Alert archive / Pennsylvania / Flash Flood Warnings
Flash Flood Warnings in Pennsylvania, 2023
123 flash flood warnings in 2023. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of flash flood warnings reaches back to 1986.
Flash Flood Warnings by county
Each county as a circle sized by its count in 2023. Tap one for its archive.
- Flash Flood Warnings
- 123
- Busiest month
- July70 flash flood warnings
- Busiest day
- July 9, 202318 flash flood warnings
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
65 of 123 flash flood warnings covering Pennsylvania in 2023 had a flash flood report inside them; 154 of 196 flash flood reports fell inside a warning, on average 90 minutes after it went out.
Pennsylvania, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Flash flood warnings | 123 | 65 | 47% | 196 | 79% | 90 min |
Each office's whole area, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Philadelphia/Mount Holly: flash flood warnings | 91 | 49 | 46% | 139 | 91% | 106 min |
| NWS Pittsburgh, PA: flash flood warnings | 32 | 19 | 41% | 63 | 71% | 49 min |
| NWS Cleveland, OH: flash flood warnings | 25 | 13 | 48% | 22 | 100% | 67 min |
| NWS State College, PA: flash flood warnings | 8 | 3 | 63% | 8 | 63% | 42 min |
| NWS Binghamton, NY: flash flood warnings | 57 | 25 | 56% | 94 | 69% | 99 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 | Counties | Lasted |
|---|---|---|---|---|
| Apr 15, 1:22 PM EDT | Flash Flood Warning | PHI | Lehigh, Northampton | 4 hr |
| Apr 15, 5:20 PM EDT | Flash Flood Warning | PHI | Lehigh | 3 hr |
| Jun 12, 5:01 PM EDT | Flash Flood Warning | PHI | Delaware | 4 hr |
| Jun 16, 12:49 PM EDT | Flash Flood Warning | PHI | Bucks, Philadelphia | 3 hr |
| Jun 23, 4:19 PM EDT | Flash Flood Warning | PHI | Delaware, Montgomery, Philadelphia | 4 hr |
| Jun 24, 12:47 PM EDT | Flash Flood Warning | PHI | Delaware, Montgomery, Philadelphia | 3 hr |
| Jun 24, 8:00 PM EDT | Flash Flood Warning | BGM | Pike | 90 min |
| Jun 25, 4:01 PM EDT | Flash Flood Warning | PHI | Montgomery, Philadelphia | 4 hr |
| Jun 26, 11:46 AM EDT | Flash Flood Warning | BGM | Susquehanna | 47 min |
| Jun 26, 2:21 PM EDT | Flash Flood Warning | CTP | Northumberland | 46 min |
| Jun 26, 2:32 PM EDT | Flash Flood Warning | PHI | Berks, Lehigh | 67 min |
| Jun 26, 6:03 PM EDT | Flash Flood Warning | PHI | Lehigh, Northampton | 6 hr |
| Jun 26, 6:37 PM EDT | Flash Flood Warning | PHI | Chester, Delaware | 2 hr |
| Jun 26, 9:30 PM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 3 hr |
| Jun 26, 11:35 PM EDT | Flash Flood Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 6 hr |
| Jun 27, 12:51 AM EDT | Flash Flood Warning | PHI | Chester, Montgomery | 4 hr |
| Jun 27, 5:44 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery, Philadelphia | 5 hr |
| Jul 1, 3:38 PM EDT | Flash Flood Warning | PBZ | Allegheny, Butler, Westmoreland | 62 min |
| Jul 1, 5:15 PM EDT | Flash Flood Warning | PBZ | Indiana, Westmoreland | 110 min |
| Jul 1, 6:06 PM EDT | Flash Flood Warning | PBZ | Beaver | 4 hr |
