Alert archive / Pennsylvania / Mesoscale Discussions
Mesoscale Discussions in Pennsylvania, 2009
122 mesoscale discussions in 2009. 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 mesoscale discussions reaches back to 2003.
Mesoscale Discussions by county
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Mesoscale Discussions
- 122
- Busiest month
- June27 mesoscale discussions
- Busiest day
- January 28, 20095 mesoscale discussions
Over time
By month
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 |
|---|---|---|---|---|
| Jan 6, 5:17 PM EST | Mesoscale Discussion | SPC | Adams, Allegheny, Armstrong, Beaver, Bedford, Berks and 38 more | 4 hr |
| Jan 7, 12:10 AM EST | Mesoscale Discussion | SPC | Adams, Berks, Bradford, Bucks, Cameron, Carbon and 36 more | 4 hr |
| Jan 7, 6:08 AM EST | Mesoscale Discussion | SPC | Carbon, Lackawanna, Monroe, Pike, Susquehanna, Wayne and 1 more | 3 hr |
| Jan 10, 6:33 AM EST | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Blair, Butler, Cambria and 18 more | 5 hr |
| Jan 10, 12:56 PM EST | Mesoscale Discussion | SPC | Bradford, Lackawanna, Lycoming, Potter, Sullivan, Susquehanna and 3 more | 4 hr |
| Jan 10, 7:58 PM EST | Mesoscale Discussion | SPC | Bucks, Carbon, Lackawanna, Lehigh, Luzerne, Monroe and 5 more | 4 hr |
| Jan 27, 7:25 PM EST | Mesoscale Discussion | SPC | Fayette, Greene, Washington | 6 hr |
| Jan 28, 12:31 AM EST | Mesoscale Discussion | SPC | Adams, Allegheny, Armstrong, Beaver, Bedford, Berks and 60 more | 5 hr |
| Jan 28, 7:40 AM EST | Mesoscale Discussion | SPC | Beaver, Crawford, Lawrence, Mercer | 5 hr |
| Jan 28, 7:53 AM EST | Mesoscale Discussion | SPC | Berks, Blair, Bradford, Cambria, Cameron, Carbon and 34 more | 5 hr |
| Jan 28, 12:24 PM EST | Mesoscale Discussion | SPC | Lackawanna, Pike, Wayne | 4 hr |
| Feb 11, 5:32 PM EST | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Bedford, Blair, Cambria and 9 more | 88 min |
| Feb 11, 8:00 PM EST | Mesoscale Discussion | SPC | Adams, Allegheny, Armstrong, Beaver, Bedford, Blair and 44 more | 60 min |
| Feb 11, 10:14 PM EST | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Chester, Cumberland, Dauphin and 6 more | 61 min |
| Feb 18, 12:38 PM EST | Mesoscale Discussion | SPC | Blair, Bradford, Cameron, Centre, Clearfield, Clinton and 17 more | 3 hr |
| Feb 18, 6:28 PM EST | Mesoscale Discussion | SPC | Wayne | 4 hr |
| Mar 1, 9:09 PM EST | Mesoscale Discussion | SPC | Bucks, Delaware, Philadelphia | 4 hr |
| Mar 2, 5:38 AM EST | Mesoscale Discussion | SPC | Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more | 3 hr |
| Mar 29, 1:49 PM EDT | Mesoscale Discussion | SPC | Adams, Bucks, Chester, Cumberland, Delaware, Franklin and 5 more | 116 min |
| Mar 29, 5:53 PM EDT | Mesoscale Discussion | SPC | Bucks, Chester, Delaware, Montgomery, Northampton, Philadelphia | 97 min |
| Apr 21, 2:12 PM EDT | Mesoscale Discussion | SPC | Franklin | 2 hr |
| Apr 24, 6:51 PM EDT | Mesoscale Discussion | SPC | Cameron, Elk, Forest, Jefferson, McKean, Potter and 1 more | 54 min |
| Apr 25, 1:24 PM EDT | Mesoscale Discussion | SPC | McKean, Potter, Warren | 66 min |
| May 1, 6:36 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Elk and 6 more | 54 min |
| May 16, 12:05 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Bedford, Blair, Bradford and 43 more | 55 min |
| May 16, 3:55 PM EDT | Mesoscale Discussion | SPC | Adams, Allegheny, Armstrong, Bedford, Berks, Blair and 43 more | 65 min |
| May 16, 6:29 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Blair, Bradford, Bucks and 41 more | 2 hr |
| May 23, 12:49 PM EDT | Mesoscale Discussion | SPC | Bedford, Blair, Bradford, Cambria, Centre, Clinton and 22 more | 56 min |
| May 24, 11:49 AM EDT | Mesoscale Discussion | SPC | Berks, Carbon, Lackawanna, Lehigh, Luzerne, Monroe and 5 more | 116 min |
| May 24, 7:11 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Chester, Cumberland, Dauphin and 10 more | 64 min |
