Alert archive / New Jersey / Mercer County
Weather alerts in Mercer County, New Jersey, 2008
123 weather alerts in 2008, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Mercer County and its neighbors
Each county as a circle sized by its count in 2008. Tap one for its archive.
- Alerts
- 123
- Warnings
- 33
- Watches
- 25
- Advisories
- 28
- Busiest month
- July28 alerts
- Busiest day
- July 23, 20088 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Mercer County, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 17 | 12 | 29% | 12 | 83% | 18 min |
| Flash flood warnings | 5 | 3 | 40% | 0 |
Each office's whole area, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Philadelphia/Mount Holly: tornado warnings | 9 | 0 | 100% | 1 | 0% | |
| NWS Philadelphia/Mount Holly: severe thunderstorm warnings | 273 | 120 | 56% | 264 | 79% | 26 min |
| NWS Philadelphia/Mount Holly: flash flood warnings | 37 | 13 | 65% | 21 | 71% | 58 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 9, 3:34 AM EST | Wind Advisory | PHI | 10 hr |
| Jan 17, 10:35 AM EST | Winter Weather Advisory | PHI | 22 hr |
| Jan 17, 12:53 PM EST | Mesoscale Discussion | SPC | 4 hr |
| Jan 29, 7:29 AM EST | Freezing Rain Advisory | PHI | 3 hr |
| Jan 29, 3:20 PM EST | Wind Advisory | PHI | 24 hr |
| Feb 5, 5:04 AM EST | Dense Fog Advisory | PHI | 6 hr |
| Feb 9, 3:49 PM EST | Wind Advisory | PHI | 35 hr |
| Feb 12, 3:17 AM EST | Winter Storm Warning | PHI | 32 hr |
| Feb 12, 1:06 PM EST | Mesoscale Discussion | SPC | 6 hr |
| Feb 12, 3:28 PM EST | Flood Watch | PHI | 29 hr |
| Feb 12, 4:15 PM EST | Mesoscale Discussion | SPC | 6 hr |
| Feb 21, 9:58 AM EST | Winter Storm Watch | PHI | 6 hr |
| Feb 21, 3:59 PM EST | Winter Storm Warning | PHI | 32 hr |
| Feb 22, 7:01 AM EST | Mesoscale Discussion | SPC | 6 hr |
| Feb 22, 11:38 PM EST | Winter Weather Advisory | PHI | 3 hr |
| Mar 3, 2:17 PM EST | Flood Watch | PHI | 44 hr |
| Mar 5, 2:32 AM EST | Mesoscale Discussion | SPC | 88 min |
| Mar 5, 3:01 AM EST | Severe Thunderstorm Watch | SPC | 3 hr |
| Mar 6, 3:22 PM EST | Flood Watch | PHI | 51 hr |
| Mar 8, 4:40 AM EST | Wind Advisory | PHI | 27 hr |
| Mar 8, 12:03 PM EST | Flash Flood Warning | PHI | 4 hr |
| Mar 8, 12:36 PM EST | Flash Flood Warning | PHI | 5 hr |
| Mar 8, 3:58 PM EST | High Wind Warning | PHI | 6 hr |
| Mar 8, 6:03 PM EST | Severe Thunderstorm Warning | PHI | 57 min |
| Mar 8, 9:33 PM EST | River Flood Warning | PHI | 13 hr |
| Mar 20, 2:59 AM EDT | Wind Advisory | PHI | 36 hr |
| Apr 15, 3:15 PM EDT | Freeze Warning | PHI | 17 hr |
| Apr 28, 5:22 PM EDT | Areal Flood Advisory | PHI | 113 min |
| May 8, 2:47 PM EDT | Flood Watch | PHI | 19 hr |
| May 11, 9:06 PM EDT | Wind Advisory | PHI | 19 hr |
| May 27, 12:24 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 27, 7:14 PM EDT | Mesoscale Discussion | SPC | 61 min |
| May 31, 10:20 AM EDT | Tornado Watch | SPC | 7 hr |
| May 31, 10:25 AM EDT | Tornado Watch | SPC | 7 hr |
| Jun 5, 4:34 AM EDT | Excessive Heat Watch | PHI | 71 hr |
| Jun 6, 4:46 AM EDT | Excessive Heat Warning | PHI | 5 days |