| Jul 1, 6:28 PM EDT | Flash Flood Warning | PBZ | Beaver, Lawrence | 108 min |
| Jul 1, 6:55 PM EDT | Flash Flood Warning | PBZ | Allegheny, Beaver, Butler, Westmoreland | 3 hr |
| Jul 2, 8:41 PM EDT | Flash Flood Warning | PBZ | Allegheny, Beaver, Washington | 3 hr |
| Jul 2, 9:20 PM EDT | Flash Flood Warning | PBZ | Allegheny | 2 hr |
| Jul 3, 6:33 PM EDT | Flash Flood Warning | BGM | Pike | 3 hr |
| Jul 3, 8:39 PM EDT | Flash Flood Warning | PHI | Chester | 5 hr |
| Jul 3, 9:07 PM EDT | Flash Flood Warning | PHI | Chester | 5 hr |
| Jul 4, 4:47 AM EDT | Flash Flood Warning | BGM | Pike | 91 min |
| Jul 5, 5:45 PM EDT | Flash Flood Warning | PHI | Delaware, Philadelphia | 107 min |
| Jul 6, 11:58 AM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
| Jul 7, 2:26 PM EDT | Flash Flood Warning | PHI | Berks | 4 hr |
| Jul 7, 3:01 PM EDT | Flash Flood Warning | PHI | Chester | 4 hr |
| Jul 7, 3:40 PM EDT | Flash Flood Warning | CTP | Northumberland, Union | 2 hr |
| Jul 7, 6:50 PM EDT | Flash Flood Warning | BGM | Lackawanna, Pike, Wayne | 3 hr |
| Jul 8, 2:40 PM EDT | Flash Flood Warning | PHI | Philadelphia | 4 hr |
| Jul 8, 5:15 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 4 hr |
| Jul 8, 5:51 PM EDT | Flash Flood Warning | PHI | Chester | 4 hr |
| Jul 9, 9:22 AM EDT | Flash Flood Warning | CTP | Columbia, Lycoming, Sullivan | 4 hr |
| Jul 9, 11:33 AM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery | 8 hr |
| Jul 9, 11:36 AM EDT | Flash Flood Warning | CTP | Juniata, Perry | 4 hr |
| Jul 9, 11:47 AM EDT | Flash Flood Warning | BGM | Luzerne | 3 hr |
| Jul 9, 11:56 AM EDT | Flash Flood Warning | CTP | Columbia, Montour, Northumberland, Snyder | 4 hr |
| Jul 9, 12:27 PM EDT | Flash Flood Warning | PHI | Berks, Bucks, Lehigh, Montgomery | 8 hr |
| Jul 9, 1:02 PM EDT | Flash Flood Warning | PHI | Bucks, Lehigh, Northampton | 8 hr |
| Jul 9, 1:16 PM EDT | Flash Flood Warning | PHI | Berks | 6 hr |
| Jul 9, 2:21 PM EDT | Flash Flood Warning | CTP | Cumberland, Dauphin, York | 117 min |
| Jul 9, 2:41 PM EDT | Flash Flood Warning | PHI | Berks | 4 hr |
| Jul 9, 2:46 PM EDT | Flash Flood Warning | PHI | Berks, Lehigh, Northampton | 6 hr |
| Jul 9, 3:51 PM EDT | Flash Flood Warning | PHI | Berks, Chester, Lehigh, Montgomery | 6 hr |
| Jul 9, 4:30 PM EDT | Flash Flood Warning | PBZ | Allegheny | 90 min |
| Jul 9, 4:31 PM EDT | Flash Flood Warning | PHI | Chester, Montgomery | 4 hr |
| Jul 9, 5:12 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery | 5 hr |
| Jul 9, 5:31 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 4 hr |
| Jul 9, 5:59 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery | 4 hr |
| Jul 9, 6:04 PM EDT | Flash Flood Warning | PBZ | Lawrence | 6 hr |
| Jul 12, 3:38 PM EDT | Flash Flood Warning | BGM | Bradford | 68 min |
| Jul 13, 11:04 PM EDT | Flash Flood Warning | BGM | Pike, Wayne | 3 hr |
| Jul 14, 1:26 AM EDT | Flash Flood Warning | BGM | Pike | 3 hr |
| Jul 14, 6:02 PM EDT | Flash Flood Warning | PHI | Carbon, Monroe | 6 hr |