| May 28, 4:54 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Cambria, Cameron and 16 more | 66 min |
| May 29, 12:20 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Chester, Cumberland, Delaware, Franklin and 6 more | 55 min |
| May 29, 4:30 PM EDT | Mesoscale Discussion | SPC | Chester, Delaware, Lancaster, Philadelphia, York | 60 min |
| May 29, 6:20 PM EDT | Mesoscale Discussion | SPC | Delaware, Philadelphia | 55 min |
| Jun 1, 9:32 PM EDT | Mesoscale Discussion | SPC | Beaver, Butler, Crawford, Lawrence, Mercer | 58 min |
| Jun 2, 1:31 PM EDT | Mesoscale Discussion | SPC | Adams, Chester, Cumberland, Delaware, Lancaster, Philadelphia and 1 more | 89 min |
| Jun 2, 4:47 PM EDT | Mesoscale Discussion | SPC | Greene, Washington | 88 min |
| Jun 2, 7:13 PM EDT | Mesoscale Discussion | SPC | Greene | 62 min |
| Jun 9, 6:01 AM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Carbon, Chester, Delaware, Lancaster and 7 more | 59 min |
| Jun 9, 11:48 AM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Blair, Bradford, Butler and 21 more | 87 min |
| Jun 9, 3:40 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bradford, Carbon, Columbia, Cumberland and 23 more | 65 min |
| Jun 10, 1:57 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Cumberland, Dauphin, Franklin, Fulton and 5 more | 93 min |
| Jun 11, 11:51 AM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Cumberland, Franklin, Fulton, Huntingdon and 1 more | 84 min |
| Jun 11, 10:01 PM EDT | Mesoscale Discussion | SPC | Adams, Chester, Cumberland, Dauphin, Delaware, Lancaster and 3 more | 59 min |
| Jun 13, 8:09 PM EDT | Mesoscale Discussion | SPC | Carbon, Lancaster, Lebanon, Schuylkill, York | 66 min |
| Jun 17, 2:00 PM EDT | Mesoscale Discussion | SPC | Allegheny, Beaver, Greene, Lawrence, Washington | 60 min |
| Jun 17, 6:33 PM EDT | Mesoscale Discussion | SPC | Allegheny, Beaver, Fayette, Greene, Lawrence, Washington and 1 more | 57 min |
| Jun 17, 9:31 PM EDT | Mesoscale Discussion | SPC | Fayette, Greene, Somerset, Washington | 59 min |
| Jun 18, 11:40 AM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Chester, Delaware, Lancaster, Montgomery and 2 more | 95 min |
| Jun 19, 5:56 PM EDT | Mesoscale Discussion | SPC | Fayette, Greene, Washington | 64 min |
| Jun 20, 3:14 AM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Bedford, Butler, Cambria and 9 more | 91 min |
| Jun 25, 3:51 PM EDT | Mesoscale Discussion | SPC | McKean, Potter, Tioga, Warren | 54 min |
| Jun 25, 4:12 PM EDT | Mesoscale Discussion | SPC | Beaver, Lawrence | 63 min |
| Jun 25, 7:09 PM EDT | Mesoscale Discussion | SPC | Crawford | 96 min |
| Jun 25, 8:21 PM EDT | Mesoscale Discussion | SPC | Monroe, Pike | 54 min |
| Jun 26, 2:19 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Bucks, Carbon, Centre and 22 more | 56 min |
| Jun 26, 6:29 PM EDT | Mesoscale Discussion | SPC | Bradford, Cameron, Clinton, Columbia, Lackawanna, Luzerne and 7 more | 61 min |
| Jun 26, 7:33 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Bucks, Chester, Cumberland and 12 more | 57 min |
| Jun 26, 9:11 PM EDT | Mesoscale Discussion | SPC | Adams, Chester, Delaware, Franklin, Fulton, Lancaster and 3 more | 64 min |
| Jun 30, 10:57 AM EDT | Mesoscale Discussion | SPC | Carbon, Lackawanna, Luzerne, Monroe, Northampton, Pike and 1 more | 93 min |
| Jun 30, 2:18 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Carbon, Chester, Delaware, Lackawanna and 8 more | 57 min |
| Jul 1, 12:03 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Chester, Columbia and 18 more | 87 min |
| Jul 2, 3:20 PM EDT | Mesoscale Discussion | SPC | Pike | 55 min |
| Jul 7, 2:00 PM EDT | Mesoscale Discussion | SPC | Bucks, Carbon, Lehigh, Monroe, Northampton | 90 min |
| Jul 11, 10:31 AM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Blair, Bradford, Butler and 25 more | 59 min |
| Jul 11, 7:06 PM EDT | Mesoscale Discussion | SPC | Armstrong, Bradford, Butler, Cameron, Centre, Clarion and 20 more | 114 min |
