Alert archive / Pennsylvania / Montgomery County
Weather alerts in Montgomery County, Pennsylvania, 2024
210 weather alerts in 2024, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Montgomery County and its neighbors
Each county as a circle sized by its count in 2024. Tap one for its archive.
- Alerts
- 210
- Warnings
- 96
- Watches
- 31
- Advisories
- 50
- Busiest month
- August40 alerts
- Busiest day
- July 17, 202410 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Montgomery County, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 36 | 23 | 36% | 15 | 73% | 30 min |
| Flash flood warnings | 6 | 4 | 33% | 1 | 100% | 68 min |
Each office's whole area, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Philadelphia/Mount Holly: tornado warnings | 7 | 1 | 86% | 1 | 100% | 13 min |
| NWS Philadelphia/Mount Holly: severe thunderstorm warnings | 219 | 137 | 37% | 463 | 90% | 23 min |
| NWS Philadelphia/Mount Holly: flash flood warnings | 66 | 27 | 59% | 61 | 84% | 86 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 5, 12:55 PM EST | Winter Weather Advisory | PHI | 34 hr |
| Jan 6, 4:27 PM EST | Mesoscale Discussion | SPC | 5 hr |
| Jan 6, 6:11 PM EST | Areal Flood Advisory | PHI | 5 hr |
| Jan 7, 3:15 PM EST | Flood Watch | PHI | 60 hr |
| Jan 8, 3:27 PM EST | Wind Advisory | PHI | 33 hr |
| Jan 9, 4:09 PM EST | River Flood Warning | PHI | 19 hr |
| Jan 9, 4:16 PM EST | River Flood Warning | PHI | 35 hr |
| Jan 9, 5:58 PM EST | Areal Flood Warning | PHI | 8 hr |
| Jan 9, 6:08 PM EST | Areal Flood Warning | PHI | 9 hr |
| Jan 9, 6:13 PM EST | Areal Flood Warning | PHI | 6 hr |
| Jan 9, 10:12 PM EST | River Flood Warning | PHI | 21 hr |
| Jan 9, 11:54 PM EST | Areal Flood Warning | PHI | 9 hr |
| Jan 9, 11:54 PM EST | Areal Flood Warning | PHI | 18 hr |
| Jan 10, 1:47 AM EST | Areal Flood Warning | PHI | 9 hr |
| Jan 10, 2:42 AM EST | Areal Flood Warning | PHI | 12 hr |
| Jan 10, 3:47 AM EST | Wind Advisory | PHI | 12 hr |
| Jan 10, 6:48 AM EST | River Flood Warning | PHI | 18 hr |
| Jan 11, 1:06 PM EST | Flood Watch | PHI | 39 hr |
| Jan 11, 3:48 PM EST | Wind Advisory | PHI | 49 hr |
| Jan 13, 4:08 AM EST | Areal Flood Warning | PHI | 3 hr |
| Jan 14, 2:48 AM EST | Wind Advisory | PHI | 15 hr |
| Jan 14, 11:07 AM EST | Snow Squall Warning | PHI | 38 min |
| Jan 14, 11:42 AM EST | Snow Squall Warning | PHI | 48 min |
| Jan 14, 12:17 PM EST | Snow Squall Warning | PHI | 28 min |
| Jan 15, 4:12 AM EST | Winter Weather Advisory | PHI | 35 hr |
| Jan 16, 8:49 AM EST | Mesoscale Discussion | SPC | 4 hr |
| Jan 17, 3:16 PM EST | Winter Weather Advisory | PHI | 53 hr |
| Jan 18, 2:48 PM EST | Winter Storm Warning | PHI | 29 hr |
| Jan 24, 10:59 AM EST | Dense Fog Advisory | PHI | 3 hr |
| Jan 24, 2:14 PM EST | Dense Fog Advisory | PHI | 11 hr |
| Jan 25, 6:41 PM EST | Dense Fog Advisory | PHI | 17 hr |
| Jan 26, 5:33 PM EST | Dense Fog Advisory | PHI | 16 hr |