| Jul 14, 7:40 PM EDT | Flash Flood Warning | PHI | Northampton | 6 hr |
| Jul 15, 5:18 PM EDT | Flash Flood Warning | PHI | Bucks | 4 hr |
| Jul 15, 6:09 PM EDT | Flash Flood Warning | PHI | Bucks | 4 hr |
| Jul 15, 8:56 PM EDT | Flash Flood Warning | PHI | Carbon | 95 min |
| Jul 15, 10:53 PM EDT | Flash Flood Warning | CTP | Lycoming, Northumberland, Sullivan, Union | 3 hr |
| Jul 16, 2:43 AM EDT | Flash Flood Warning | PHI | Carbon, Lehigh, Monroe, Northampton | 4 hr |
| Jul 16, 3:40 AM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 7 hr |
| Jul 16, 4:05 AM EDT | Flash Flood Warning | PHI | Berks, Bucks, Chester, Lehigh, Montgomery, Northampton | 6 hr |
| Jul 16, 9:12 AM EDT | Flash Flood Warning | PHI | Chester | 2 hr |
| Jul 16, 9:40 AM EDT | Flash Flood Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 3 hr |
| Jul 16, 11:08 AM EDT | Flash Flood Warning | PHI | Delaware, Philadelphia | 3 hr |
| Jul 20, 5:34 PM EDT | Flash Flood Warning | CLE | Erie | 3 hr |
| Jul 20, 8:18 PM EDT | Flash Flood Warning | PBZ | Mercer, Venango | 3 hr |
| Jul 20, 9:02 PM EDT | Flash Flood Warning | PBZ | Butler, Lawrence, Mercer | 3 hr |
| Jul 20, 9:42 PM EDT | Flash Flood Warning | PBZ | Armstrong, Beaver, Butler, Lawrence | 3 hr |
| Jul 20, 10:29 PM EDT | Flash Flood Warning | PBZ | Allegheny, Armstrong, Beaver, Butler, Indiana, Washington and 1 more | 3 hr |
| Jul 20, 11:02 PM EDT | Flash Flood Warning | PBZ | Allegheny, Fayette, Indiana, Washington, Westmoreland | 3 hr |
| Jul 25, 1:20 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery | 5 hr |
| Jul 25, 1:38 PM EDT | Flash Flood Warning | PHI | Delaware | 4 hr |
| Jul 25, 1:54 PM EDT | Flash Flood Warning | PHI | Delaware, Philadelphia | 4 hr |
| Jul 25, 2:51 PM EDT | Flash Flood Warning | PHI | Chester, Montgomery | 3 hr |
| Jul 25, 3:13 PM EDT | Flash Flood Warning | PHI | Chester | 4 hr |
| Jul 25, 3:34 PM EDT | Flash Flood Warning | PHI | Chester, Montgomery | 3 hr |
| Jul 25, 4:55 PM EDT | Flash Flood Warning | PHI | Chester | 118 min |
| Jul 26, 10:16 PM EDT | Flash Flood Warning | PBZ | Clarion | 3 hr |
| Jul 26, 10:37 PM EDT | Flash Flood Warning | PBZ | Clarion | 2 hr |
| Jul 26, 10:44 PM EDT | Flash Flood Warning | PBZ | Jefferson | 2 hr |
| Jul 28, 7:34 PM EDT | Flash Flood Warning | CLE | Crawford | 3 hr |
| Aug 12, 5:48 PM EDT | Flash Flood Warning | PBZ | Lawrence | 2 hr |
| Aug 12, 6:02 PM EDT | Flash Flood Warning | PBZ | Allegheny, Beaver, Butler, Lawrence | 2 hr |
| Aug 12, 6:57 PM EDT | Flash Flood Warning | PBZ | Allegheny, Armstrong, Butler, Indiana, Westmoreland | 2 hr |
| Aug 12, 9:08 PM EDT | Flash Flood Warning | PBZ | Fayette, Greene, Washington | 63 min |
| Aug 30, 1:27 AM EDT | Flash Flood Warning | CTP | Clinton, Lycoming | 2 hr |
| Aug 30, 3:40 AM EDT | Flash Flood Warning | BGM | Wyoming | 3 hr |
| Sep 7, 6:40 PM EDT | Flash Flood Warning | PBZ | Allegheny | 77 min |
| Sep 8, 5:21 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery | 4 hr |
| Sep 8, 5:56 PM EDT | Flash Flood Warning | BGM | Pike | 4 hr |
