 22, 5:17 PM EDT	Areal Flood Warning	LWX	4 hr
May 27, 4:25 AM EDT	Flash Flood Watch	LWX	16 hr
May 27, 1:29 PM EDT	Mesoscale Discussion	SPC	3 hr
May 31, 4:06 AM EDT	Flash Flood Watch	LWX	17 hr
May 31, 6:20 PM EDT	Areal Flood Warning	LWX	115 min
May 31, 7:50 PM EDT	Areal Flood Warning	LWX	115 min
Jun 2, 3:13 AM EDT	Flash Flood Watch	LWX	25 hr
Jun 2, 3:27 AM EDT	River Flood Watch	LWX	36 hr
Jun 2, 3:22 PM EDT	Areal Flood Warning	LWX	10 hr
Jun 3, 4:11 AM EDT	Flood Watch	LWX	14 hr
Jun 3, 2:44 PM EDT	Areal Flood Warning	LWX	7 hr
Jun 3, 3:48 PM EDT	River Flood Warning	LWX	53 hr
Jun 3, 6:03 PM EDT	Flood Watch	LWX	3 hr
Jun 9, 1:34 PM EDT	Mesoscale Discussion	SPC	2 hr
Jun 9, 6:34 PM EDT	Severe Thunderstorm Warning	LWX	45 min
Jun 10, 3:47 AM EDT	Flash Flood Watch	LWX	24 hr
Jun 18, 9:42 AM EDT	Heat Advisory	LWX	10 hr
Jun 19, 12:04 PM EDT	Mesoscale Discussion	SPC	116 min
Jun 19, 2:16 PM EDT	Severe Thunderstorm Warning	LWX	29 min
Jun 19, 2:32 PM EDT	Severe Thunderstorm Warning	LWX	28 min
Jun 23, 5:40 PM EDT	Mesoscale Discussion	SPC	2 hr
Jun 24, 2:04 PM EDT	Mesoscale Discussion	SPC	116 min
Jun 27, 7:37 PM EDT	Mesoscale Discussion	SPC	3 hr
Jun 30, 2:14 PM EDT	Heat Advisory	LWX	27 hr
Jul 1, 2:10 PM EDT	Heat Advisory	LWX	30 hr
Jul 2, 1:40 PM EDT	Heat Advisory	LWX	30 hr
Jul 3, 2:16 PM EDT	Excessive Heat Warning	LWX	6 hr
Jul 5, 9:56 AM EDT	Flash Flood Watch	LWX	17 hr
Jul 17, 3:29 PM EDT	Areal Flood Warning	LWX	3 hr
Jul 21, 5:05 AM EDT	Flash Flood Watch	LWX	21 hr
Jul 21, 4:41 PM EDT	Areal Flood Warning	LWX	27 hr
Jul 21, 7:23 PM EDT	Flash Flood Warning	LWX	3 hr
Jul 21, 8:49 PM EDT	Flash Flood Warning	LWX	3 hr
Jul 21, 9:29 PM EDT	Flash Flood Warning	LWX	3 hr
Jul 22, 11:35 AM EDT	Flash Flood Watch	LWX	17 hr
Jul 23, 2:57 AM EDT	Mesoscale Discussion	SPC	3 hr
Jul 23, 4:59 AM EDT	Flash Flood Watch	LWX	68 hr
Jul 23, 2:40 PM EDT	Mesoscale Discussion	SPC	3 hr
Jul 24, 5:54 AM EDT	Tornado Warning	LWX	21 min
Jul 24, 6:14 AM EDT	Areal Flood Warning	LWX	8 hr
Jul 25, 4:41 PM EDT	Areal Flood Warning	LWX	21 hr
Jul 25, 5:56 PM EDT	Areal Flood Warning	LWX	11 hr
Jul 25, 6:16 PM EDT	Flash Flood Warning	LWX	3 hr
Jul 27, 4:06 AM EDT	Flash Flood Watch	LWX	17 hr
Jul 27, 1:28 PM EDT	Mesoscale Discussion	SPC	62 min
Jul 27, 1:52 PM EDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 27, 4:50 PM EDT	Mesoscale Discussion	SPC	55 min
