Alert archive / U.S. Virgin Islands
Weather alerts in U.S. Virgin Islands, 2011
98 weather alerts in 2011, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
- Alerts
- 98
- Warnings
- 17
- Watches
- 19
- Advisories
- 61
- Busiest month
- September20 alerts
- Busiest day
- November 9, 20116 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
U.S. Virgin Islands, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 0 | 0 | ||||
| Flash flood warnings | 13 | 0 | 100% | 0 |
Each office's whole area, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS JSJ: tornado warnings | 2 | 0 | 100% | 1 | 0% | |
| NWS JSJ: severe thunderstorm warnings | 22 | 7 | 68% | 18 | 33% | 10 min |
| NWS JSJ: flash flood warnings | 166 | 8 | 95% | 20 | 55% | 105 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, Central Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 21, 2:08 AM CST | High Surf Advisory | JSJ | 54 hr | |
| Feb 21, 8:04 PM CST | Coastal Flood Watch | JSJ | 12 hr | |
| Apr 14, 1:00 PM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| Apr 14, 7:00 PM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| Apr 14, 7:20 PM CDT | Flash Flood Warning | JSJ | 115 min | |
| Apr 14, 7:22 PM CDT | Flash Flood Warning | JSJ | 113 min | |
| May 1, 3:13 AM CDT | Flash Flood Watch | JSJ | 40 hr | |
| May 12, 5:38 PM CDT | Areal Flood Advisory | JSJ | 112 min | |
| May 12, 7:41 PM CDT | Areal Flood Advisory | JSJ | 104 min | |
| May 13, 12:20 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 13, 1:32 AM CDT | Areal Flood Advisory | JSJ | 111 min | |
| May 14, 5:56 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 14, 8:37 PM CDT | Flash Flood Watch | JSJ | 22 hr | |
| May 14, 10:36 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 15, 1:28 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 16, 10:51 PM CDT | Areal Flood Advisory | JSJ | 4 hr | |
| May 17, 5:35 PM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| May 19, 8:41 AM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| May 20, 2:44 AM CDT | Flash Flood Watch | JSJ | 24 hr | |
| May 20, 6:13 AM CDT | Areal Flood Advisory | JSJ | 105 min | |
| May 20, 12:54 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 20, 3:18 PM CDT | Flash Flood Warning | JSJ | 3 hr | |
| May 20, 8:15 PM CDT | Flash Flood Warning | JSJ | 3 hr | |
| May 24, 9:17 AM CDT | Areal Flood Advisory | JSJ | 118 min | |
| Jun 5, 3:44 AM CDT | Flash Flood Watch | JSJ | 4 days | |
| Jun 5, 3:09 PM CDT | Areal Flood Advisory | JSJ | 6 hr | |
| Jun 6, 6:41 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Jun 6, 8:44 PM CDT | Areal Flood Advisory | JSJ | 6 hr | |
| Jun 6, 11:11 PM CDT | Flash Flood Warning | JSJ | 6 hr | |
| Jun 7, 2:43 AM CDT | Areal Flood Advisory | JSJ | 5 hr | |
| Jun 7, 7:31 AM CDT | Flash Flood Warning | JSJ | 5 hr | |
| Jun 7, 1:46 PM CDT | Flash Flood Warning | JSJ | 3 hr | |
| Jun 15, 9:51 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Jun 16, 12:45 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Jul 1, 1:38 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Jul 1, 2:26 PM CDT | Flash Flood Watch | JSJ | 36 hr | |
| Jul 3, 8:26 AM CDT | Flash Flood Watch | JSJ | 19 hr | |
| Jul 3, 8:41 AM CDT | Areal Flood Advisory | JSJ | 5 hr | |
| Jul 3, 4:00 PM CDT | Flash Flood Warning | JSJ | 7 hr | |
| Jul 8, 6:21 AM CDT | Areal Flood Advisory | JSJ | 6 hr | |
| Jul 15, 10:22 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Jul 23, 7:04 AM CDT | Flash Flood Watch | JSJ | 29 hr | |
| Jul 23, 10:50 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Jul 27, 12:13 PM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| Aug 1, 6:00 PM CDT | Tropical Storm Watch | NHC | 34 hr | |
| Aug 1, 8:10 PM CDT | Tropical Storm Watch | JSJ | 34 hr | |
