Pennsylvania 2010 Severe Weather Season Wrapup
UPDATE: I have added "Warnings" to the graphs below (thanks DJ!)
In order to gauge how the severe weather (thunderstorm) season was this year in our home state of Pennsylvania for the Pennsylvania Storm Chasers Facebook Group, I have updated the graphs that I did earlier this Spring.* Disclaimer: Although the season isn't over yet, very few reports typically come in after the end of August.* I will update this report at the end of September if necessary.
I was a little surprised with the results. When comparing the total number of Storm Spotter Reports to the 11-year average, this was the 2nd least active year, though it did better than 2009, which was pitiful.* I felt that I had a better experience trying to document severe weather this season, but that could have been because last year's numbers were so low, or because this season included the most severe storm (including my first PA funnel cloud and the largest hail) to hit since I've lived here. Here's how the spotter reports stacked up versus previous years:
There are a couple things of interest here: We had more tornadoes this season than any since 2004, and had the 3rd most active tornado season during the period, but tied with 2003 for the least hail reports! This may have been due to the unusually warm summer, which unlike last year, raises the freezing level in the atmosphere and makes hail less likely.
Geographically speaking, the reports were more equally distributed across western and central Pennsylvania (unlike last year when Central Pennsylvania was lacking for reports*), but the southeastern part of the state clearly had more reports than usual.
There were less Severe Thunderstorm Warnings issued this year (by NWS offices in Pittsburgh, State College and Philadelphia - this leaves out northeasternmost PA), but that could be due to the change that the NWS made in not issuing warnings unless hail exceeds 1 inch in diameter (previously it was 3/4"). The number of Tornado Warnings issued was similar (34) to 2009 (35) but more than 2008 (22).
We can also look at the number of "severe weather days" (as defined as one or more spotter reports in the state) and "lightning days" (ditto for lightning strikes, courtesy the Pennsylvania State Climatologist). I only have this data for the last couple of years, but it shows that we didn't have as much lightning this year as last (surprising since last year's season was so lame). It also says that we had less severe weather days in 2010, while the previous three years were identical despite differing numbers of spotter reports (I guess we'll see if those fill in later this summer but I'm doubtful).
All said, it seems like this severe weather season was "disappointing" for severe weather photographers and enthusiasts. Although you can't necessarily tie human impact to these numbers, presumably this calmer season resulted in less damage, injuries and deaths, which is of course a good thing.
*All of these statements were explained in my blog from this Spring "Pennsylvania Severe Weather 2000-2009, Hopes."
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