Alert archive / Virginia / Amherst County
Weather alerts in Amherst County, Virginia, 2009
123 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Amherst County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 123
- Warnings
- 24
- Watches
- 23
- Advisories
- 29
- Busiest month
- June22 alerts
- Busiest day
- June 3, 20096 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Amherst County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 13 | 7 | 46% | 3 | 100% | 9 min |
| Flash flood warnings | 3 | 1 | 67% | 1 | 100% | 70 min |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Blacksburg, VA: tornado warnings | 19 | 1 | 95% | 9 | 11% | 4 min |
| NWS Blacksburg, VA: severe thunderstorm warnings | 264 | 144 | 45% | 348 | 82% | 26 min |
| NWS Blacksburg, VA: flash flood warnings | 108 | 53 | 51% | 135 | 81% | 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, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 5, 4:02 AM EST | Winter Storm Watch | RNK | 12 hr |
| Jan 5, 3:57 PM EST | Freezing Rain Advisory | RNK | 20 hr |
| Jan 7, 4:19 AM EST | Wind Advisory | RNK | 23 hr |
| Jan 15, 4:19 AM EST | Wind Chill Advisory | RNK | 33 hr |
| Jan 25, 2:05 PM EST | Winter Storm Watch | RNK | 25 hr |
| Jan 26, 3:20 PM EST | Winter Storm Warning | RNK | 45 hr |
| Jan 27, 3:48 PM EST | Wind Advisory | RNK | 29 hr |
| Feb 10, 3:01 PM EST | High Wind Watch | RNK | 14 hr |
| Feb 11, 4:40 AM EST | High Wind Warning | RNK | 35 hr |
| Feb 11, 4:40 AM EST | Wind Advisory | RNK | 43 hr |
| Feb 11, 5:32 PM EST | Mesoscale Discussion | SPC | 88 min |
| Feb 11, 5:53 PM EST | Severe Thunderstorm Watch | SPC | 4 hr |
| Feb 11, 7:58 PM EST | Severe Thunderstorm Warning | RNK | 62 min |
| Feb 11, 8:00 PM EST | Mesoscale Discussion | SPC | 60 min |
| Feb 18, 1:05 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Feb 18, 4:14 AM EST | Winter Weather Advisory | RNK | 7 hr |
| Feb 28, 5:24 AM EST | Winter Storm Watch | RNK | 23 hr |
| Feb 28, 4:12 PM EST | Winter Weather Advisory | RNK | 18 hr |
| Mar 1, 4:39 AM EST | Winter Storm Warning | RNK | 28 hr |
| Mar 1, 1:16 PM EST | Mesoscale Discussion | SPC | 3 hr |
| Mar 1, 5:01 PM EST | Mesoscale Discussion | SPC | 2 hr |
| Mar 12, 3:59 PM EDT | Winter Weather Advisory | RNK | 19 hr |
| Mar 13, 9:00 PM EDT | Freezing Rain Advisory | RNK | 12 hr |
| Mar 27, 4:12 AM EDT | Dense Fog Advisory | RNK | 6 hr |
| Apr 2, 4:17 AM EDT | Dense Fog Advisory | RNK | 5 hr |
| Apr 2, 9:54 PM EDT | High Wind Watch | RNK | 6 hr |
| Apr 3, 3:57 AM EDT | High Wind Warning | RNK | 29 hr |
| Apr 3, 3:57 AM EDT | Wind Advisory | RNK | 32 hr |
| Apr 3, 8:24 AM EDT | Special Weather Statement | RNK | 66 min |
| Apr 10, 12:51 PM EDT | Special Weather Statement | RNK | 54 min |
| Apr 16, 2:42 PM EDT | Frost Advisory | RNK | 17 hr |
| Apr 20, 2:50 PM EDT | Tornado Watch | SPC | 7 hr |
| Apr 20, 3:23 PM EDT | Severe Thunderstorm Warning | RNK | 82 min |
