Alert archive / New Jersey / Mercer County
Weather alerts in Mercer County, New Jersey, 2018
213 weather alerts in 2018, 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 2018. Tap one for its archive.
- Alerts
- 213
- Warnings
- 47
- Watches
- 32
- Advisories
- 97
- Busiest month
- May30 alerts
- Busiest day
- May 27, 201810 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
0 of 1 tornado warnings covering Mercer County in 2018 had a tornado report inside them.
Mercer County, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 8 | 5 | 38% | 3 | 67% | 24 min |
| Flash flood warnings | 10 | 6 | 40% | 10 | 100% | 86 min |
Each office's whole area, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Philadelphia/Mount Holly: tornado warnings | 10 | 2 | 80% | 4 | 50% | 6 min |
| NWS Philadelphia/Mount Holly: severe thunderstorm warnings | 110 | 56 | 49% | 277 | 81% | 27 min |
| NWS Philadelphia/Mount Holly: flash flood warnings | 113 | 54 | 52% | 174 | 94% | 92 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 3, 4:03 AM EST | Winter Storm Warning | PHI | 38 hr |
| Jan 3, 4:03 AM EST | Winter Weather Advisory | PHI | 38 hr |
| Jan 4, 3:48 AM EST | Wind Chill Advisory | PHI | 3 days |
| Jan 7, 2:50 PM EST | Winter Weather Advisory | PHI | 33 hr |
| Jan 15, 5:28 AM EST | Areal Flood Warning | PHI | 12 hr |
| Jan 15, 7:59 AM EST | River Flood Warning | PHI | 27 hr |
| Jan 23, 6:00 AM EST | Areal Flood Advisory | PHI | 4 hr |
| Jan 23, 11:23 AM EST | Special Weather Statement | PHI | 37 min |
| Jan 23, 11:58 AM EST | Special Weather Statement | PHI | 47 min |
| Feb 6, 3:37 PM EST | Winter Weather Advisory | PHI | 27 hr |
| Feb 10, 3:20 AM EST | Flood Watch | PHI | 39 hr |
| Feb 10, 11:01 PM EST | Dense Fog Advisory | PHI | 8 hr |
| Feb 11, 10:38 AM EST | Areal Flood Advisory | PHI | 14 hr |
| Feb 16, 3:51 AM EST | Winter Storm Watch | PHI | 24 hr |
| Feb 17, 3:45 AM EST | Winter Weather Advisory | PHI | 20 hr |
| Feb 17, 6:32 PM EST | Mesoscale Discussion | SPC | 4 hr |
| Feb 19, 11:00 PM EST | Dense Fog Advisory | PHI | 11 hr |
| Feb 28, 3:12 PM EST | High Wind Watch | PHI | 24 hr |
| Feb 28, 3:45 PM EST | Flood Watch | PHI | 45 hr |
| Mar 1, 11:44 AM EST | High Wind Warning | PHI | 40 hr |
| Mar 1, 3:30 PM EST | Wind Advisory | PHI | 45 hr |
| Mar 1, 3:41 PM EST | Winter Weather Advisory | PHI | 30 hr |
| Mar 2, 2:26 AM EST | Areal Flood Advisory | PHI | 4 hr |
| Mar 2, 6:29 AM EST | Areal Flood Advisory | PHI | 4 hr |
| Mar 2, 10:23 AM EST | Areal Flood Advisory | PHI | 4 hr |
| Mar 4, 2:57 PM EST | Coastal Flood Advisory | PHI | 3 hr |
| Mar 4, 2:57 PM EST | Coastal Flood Advisory | PHI | 23 hr |
| Mar 5, 3:34 AM EST | Winter Storm Watch | PHI | 36 hr |
| Mar 6, 3:37 AM EST | Winter Storm Warning | PHI | 41 hr |
| Mar 6, 2:30 PM EST | Coastal Flood Advisory | PHI | 15 hr |
| Mar 6, 2:30 PM EST | Coastal Flood Advisory | PHI | 37 hr |
| Mar 7, 1:25 PM EST | Mesoscale Discussion | SPC | 6 hr |
| Mar 12, 3:18 AM EDT | Winter Weather Advisory | PHI | 32 hr |