| Jan 28, 10:05 AM EST | Areal Flood Warning | PHI | 2 hr |
| Feb 11, 3:16 PM EST | Winter Storm Warning | PHI | 46 hr |
| Feb 12, 4:15 AM EST | Winter Weather Advisory | PHI | 33 hr |
| Feb 15, 3:33 PM EST | Winter Weather Advisory | PHI | 42 hr |
| Feb 16, 3:28 PM EST | Winter Storm Warning | PHI | 18 hr |
| Feb 16, 10:33 PM EST | Mesoscale Discussion | SPC | 4 hr |
| Feb 17, 2:26 PM EST | Snow Squall Warning | PHI | 34 min |
| Feb 17, 2:57 PM EST | Snow Squall Warning | PHI | 33 min |
| Feb 17, 3:28 PM EST | Snow Squall Warning | PHI | 47 min |
| Feb 17, 4:16 PM EST | Snow Squall Warning | PHI | 29 min |
| Feb 27, 3:16 PM EST | Wind Advisory | PHI | 35 hr |
| Mar 2, 1:31 PM EST | Areal Flood Advisory | PHI | 4 hr |
| Mar 8, 1:03 PM EST | Flood Watch | PHI | 37 hr |
| Mar 9, 2:43 PM EST | Wind Advisory | PHI | 51 hr |
| Mar 9, 8:00 PM EST | Areal Flood Advisory | PHI | 3 hr |
| Mar 9, 8:03 PM EST | Areal Flood Advisory | PHI | 3 hr |
| Mar 9, 9:27 PM EST | Areal Flood Warning | PHI | 6 hr |
| Mar 10, 5:33 PM EDT | Special Weather Statement | PHI | 27 min |
| Mar 21, 3:29 PM EDT | Flood Watch | PHI | 51 hr |
| Mar 22, 2:17 PM EDT | Wind Advisory | PHI | 36 hr |
| Mar 23, 8:50 AM EDT | Areal Flood Advisory | PHI | 2 hr |
| Mar 23, 11:15 AM EDT | Areal Flood Warning | PHI | 6 hr |
| Mar 23, 11:21 AM EDT | Areal Flood Warning | PHI | 6 hr |
| Mar 23, 12:42 PM EDT | Areal Flood Advisory | PHI | 5 hr |
| Mar 23, 2:43 PM EDT | River Flood Warning | PHI | 6 hr |
| Mar 23, 3:32 PM EDT | River Flood Warning | PHI | 7 hr |
| Mar 23, 4:56 PM EDT | Areal Flood Warning | PHI | 7 hr |
| Mar 23, 5:15 PM EDT | Areal Flood Warning | PHI | 5 hr |
| Apr 2, 1:59 PM EDT | Flood Watch | PHI | 37 hr |
| Apr 2, 5:07 PM EDT | Areal Flood Warning | PHI | 3 hr |
| Apr 3, 7:32 AM EDT | Areal Flood Warning | PHI | 4 hr |
| Apr 3, 11:09 AM EDT | River Flood Warning | PHI | 30 hr |
| Apr 3, 11:23 AM EDT | Areal Flood Warning | PHI | 16 hr |
| Apr 3, 4:23 PM EDT | Areal Flood Warning | PHI | 5 hr |
| Apr 3, 4:56 PM EDT | River Flood Warning | PHI | 12 hr |
| Apr 3, 5:17 PM EDT | River Flood Warning | PHI | 5 hr |
| Apr 4, 3:25 AM EDT | Areal Flood Warning | PHI | 6 hr |
| Apr 13, 2:52 AM EDT | Wind Advisory | PHI | 12 hr |
| Apr 15, 12:10 AM EDT | Special Weather Statement | PHI | 35 min |
| Apr 21, 3:16 PM EDT | Frost Advisory | PHI | 18 hr |
| Apr 22, 9:51 AM EDT | Frost Advisory | PHI | 23 hr |
| Apr 22, 6:36 PM EDT | Freeze Warning | PHI | 14 hr |
| Apr 25, 1:12 AM EDT | Freeze Watch | PHI | 11 hr |
| Apr 25, 12:37 PM EDT | Freeze Warning | PHI | 20 hr |
| Apr 26, 1:59 PM EDT | Frost Advisory | PHI | 19 hr |
| May 6, 12:06 AM EDT | Dense Fog Advisory | PHI | 10 hr |
| May 7, 4:07 AM EDT | Coastal Flood Advisory | PHI | 25 hr |
| May 23, 5:53 AM EDT | Severe Thunderstorm Warning | PHI | 24 min |
| May 27, 11:53 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 27, 1:42 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 27, 4:40 PM EDT | Mesoscale Discussion | SPC | 95 min |