| Apr 21, 2:12 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 22, 1:14 PM EDT | Wind Advisory | RNK | 8 hr |
| May 3, 10:43 PM EDT | Flood Watch | RNK | 13 hr |
| May 4, 12:44 AM EDT | Special Weather Statement | RNK | 61 min |
| May 6, 3:45 PM EDT | Special Weather Statement | RNK | 60 min |
| May 6, 11:53 PM EDT | Severe Thunderstorm Warning | RNK | 37 min |
| May 8, 10:01 PM EDT | Tornado Watch | SPC | 4 hr |
| May 9, 1:17 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 14, 8:47 PM EDT | Special Weather Statement | RNK | 58 min |
| May 14, 10:12 PM EDT | Flash Flood Warning | RNK | 6 hr |
| May 18, 3:57 AM EDT | Frost Advisory | RNK | 29 hr |
| May 26, 12:07 PM EDT | Flash Flood Watch | RNK | 20 hr |
| May 28, 3:49 PM EDT | Mesoscale Discussion | SPC | 56 min |
| May 29, 1:26 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 29, 4:30 PM EDT | Mesoscale Discussion | SPC | 60 min |
| Jun 3, 12:41 PM EDT | Mesoscale Discussion | SPC | 64 min |
| Jun 3, 1:06 PM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 3, 1:51 PM EDT | Flash Flood Watch | RNK | 15 hr |
| Jun 3, 3:51 PM EDT | Severe Thunderstorm Warning | RNK | 54 min |
| Jun 3, 4:34 PM EDT | Mesoscale Discussion | SPC | 86 min |
| Jun 3, 7:10 PM EDT | Mesoscale Discussion | SPC | 95 min |
| Jun 4, 4:48 AM EDT | Flood Watch | RNK | 31 hr |
| Jun 9, 2:31 PM EDT | Mesoscale Discussion | SPC | 89 min |
| Jun 9, 6:24 PM EDT | Severe Thunderstorm Warning | RNK | 96 min |
| Jun 9, 6:48 PM EDT | Severe Thunderstorm Warning | RNK | 87 min |
| Jun 9, 9:30 PM EDT | Flash Flood Warning | RNK | 6 hr |
| Jun 10, 1:57 PM EDT | Mesoscale Discussion | SPC | 93 min |
| Jun 10, 5:19 PM EDT | Flash Flood Warning | RNK | 6 hr |
| Jun 11, 11:51 AM EDT | Mesoscale Discussion | SPC | 84 min |
| Jun 11, 1:11 PM EDT | Special Weather Statement | RNK | 64 min |
| Jun 11, 8:00 PM EDT | Special Weather Statement | RNK | 60 min |
| Jun 11, 8:24 PM EDT | Mesoscale Discussion | SPC | 66 min |
| Jun 11, 8:51 PM EDT | Special Weather Statement | RNK | 54 min |
| Jun 12, 4:52 PM EDT | Special Weather Statement | RNK | 53 min |
| Jun 12, 5:17 PM EDT | Special Weather Statement | RNK | 58 min |
| Jun 16, 2:58 PM EDT | Flash Flood Watch | RNK | 29 hr |
| Jun 19, 9:19 PM EDT | Mesoscale Discussion | SPC | 26 min |
| Jul 1, 12:48 PM EDT | Mesoscale Discussion | SPC | 57 min |
| Jul 1, 4:57 PM EDT | Special Weather Statement | RNK | 63 min |
| Jul 1, 5:17 PM EDT | Severe Thunderstorm Warning | RNK | 58 min |
| Jul 12, 2:37 PM EDT | Severe Thunderstorm Warning | RNK | 53 min |
| Jul 17, 10:29 AM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 17, 8:02 PM EDT | Special Weather Statement | RNK | 43 min |
| Jul 20, 9:27 AM EDT | Flash Flood Watch | RNK | 12 hr |
| Jul 20, 11:27 AM EDT | Severe Thunderstorm Warning | RNK | 63 min |
