Alert archive / New Jersey / Mercer County

Weather alerts in Mercer County, New Jersey, 2023

191 weather alerts in 2023, 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 2023. Tap one for its archive.

Alerts: 191
Warnings: 62
Watches: 32
Advisories: 41
Busiest month: July58 alerts
Busiest day: June 27, 202314 alerts

Over time

By month

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

2 of 3 tornado warnings covering Mercer County in 2023 had a tornado report inside them; 0 of 1 tornado reports fell inside a warning.

Mercer County, 2023

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	3	2	33%	1	0%
Severe thunderstorm warnings	34	25	26%	24	96%	25 min
Flash flood warnings	6	6	0%	0

Each office's whole area, 2023

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Philadelphia/Mount Holly: tornado warnings	35	7	80%	24	46%	6 min
NWS Philadelphia/Mount Holly: severe thunderstorm warnings	364	198	46%	662	84%	22 min
NWS Philadelphia/Mount Holly: flash flood warnings	91	49	46%	139	91%	106 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, 6:54 PM EST	Dense Fog Advisory	PHI	16 hr
Feb 17, 12:42 PM EST	Special Weather Statement	PHI	48 min
Feb 21, 2:22 PM EST	Mesoscale Discussion	SPC	53 min
Feb 21, 3:15 PM EST	Severe Thunderstorm Warning	PHI	45 min
Feb 21, 3:40 PM EST	Tornado Warning	PHI	22 min
Mar 2, 6:15 AM EST	Dense Fog Advisory	PHI	4 hr
Mar 3, 3:49 AM EST	Coastal Flood Advisory	PHI	38 hr
Mar 13, 2:56 PM EDT	Wind Advisory	PHI	32 hr
Mar 18, 7:34 PM EDT	Red Flag Warning	PHI	24 hr
Mar 31, 3:05 PM EDT	Wind Advisory	PHI	35 hr
Apr 1, 4:37 PM EDT	Mesoscale Discussion	SPC	113 min
Apr 1, 5:30 PM EDT	Tornado Watch	SPC	5 hr
Apr 1, 6:31 PM EDT	Severe Thunderstorm Warning	PHI	44 min
Apr 1, 6:37 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	53 min
Apr 1, 6:45 PM EDT	Tornado Warning	PHI	30 min
Apr 1, 6:55 PM EDT	Mesoscale Discussion	SPC	95 min
Apr 1, 7:07 PM EDT	Tornado Warning	PHI	38 min
Apr 1, 7:11 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	64 min
Apr 2, 11:40 AM EDT	Freeze Warning	PHI	21 hr
Apr 7, 8:09 PM EDT	Freeze Watch	PHI	7 hr
Apr 8, 3:31 AM EDT	Freeze Warning	PHI	29 hr
Apr 9, 9:10 AM EDT	Freeze Warning	PHI	24 hr
Apr 15, 2:06 PM EDT	Areal Flood Advisory	PHI	6 hr
Apr 15, 4:05 PM EDT	Severe Thunderstorm Warning	PHI	25 min
Apr 15, 4:49 PM EDT	Severe Thunderstorm Warning	PHI	26 min
Apr 15, 6:05 PM EDT	Areal Flood Advisory	PHI	96 min
Apr 19, 3:43 AM EDT	Red Flag Warning	PHI	16 hr
Apr 22, 2:47 PM EDT	Mesoscale Discussion	SPC	118 min
Apr 22, 3:04 PM EDT	Severe Thunderstorm Watch	SPC	5 hr
Apr 22, 6:11 PM EDT	Mesoscale Discussion	SPC	64 min
Apr 22, 6:32 PM EDT	Severe Thunderstorm Warning	PHI	28 min
Apr 22, 7:52 PM EDT	Special Weather Statement	PHI	53 min
Apr 29, 3:46 PM EDT	Flood Watch	PHI	30 hr
Apr 30, 4:00 PM EDT	Areal Flood Advisory	PHI	3 hr
Apr 30, 8:34 PM EDT	Areal Flood Advisory	PHI	100 min
Apr 30, 10:14 PM EDT	Areal Flood Warning	PHI	3 hr
May 1, 12:47 AM EDT	Areal Flood Warning	PHI	10 hr