| May 27, 7:40 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 6, 12:58 PM EDT | Mesoscale Discussion | SPC | 92 min |
| Jun 6, 2:26 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 14, 2:34 PM EDT | Mesoscale Discussion | SPC | 116 min |
| Jun 14, 4:57 PM EDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Jun 14, 5:17 PM EDT | Severe Thunderstorm Warning | PHI | 43 min |
| Jun 14, 5:37 PM EDT | Severe Thunderstorm Warning | PHI | 38 min |
| Jun 14, 5:59 PM EDT | Flash Flood Warning | PHI | 4 hr |
| Jun 16, 3:47 AM EDT | Heat Advisory | PHI | 8 days |
| Jun 16, 3:14 PM EDT | Excessive Heat Watch | PHI | 6 days |
| Jun 22, 3:47 AM EDT | Excessive Heat Warning | PHI | 40 hr |
| Jun 23, 4:33 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 23, 5:22 PM EDT | Severe Thunderstorm Warning | PHI | 53 min |
| Jun 23, 7:24 PM EDT | Severe Thunderstorm Warning | PHI | 51 min |
| Jun 25, 2:50 AM EDT | Heat Advisory | PHI | 42 hr |
| Jun 26, 4:02 PM EDT | Mesoscale Discussion | SPC | 118 min |
| Jun 26, 6:19 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 26, 10:51 PM EDT | Severe Thunderstorm Warning | PHI | 39 min |
| Jun 28, 2:33 PM EDT | Heat Advisory | PHI | 52 hr |
| Jun 29, 5:13 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jun 29, 6:38 PM EDT | Mesoscale Discussion | SPC | 97 min |
| Jun 29, 6:54 PM EDT | Severe Thunderstorm Warning | PHI | 51 min |
| Jun 29, 7:46 PM EDT | Severe Thunderstorm Warning | PHI | 44 min |
| Jun 29, 8:22 PM EDT | Severe Thunderstorm Warning | PHI | 53 min |
| Jun 30, 9:55 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 30, 11:09 AM EDT | Severe Thunderstorm Watch | SPC | 10 hr |
| Jun 30, 3:01 PM EDT | Severe Thunderstorm Warning | PHI | 59 min |
| Jun 30, 3:46 PM EDT | Severe Thunderstorm Warning | PHI | 44 min |
| Jun 30, 3:52 PM EDT | Severe Thunderstorm Warning | PHI | 38 min |
| Jun 30, 4:25 PM EDT | Severe Thunderstorm Warning | PHI | 50 min |
| Jun 30, 4:54 PM EDT | Severe Thunderstorm Warning | PHI | 51 min |
| Jun 30, 5:41 PM EDT | Mesoscale Discussion | SPC | 94 min |
| Jul 4, 3:34 AM EDT | Heat Advisory | PHI | 64 hr |
| Jul 6, 3:05 AM EDT | Excessive Heat Warning | PHI | 17 hr |
| Jul 7, 2:42 PM EDT | Heat Advisory | PHI | 3 days |
| Jul 9, 3:01 PM EDT | Excessive Heat Warning | PHI | 29 hr |
| Jul 11, 2:43 PM EDT | Flood Watch | PHI | 43 hr |
| Jul 12, 3:37 PM EDT | Excessive Heat Watch | PHI | 72 hr |
| Jul 12, 3:37 PM EDT | Heat Advisory | PHI | 5 days |
| Jul 14, 12:44 PM EDT | Severe Thunderstorm Warning | PHI | 46 min |
| Jul 14, 12:56 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 14, 1:23 PM EDT | Severe Thunderstorm Warning | PHI | 52 min |
| Jul 14, 2:19 PM EDT | Severe Thunderstorm Warning | PHI | 41 min |
| Jul 14, 2:24 PM EDT | Severe Thunderstorm Warning | PHI | 23 min |
| Jul 14, 2:52 PM EDT | Severe Thunderstorm Warning | PHI | 38 min |
