National Weather ServicePennsylvaniaFlash Flood WarningArchive to October 1, 2026
Flash Flood Warnings in Pennsylvania
The National Weather Service issued 240 flash flood warnings for Pennsylvania in 2025 and 111 a year on average in 2008-2025; in 2021-2025 it had the 13th most of any state. 2026 through September: 300, 178% above the average of 108 for those months in 2008-2025. Allegheny was covered most often (233 times since 2008).
How many flash flood warnings does Pennsylvania get?
Every flash flood warning that covered part of Pennsylvania. 2026 is an outline: the year is not over.
The numbers
| Year | Count |
|---|---|
| 2026 (through September) | 300 |
| 2025 | 240 |
| 2024 | 125 |
| 2023 | 123 |
| 2022 | 36 |
| 2021 | 155 |
| 2020 | 71 |
| 2019 | 167 |
| 2018 | 198 |
| 2017 | 128 |
| 2016 | 44 |
| 2015 | 75 |
| 2014 | 53 |
| 2013 | 119 |
| 2012 | 55 |
| 2011 | 201 |
| 2010 | 65 |
| 2009 | 98 |
| 2008 | 45 |
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
When in the year does Pennsylvania get them?
Sum of 2008-2025; the busiest month is labelled.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
Where in Pennsylvania?
| County or forecast zone | Since 2008 | Since 2023 | Last issued |
|---|---|---|---|
| Allegheny | 233 | 89 | September 12, 2026 |
| Montgomery | 229 | 84 | September 13, 2026 |
| Bucks | 214 | 82 | September 13, 2026 |
| Chester | 196 | 68 | September 3, 2026 |
| Philadelphia | 186 | 72 | September 13, 2026 |
| Westmoreland | 179 | 69 | September 12, 2026 |
| Delaware | 168 | 74 | September 13, 2026 |
| Berks | 139 | 38 | September 1, 2026 |
| Bradford | 125 | 23 | August 12, 2026 |
| Washington | 125 | 54 | September 20, 2026 |
| Luzerne | 113 | 36 | September 1, 2026 |
| York | 112 | 31 | August 7, 2026 |
The NWS issues these products for counties or forecast zones; a zone can be part of a county or a mountain range.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
The latest flash flood warnings for Pennsylvania in AreaZine's record
NWS PittsburghWarningSeptember 20, 2026
Flash Flood Warning: Washington County, PA
Expired 1:30 p.m. EDT, September 20, 2026
NWS PittsburghWarningSeptember 20, 2026
Flash Flood Warning: Harrison, Jefferson, Washington County and 1 more, OH and PA
Expired 5:45 a.m. EDT, September 20, 2026
NWS State CollegeWarningSeptember 17, 2026
Flash Flood Warning: Somerset, PA
Expired 12:15 a.m. EDT, September 18, 2026
NWS PittsburghWarningSeptember 13, 2026
Flash Flood Warning: Mercer, PA
Expired 8:30 p.m. EDT, September 13, 2026
NWS Mount HollyWarningSeptember 13, 2026
Flash Flood Warning: Mercer, Middlesex, Bucks and 3 more, NJ and PA
Expired 12:00 p.m. EDT, September 13, 2026
NWS PittsburghWarningSeptember 13, 2026
Flash Flood Warning: Clarion, PA
Expired 5:30 a.m. EDT, September 13, 2026
NWS State CollegeWarningSeptember 12, 2026
Flash Flood Warning: Elk, PA
Expired 2:45 a.m. EDT, September 13, 2026
NWS PittsburghWarningSeptember 12, 2026
Flash Flood Warning: Fayette, Greene, Washington County and 1 more, PA and WV
Expired 9:15 p.m. EDT, September 12, 2026
This list is AreaZine's record of the NWS alert feed, kept since April 6, 2026; the counts above come from the complete IEM archive.
Source: National Weather Service alerts (api.weather.gov).
What is a flash flood warning?
A flash flood warning means flash flooding is happening or about to happen: water rising fast in streams, streets or dry washes, usually within six hours of heavy rain or a dam or levee failure. A warning means the hazard is happening, about to happen, or very likely: act now to protect people and property. The national record · Every warning type in Pennsylvania.