| Aug 16, 11:05 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Aug 20, 2:28 PM CDT | Flash Flood Watch | JSJ | 4 days | |
| Aug 20, 6:00 PM CDT | Tropical Storm Warning | NHC | 8 days | |
| Aug 20, 6:45 PM CDT | Tropical Storm Warning | JSJ | 51 hr | |
| Aug 21, 4:00 AM CDT | Hurricane Watch | NHC | 5 days | |
| Aug 21, 4:54 AM CDT | Hurricane Watch | JSJ | 25 hr | |
| Aug 21, 4:44 PM CDT | Flash Flood Warning | JSJ | 19 hr | |
| Aug 21, 7:17 PM CDT | Flash Flood Warning | JSJ | 11 hr | |
| Aug 22, 11:56 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 3, 1:43 PM CDT | Areal Flood Advisory | JSJ | 68 min | |
| Sep 4, 1:52 PM CDT | High Surf Advisory | JSJ | 16 hr | |
| Sep 7, 9:42 PM CDT | Hurricane Local Statement | JSJ | 25 hr | |
| Sep 7, 10:00 PM CDT | Tropical Storm Watch | NHC | 36 hr | |
| Sep 8, 1:10 PM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| Sep 8, 10:13 PM CDT | Tropical Storm Watch | JSJ | 13 hr | |
| Sep 9, 4:00 AM CDT | Tropical Storm Warning | NHC | 30 hr | |
| Sep 9, 5:08 AM CDT | Tropical Storm Warning | JSJ | 71 hr | |
| Sep 9, 1:06 PM CDT | Flash Flood Watch | JSJ | 29 hr | |
| Sep 10, 5:13 PM CDT | Flash Flood Watch | JSJ | 24 hr | |
| Sep 11, 4:45 PM CDT | Flash Flood Watch | JSJ | 48 hr | |
| Sep 12, 4:46 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 12, 7:23 AM CDT | Areal Flood Advisory | JSJ | 8 hr | |
| Sep 12, 3:30 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 12, 6:30 PM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| Sep 13, 3:22 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 16, 2:30 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 16, 4:03 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 19, 9:56 PM CDT | Areal Flood Advisory | JSJ | 115 min | |
| Sep 20, 6:17 AM CDT | Areal Flood Advisory | JSJ | 6 hr | |
| Nov 3, 7:32 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Nov 4, 1:47 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Nov 4, 4:46 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Nov 4, 7:45 AM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| Nov 6, 9:19 PM CST | High Surf Advisory | JSJ | 47 hr | |
| Nov 7, 8:57 AM CST | Coastal Flood Advisory | JSJ | 11 hr | |
| Nov 9, 7:37 AM CST | Areal Flood Advisory | JSJ | 2 hr | |
| Nov 9, 7:51 AM CST | Areal Flood Advisory | JSJ | 106 min | |
| Nov 9, 8:34 AM CST | Areal Flood Advisory | JSJ | 64 min | |
| Nov 9, 9:05 AM CST | Flash Flood Warning | JSJ | 3 hr | |
| Nov 9, 9:35 AM CST | Flash Flood Warning | JSJ | 102 min | |
| Nov 9, 9:37 AM CST | Flash Flood Warning | JSJ | 3 hr | |
| Nov 20, 10:40 PM CST | High Surf Advisory | JSJ | 53 hr | |
| Nov 26, 2:30 AM CST | Flash Flood Watch | JSJ | 58 hr | |
| Nov 26, 11:49 PM CST | Areal Flood Advisory | JSJ | 2 hr | |
| Dec 6, 1:11 AM CST | High Surf Advisory | JSJ | 63 hr | |
| Dec 9, 2:28 PM CST | Areal Flood Advisory | JSJ | 3 hr | |
| Dec 9, 7:11 PM CST | Areal Flood Advisory | JSJ | 3 hr | |
| Dec 14, 10:13 AM CST | Wind Advisory | JSJ | 16 hr | |
| Dec 15, 2:21 AM CST | High Surf Advisory | JSJ | 30 hr | |
| Dec 17, 7:42 PM CST | High Surf Advisory | JSJ | 30 hr | |
| Dec 19, 6:53 PM CST | High Surf Advisory | JSJ | 4 days | |
| Dec 29, 2:01 AM CST | High Surf Advisory | JSJ | 41 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
| Product | Alerts |
|---|---|
| Flooding | |
| Flash Flood Warning | 13 |
| Flash Flood Watch | 12 |
| Areal Flood Advisory | 50 |
| Wind and dust | |
| Wind Advisory | 1 |
| Tropical | |
| Tropical Storm Warning | 4 |
| Hurricane Watch | 2 |
| Tropical Storm Watch | 4 |
| Hurricane Local Statement | 1 |
| Coast and beach | |
| Coastal Flood Watch | 1 |
| Coastal Flood Advisory | 1 |
| High Surf Advisory | 9 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe 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.