| Sep 8, 6:33 PM EDT | Flash Flood Warning | BGM | Pike | 3 hr |
| Sep 9, 4:05 PM EDT | Flash Flood Warning | PHI | Philadelphia | 4 hr |
| Sep 9, 5:27 PM EDT | Flash Flood Warning | BGM | Luzerne | 3 hr |
| Sep 9, 6:03 PM EDT | Flash Flood Warning | BGM | Lackawanna | 5 hr |
| Sep 9, 6:22 PM EDT | Flash Flood Warning | BGM | Bradford, Lackawanna, Luzerne, Susquehanna, Wyoming | 4 hr |
| Sep 9, 7:33 PM EDT | Flash Flood Warning | BGM | Lackawanna, Luzerne | 3 hr |
| Sep 9, 8:29 PM EDT | Flash Flood Warning | PHI | Berks | 2 hr |
| Sep 10, 6:03 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery, Philadelphia | 3 hr |
| Sep 10, 7:55 PM EDT | Flash Flood Warning | PHI | Bucks | 3 hr |
| Sep 10, 11:40 PM EDT | Flash Flood Warning | BGM | Bradford | 3 hr |
| Sep 11, 12:50 AM EDT | Flash Flood Warning | BGM | Bradford | 2 hr |
| Sep 11, 2:30 AM EDT | Flash Flood Warning | BGM | Bradford, Susquehanna | 3 hr |
| Dec 18, 4:58 AM EST | Flash Flood Warning | BGM | Wayne | 3 hr |
| Dec 18, 5:24 AM EST | Flash Flood Warning | BGM | Susquehanna | 5 hr |
| Dec 18, 5:27 AM EST | Flash Flood Warning | BGM | Bradford | 4 hr |
| Dec 18, 5:53 AM EST | Flash Flood Warning | BGM | Lackawanna, Susquehanna, Wyoming | 3 hr |
| Dec 18, 6:17 AM EST | Flash Flood Warning | BGM | Lackawanna, Luzerne | 4 hr |
| Dec 18, 6:48 AM EST | Flash Flood Warning | BGM | Susquehanna | 3 hr |
| Dec 18, 7:15 AM EST | Flash Flood Warning | BGM | Pike | 3 hr |
| Dec 18, 7:27 AM EST | Flash Flood Warning | BGM | Lackawanna, Susquehanna, Wayne | 3 hr |
| Dec 18, 8:04 AM EST | Flash Flood Warning | BGM | Wayne | 4 hr |
| Dec 18, 8:37 AM EST | Flash Flood Warning | BGM | Bradford, Lackawanna, Luzerne, Susquehanna, Wyoming | 5 hr |
| Dec 18, 8:48 AM EST | Flash Flood Warning | BGM | Lackawanna, Luzerne, Pike, Wayne | 5 hr |
| Dec 18, 8:58 AM EST | Flash Flood Warning | BGM | Bradford, Lackawanna, Susquehanna, Wyoming | 5 hr |
| Dec 18, 10:21 AM EST | Flash Flood Warning | BGM | Lackawanna, Pike, Susquehanna, Wayne | 4 hr |
| Dec 18, 10:22 AM EST | Flash Flood Warning | BGM | Lackawanna, Luzerne | 4 hr |
| Dec 18, 10:28 AM EST | Flash Flood Warning | BGM | Pike | 4 hr |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Montgomery County21
- Chester County19
- Bucks County15
- Philadelphia County15
- Delaware County13
- Pike County12
- Lackawanna County12
- Lehigh County10
- Susquehanna County10
- Berks County10
- Allegheny County10
- Northampton County9
- Luzerne County8
- Bradford County8
- Butler County7
- Beaver County7
- Wayne County7
- Westmoreland County6
- Lawrence County6
- Wyoming County5
- Northumberland County4
- Monroe County4
- Indiana County4
- Washington County4
- Lycoming County3
- Carbon County3
- Armstrong County3
- Union County2
- Columbia County2
- Sullivan County2
- Mercer County2
- Fayette County2
- Clarion County2
- Juniata County1
- Perry County1
- Montour County1
- Snyder County1
- Cumberland County1
- Dauphin County1
- York County1
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20222024
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.