Snowless Decembers and Following Snow Seasons

[ChescoWx]

While we already have had over 7" of snow this season - December will finish as just our 17th snowless December in 125 years of local data here in Chester County PA. So with that in mind you would think we will not be having an above normal snow year in this area.  In those 16 years of snowless Decembers we have ended with between no snow at all in the 72/73 winter to as much as 40.8" in 2015/16. Overall only 2 of those 16 winters ( 2015/16 and 1978/79) ended with above normal snowfall (~36") in this area of the Philadelphia suburbs. All of that said I still like our chances of just the 3rd above normal snow season totals despite the lack of December snowfall.

[KamuSnow]

5 hours ago, ChescoPaWxman said:

While we already have had over 7" of snow this season - December will finish as just our 17th snowless December in 125 years of local data here in Chester County PA. So with that in mind you would think we will not be having an above normal snow year in this area.  In those 16 years of snowless Decembers we have ended with between no snow at all in the 72/73 winter to as much as 40.8" in 2015/16. Overall only 2 of those 16 winters ( 2015/16 and 1978/79) ended with above normal snowfall (~36") in this area of the Philadelphia suburbs. All of that said I still like our chances of just the 3rd above normal snow season totals despite the lack of December snowfall.

I was looking at PHL and technically it wasn't snowless in December due to the inverted trough that gave 0.3" of snow there. So I went back to 1951 and found (8) winters where there was a weak or moderate El Nino and where there was also 0.3" or less snow at PHL in December. (2) of those years also had measurable snow in November. The seasonal totals for those (8) years ranged from a low of 5.1" in 1958-59 to a high of 54.9" in 1977-78. 1958-59 had no snow in November while 1977-78 had 0.2". The average snowfall for those 8 years at PHL was 24.6", which is about 2" above normal. Of course if you took 1977-78 out it would be about 2" less than normal (20.2"), but why would we do that?

So far this winter PHL has had 3.9" of snow.

Even though our samples and locations are different, they both point to a reasonable chance for at least normal snowfall from January through March.

Disclaimer: Based on the unusual atmospheric goings on, due to climate in general and just because, analogs may have limited value currently (uncharted territory in some respects it appears). At the same time, going with what we do know, it's way too early to toss in the towel. And remember how the seasons have seemed to lag the last couple or few years.

[Hurricane Agnes]

7 hours ago, KamuSnow said:

I was looking at PHL and technically it wasn't snowless in December due to the inverted trough that gave 0.3" of snow there. So I went back to 1951 and found (8) winters where there was a weak or moderate El Nino and where there was also 0.3" or less snow at PHL in December. (2) of those years also had measurable snow in November. The seasonal totals for those (8) years ranged from a low of 5.1" in 1958-59 to a high of 54.9" in 1977-78. 1958-59 had no snow in November while 1977-78 had 0.2". The average snowfall for those 8 years at PHL was 24.6", which is about 2" above normal. Of course if you took 1977-78 out it would be about 2" less than normal (20.2"), but why would we do that?

So far this winter PHL has had 3.9" of snow.

Even though our samples and locations are different, they both point to a reasonable chance for at least normal snowfall from January through March.

Disclaimer: Based on the unusual atmospheric goings on, due to climate in general and just because, analogs may have limited value currently (uncharted territory in some respects it appears). At the same time, going with what we do know, it's way too early to toss in the towel. And remember how the seasons have seemed to lag the last couple or few years.

The one major thing that I have always mentally taken note of is the actual "urban heat island" that Philadelphia has become over the past 30 years.  I.e., if you look at the historical construction here in the city, there used to be the old "gentleman's agreement" that no building would be "taller than Billy Penn's hat" (meaning the hat on the statue at the top of City Hall).  That "agreement" eventually fell by the wayside in the mid-80s after much angst, to produce the first Liberty Place Tower in 1987. I used to go to school downtown in the early '70s and caught the 2 bus to school, and that tower is on the old site of a couple movie theaters (one of which was where I had seen "The Exorcist" when it first released ). 

When the tower opened, the skyline looked like this (City Hall to the far right) -

30 years later, there are 9 towers (or sets of towers) that are taller than City Hall and literally dozens more that are at or near City Hall's height (City Hall in the foreground to the right) -

And as of last year (City Hall in the center far right, but not able to see the Comcast Innovation Center construction, where that tower will eventually be the tallest in the city and 9th tallest in the country) -

Cool video showing the evolution of the tower construction here (only includes buildings up until 2013 and a pile more have been built or are under construction since) -

In a nutshell, although perhaps not definitive due to regular climate cycles, the city has not recorded a below zero temperature since 1994, and that seems to correspond with the urban building density that has exploded and continues to this day.  So speculating, that may mean that events in the immediate metro area that might have been snow, may have ended up as mixed or rain because of the heat radiation from these buildings, and it might be dicey to look at analogues at this point because there are underlying variables that are not being taken into account.  Of course the overall planet warming and SSW events have sent pieces of the PV into North America that have and could offset the heat islands.  But this is something that might need to be considered in any event!

[KamuSnow]

^ I did some work on the Innovation Center building....the elevation at the top of the upper cooling towers is about 1020 ft asl (the spire on top is about another 125 ft). It gets pretty windy up there!

[Hurricane Agnes]

2 hours ago, KamuSnow said:

^ I did some work on the Innovation Center building....the elevation at the top of the upper cooling towers is about 1020 ft asl (the spire on top is about another 125 ft). It gets pretty windy up there!

There's also a little Billy Penn statue up there too from what I read when they topped the tower!

[KamuSnow]

21 hours ago, Hurricane Agnes said:

There's also a little Billy Penn statue up there too from what I read when they topped the tower!

Cool, I didn't know that. Does it face northeast like the original?

[Hurricane Agnes]

From the various pics posted of it, it's hard to tell which way it is facing.  It's on a beam associated with some kind of electronics array -

There was some concern that because it wasn't on the very tippy top of the building that it might have been a curse on the Eagles for last year's Super Bowl but obviously where it was placed was good enough!   The earlier Comcast building had a miniature one too when it was first built and topped, and the fall of that year, the Phillies won the World Series.