Jul 27, 5:02 PM EDT	Severe Thunderstorm Warning	LWX	23 min
Jul 27, 7:06 PM EDT	Mesoscale Discussion	SPC	54 min
Aug 1, 2:22 AM EDT	Areal Flood Warning	LWX	9 hr
Aug 1, 4:10 AM EDT	Flash Flood Watch	LWX	3 days
Aug 1, 10:35 AM EDT	Areal Flood Warning	LWX	4 hr
Aug 1, 11:05 PM EDT	Areal Flood Warning	LWX	4 hr
Aug 1, 11:05 PM EDT	Severe Thunderstorm Warning	LWX	25 min
Aug 2, 11:46 AM EDT	Mesoscale Discussion	SPC	119 min
Aug 2, 1:55 PM EDT	Severe Thunderstorm Warning	LWX	50 min
Aug 2, 2:22 PM EDT	Areal Flood Warning	LWX	5 hr
Aug 2, 2:51 PM EDT	Areal Flood Warning	LWX	5 hr
Aug 11, 10:50 AM EDT	Flash Flood Watch	LWX	10 hr
Aug 12, 12:23 PM EDT	Flash Flood Watch	LWX	9 hr
Aug 13, 4:21 AM EDT	Flash Flood Watch	LWX	18 hr
Aug 13, 3:46 PM EDT	Severe Thunderstorm Warning	LWX	44 min
Aug 13, 4:11 PM EDT	Severe Thunderstorm Warning	LWX	49 min
Aug 13, 4:22 PM EDT	Severe Thunderstorm Warning	LWX	38 min
Aug 17, 3:10 PM EDT	Mesoscale Discussion	SPC	3 hr
Aug 18, 2:22 AM EDT	Severe Thunderstorm Warning	LWX	23 min
Aug 21, 1:16 PM EDT	Areal Flood Warning	LWX	21 hr
Aug 21, 7:06 PM EDT	Mesoscale Discussion	SPC	84 min
Aug 21, 11:16 PM EDT	Areal Flood Warning	LWX	6 hr
Aug 28, 3:52 AM EDT	Heat Advisory	LWX	16 hr
Aug 29, 3:49 AM EDT	Heat Advisory	LWX	16 hr
Aug 31, 11:03 AM EDT	Flash Flood Watch	LWX	13 hr
Aug 31, 9:51 PM EDT	Areal Flood Warning	LWX	4 hr
Aug 31, 10:48 PM EDT	Areal Flood Warning	LWX	6 hr
Aug 31, 11:42 PM EDT	Areal Flood Warning	LWX	6 hr
Sep 1, 12:00 AM EDT	Flash Flood Warning	LWX	52 min
Sep 1, 9:52 PM EDT	Areal Flood Warning	LWX	109 min
Sep 4, 2:17 AM EDT	Heat Advisory	LWX	17 hr
Sep 7, 3:29 AM EDT	Flash Flood Watch	LWX	19 hr
Sep 7, 5:10 PM EDT	Areal Flood Warning	LWX	4 hr
Sep 7, 6:00 PM EDT	Flash Flood Warning	LWX	3 hr
Sep 7, 8:48 PM EDT	Areal Flood Warning	LWX	4 hr
Sep 8, 2:46 PM EDT	Flood Watch	LWX	39 hr
Sep 9, 12:32 PM EDT	Areal Flood Warning	LWX	6 hr
Sep 9, 12:57 PM EDT	River Flood Watch	LWX	5 days
Sep 10, 4:47 AM EDT	River Flood Warning	LWX	49 hr
Sep 11, 5:24 AM EDT	Dense Fog Advisory	LWX	4 hr
Sep 16, 3:11 PM EDT	Flash Flood Watch	LWX	52 hr
Sep 16, 9:31 PM EDT	River Flood Watch	LWX	24 hr
Sep 17, 3:42 PM EDT	Tornado Watch	SPC	4 hr
Sep 17, 7:09 PM EDT	Mesoscale Discussion	SPC	2 hr
Sep 26, 3:40 PM EDT	Mesoscale Discussion	SPC	3 hr
Sep 26, 5:02 PM EDT	Severe Thunderstorm Watch	SPC	4 hr
Sep 26, 5:31 PM EDT	Severe Thunderstorm Warning	LWX	26 min
