Alert archive / U.S. Virgin Islands
Weather alerts in U.S. Virgin Islands, 2009
58 weather alerts in 2009, 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
- 58
- Warnings
- 7
- Watches
- 12
- Advisories
- 37
- Busiest month
- September14 alerts
- Busiest day
- September 5, 20095 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, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 0 | 1 | 0% | |||
| Flash flood warnings | 3 | 3 | 0% | 4 | 100% | 102 min |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS JSJ: severe thunderstorm warnings | 5 | 1 | 80% | 7 | 14% | 20 min |
| NWS JSJ: flash flood warnings | 76 | 15 | 80% | 68 | 46% | 102 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 |
|---|---|---|---|---|
| Jan 2, 1:52 PM CST | High Surf Advisory | JSJ | 44 hr | |
| Feb 1, 2:57 PM CST | High Surf Advisory | JSJ | 41 hr | |
| Feb 5, 11:53 PM CST | High Surf Advisory | JSJ | 58 hr | |
| Feb 10, 6:31 PM CST | Wind Advisory | JSJ | 15 hr | |
| Feb 17, 1:45 AM CST | High Surf Advisory | JSJ | 4 days | |
| Mar 6, 8:43 PM CST | High Surf Advisory | JSJ | 4 days | |
| Mar 11, 8:06 PM CDT | High Surf Advisory | JSJ | 4 days | |
| Mar 21, 10:04 AM CDT | High Surf Advisory | JSJ | 28 hr | |
| Mar 25, 1:53 PM CDT | High Surf Advisory | JSJ | 4 days | |
| Mar 27, 7:35 AM CDT | Coastal Flood Advisory | JSJ | 26 hr | |
| May 4, 7:52 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 4, 10:43 AM CDT | Areal Flood Advisory | JSJ | 6 hr | |
| May 4, 2:45 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 4, 9:34 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| May 5, 3:07 AM CDT | Flash Flood Watch | JSJ | 63 hr | |
| Jun 11, 9:46 AM CDT | Areal Flood Advisory | JSJ | 114 min | |
| Jun 16, 2:03 PM CDT | Areal Flood Advisory | JSJ | 115 min | |
| Jun 29, 1:07 PM CDT | Areal Flood Advisory | JSJ | 94 min | |
| Jul 21, 11:12 AM CDT | Wind Advisory | JSJ | 10 hr | |
| Aug 12, 3:30 PM CDT | Flash Flood Watch | JSJ | 18 hr | |
| Aug 15, 12:01 PM CDT | Hurricane Local Statement | JSJ | 11 hr | |
| Aug 15, 10:00 PM CDT | Tropical Storm Watch | NHC | 42 hr | |
| Aug 15, 11:14 PM CDT | Tropical Storm Watch | JSJ | 42 hr | |
| Aug 20, 1:10 PM CDT | High Surf Advisory | JSJ | 20 hr | |
| Aug 31, 1:54 PM CDT | Hurricane Local Statement | JSJ | 54 hr | |
| Sep 2, 4:00 PM CDT | Tropical Storm Watch | NHC | 18 hr | |
| Sep 2, 7:38 PM CDT | Tropical Storm Watch | JSJ | 15 hr | |
| Sep 3, 9:20 AM CDT | Flash Flood Watch | JSJ | 64 hr | |
| Sep 3, 10:00 AM CDT | Tropical Storm Warning | NHC | 6 hr | |
| Sep 3, 10:32 AM CDT | Tropical Storm Warning | JSJ | 7 hr | |
| Sep 4, 8:12 AM CDT | Areal Flood Advisory | JSJ | 5 hr | |
| Sep 4, 8:13 PM CDT | Areal Flood Advisory | JSJ | 9 hr | |
| Sep 5, 8:26 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 5, 9:34 AM CDT | Flash Flood Warning | JSJ | 3 hr | |
| Sep 5, 4:09 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 5, 6:00 PM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 5, 7:27 PM CDT | Areal Flood Advisory | JSJ | 83 min | |
| Sep 22, 11:05 AM CDT | Areal Flood Advisory | JSJ | 3 hr | |
| Sep 22, 11:09 AM CDT | Areal Flood Advisory | JSJ | 2 hr | |
| Oct 31, 1:18 PM CDT | High Surf Advisory | JSJ | 70 hr | |
| Nov 8, 12:10 PM CST | High Surf Advisory | JSJ | 3 days | |
| Nov 10, 5:35 PM CST | Flash Flood Watch | JSJ | 27 hr | |
| Nov 11, 9:26 AM CST | Areal Flood Advisory | JSJ | 3 hr | |
| Nov 16, 2:19 AM CST | Flash Flood Watch | JSJ | 34 hr | |
| Nov 16, 5:19 AM CST | Flash Flood Warning | JSJ | 4 hr | |
| Nov 16, 8:14 AM CST | Flash Flood Warning | JSJ | 6 hr | |
| Nov 26, 2:15 AM CST | High Surf Advisory | JSJ | 29 hr | |
| Nov 28, 10:59 AM CST | Areal Flood Advisory | JSJ | 110 min | |
| Dec 19, 1:38 AM CST | High Surf Advisory | JSJ | 17 hr | |
| Dec 23, 6:30 AM CST | High Surf Advisory | JSJ | 34 hr | |
| Dec 24, 7:15 PM CST | Flash Flood Watch | JSJ | 14 hr | |
| Dec 24, 8:40 PM CST | Areal Flood Advisory | JSJ | 9 hr | |
| Dec 26, 12:04 PM CST | High Surf Advisory | JSJ | 6 days | |
| Dec 27, 1:13 PM CST | Coastal Flood Watch | JSJ | 30 hr | |
| Dec 27, 3:38 PM CST | Areal Flood Advisory | JSJ | 39 min | |
| Dec 28, 9:45 AM CST | High Surf Warning | JSJ | 32 hr | |
| Dec 28, 1:45 PM CST | Coastal Flood Watch | JSJ | 48 hr | |
| Dec 28, 1:45 PM CST | Coastal Flood Warning | JSJ | 28 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 | 3 |
| Flash Flood Watch | 6 |
| Areal Flood Advisory | 19 |
| Wind and dust | |
| Wind Advisory | 2 |
| Tropical | |
| Tropical Storm Warning | 2 |
| Tropical Storm Watch | 4 |
| Hurricane Local Statement | 2 |
| Coast and beach | |
| Coastal Flood Warning | 1 |
| High Surf Warning | 1 |
| Coastal Flood Watch | 2 |
| Coastal Flood Advisory | 1 |
| High Surf Advisory | 15 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe 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.