| Jul 16, 4:04 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Carbon, Chester, Delaware, Lancaster and 5 more | 86 min |
| Jul 16, 4:55 PM EDT | Mesoscale Discussion | SPC | Carbon, Lackawanna, Monroe, Pike, Susquehanna, Wayne | 65 min |
| Jul 17, 6:18 PM EDT | Mesoscale Discussion | SPC | Bucks, Delaware, Montgomery, Philadelphia | 57 min |
| Jul 21, 1:56 PM EDT | Mesoscale Discussion | SPC | Adams, Allegheny, Armstrong, Beaver, Bedford, Blair and 38 more | 64 min |
| Jul 24, 2:20 PM EDT | Mesoscale Discussion | SPC | Blair, Bradford, Cameron, Carbon, Centre, Clearfield and 26 more | 115 min |
| Jul 24, 3:34 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Chester, Cumberland and 11 more | 86 min |
| Jul 25, 3:05 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Blair, Cambria, Cameron, Centre and 23 more | 55 min |
| Jul 25, 7:43 PM EDT | Mesoscale Discussion | SPC | Adams, Blair, Cameron, Centre, Clinton, Columbia and 16 more | 62 min |
| Jul 26, 12:56 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Cambria, Cameron and 16 more | 2 hr |
| Jul 26, 1:40 PM EDT | Mesoscale Discussion | SPC | Adams, Chester, Cumberland, Delaware, Lancaster, Philadelphia and 1 more | 2 hr |
| Jul 26, 3:14 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Chester, Columbia and 22 more | 2 hr |
| Jul 26, 6:37 PM EDT | Mesoscale Discussion | SPC | Bucks, Chester, Delaware, Lancaster, Lehigh, Montgomery and 2 more | 113 min |
| Jul 26, 10:06 PM EDT | Mesoscale Discussion | SPC | Bucks | 54 min |
| Jul 29, 12:22 PM EDT | Mesoscale Discussion | SPC | Bucks, Carbon, Lackawanna, Lehigh, Luzerne, Monroe and 7 more | 23 min |
| Jul 29, 2:22 PM EDT | Mesoscale Discussion | SPC | Bucks, Carbon, Lackawanna, Lehigh, Luzerne, Monroe and 5 more | 23 min |
| Jul 29, 5:05 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Carbon, Chester, Columbia, Dauphin and 19 more | 55 min |
| Jul 29, 7:14 PM EDT | Mesoscale Discussion | SPC | Bucks, Delaware, Lehigh, Monroe, Montgomery, Northampton and 2 more | 61 min |
| Jul 31, 10:20 AM EDT | Mesoscale Discussion | SPC | Berks, Carbon, Columbia, Cumberland, Dauphin, Juniata and 18 more | 85 min |
| Jul 31, 12:06 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Chester, Delaware, Lancaster, Montgomery and 1 more | 84 min |
| Jul 31, 3:05 PM EDT | Mesoscale Discussion | SPC | Bucks, Chester, Delaware, Montgomery, Philadelphia | 85 min |
| Aug 2, 10:01 AM EDT | Mesoscale Discussion | SPC | Bucks, Delaware, Montgomery, Philadelphia | 119 min |
| Aug 4, 6:09 PM EDT | Mesoscale Discussion | SPC | Crawford, Erie, Forest, McKean, Warren | 66 min |
| Aug 9, 11:36 AM EDT | Mesoscale Discussion | SPC | Bradford, Cameron, Centre, Clarion, Clearfield, Clinton and 10 more | 24 min |
| Aug 9, 2:45 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Blair, Bradford, Bucks, Cameron and 42 more | 60 min |
| Aug 9, 7:11 PM EDT | Mesoscale Discussion | SPC | Berks, Bradford, Bucks, Cameron, Carbon, Centre and 37 more | 2 hr |
| Aug 9, 10:47 PM EDT | Mesoscale Discussion | SPC | Bradford, Cameron, Centre, Clarion, Clearfield, Clinton and 20 more | 118 min |
| Aug 10, 2:26 PM EDT | Mesoscale Discussion | SPC | Clarion, Crawford, Elk, Erie, Forest, McKean and 4 more | 2 hr |
| Aug 10, 4:40 PM EDT | Mesoscale Discussion | SPC | Carbon, Lackawanna, Luzerne, Monroe, Northampton, Pike and 2 more | 2 hr |
| Aug 10, 8:15 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Blair, Bradford, Cambria and 35 more | 2 hr |
| Aug 11, 12:39 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Cameron, Clarion and 14 more | 2 hr |
| Aug 12, 12:36 PM EDT | Mesoscale Discussion | SPC | Bedford, Blair, Cambria, Centre, Clearfield, Clinton and 16 more | 84 min |
| Aug 12, 1:01 PM EDT | Mesoscale Discussion | SPC | Bucks, Chester, Delaware, Montgomery, Philadelphia | 89 min |
| Aug 18, 2:32 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Bedford, Blair, Bradford and 33 more | 88 min |