Sep 27, 2:39 AM EDT	Flood Watch	LWX	27 hr
Sep 28, 1:09 AM EDT	Areal Flood Warning	LWX	11 hr
Sep 28, 3:49 AM EDT	River Flood Warning	LWX	56 hr
Sep 28, 4:58 AM EDT	Areal Flood Warning	LWX	16 hr
Oct 8, 2:58 AM EDT	Dense Fog Advisory	LWX	7 hr
Oct 11, 3:12 AM EDT	Wind Advisory	LWX	29 hr
Oct 11, 6:51 PM EDT	Areal Flood Warning	LWX	2 hr
Oct 11, 9:14 PM EDT	Areal Flood Warning	LWX	5 hr
Oct 18, 2:57 PM EDT	Frost Advisory	LWX	18 hr
Oct 21, 4:05 AM EDT	Frost Advisory	LWX	30 hr
Nov 2, 6:55 PM EDT	Mesoscale Discussion	SPC	95 min
Nov 2, 10:05 PM EDT	Areal Flood Warning	LWX	2 hr
Nov 5, 10:45 AM EST	Areal Flood Warning	LWX	4 hr
Nov 14, 3:54 PM EST	Winter Weather Advisory	LWX	36 hr
Nov 15, 12:28 AM EST	Flood Watch	LWX	14 hr
Nov 15, 3:18 AM EST	Mesoscale Discussion	SPC	6 hr
Nov 16, 4:23 AM EST	Areal Flood Warning	LWX	6 hr
Nov 23, 3:32 AM EST	Winter Weather Advisory	LWX	36 hr
Nov 24, 6:24 PM EST	Areal Flood Warning	LWX	11 hr
Nov 25, 2:07 AM EST	Areal Flood Warning	LWX	5 hr
Nov 25, 7:27 AM EST	Areal Flood Warning	LWX	3 hr
Nov 27, 2:03 PM EST	Wind Advisory	LWX	24 hr
Dec 13, 2:04 PM EST	Flood Watch	LWX	63 hr
Dec 15, 1:38 PM EST	Areal Flood Warning	LWX	33 hr
Dec 15, 3:17 PM EST	River Flood Watch	LWX	24 hr
Dec 15, 4:34 PM EST	Areal Flood Warning	LWX	25 hr
Dec 16, 3:21 AM EST	River Flood Warning	LWX	65 hr
Dec 19, 3:48 AM EST	Flood Watch	LWX	59 hr
Dec 20, 5:18 PM EST	River Flood Watch	LWX	24 hr
Dec 21, 4:00 PM EST	Severe Thunderstorm Warning	LWX	45 min
Dec 21, 4:16 PM EST	Mesoscale Discussion	SPC	59 min
Dec 27, 3:41 AM EST	Flood Watch	LWX	39 hr
Dec 28, 7:45 PM EST	Dense Fog Advisory	LWX	11 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	20
Tornado Warning	2
Severe Thunderstorm Watch	7
Tornado Watch	1
Mesoscale Discussion	28
Special Weather Statement	2
Flooding
Areal Flood Warning	41
Flash Flood Warning	8
River Flood Warning	5
Flash Flood Watch	17
Flood Watch	10
River Flood Watch	5
Winter
Winter Storm Warning	1
Winter Storm Watch	1
Winter Weather Advisory	8
Heat
Excessive Heat Warning	1
Heat Advisory	7
Cold
Freeze Warning	2
Freeze Watch	2
Frost Advisory	3
Wind Chill Advisory	3
Wind and dust
High Wind Warning	1
High Wind Watch	1
Wind Advisory	5
Fire
Red Flag Warning	2
Fire Weather Watch	2
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 2017 2019

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.