Alert archive / Virginia / Prince William County
Weather alerts in Prince William County, Virginia, 2019
146 weather alerts in 2019, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Prince William County and its neighbors
Each county as a circle sized by its count in 2019. Tap one for its archive.
- Alerts
- 146
- Warnings
- 79
- Watches
- 17
- Advisories
- 0
- Busiest month
- May30 alerts
- Busiest day
- August 20, 20199 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Prince William County, 2019
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 67 | 53 | 21% | 58 | 60% | 15 min |
| Flash flood warnings | 2 | 0 | 100% | 0 |
Each office's whole area, 2019
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Baltimore/Washington: tornado warnings | 34 | 4 | 88% | 8 | 50% | 5 min |
| NWS Baltimore/Washington: severe thunderstorm warnings | 694 | 468 | 33% | 1,610 | 81% | 19 min |
| NWS Baltimore/Washington: flash flood warnings | 36 | 16 | 56% | 74 | 96% | 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 13, 3:54 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Jan 13, 6:19 PM EST | Special Weather Statement | LWX | 116 min |
| Jan 20, 8:23 AM EST | Areal Flood Warning | LWX | 6 hr |
| Jan 24, 2:08 PM EST | Areal Flood Warning | LWX | 15 hr |
| Jan 30, 11:13 AM EST | Snow Squall Warning | LWX | 92 min |
| Mar 19, 10:00 AM EDT | Special Weather Statement | LWX | 15 min |
| Mar 21, 4:01 PM EDT | Areal Flood Warning | LWX | 24 hr |
| Mar 22, 3:52 PM EDT | Severe Thunderstorm Warning | LWX | 38 min |
| Mar 22, 4:21 PM EDT | Severe Thunderstorm Warning | LWX | 39 min |
| Apr 14, 4:50 PM EDT | Mesoscale Discussion | SPC | 85 min |
| Apr 14, 5:49 PM EDT | Mesoscale Discussion | SPC | 26 min |
| Apr 14, 6:08 PM EDT | Tornado Watch | SPC | 9 hr |
| Apr 14, 7:42 PM EDT | Mesoscale Discussion | SPC | 63 min |
| Apr 15, 1:18 AM EDT | Severe Thunderstorm Warning | LWX | 42 min |
| Apr 15, 1:43 AM EDT | Severe Thunderstorm Warning | LWX | 36 min |
| Apr 19, 12:08 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 19, 12:48 PM EDT | Tornado Watch | SPC | 9 hr |
| Apr 19, 4:32 PM EDT | Mesoscale Discussion | SPC | 58 min |
| Apr 19, 6:21 PM EDT | Mesoscale Discussion | SPC | 84 min |
| Apr 19, 8:21 PM EDT | Severe Thunderstorm Warning | LWX | 39 min |
| Apr 19, 8:41 PM EDT | Severe Thunderstorm Warning | LWX | 34 min |
| Apr 26, 11:37 AM EDT | Mesoscale Discussion | SPC | 113 min |
| Apr 26, 1:33 PM EDT | Tornado Watch | SPC | 6 hr |
| Apr 26, 1:51 PM EDT | Severe Thunderstorm Warning | LWX | 39 min |
| Apr 26, 2:56 PM EDT | Severe Thunderstorm Warning | LWX | 49 min |
| May 2, 3:03 PM EDT | Severe Thunderstorm Warning | LWX | 42 min |
| May 2, 3:28 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 3, 4:45 PM EDT | Mesoscale Discussion | SPC | 60 min |
| May 4, 10:38 PM EDT | Areal Flood Warning | LWX | 10 hr |
| May 4, 10:57 PM EDT | Flash Flood Warning | LWX | 3 hr |
| May 5, 5:22 PM EDT | Areal Flood Warning | LWX | 13 hr |
| May 5, 10:02 PM EDT | Areal Flood Warning | LWX | 6 hr |
| May 18, 6:31 PM EDT | Severe Thunderstorm Warning | LWX | 44 min |
| May 23, 1:02 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 23, 3:11 PM EDT | Severe Thunderstorm Warning | LWX | 34 min |
| May 23, 3:28 PM EDT | Severe Thunderstorm Warning | LWX | 32 min |
| May 23, 3:36 PM EDT | Severe Thunderstorm Warning | LWX | 39 min |
| May 23, 3:42 PM EDT | Mesoscale Discussion | SPC | 93 min |
| May 23, 3:55 PM EDT | Severe Thunderstorm Warning | LWX | 65 min |
| May 25, 5:43 PM EDT | Mesoscale Discussion | SPC | 62 min |
| May 25, 7:03 PM EDT | Severe Thunderstorm Warning | LWX | 42 min |
