Flash Flood Warnings in Pennsylvania, 2008

By month

22 of 45 flash flood warnings covering Pennsylvania in 2008 had a flash flood report inside them; 21 of 35 flash flood reports fell inside a warning, on average 59 minutes after it went out.

Pennsylvania, 2008

Each office's whole area, 2008

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.

• Chester County7
• Montgomery County7
• Bucks County6
• Allegheny County5
• Delaware County4
• Philadelphia County4
• Warren County3
• Wayne County3
• Monroe County3
• Crawford County2
• Erie County2
• Bradford County2
• Luzerne County2
• Pike County2
• Susquehanna County2
• Berks County2
• Carbon County2
• Greene County2
• Washington County2
• Westmoreland County2
• Lackawanna County1
• Wyoming County1
• Lehigh County1
• Fayette County1
• Indiana County1
• Jefferson County1
• Lancaster County1
• Northampton County1

1. June 14, 20084flash flood warnings
2. March 8, 20083flash flood warnings
3. July 23, 20083flash flood warnings
4. August 10, 20083flash flood warnings
5. August 14, 20083flash flood warnings
6. August 15, 20083flash flood warnings
7. September 9, 20083flash flood warnings
8. February 6, 20082flash flood warnings
9. March 5, 20082flash flood warnings
10. March 20, 20082flash flood warnings
11. July 6, 20082flash flood warnings
12. July 8, 20082flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20072009

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.