| Jun 8, 11:56 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 8, 2:40 PM EDT | Mesoscale Discussion | SPC | 95 min |
| Jun 10, 4:52 PM EDT | Mesoscale Discussion | SPC | 53 min |
| Jun 10, 5:47 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 10, 6:51 PM EDT | Mesoscale Discussion | SPC | 54 min |
| Jun 10, 8:11 PM EDT | Severe Thunderstorm Warning | PHI | 64 min |
| Jun 14, 8:35 PM EDT | Severe Thunderstorm Warning | PHI | 55 min |
| Jun 16, 12:54 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 16, 1:21 PM EDT | Severe Thunderstorm Watch | SPC | 10 hr |
| Jun 16, 6:18 PM EDT | Mesoscale Discussion | SPC | 87 min |
| Jun 23, 3:30 AM EDT | Mesoscale Discussion | SPC | 90 min |
| Jun 27, 11:37 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 29, 4:11 PM EDT | Severe Thunderstorm Warning | PHI | 64 min |
| Jun 29, 4:11 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 29, 7:13 PM EDT | Mesoscale Discussion | SPC | 92 min |
| Jun 29, 8:09 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 29, 9:30 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 29, 11:58 PM EDT | Mesoscale Discussion | SPC | 92 min |
| Jun 30, 12:15 AM EDT | Mesoscale Discussion | SPC | 90 min |
| Jul 1, 12:19 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 6, 4:25 PM EDT | Areal Flood Advisory | PHI | 72 min |
| Jul 6, 4:53 PM EDT | Flash Flood Warning | PHI | 59 min |
| Jul 15, 3:41 PM EDT | Excessive Heat Watch | PHI | 4 days |
| Jul 17, 4:09 PM EDT | Excessive Heat Warning | PHI | 3 days |
| Jul 22, 2:15 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 23, 3:51 AM EDT | Flash Flood Watch | PHI | 25 hr |
| Jul 23, 12:33 PM EDT | Mesoscale Discussion | SPC | 57 min |
| Jul 23, 2:34 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 23, 2:55 PM EDT | Severe Thunderstorm Warning | PHI | 35 min |
| Jul 23, 3:26 PM EDT | Severe Thunderstorm Warning | PHI | 64 min |
| Jul 23, 4:11 PM EDT | Mesoscale Discussion | SPC | 94 min |
| Jul 23, 5:03 PM EDT | Severe Thunderstorm Warning | PHI | 57 min |
| Jul 23, 5:13 PM EDT | Severe Thunderstorm Warning | PHI | 62 min |
| Jul 23, 8:36 PM EDT | Severe Thunderstorm Warning | PHI | 54 min |
| Jul 23, 8:49 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| Jul 23, 9:26 PM EDT | Mesoscale Discussion | SPC | 64 min |
| Jul 27, 11:03 AM EDT | Mesoscale Discussion | SPC | 57 min |
| Jul 27, 11:26 AM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 27, 1:44 PM EDT | Severe Thunderstorm Warning | PHI | 61 min |
| Jul 27, 2:11 PM EDT | Severe Thunderstorm Warning | PHI | 64 min |
| Jul 27, 2:14 PM EDT | Severe Thunderstorm Warning | PHI | 61 min |
| Jul 27, 2:30 PM EDT | Areal Flood Advisory | PHI | 2 hr |
| Jul 27, 2:52 PM EDT | Severe Thunderstorm Warning | PHI | 53 min |
| Jul 28, 3:54 AM EDT | Dense Fog Advisory | PHI | 5 hr |
| Jul 29, 4:47 AM EDT | Heat Advisory | PHI | 34 hr |
| Jul 30, 4:53 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jul 30, 7:47 PM EDT | Mesoscale Discussion | SPC | 88 min |
| Aug 2, 10:11 AM EDT | Mesoscale Discussion | SPC | 94 min |
| Aug 2, 10:39 AM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Aug 2, 12:06 PM EDT | Severe Thunderstorm Warning | PHI | 54 min |