| Jul 25, 6:11 PM EDT | Severe Thunderstorm Warning | RNK | 44 min |
| Jul 25, 9:06 PM EDT | Special Weather Statement | RNK | 84 min |
| Jul 25, 9:16 PM EDT | Severe Thunderstorm Warning | RNK | 59 min |
| Jul 26, 1:40 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 28, 7:16 PM EDT | Special Weather Statement | RNK | 59 min |
| Jul 29, 12:21 AM EDT | Special Weather Statement | RNK | 39 min |
| Jul 29, 1:04 AM EDT | Special Weather Statement | RNK | 56 min |
| Jul 30, 4:42 PM EDT | Special Weather Statement | RNK | 33 min |
| Aug 4, 4:48 PM EDT | Severe Thunderstorm Warning | RNK | 57 min |
| Aug 5, 8:13 PM EDT | Areal Flood Advisory | RNK | 3 hr |
| Aug 18, 5:43 PM EDT | Special Weather Statement | RNK | 32 min |
| Aug 20, 6:27 PM EDT | Special Weather Statement | RNK | 63 min |
| Aug 21, 12:36 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 22, 1:15 AM EDT | Special Weather Statement | RNK | 30 min |
| Aug 22, 1:44 AM EDT | Special Weather Statement | RNK | 31 min |
| Aug 22, 1:53 AM EDT | Severe Thunderstorm Warning | RNK | 24 min |
| Sep 25, 3:45 PM EDT | Flash Flood Watch | RNK | 31 hr |
| Sep 28, 1:45 PM EDT | Special Weather Statement | RNK | 45 min |
| Sep 28, 2:28 PM EDT | Special Weather Statement | RNK | 62 min |
| Oct 6, 9:53 PM EDT | Wind Advisory | RNK | 18 hr |
| Oct 9, 9:47 PM EDT | Special Weather Statement | RNK | 58 min |
| Oct 9, 10:49 PM EDT | Special Weather Statement | RNK | 41 min |
| Oct 17, 3:48 PM EDT | Freeze Watch | RNK | 19 hr |
| Oct 18, 10:25 AM EDT | Freeze Warning | RNK | 24 hr |
| Nov 3, 1:44 PM EST | Frost Advisory | RNK | 17 hr |
| Nov 10, 2:46 PM EST | Flood Watch | RNK | 45 hr |
| Nov 11, 4:10 AM EST | Wind Advisory | RNK | 50 hr |
| Nov 11, 10:57 AM EST | Areal Flood Warning | RNK | 46 hr |
| Nov 26, 1:34 AM EST | Dense Fog Advisory | RNK | 7 hr |
| Dec 1, 2:58 PM EST | Wind Advisory | RNK | 45 hr |
| Dec 4, 3:57 PM EST | Winter Weather Advisory | RNK | 27 hr |
| Dec 8, 5:01 AM EST | Winter Weather Advisory | RNK | 25 hr |
| Dec 8, 5:11 AM EST | Wind Advisory | RNK | 64 hr |
| Dec 9, 4:40 AM EST | Areal Flood Warning | RNK | 10 hr |
| Dec 12, 4:41 AM EST | Winter Weather Advisory | RNK | 31 hr |
| Dec 13, 8:05 PM EST | Dense Fog Advisory | RNK | 13 hr |
| Dec 17, 3:20 PM EST | Winter Storm Warning | RNK | 60 hr |
| Dec 18, 7:22 PM EST | Mesoscale Discussion | SPC | 5 hr |
| Dec 19, 12:34 AM EST | Mesoscale Discussion | SPC | 5 hr |
| Dec 23, 3:49 PM EST | Winter Storm Watch | RNK | 24 hr |
| Dec 24, 4:04 AM EST | Freezing Rain Advisory | RNK | 35 hr |
| Dec 24, 4:17 AM EST | Wind Advisory | RNK | 36 hr |
| Dec 25, 6:31 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Dec 30, 3:22 PM EST | Winter Weather Advisory | RNK | 21 hr |
| Dec 30, 10:57 PM EST | Mesoscale Discussion | SPC | 6 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20082010
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.