May 1, 11:00 PM EDT	Special Weather Statement	PHI	45 min
Jun 2, 5:50 PM EDT	Coastal Flood Advisory	PHI	35 hr
Jun 2, 7:11 PM EDT	Special Weather Statement	PHI	34 min
Jun 2, 7:33 PM EDT	Severe Thunderstorm Warning	PHI	42 min
Jun 5, 3:23 PM EDT	Fire Weather Watch	PHI	12 hr
Jun 6, 3:49 AM EDT	Red Flag Warning	PHI	16 hr
Jun 12, 12:30 PM EDT	Mesoscale Discussion	SPC	60 min
Jun 14, 12:06 PM EDT	Mesoscale Discussion	SPC	2 hr
Jun 14, 3:31 PM EDT	Special Weather Statement	PHI	29 min
Jun 16, 10:50 AM EDT	Mesoscale Discussion	SPC	55 min
Jun 16, 11:06 AM EDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 16, 11:58 AM EDT	Severe Thunderstorm Warning	PHI	47 min
Jun 16, 12:34 PM EDT	Mesoscale Discussion	SPC	26 min
Jun 16, 12:41 PM EDT	Severe Thunderstorm Warning	PHI	49 min
Jun 16, 12:46 PM EDT	Areal Flood Advisory	PHI	3 hr
Jun 16, 1:15 PM EDT	Severe Thunderstorm Warning	PHI	60 min
Jun 23, 4:32 PM EDT	Areal Flood Advisory	PHI	3 hr
Jun 26, 3:33 AM EDT	Flood Watch	PHI	23 hr
Jun 26, 9:37 AM EDT	Mesoscale Discussion	SPC	83 min
Jun 26, 12:36 PM EDT	Mesoscale Discussion	SPC	2 hr
Jun 26, 1:11 PM EDT	Severe Thunderstorm Watch	SPC	11 hr
Jun 26, 3:22 PM EDT	Mesoscale Discussion	SPC	113 min
Jun 26, 4:14 PM EDT	Special Weather Statement	PHI	31 min
Jun 26, 8:03 PM EDT	Mesoscale Discussion	SPC	87 min
Jun 26, 8:42 PM EDT	Severe Thunderstorm Warning	PHI	48 min
Jun 26, 9:21 PM EDT	Special Weather Statement	PHI	24 min
Jun 26, 9:31 PM EDT	Severe Thunderstorm Warning	PHI	44 min
Jun 26, 10:50 PM EDT	Mesoscale Discussion	SPC	55 min
Jun 26, 11:07 PM EDT	Severe Thunderstorm Warning	PHI	53 min
Jun 26, 11:27 PM EDT	Areal Flood Advisory	PHI	3 hr
Jun 26, 11:35 PM EDT	Flash Flood Warning	PHI	6 hr
Jun 26, 11:42 PM EDT	Severe Thunderstorm Warning	PHI	33 min
Jun 27, 3:02 AM EDT	Flood Watch	PHI	46 min
Jun 27, 3:48 AM EDT	Flood Watch	PHI	17 hr
Jun 27, 4:39 PM EDT	Severe Thunderstorm Warning	PHI	51 min
Jun 27, 5:57 PM EDT	Areal Flood Advisory	PHI	3 hr
Jun 27, 6:52 PM EDT	Areal Flood Advisory	PHI	3 hr
Jul 2, 4:31 PM EDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 2, 7:42 PM EDT	Mesoscale Discussion	SPC	93 min
Jul 2, 11:19 PM EDT	Severe Thunderstorm Warning	PHI	41 min
Jul 3, 2:55 PM EDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 3, 4:49 PM EDT	Mesoscale Discussion	SPC	116 min
Jul 4, 3:16 PM EDT	Special Weather Statement	PHI	29 min
Jul 4, 3:22 PM EDT	Severe Thunderstorm Warning	PHI	38 min
Jul 4, 3:52 PM EDT	Severe Thunderstorm Warning	PHI	38 min
Jul 4, 4:11 PM EDT	Areal Flood Advisory	PHI	2 hr
Jul 4, 4:43 PM EDT	Areal Flood Advisory	PHI	2 hr
Jul 8, 3:17 PM EDT	Flood Watch	PHI	31 hr
Jul 8, 3:55 PM EDT	Special Weather Statement	PHI	35 min
Jul 9, 10:28 AM EDT	Mesoscale Discussion	SPC	92 min
Jul 9, 11:06 AM EDT	Severe Thunderstorm Watch	SPC	9 hr
Jul 9, 1:20 PM EDT	Mesoscale Discussion	SPC	85 min
Jul 9, 5:59 PM EDT	Flash Flood Warning	PHI	4 hr
Jul 9, 6:52 PM EDT	Flash Flood Warning	PHI	4 hr