| Mar 19, 3:36 PM EDT | Winter Storm Watch | PHI | 13 hr |
| Mar 20, 4:41 AM EDT | Winter Storm Warning | PHI | 47 hr |
| Mar 20, 12:19 PM EDT | Mesoscale Discussion | SPC | 4 hr |
| Apr 1, 4:08 AM EDT | Winter Weather Advisory | PHI | 33 hr |
| Apr 2, 3:47 AM EDT | Mesoscale Discussion | SPC | 6 hr |
| Apr 3, 3:32 PM EDT | Wind Advisory | PHI | 28 hr |
| Apr 4, 12:01 AM EDT | Dense Fog Advisory | PHI | 10 hr |
| Apr 4, 3:44 AM EDT | High Wind Warning | PHI | 16 hr |
| Apr 4, 12:39 PM EDT | Severe Thunderstorm Warning | PHI | 51 min |
| Apr 15, 6:08 AM EDT | Coastal Flood Advisory | PHI | 39 hr |
| Apr 15, 3:41 PM EDT | Flash Flood Watch | PHI | 20 hr |
| Apr 16, 5:52 AM EDT | Areal Flood Advisory | PHI | 7 hr |
| Apr 16, 7:26 AM EDT | Special Weather Statement | PHI | 34 min |
| Apr 16, 9:08 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| Apr 16, 9:26 AM EDT | Areal Flood Warning | PHI | 4 hr |
| Apr 16, 1:31 PM EDT | Areal Flood Warning | PHI | 4 hr |
| Apr 16, 2:45 PM EDT | Coastal Flood Warning | PHI | 3 hr |
| Apr 20, 3:35 PM EDT | Frost Advisory | PHI | 16 hr |
| Apr 20, 3:35 PM EDT | Freeze Warning | PHI | 16 hr |
| Apr 28, 5:16 AM EDT | Dense Fog Advisory | PHI | 4 hr |
| Apr 28, 6:21 PM EDT | Special Weather Statement | PHI | 24 min |
| Apr 28, 8:11 PM EDT | Special Weather Statement | PHI | 34 min |
| May 2, 3:42 AM EDT | Red Flag Warning | PHI | 17 hr |
| May 3, 3:35 AM EDT | Red Flag Warning | PHI | 16 hr |
| May 3, 6:03 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 4, 10:28 PM EDT | Special Weather Statement | PHI | 62 min |
| May 12, 6:53 PM EDT | Special Weather Statement | PHI | 52 min |
| May 12, 7:16 PM EDT | Mesoscale Discussion | SPC | 59 min |
| May 12, 7:37 PM EDT | Areal Flood Advisory | PHI | 2 hr |
| May 15, 3:40 AM EDT | Flash Flood Watch | PHI | 21 hr |
| May 15, 1:46 PM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| May 15, 3:33 PM EDT | Mesoscale Discussion | SPC | 117 min |
| May 15, 4:41 PM EDT | Severe Thunderstorm Warning | PHI | 64 min |
| May 15, 5:22 PM EDT | Severe Thunderstorm Warning | PHI | 38 min |
| May 15, 5:31 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| May 15, 5:35 PM EDT | Areal Flood Advisory | PHI | 4 hr |
| May 15, 5:53 PM EDT | Severe Thunderstorm Warning | PHI | 52 min |
| May 16, 3:35 PM EDT | Flood Watch | PHI | 3 days |
| May 17, 4:26 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| May 18, 4:04 AM EDT | Coastal Flood Advisory | PHI | 27 hr |
| May 19, 9:27 PM EDT | Dense Fog Advisory | PHI | 9 hr |
| May 26, 11:38 PM EDT | Flash Flood Watch | PHI | 23 hr |
| May 27, 5:35 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| May 27, 6:12 AM EDT | Flash Flood Warning | PHI | 4 hr |
| May 27, 7:30 AM EDT | Flash Flood Warning | PHI | 4 hr |
| May 27, 9:05 AM EDT | River Flood Warning | PHI | 13 hr |
| May 27, 9:17 AM EDT | Areal Flood Advisory | PHI | 3 hr |
| May 27, 10:19 AM EDT | Areal Flood Warning | PHI | 8 hr |
