KamuSnow Posted December 25, 2016 Share Posted December 25, 2016 The results of some data gathering to see what the ranges for snowfall are at PHL by decade. Used annual snowfall data for Philadelphia that goes back into the 1880's (feel free to verify the data or math - QC is good). This started as an exercise in looking at average snowfall over 10 year time frames (at PHL), to inform snowfall expectations from mid-decade on. The possibility of winding up at the high end of both 10 year and decadal totals over the next few years is intriguing. By decade: - Through the first 5 winters of this decade (2010-11 thru 2014-15) PHL has received 151.3" of snow. - Through the first 6 winters of this decade (2010-11 thru 2015-16) PHL has received 178.8" of snow. - Need 110.7" over the next 4 winters (2016-17 through 2019-20) to tie the highest snowfall in any given decade (289.5") By any 10 consecutive year period: - For the 7 winters from 2009-10 through 2015-16 PHL has received 257.5" of snow. - For the 8 winters from 2008-09 through 2015-16 PHL has received 280.3" of snow. - Need 20.4" over the next 2 winters (2016-17 and 2017-18) to tie the highest snowfall in any given 10 year period (300.7") - Need 43.2" over the next 3 winters (2016-17 thru 2018-19) to tie the highest snowfall in any given 10 year period (300.7") Link to comment Share on other sites More sharing options...
RedSky Posted December 25, 2016 Share Posted December 25, 2016 Great chart Kamu. Knowing how bad the 70's through the 90's were for snow the 20's through the 50's were even worse. So where did the old timers come up with that "when I was younger that's when we saw snow" Link to comment Share on other sites More sharing options...
KamuSnow Posted December 25, 2016 Author Share Posted December 25, 2016 8 hours ago, RedSky said: Great chart Kamu. Knowing how bad the 70's through the 90's were for snow the 20's through the 50's were even worse. So where did the old timers come up with that "when I was younger that's when we saw snow" Thanks! Could be a memory issue.... Link to comment Share on other sites More sharing options...
Hurricane Agnes Posted December 25, 2016 Share Posted December 25, 2016 1 hour ago, KamuSnow said: Thanks! Could be a memory issue.... Or it could have been there were more frequent small/moderate snow events (and colder temps) versus less of those types but more of the MECS and HECS variety that we have seen the past 20 years. It seems because of the heat island effect, we are observing more marginal temperature/changeover type precipitation. And as a side note, the official temp for PHL hasn't gone below 0 since 1994 (not that it can't happen in the future). I have noticed that since the building height restriction (i.e., nothing taller than Billy Penn's hat on the statue on top of City Hall) was "lifted" in the city around 1984, a huge number of large skyscrapers have erupted, and this can't but help but increase the heat island. One of the sites I enjoy looking at for historical weather is the Franklin Institute - https://www.fi.edu/history-resources/philadelphia-weather-data They recently re-did that page where the historical data used to be displayed as HTML tables, but is now presented as a downloadable spreadsheet that is tabbed for various decade ranges. It has all the available data from their obs going back to 1872 and they keep it updated with current obs from the existing weather station at the Franklin Institute. Link to comment Share on other sites More sharing options...
KamuSnow Posted December 27, 2016 Author Share Posted December 27, 2016 On 12/25/2016 at 11:39 AM, Hurricane Agnes said: Or it could have been there were more frequent small/moderate snow events (and colder temps) versus less of those types but more of the MECS and HECS variety that we have seen the past 20 years. It seems because of the heat island effect, we are observing more marginal temperature/changeover type precipitation. And as a side note, the official temp for PHL hasn't gone below 0 since 1994 (not that it can't happen in the future). I have noticed that since the building height restriction (i.e., nothing taller than Billy Penn's hat on the statue on top of City Hall) was "lifted" in the city around 1984, a huge number of large skyscrapers have erupted, and this can't but help but increase the heat island. One of the sites I enjoy looking at for historical weather is the Franklin Institute - https://www.fi.edu/history-resources/philadelphia-weather-data They recently re-did that page where the historical data used to be displayed as HTML tables, but is now presented as a downloadable spreadsheet that is tabbed for various decade ranges. It has all the available data from their obs going back to 1872 and they keep it updated with current obs from the existing weather station at the Franklin Institute. Yeah, I was kidding about the memory thing. Maybe also from not being as insulated from the weather, like walking to school in snowstorms, etc. Currently it does seem possible that warmer ocean temps (whatever the cause) could lead to more atmospheric moisture which would create more opportunities for higher snowfall events given the right circumstances. I got a lot of the data for the chart above from the same site you mentioned. Link to comment Share on other sites More sharing options...
Hurricane Agnes Posted December 27, 2016 Share Posted December 27, 2016 7 hours ago, KamuSnow said: Yeah, I was kidding about the memory thing. Maybe also from not being as insulated from the weather, like walking to school in snowstorms, etc. Currently it does seem possible that warmer ocean temps (whatever the cause) could lead to more atmospheric moisture which would create more opportunities for higher snowfall events given the right circumstances. I got a lot of the data for the chart above from the same site you mentioned. Well it was usually the "old folks" who would go on about the snowier weather in the past and now that some of us are rapidly becoming "the old folks", my stories (from the late '70s living in this hilly area) consist of being forced by the driver to get off one of the SEPTA buses that I took to school, and walk a couple blocks up one of the steep hills along the route in Mt. Airy and then get back on at the top of the hill because the bus couldn't make it up the snow-clogged street with people on it. Great (but true) winter tale fodder. As a note, they eventually changed that bus route a couple decades later because of that issue. For some similar types of bus routes in Roxborough, they usually just cancel those buses during/after significant snowstorms. Agree that the changes in SST (perhaps from a lack of deep mixing too) might be impacting/influencing the severity of the storms (both winter and summer) of late. I ran a quick plot from NCEI's tool to see the land/sea anomalies from 1966 - 2016 and you can see the trends -https://www.ncdc.noaa.gov/cag/time-series/global/globe/land_ocean/3/2/1966-2016 Link to comment Share on other sites More sharing options...
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