Jul 9, 7:11 PM EDT	Areal Flood Advisory	PHI	3 hr
Jul 14, 5:54 AM EDT	Severe Thunderstorm Warning	PHI	51 min
Jul 14, 6:02 AM EDT	Special Weather Statement	PHI	28 min
Jul 14, 6:20 AM EDT	Severe Thunderstorm Warning	PHI	40 min
Jul 14, 2:02 PM EDT	Mesoscale Discussion	SPC	2 hr
Jul 14, 11:32 PM EDT	Special Weather Statement	PHI	28 min
Jul 15, 3:44 AM EDT	Flood Watch	PHI	38 hr
Jul 15, 2:56 PM EDT	Special Weather Statement	PHI	34 min
Jul 15, 3:50 PM EDT	Mesoscale Discussion	SPC	2 hr
Jul 15, 4:08 PM EDT	Severe Thunderstorm Warning	PHI	67 min
Jul 15, 4:31 PM EDT	Areal Flood Advisory	PHI	106 min
Jul 15, 5:00 PM EDT	Areal Flood Advisory	PHI	2 hr
Jul 15, 5:12 PM EDT	Severe Thunderstorm Warning	PHI	63 min
Jul 15, 5:18 PM EDT	Flash Flood Warning	PHI	4 hr
Jul 15, 6:09 PM EDT	Flash Flood Warning Considerable damage threat	PHI	4 hr
Jul 15, 6:21 PM EDT	Special Weather Statement	PHI	24 min
Jul 16, 12:22 PM EDT	Areal Flood Advisory	PHI	3 hr
Jul 17, 12:52 AM EDT	Dense Fog Advisory	PHI	10 hr
Jul 18, 3:06 PM EDT	Areal Flood Advisory	PHI	89 min
Jul 19, 4:48 PM EDT	Mesoscale Discussion	SPC	87 min
Jul 20, 10:28 PM EDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 21, 4:26 AM EDT	Mesoscale Discussion	SPC	94 min
Jul 25, 10:58 AM EDT	Mesoscale Discussion	SPC	2 hr
Jul 25, 12:13 PM EDT	Severe Thunderstorm Watch	SPC	10 hr
Jul 25, 1:27 PM EDT	Severe Thunderstorm Warning	PHI	48 min
Jul 25, 2:08 PM EDT	Severe Thunderstorm Warning	PHI	52 min
Jul 25, 2:44 PM EDT	Areal Flood Advisory	PHI	2 hr
Jul 25, 3:16 PM EDT	Severe Thunderstorm Warning	PHI	44 min
Jul 26, 3:32 AM EDT	Excessive Heat Watch	PHI	23 hr
Jul 26, 3:32 AM EDT	Heat Advisory	PHI	4 days
Jul 27, 3:01 AM EDT	Excessive Heat Warning	PHI	43 hr
Jul 27, 11:40 AM EDT	Mesoscale Discussion	SPC	2 hr
Jul 27, 3:07 PM EDT	Heat Advisory	PHI	53 hr
Jul 27, 3:18 PM EDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 27, 4:46 PM EDT	Mesoscale Discussion	SPC	89 min
Jul 28, 9:44 PM EDT	Special Weather Statement	PHI	61 min
Jul 29, 1:56 PM EDT	Mesoscale Discussion	SPC	64 min
Jul 29, 2:48 PM EDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 29, 4:45 PM EDT	Mesoscale Discussion	SPC	2 hr
Jul 29, 6:13 PM EDT	Severe Thunderstorm Warning	PHI	47 min
Jul 29, 6:41 PM EDT	Severe Thunderstorm Warning	PHI	49 min
Aug 7, 2:31 PM EDT	Mesoscale Discussion	SPC	59 min
Aug 7, 3:13 PM EDT	Tornado Watch	SPC	8 hr
Aug 7, 5:01 PM EDT	Mesoscale Discussion	SPC	89 min
Aug 7, 6:21 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	69 min
Aug 7, 6:57 PM EDT	Mesoscale Discussion	SPC	93 min
Aug 7, 7:20 PM EDT	Severe Thunderstorm Warning	PHI	58 min
Aug 10, 3:15 PM EDT	Areal Flood Advisory	PHI	76 min
Aug 12, 2:37 PM EDT	Special Weather Statement	PHI	38 min
Aug 12, 5:38 PM EDT	Mesoscale Discussion	SPC	2 hr
Aug 12, 6:07 PM EDT	Severe Thunderstorm Watch	SPC	6 hr
Aug 12, 9:02 PM EDT	Mesoscale Discussion	SPC	88 min
Aug 13, 1:10 AM EDT	Severe Thunderstorm Warning	PHI	50 min
Aug 14, 3:40 PM EDT	Flood Watch	PHI	13 hr