| Aug 19, 1:21 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Bedford, Berks, Blair, Bradford and 44 more | 84 min |
| Aug 19, 6:05 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Carbon, Chester, Delaware, Lancaster and 6 more | 55 min |
| Aug 20, 6:20 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 14 more | 55 min |
| Aug 20, 10:40 PM EDT | Mesoscale Discussion | SPC | Armstrong, Bedford, Blair, Cambria, Cameron, Centre and 14 more | 95 min |
| Aug 21, 10:01 AM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Carbon, Chester, Delaware, Lancaster and 8 more | 119 min |
| Aug 21, 1:58 PM EDT | Mesoscale Discussion | SPC | Bucks, Montgomery, Northampton, Philadelphia | 92 min |
| Aug 21, 5:55 PM EDT | Mesoscale Discussion | SPC | Philadelphia | 80 min |
| Aug 28, 12:24 PM EDT | Mesoscale Discussion | SPC | Delaware | 2 hr |
| Sep 23, 6:16 PM EDT | Mesoscale Discussion | SPC | Bradford, Clinton, Lycoming, Potter, Sullivan, Susquehanna and 3 more | 89 min |
| Oct 24, 5:25 AM EDT | Mesoscale Discussion | SPC | Bedford, Franklin, Fulton, Somerset | 95 min |
| Oct 24, 12:19 PM EDT | Mesoscale Discussion | SPC | Chester, Delaware, Montgomery, Philadelphia | 116 min |
| Dec 8, 11:32 PM EST | Mesoscale Discussion | SPC | Bradford, Cameron, Clinton, Columbia, Elk, Forest and 14 more | 6 hr |
| Dec 9, 11:02 AM EST | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 11 more | 88 min |
| Dec 10, 10:34 AM EST | Mesoscale Discussion | SPC | Erie | 6 hr |
| Dec 10, 7:05 PM EST | Mesoscale Discussion | SPC | Erie | 4 hr |
| Dec 11, 9:27 PM EST | Mesoscale Discussion | SPC | Warren | 4 hr |
| Dec 13, 5:16 AM EST | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Blair, Bradford, Butler and 23 more | 4 hr |
| Dec 19, 12:34 AM EST | Mesoscale Discussion | SPC | Adams, Chester, Delaware, Franklin, Fulton, Lancaster and 1 more | 5 hr |
| Dec 19, 6:57 AM EST | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Bucks, Chester, Cumberland and 10 more | 6 hr |
| Dec 19, 12:27 PM EST | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Chester, Cumberland and 12 more | 6 hr |
| Dec 19, 7:25 PM EST | Mesoscale Discussion | SPC | Bucks, Chester, Delaware, Montgomery, Philadelphia | 5 hr |
| Dec 25, 7:50 AM EST | Mesoscale Discussion | SPC | Armstrong, Bedford, Blair, Cambria, Cameron, Centre and 13 more | 4 hr |
| Dec 26, 12:37 AM EST | Mesoscale Discussion | SPC | Wayne | 4 hr |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Delaware County42
- Philadelphia County41
- Bucks County39
- Montgomery County39
- Lancaster County38
- Cumberland County36
- York County36
- Chester County36
- Carbon County33
- Northampton County33
- Potter County33
- Wayne County33
- Berks County32
- Cameron County32
- Elk County32
- Lackawanna County32
- Dauphin County31
- Lebanon County31
- Lehigh County31
- McKean County31
- Adams County30
- Clinton County30
- Forest County30
- Lycoming County30
- Union County30
- Centre County29
- Clearfield County29
- Franklin County29
- Huntingdon County29
- Jefferson County29
- Monroe County29
- Tioga County29
- Mifflin County28
- Perry County28
- Luzerne County28
- Pike County28
- Sullivan County28
- Susquehanna County28
- Wyoming County28
- Fulton County27
27 more counties
- Bradford County27
- Warren County27
- Schuylkill County26
- Blair County25
- Indiana County25
- Cambria County24
- Clarion County24
- Columbia County24
- Juniata County24
- Montour County24
- Snyder County24
- Washington County24
- Armstrong County23
- Beaver County23
- Bedford County23
- Northumberland County23
- Allegheny County22
- Lawrence County22
- Fayette County21
- Greene County21
- Westmoreland County21
- Butler County20
- Somerset County20
- Venango County20
- Crawford County20
- Mercer County18
- Erie County11
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20082010
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.