| Aug 10, 10:27 AM EDT | Mesoscale Discussion | SPC | 33 min |
| Aug 10, 10:46 AM EDT | Severe Thunderstorm Watch | SPC | 10 hr |
| Aug 10, 1:05 PM EDT | Mesoscale Discussion | SPC | 85 min |
| Aug 11, 8:50 AM EDT | Severe Thunderstorm Warning | PHI | 40 min |
| Aug 11, 10:56 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 14, 6:15 PM EDT | Mesoscale Discussion | SPC | 60 min |
| Aug 15, 2:47 PM EDT | Mesoscale Discussion | SPC | 88 min |
| Aug 15, 6:20 PM EDT | Mesoscale Discussion | SPC | 85 min |
| Sep 4, 3:00 PM EDT | Flood Watch | PHI | 57 hr |
| Sep 5, 12:44 PM EDT | Inland Tropical Storm Warning | PHI | 34 hr |
| Sep 6, 5:39 PM EDT | Flash Flood Warning | PHI | 5 hr |
| Sep 9, 8:35 AM EDT | Mesoscale Discussion | SPC | 115 min |
| Sep 9, 9:21 AM EDT | Severe Thunderstorm Warning | PHI | 39 min |
| Sep 9, 9:33 AM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Sep 9, 10:04 AM EDT | Flash Flood Warning | PHI | 3 hr |
| Sep 9, 10:57 AM EDT | Severe Thunderstorm Warning | PHI | 48 min |
| Sep 9, 12:11 PM EDT | Mesoscale Discussion | SPC | 94 min |
| Oct 19, 3:04 AM EDT | Frost Advisory | PHI | 30 hr |
| Oct 23, 4:30 AM EDT | Freeze Warning | PHI | 29 hr |
| Oct 27, 2:45 PM EDT | Wind Advisory | PHI | 36 hr |
| Nov 14, 1:28 AM EST | Dense Fog Advisory | PHI | 8 hr |
| Nov 15, 12:22 PM EST | Tornado Watch | SPC | 7 hr |
| Nov 15, 6:15 PM EST | Mesoscale Discussion | SPC | 2 hr |
| Dec 7, 2:57 AM EST | Wind Advisory | PHI | 18 hr |
| Dec 10, 3:28 PM EST | Flood Watch | PHI | 42 hr |
| Dec 11, 9:00 PM EST | Areal Flood Advisory | PHI | 13 hr |
| Dec 11, 9:32 PM EST | Areal Flood Warning | PHI | 12 hr |
| Dec 16, 5:30 AM EST | Winter Weather Advisory | PHI | 32 hr |
| Dec 16, 11:55 PM EST | Mesoscale Discussion | SPC | 4 hr |
| Dec 18, 3:41 PM EST | Winter Weather Advisory | PHI | 28 hr |
| Dec 20, 2:44 PM EST | Winter Weather Advisory | PHI | 22 hr |
| Dec 21, 6:35 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Dec 21, 2:08 PM EST | Wind Advisory | PHI | 23 hr |
| Dec 23, 1:49 PM EST | Winter Weather Advisory | PHI | 22 hr |
| Dec 27, 3:32 PM EST | Dense Fog Advisory | PHI | 15 hr |
| Dec 31, 5:01 AM EST | High Wind Warning | PHI | 14 hr |
| Dec 31, 3:27 PM EST | Wind Advisory | PHI | 7 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 | 17 |
| Severe Thunderstorm Watch | 12 |
| Tornado Watch | 3 |
| Mesoscale Discussion | 37 |
| Flooding | |
| Areal Flood Warning | 1 |
| Flash Flood Warning | 5 |
| River Flood Warning | 1 |
| Flash Flood Watch | 1 |
| Flood Watch | 6 |
| Areal Flood Advisory | 5 |
| Winter | |
| Winter Storm Warning | 2 |
| Winter Storm Watch | 1 |
| Freezing Rain Advisory | 1 |
| Winter Weather Advisory | 6 |
| Heat | |
| Excessive Heat Warning | 2 |
| Excessive Heat Watch | 2 |
| Heat Advisory | 1 |
| Cold | |
| Freeze Warning | 2 |
| Frost Advisory | 1 |
| Wind and dust | |
| High Wind Warning | 2 |
| Wind Advisory | 10 |
| Fog and smoke | |
| Dense Fog Advisory | 4 |
| Tropical | |
| Inland Tropical Storm Warning | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20072009
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.