| May 27, 11:18 AM EDT | Areal Flood Warning | PHI | 7 hr |
| May 27, 3:22 PM EDT | Coastal Flood Advisory | PHI | 12 hr |
| May 27, 6:07 PM EDT | Areal Flood Warning | PHI | 4 hr |
| May 30, 4:43 AM EDT | Dense Fog Advisory | PHI | 4 hr |
| Jun 2, 3:26 AM EDT | Flash Flood Watch | PHI | 24 hr |
| Jun 5, 3:05 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 13, 10:46 PM EDT | Mesoscale Discussion | SPC | 59 min |
| Jun 17, 2:39 PM EDT | Heat Advisory | PHI | 29 hr |
| Jun 18, 5:55 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 18, 8:36 PM EDT | Special Weather Statement | PHI | 24 min |
| Jun 18, 8:56 PM EDT | Special Weather Statement | PHI | 64 min |
| Jun 24, 6:16 PM EDT | Mesoscale Discussion | SPC | 119 min |
| Jun 28, 5:49 AM EDT | Areal Flood Advisory | PHI | 2 hr |
| Jun 29, 3:41 PM EDT | Excessive Heat Warning | PHI | 4 days |
| Jun 29, 3:41 PM EDT | Heat Advisory | PHI | 5 days |
| Jul 3, 4:52 PM EDT | Special Weather Statement | PHI | 53 min |
| Jul 3, 5:29 PM EDT | Areal Flood Advisory | PHI | 4 hr |
| Jul 3, 5:47 PM EDT | Flash Flood Warning | PHI | 2 hr |
| Jul 5, 2:59 PM EDT | Flash Flood Watch | PHI | 20 hr |
| Jul 6, 4:39 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| Jul 6, 5:37 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| Jul 6, 7:01 AM EDT | Flash Flood Warning | PHI | 4 hr |
| Jul 6, 7:19 AM EDT | Special Weather Statement | PHI | 26 min |
| Jul 17, 3:36 AM EDT | Flash Flood Watch | PHI | 15 hr |
| Jul 17, 11:49 AM EDT | Mesoscale Discussion | SPC | 116 min |
| Jul 17, 2:48 PM EDT | Special Weather Statement | PHI | 27 min |
| Jul 17, 2:50 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| Jul 17, 2:58 PM EDT | Severe Thunderstorm Warning | PHI | 32 min |
| Jul 17, 4:03 PM EDT | Areal Flood Advisory | PHI | 2 hr |
| Jul 20, 2:44 PM EDT | Flash Flood Watch | PHI | 34 hr |
| Jul 23, 3:45 AM EDT | Flash Flood Watch | PHI | 68 hr |
| Jul 25, 7:23 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| Jul 27, 9:50 AM EDT | Flash Flood Watch | PHI | 13 hr |
| Jul 27, 12:59 PM EDT | Mesoscale Discussion | SPC | 91 min |
| Jul 27, 1:17 PM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 27, 4:43 PM EDT | Areal Flood Advisory | PHI | 5 hr |
| Jul 27, 4:50 PM EDT | Mesoscale Discussion | SPC | 55 min |
| Jul 27, 6:10 PM EDT | Areal Flood Advisory | PHI | 4 hr |
| Jul 27, 7:06 PM EDT | Mesoscale Discussion | SPC | 54 min |
| Jul 27, 7:55 PM EDT | Areal Flood Advisory | PHI | 108 min |
| Aug 3, 1:14 PM EDT | Special Weather Statement | PHI | 46 min |
| Aug 3, 1:27 PM EDT | Severe Thunderstorm Warning | PHI | 48 min |
| Aug 4, 6:55 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| Aug 5, 3:05 PM EDT | Heat Advisory | PHI | 27 hr |
| Aug 7, 12:19 PM EDT | Heat Advisory | PHI | 6 hr |
| Aug 7, 3:31 PM EDT | Heat Advisory | PHI | 26 hr |
| Aug 7, 8:46 PM EDT | Special Weather Statement | PHI | 44 min |
| Aug 8, 8:09 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| Aug 9, 5:29 PM EDT | Coastal Flood Advisory | PHI | 10 hr |