| Jul 14, 3:03 PM EDT | Excessive Heat Warning | PHI | 3 days |
| Jul 14, 3:44 PM EDT | Severe Thunderstorm Warning | PHI | 46 min |
| Jul 16, 2:35 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Jul 16, 3:36 PM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 16, 4:41 PM EDT | Severe Thunderstorm Warning | PHI | 49 min |
| Jul 16, 5:15 PM EDT | Severe Thunderstorm Warning | PHI | 60 min |
| Jul 16, 6:20 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Jul 16, 7:06 PM EDT | Severe Thunderstorm Warning | PHI | 54 min |
| Jul 16, 7:23 PM EDT | Severe Thunderstorm Warning | PHI | 52 min |
| Jul 16, 7:54 PM EDT | Severe Thunderstorm Warning | PHI | 66 min |
| Jul 16, 8:13 PM EDT | Severe Thunderstorm Warning | PHI | 62 min |
| Jul 16, 8:19 PM EDT | Mesoscale Discussion | SPC | 116 min |
| Jul 16, 8:23 PM EDT | Severe Thunderstorm Warning | PHI | 67 min |
| Jul 17, 12:27 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 17, 12:58 PM EDT | Severe Thunderstorm Watch | SPC | 10 hr |
| Jul 17, 2:16 PM EDT | Severe Thunderstorm Warning | PHI | 59 min |
| Jul 17, 3:05 PM EDT | Severe Thunderstorm Warning | PHI | 39 min |
| Jul 17, 3:50 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Jul 17, 7:06 PM EDT | Severe Thunderstorm Warning | PHI | 54 min |
| Jul 17, 7:11 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 24, 12:07 PM EDT | Flash Flood Warning | PHI | 3 hr |
| Jul 31, 3:56 AM EDT | Heat Advisory | PHI | 64 hr |
| Aug 1, 2:53 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 2, 4:17 AM EDT | Excessive Heat Warning | PHI | 16 hr |
| Aug 2, 3:45 PM EDT | Mesoscale Discussion | SPC | 60 min |
| Aug 2, 3:48 PM EDT | Severe Thunderstorm Warning | PHI | 42 min |
| Aug 2, 4:07 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 3, 3:17 AM EDT | Heat Advisory | PHI | 17 hr |
| Aug 3, 12:20 PM EDT | Flood Watch | PHI | 9 hr |
| Aug 3, 12:56 PM EDT | Mesoscale Discussion | SPC | 94 min |
| Aug 3, 1:20 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 3, 2:53 PM EDT | Mesoscale Discussion | SPC | 67 min |
| Aug 3, 6:16 PM EDT | Severe Thunderstorm Warning | PHI | 59 min |
| Aug 5, 3:16 AM EDT | Flood Watch | PHI | 48 hr |
| Aug 6, 9:37 AM EDT | Heat Advisory | PHI | 9 hr |
| Aug 6, 1:06 PM EDT | Mesoscale Discussion | SPC | 84 min |
| Aug 6, 1:54 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 6, 4:00 PM EDT | Severe Thunderstorm Warning | PHI | 47 min |
| Aug 6, 4:29 PM EDT | Mesoscale Discussion | SPC | 61 min |
| Aug 6, 4:32 PM EDT | Flash Flood Warning | PHI | 8 hr |
| Aug 6, 6:31 PM EDT | Mesoscale Discussion | SPC | 89 min |
| Aug 6, 7:09 PM EDT | Severe Thunderstorm Warning | PHI | 48 min |
| Aug 6, 8:29 PM EDT | Flash Flood Warning | PHI | 4 hr |
| Aug 7, 12:07 AM EDT | Areal Flood Warning | PHI | 4 hr |
| Aug 8, 3:13 PM EDT | Wind Advisory | PHI | 27 hr |
| Aug 8, 6:04 PM EDT | Flood Watch | PHI | 24 hr |
| Aug 9, 4:38 AM EDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 9, 6:17 AM EDT | Tornado Watch | SPC | 8 hr |