| May 25, 7:43 PM EDT | Severe Thunderstorm Warning | LWX | 47 min |
| May 25, 8:14 PM EDT | Severe Thunderstorm Warning | LWX | 33 min |
| May 26, 11:14 AM EDT | Mesoscale Discussion | SPC | 3 hr |
| May 26, 1:45 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 26, 5:45 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 26, 8:32 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| May 26, 10:26 PM EDT | Mesoscale Discussion | SPC | 94 min |
| May 30, 12:15 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 30, 2:01 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 30, 2:32 PM EDT | Severe Thunderstorm Warning | LWX | 43 min |
| May 30, 3:10 PM EDT | Severe Thunderstorm Warning | LWX | 50 min |
| May 30, 3:42 PM EDT | Severe Thunderstorm Warning | LWX | 48 min |
| May 30, 4:03 PM EDT | Severe Thunderstorm Warning | LWX | 27 min |
| May 30, 6:35 PM EDT | Mesoscale Discussion | SPC | 55 min |
| Jun 2, 12:53 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 2, 3:33 PM EDT | Mesoscale Discussion | SPC | 87 min |
| Jun 2, 4:21 PM EDT | Severe Thunderstorm Warning | LWX | 25 min |
| Jun 2, 4:45 PM EDT | Severe Thunderstorm Warning | LWX | 45 min |
| Jun 2, 5:37 PM EDT | Severe Thunderstorm Warning | LWX | 38 min |
| Jun 2, 5:57 PM EDT | Severe Thunderstorm Warning | LWX | 48 min |
| Jun 2, 5:57 PM EDT | Mesoscale Discussion | SPC | 93 min |
| Jun 13, 4:28 PM EDT | Severe Thunderstorm Warning | LWX | 47 min |
| Jun 13, 4:47 PM EDT | Severe Thunderstorm Warning | LWX | 43 min |
| Jun 13, 5:04 PM EDT | Severe Thunderstorm Warning | LWX | 41 min |
| Jun 16, 1:53 PM EDT | Mesoscale Discussion | SPC | 97 min |
| Jun 17, 2:03 PM EDT | Mesoscale Discussion | SPC | 117 min |
| Jun 17, 4:05 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 17, 7:11 PM EDT | Severe Thunderstorm Warning | LWX | 34 min |
| Jun 18, 12:23 PM EDT | Mesoscale Discussion | SPC | 97 min |
| Jun 18, 2:11 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 18, 4:47 PM EDT | Mesoscale Discussion | SPC | 88 min |
| Jun 18, 5:54 PM EDT | Severe Thunderstorm Warning | LWX | 29 min |
| Jun 20, 12:23 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 24, 7:17 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 27, 5:36 PM EDT | Severe Thunderstorm Warning | LWX | 39 min |
| Jun 27, 6:14 PM EDT | Severe Thunderstorm Warning | LWX | 46 min |
| Jun 27, 6:15 PM EDT | Severe Thunderstorm Warning | LWX | 45 min |
| Jun 28, 5:59 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 29, 2:04 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 29, 4:45 PM EDT | Severe Thunderstorm Warning | LWX | 45 min |
| Jun 29, 6:49 PM EDT | Severe Thunderstorm Warning | LWX | 16 min |
| Jul 2, 5:53 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 2, 6:31 PM EDT | Severe Thunderstorm Warning | LWX | 33 min |
| Jul 2, 6:40 PM EDT | Severe Thunderstorm Warning | LWX | 35 min |
| Jul 4, 5:08 PM EDT | Severe Thunderstorm Warning | LWX | 35 min |
| Jul 4, 6:08 PM EDT | Flash Flood Warning | LWX | 72 min |
| Jul 6, 1:48 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 6, 5:49 PM EDT | Severe Thunderstorm Warning | LWX | 41 min |
| Jul 11, 12:51 PM EDT | Mesoscale Discussion | SPC | 84 min |
| Jul 11, 5:14 PM EDT | Severe Thunderstorm Warning | LWX | 46 min |
| Jul 16, 3:28 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 17, 1:29 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 17, 4:12 PM EDT | Severe Thunderstorm Warning | LWX | 48 min |
| Jul 17, 4:20 PM EDT | Severe Thunderstorm Warning | LWX | 40 min |
| Jul 17, 4:48 PM EDT | Severe Thunderstorm Warning | LWX | 42 min |