| Aug 10, 5:10 PM EDT | Coastal Flood Advisory | PHI | 11 hr |
| Aug 11, 3:24 AM EDT | Flash Flood Watch | PHI | 20 hr |
| Aug 11, 4:26 AM EDT | Coastal Flood Advisory | PHI | 24 hr |
| Aug 11, 6:31 AM EDT | Areal Flood Advisory | PHI | 7 hr |
| Aug 11, 2:46 PM EDT | Flash Flood Warning | PHI | 3 hr |
| Aug 11, 5:36 PM EDT | Areal Flood Warning | PHI | 4 hr |
| Aug 11, 9:30 PM EDT | Areal Flood Warning | PHI | 88 min |
| Aug 12, 5:28 AM EDT | Coastal Flood Advisory | PHI | 24 hr |
| Aug 12, 10:08 PM EDT | Flash Flood Watch | PHI | 24 hr |
| Aug 17, 7:31 PM EDT | Mesoscale Discussion | SPC | 89 min |
| Aug 17, 8:47 PM EDT | Severe Thunderstorm Warning | PHI | 43 min |
| Aug 17, 9:26 PM EDT | Special Weather Statement | PHI | 34 min |
| Aug 18, 3:16 AM EDT | Flash Flood Watch | PHI | 20 hr |
| Aug 21, 11:18 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| Aug 27, 2:58 AM EDT | Heat Advisory | PHI | 65 hr |
| Sep 3, 3:02 AM EDT | Heat Advisory | PHI | 4 days |
| Sep 8, 2:43 AM EDT | Areal Flood Advisory | PHI | 6 hr |
| Sep 8, 3:34 AM EDT | Flood Watch | PHI | 60 hr |
| Sep 8, 5:31 AM EDT | Coastal Flood Advisory | PHI | 24 hr |
| Sep 9, 12:05 AM EDT | Coastal Flood Warning | PHI | 54 hr |
| Sep 9, 5:04 AM EDT | Coastal Flood Watch | PHI | 11 hr |
| Sep 10, 5:02 AM EDT | Coastal Flood Watch | PHI | 11 hr |
| Sep 11, 5:48 AM EDT | Coastal Flood Advisory | PHI | 14 hr |
| Sep 12, 2:05 AM EDT | Dense Fog Advisory | PHI | 8 hr |
| Sep 18, 9:27 AM EDT | Flash Flood Watch | PHI | 6 hr |
| Sep 18, 10:59 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| Sep 18, 12:01 PM EDT | Flash Flood Warning | PHI | 4 hr |
| Sep 18, 12:36 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| Sep 24, 4:27 AM EDT | Coastal Flood Advisory | PHI | 42 hr |
| Sep 25, 4:03 PM EDT | Areal Flood Advisory | PHI | 3 hr |
| Sep 25, 5:14 PM EDT | Flash Flood Warning | PHI | 4 hr |
| Sep 25, 5:35 PM EDT | Flash Flood Warning | PHI | 4 hr |
| Sep 25, 5:38 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 25, 6:03 PM EDT | Flash Flood Warning | PHI | 3 hr |
| Sep 26, 5:02 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Sep 27, 3:24 AM EDT | Flood Watch | PHI | 27 hr |
| Sep 28, 1:44 AM EDT | Areal Flood Advisory | PHI | 5 hr |
| Sep 28, 3:13 AM EDT | Areal Flood Warning | PHI | 4 hr |
| Sep 28, 7:46 AM EDT | Areal Flood Warning | PHI | 12 hr |
| Oct 2, 9:51 PM EDT | Special Weather Statement | PHI | 114 min |
| Oct 2, 10:43 PM EDT | Severe Thunderstorm Warning | PHI | 37 min |
| Oct 5, 11:57 PM EDT | Coastal Flood Advisory | PHI | 3 hr |
| Oct 6, 5:31 AM EDT | Coastal Flood Advisory | PHI | 21 hr |
| Oct 7, 5:00 AM EDT | Coastal Flood Advisory | PHI | 22 hr |
| Oct 10, 2:59 AM EDT | Dense Fog Advisory | PHI | 6 hr |
| Oct 10, 3:16 PM EDT | Flash Flood Watch | PHI | 38 hr |
| Oct 11, 3:58 PM EDT | Areal Flood Advisory | PHI | 4 hr |
| Oct 12, 12:50 AM EDT | Areal Flood Advisory | PHI | 3 hr |
| Oct 12, 2:55 AM EDT | Areal Flood Advisory | PHI | 2 hr |