| Aug 9, 10:26 AM EDT | Mesoscale Discussion | SPC | 94 min |
| Aug 9, 3:50 PM EDT | Flash Flood Warning | PHI | 2 hr |
| Aug 9, 6:46 PM EDT | Areal Flood Warning | PHI | 4 hr |
| Aug 17, 3:26 PM EDT | Flood Watch | PHI | 33 hr |
| Aug 18, 1:35 AM EDT | Flash Flood Warning | PHI | 2 hr |
| Aug 18, 1:09 PM EDT | Mesoscale Discussion | SPC | 96 min |
| Aug 18, 2:02 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 18, 3:34 PM EDT | Severe Thunderstorm Warning | PHI | 41 min |
| Aug 18, 4:25 PM EDT | Severe Thunderstorm Warning | PHI | 28 min |
| Aug 18, 4:30 PM EDT | Mesoscale Discussion | SPC | 90 min |
| Aug 19, 2:25 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 26, 3:20 PM EDT | Excessive Heat Watch | PHI | 13 hr |
| Aug 27, 3:59 AM EDT | Excessive Heat Warning | PHI | 40 hr |
| Aug 27, 3:59 AM EDT | Heat Advisory | PHI | 40 hr |
| Sep 12, 4:15 AM EDT | Dense Fog Advisory | PHI | 6 hr |
| Sep 27, 5:07 AM EDT | Dense Fog Advisory | PHI | 4 hr |
| Oct 10, 3:19 AM EDT | Frost Advisory | PHI | 30 hr |
| Oct 14, 3:03 PM EDT | Frost Advisory | PHI | 18 hr |
| Oct 16, 2:18 PM EDT | Frost Advisory | PHI | 19 hr |
| Oct 26, 3:06 AM EDT | Freeze Watch | PHI | 24 hr |
| Oct 27, 2:58 AM EDT | Freeze Warning | PHI | 30 hr |
| Oct 31, 2:50 PM EDT | Fire Weather Watch | PHI | 18 hr |
| Oct 31, 2:50 PM EDT | Red Flag Warning | PHI | 28 hr |
| Nov 7, 2:54 PM EST | Red Flag Warning | PHI | 27 hr |
| Nov 14, 3:37 PM EST | Fire Weather Watch | PHI | 23 hr |
| Nov 15, 2:28 PM EST | Red Flag Warning | PHI | 28 hr |
| Nov 20, 3:19 PM EST | Wind Advisory | PHI | 12 hr |
| Dec 3, 3:03 PM EST | Wind Advisory | PHI | 55 hr |
| Dec 5, 8:39 AM EST | Snow Squall Warning | PHI | 36 min |
| Dec 5, 9:15 AM EST | Snow Squall Warning | PHI | 45 min |
| Dec 9, 9:43 PM EST | Dense Fog Advisory | PHI | 13 hr |
| Dec 10, 2:42 PM EST | Wind Advisory | PHI | 30 hr |
| Dec 23, 2:24 AM EST | Winter Weather Advisory | PHI | 33 hr |
| Dec 28, 6:16 PM EST | Dense Fog Advisory | PHI | 16 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 | 36 |
| Severe Thunderstorm Watch | 13 |
| Tornado Watch | 1 |
| Mesoscale Discussion | 31 |
| Special Weather Statement | 2 |
| Flooding | |
| Areal Flood Warning | 21 |
| Flash Flood Warning | 6 |
| River Flood Warning | 9 |
| Flood Watch | 10 |
| Areal Flood Advisory | 6 |
| Winter | |
| Snow Squall Warning | 9 |
| Winter Storm Warning | 3 |
| Winter Weather Advisory | 6 |
| Heat | |
| Excessive Heat Warning | 6 |
| Excessive Heat Watch | 3 |
| Heat Advisory | 10 |
| Cold | |
| Freeze Warning | 3 |
| Freeze Watch | 2 |
| Frost Advisory | 6 |
| Wind and dust | |
| Wind Advisory | 12 |
| Fire | |
| Red Flag Warning | 3 |
| Fire Weather Watch | 2 |
| Fog and smoke | |
| Dense Fog Advisory | 9 |
| Coast and beach | |
| Coastal Flood Advisory | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20232025
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.