| Jul 17, 4:51 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 17, 5:08 PM EDT | Severe Thunderstorm Warning | LWX | 41 min |
| Jul 18, 1:49 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 21, 6:07 PM EDT | Mesoscale Discussion | SPC | 83 min |
| Jul 22, 1:11 PM EDT | Mesoscale Discussion | SPC | 94 min |
| Jul 22, 2:17 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 22, 7:20 PM EDT | Mesoscale Discussion | SPC | 55 min |
| Jul 22, 7:43 PM EDT | Severe Thunderstorm Warning | LWX | 47 min |
| Jul 22, 8:51 PM EDT | Mesoscale Discussion | SPC | 84 min |
| Jul 30, 7:38 PM EDT | Severe Thunderstorm Warning | LWX | 23 min |
| Jul 31, 1:17 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 31, 4:19 PM EDT | Mesoscale Discussion | SPC | 56 min |
| Aug 7, 1:02 PM EDT | Mesoscale Discussion | SPC | 88 min |
| Aug 7, 1:53 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 7, 3:24 PM EDT | Severe Thunderstorm Warning | LWX | 51 min |
| Aug 9, 2:25 PM EDT | Mesoscale Discussion | SPC | 95 min |
| Aug 13, 8:58 PM EDT | Severe Thunderstorm Warning | LWX | 32 min |
| Aug 15, 1:15 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 17, 4:13 PM EDT | Severe Thunderstorm Warning | LWX | 47 min |
| Aug 19, 9:00 PM EDT | Severe Thunderstorm Warning | LWX | 30 min |
| Aug 19, 10:28 PM EDT | Severe Thunderstorm Warning | LWX | 47 min |
| Aug 20, 2:19 PM EDT | Mesoscale Discussion | SPC | 56 min |
| Aug 20, 3:02 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 20, 4:44 PM EDT | Severe Thunderstorm Warning | LWX | 46 min |
| Aug 20, 5:43 PM EDT | Severe Thunderstorm Warning | LWX | 32 min |
| Aug 20, 6:12 PM EDT | Severe Thunderstorm Warning | LWX | 48 min |
| Aug 20, 7:00 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 20, 7:11 PM EDT | Areal Flood Warning | LWX | 3 hr |
| Aug 20, 8:09 PM EDT | Areal Flood Warning | LWX | 106 min |
| Aug 21, 3:27 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Sep 2, 4:53 PM EDT | Severe Thunderstorm Warning | LWX | 37 min |
| Sep 2, 5:36 PM EDT | Severe Thunderstorm Warning | LWX | 24 min |
| Sep 2, 5:52 PM EDT | Severe Thunderstorm Warning | LWX | 38 min |
| Sep 2, 6:13 PM EDT | Severe Thunderstorm Warning | LWX | 28 min |
| Sep 2, 6:26 PM EDT | Severe Thunderstorm Warning | LWX | 49 min |
| Sep 11, 3:08 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 11, 3:46 PM EDT | Severe Thunderstorm Warning | LWX | 44 min |
| Sep 11, 3:48 PM EDT | Severe Thunderstorm Warning | LWX | 42 min |
| Sep 11, 4:11 PM EDT | Severe Thunderstorm Warning | LWX | 49 min |
| Sep 11, 4:41 PM EDT | Severe Thunderstorm Warning | LWX | 49 min |
| Sep 11, 4:57 PM EDT | Severe Thunderstorm Warning | LWX | 48 min |
| Sep 11, 5:22 PM EDT | Severe Thunderstorm Warning | LWX | 53 min |
| Sep 12, 2:02 PM EDT | Mesoscale Discussion | SPC | 118 min |
| Oct 31, 1:11 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 31, 2:56 PM EDT | Tornado Watch | SPC | 10 hr |
| Oct 31, 4:01 PM EDT | Mesoscale Discussion | SPC | 119 min |
| Oct 31, 7:14 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 31, 9:24 PM EDT | Severe Thunderstorm Warning | LWX | 36 min |
| Oct 31, 10:07 PM EDT | Severe Thunderstorm Warning | LWX | 38 min |
| Nov 1, 6:58 AM EDT | Areal Flood Warning | LWX | 2 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 | 67 |
| Severe Thunderstorm Watch | 13 |
| Tornado Watch | 4 |
| Mesoscale Discussion | 48 |
| Special Weather Statement | 2 |
| Flooding | |
| Areal Flood Warning | 9 |
| Flash Flood Warning | 2 |
| Winter | |
| Snow Squall Warning | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20182020
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.