Aug 15, 2:08 PM EDT	Severe Thunderstorm Watch	SPC	6 hr
Aug 15, 5:59 PM EDT	Areal Flood Advisory	PHI	3 hr
Aug 25, 7:25 AM EDT	Areal Flood Advisory	PHI	3 hr
Sep 4, 2:41 PM EDT	Heat Advisory	PHI	3 days
Sep 7, 7:51 PM EDT	Mesoscale Discussion	SPC	84 min
Sep 8, 2:46 PM EDT	Mesoscale Discussion	SPC	119 min
Sep 8, 2:53 PM EDT	Severe Thunderstorm Warning	PHI	52 min
Sep 8, 3:11 PM EDT	Severe Thunderstorm Watch	SPC	8 hr
Sep 8, 3:27 PM EDT	Severe Thunderstorm Warning	PHI	63 min
Sep 8, 4:30 PM EDT	Severe Thunderstorm Warning	PHI	60 min
Sep 8, 4:52 PM EDT	Mesoscale Discussion	SPC	83 min
Sep 8, 6:34 PM EDT	Mesoscale Discussion	SPC	86 min
Sep 9, 2:08 PM EDT	Mesoscale Discussion	SPC	3 hr
Sep 9, 4:23 PM EDT	Severe Thunderstorm Watch	SPC	5 hr
Sep 9, 6:06 PM EDT	Mesoscale Discussion	SPC	114 min
Sep 9, 8:08 PM EDT	Mesoscale Discussion	SPC	2 hr
Sep 10, 10:14 AM EDT	Areal Flood Advisory	PHI	107 min
Sep 10, 7:37 PM EDT	Areal Flood Advisory	PHI	3 hr
Sep 10, 7:55 PM EDT	Flash Flood Warning	PHI	3 hr
Sep 12, 2:39 PM EDT	Flood Watch	PHI	16 hr
Sep 28, 11:15 AM EDT	Flood Watch	PHI	34 hr
Sep 29, 7:40 AM EDT	Areal Flood Advisory	PHI	3 hr
Sep 29, 7:48 AM EDT	Areal Flood Warning	PHI	6 hr
Sep 29, 9:08 AM EDT	Areal Flood Advisory	PHI	4 hr
Oct 23, 3:28 PM EDT	Frost Advisory	PHI	18 hr
Oct 31, 3:10 AM EDT	Freeze Watch	PHI	24 hr
Nov 1, 3:16 AM EDT	Freeze Warning	PHI	31 hr
Nov 22, 1:48 AM EST	Areal Flood Advisory	PHI	3 hr
Nov 26, 8:35 PM EST	Areal Flood Advisory	PHI	3 hr
Nov 28, 8:12 AM EST	Special Weather Statement	PHI	33 min
Nov 28, 8:51 AM EST	Special Weather Statement	PHI	39 min
Dec 2, 5:05 AM EST	Dense Fog Advisory	PHI	5 hr
Dec 2, 8:05 PM EST	Dense Fog Advisory	PHI	6 hr
Dec 8, 3:26 PM EST	Flood Watch	PHI	66 hr
Dec 15, 3:36 PM EST	Flood Watch	PHI	69 hr
Dec 18, 2:30 AM EST	Areal Flood Warning	PHI	16 hr
Dec 18, 4:14 AM EST	River Flood Warning	PHI	11 hr
Dec 18, 5:56 AM EST	Areal Flood Warning	PHI	14 hr
Dec 18, 3:04 PM EST	River Flood Warning	PHI	5 hr
Dec 18, 4:28 PM EST	Areal Flood Warning	PHI	19 hr
Dec 19, 2:15 AM EST	River Flood Warning	PHI	16 hr
Dec 25, 3:20 PM EST	Dense Fog Advisory	PHI	21 hr
Dec 27, 11:38 AM EST	Flood Watch	PHI	22 hr
Dec 27, 11:29 PM EST	Areal Flood Warning	PHI	8 hr
Dec 28, 12:26 AM EST	Areal Flood Advisory	PHI	84 min
Dec 28, 1:50 AM EST	Areal Flood Warning	PHI	6 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	34
Tornado Warning	3
Severe Thunderstorm Watch	14
Tornado Watch	2
Mesoscale Discussion	39
Special Weather Statement	17
Flooding
Areal Flood Warning	8
Flash Flood Warning	6
River Flood Warning	3
Flood Watch	12
Areal Flood Advisory	27
Heat
Excessive Heat Warning	1
Excessive Heat Watch	1
Heat Advisory	3
Cold
Freeze Warning	4
Freeze Watch	2
Frost Advisory	1
Wind and dust
Wind Advisory	2
Fire
Red Flag Warning	3
Fire Weather Watch	1
Fog and smoke
Dense Fog Advisory	6
Coast and beach
Coastal Flood Advisory	2

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2022 2024

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.