| Oct 12, 3:17 AM EDT | Flash Flood Warning | PHI | 4 hr |
| Oct 12, 7:02 AM EDT | Areal Flood Warning | PHI | 4 hr |
| Oct 15, 11:19 PM EDT | Special Weather Statement | PHI | 56 min |
| Oct 18, 3:05 AM EDT | Frost Advisory | PHI | 30 hr |
| Oct 21, 3:07 AM EDT | Frost Advisory | PHI | 30 hr |
| Oct 26, 3:20 PM EDT | Coastal Flood Advisory | PHI | 27 hr |
| Nov 2, 2:52 PM EDT | Wind Advisory | PHI | 25 hr |
| Nov 2, 11:49 PM EDT | Tornado Warning | PHI | 26 min |
| Nov 2, 11:53 PM EDT | Areal Flood Advisory | PHI | 4 hr |
| Nov 3, 1:00 AM EDT | Special Weather Statement | PHI | 60 min |
| Nov 3, 1:41 AM EDT | Areal Flood Advisory | PHI | 4 hr |
| Nov 6, 4:32 AM EST | Coastal Flood Advisory | PHI | 11 hr |
| Nov 6, 11:47 AM EST | Areal Flood Advisory | PHI | 2 hr |
| Nov 8, 3:20 PM EST | Flood Watch | PHI | 29 hr |
| Nov 9, 3:23 AM EST | Coastal Flood Advisory | PHI | 14 hr |
| Nov 9, 4:42 PM EST | Areal Flood Advisory | PHI | 4 hr |
| Nov 14, 3:31 PM EST | Winter Weather Advisory | PHI | 29 hr |
| Nov 15, 9:56 AM EST | Mesoscale Discussion | SPC | 6 hr |
| Nov 15, 4:39 PM EST | Mesoscale Discussion | SPC | 6 hr |
| Nov 24, 7:54 PM EST | Areal Flood Advisory | PHI | 8 hr |
| Nov 25, 12:20 AM EST | River Flood Warning | PHI | 14 hr |
| Nov 25, 3:25 PM EST | Coastal Flood Advisory | PHI | 34 hr |
| Nov 25, 3:35 PM EST | Flood Watch | PHI | 27 hr |
| Nov 27, 3:13 PM EST | Wind Advisory | PHI | 27 hr |
| Dec 2, 3:17 AM EST | Coastal Flood Advisory | PHI | 9 hr |
| Dec 2, 8:24 AM EST | Dense Fog Advisory | PHI | 21 hr |
| Dec 18, 3:16 PM EST | Flood Watch | PHI | 3 days |
| Dec 20, 3:39 PM EST | Coastal Flood Advisory | PHI | 22 hr |
| Dec 21, 4:09 AM EST | Areal Flood Warning | PHI | 16 hr |
| Dec 21, 4:36 AM EST | Areal Flood Warning | PHI | 7 hr |
| Dec 21, 6:30 AM EST | River Flood Warning | PHI | 5 hr |
| Dec 27, 3:13 PM EST | Flood Watch | PHI | 28 hr |
| Dec 28, 11:39 AM EST | Areal Flood Advisory | PHI | 8 hr |
| Dec 28, 3:38 PM EST | Areal Flood Advisory | PHI | 4 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 | 8 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 3 |
| Mesoscale Discussion | 19 |
| Special Weather Statement | 18 |
| Flooding | |
| Areal Flood Warning | 13 |
| Flash Flood Warning | 10 |
| River Flood Warning | 4 |
| Flash Flood Watch | 14 |
| Flood Watch | 9 |
| Areal Flood Advisory | 42 |
| Winter | |
| Winter Storm Warning | 3 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 8 |
| Heat | |
| Excessive Heat Warning | 1 |
| Heat Advisory | 7 |
| Cold | |
| Freeze Warning | 1 |
| Frost Advisory | 3 |
| Wind Chill Advisory | 1 |
| Wind and dust | |
| High Wind Warning | 2 |
| High Wind Watch | 1 |
| Wind Advisory | 4 |
| Fire | |
| Red Flag Warning | 2 |
| Fog and smoke | |
| Dense Fog Advisory | 9 |
| Coast and beach | |
| Coastal Flood Warning | 2 |
| Coastal Flood Watch | 2 |
| Coastal Flood Advisory | 23 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20172019
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.