Philly: Winter 2005-06 Snowfall Is Not Finished

[donsutherland1]

As Winter 2005-06 continues its temporary hibernation—or at least I strongly believe it will prove temporary—let’s take a closer look with respect to whether accumulating snow will return to Philadelphia.

In this sample, I took a look at January 1-15 snowfall, January 16-31 snowfall, February 1-15 snowfall, snowfall after February 15, and snowfall after January 15 for Winters 1948-49 through 2004-05. That’s 57 winters.

The baseline for the entire sample follows:

January 1-15: Median snowfall: 1.7”; Mean snowfall: 3.3”
January 16-31: Median snowfall: 1.7”; Mean snowfall: 3.5”
February 1-15: Median snowfall: 1.5”; Mean snowfall: 4.1”
After February 15: Median snowfall: 6.1”; Mean snowfall: 6.5”
After January 15: Median snowfall: 11.8”; Mean snowfall: 14.1”

The frequency of the following total amounts occurring was:

January 16-31:
2” or more: 49%
4” or more: 25%
6” or more: 18%

February 1-15:
2” or more: 47%
4” or more: 33%
6” or more: 28%

After February 15:
2” or more: 74%
4” or more: 65%
6” or more: 53%

After January 15:
20” or more: 25%
Less than 10”: 37%

Barring some dramatic changes in the computer guidance, it appears that the January 1-15 period will see less than 1” snowfall in Philadelphia. Beginning with Winter 1948-49, there were 23 such occurrences. Here’s how the rest of winter fared in terms of snowfall during those seasons:

January 1-15: Median snowfall: 0.0”; Mean snowfall: 0.2”
January 16-31: Median snowfall: 3.1”; Mean snowfall: 4.4”
February 1-15: Median snowfall: 1.4”; Mean snowfall: 4.6”
After February 15: Median snowfall: 4.8”; Mean snowfall: 5.2”
After January 15: Median snowfall: 12.6”; Mean snowfall: 14.6”

The frequency of the following total amounts occurring was:

January 16-31:
2” or more: 61%
4” or more: 30%
6” or more: 26%
Most: 16.0”, 1966

February 1-15:
2” or more: 48%
4” or more: 35%
6” or more: 30%
Most: 26.1”, 1983

After February 15:
2” or more: 65%
4” or more: 57%
6” or more: 39%
Most: 13.9”, 1960

After January 15:
20” or more: 35%
Less than 10”: 35%
Most: 31.1”, 1983

Conclusions:
∙ Lack of snowfall in the January 1-15 period does not mean an elevated risk of less than normal snowfall for the remainder of winter.
∙ Years in which < 1” snow fell in the January 1-15 period had a somewhat higher than normal frequency of picking up a total of 6” or more snowfall in the second half of January (26% vs. the baseline figure of 18%).
∙ Years in which < 1” snow fell in the January 1-15 period had a somewhat higher than normal frequency of picking up 20” or more snowfall for the remainder of winter (35% vs. the baseline figure of 25%)

Additional Notes:
∙ 10 winters saw 6” or more total snowfall in the January 1-15 period.
∙ Winters that saw 6” or more snow fall during the January 1-15 period, saw less than 10” of snow after January 15 in 50% cases and 20” or more snowfall after January 15 in 10% cases.
∙ Winters that saw 6” or more snow fall during the January 1-15 period saw no instances of 6” or more total snowfall in the January 16-31 period.
∙ Winters that saw 6” or more snow fall during the January 1-15 saw 6” or more snow accumulate after February 15 in 60% cases.

[angelwing]

Crossing fingers for the white stuff!

[iwantsnow321]

Thanks for keeping my hopes up.

[donsutherland1]

From my opening post in this thread, it is clear that I expect that Philadelphia will see additional accumulating snow this winter. My thinking remains unchanged with the idea that PHL will pick up 20"-30" for the 2005-06 season.

Having said that, the current pattern has created some pessimism. Now let's turn the calendar ahead and let's say January 15 passes and Philadelphia has still not received any snow. Then, the blaze of pessimism could well be raging out of control.

But would there still be some hope?

Philly's Greatest Comebacks following 0.0" Snowfall in the January 1-15 Period:

January 16-31 Snowfall:
1966: 16.0"
2005: 15.6" (that's last year; surely, it hasn't been forgotten, has it?)
2000: 13.7"

But what if PHL still picks up less than 1" of snow in the January 16-31 period?

February 1-15 Snowfall:
1983: January 1-15: 0.0"; January 16-31: 0.2"; February 1-15: 26.1"
1967: January 1-15: 0.0"; January 16-31: 0.6"; February 1-15: 14.0"
1995: January 1-15: 0.0"; January 16-31: 0.0"; February 1-15: 9.5"

And, if one is looking for a "miracle," 1960 is one such year:

January 1-15: 0.4"
January 16-31: 0.4"
February 1-15: 1.4"
February 16-29: 1.7"
March 1-15: 9.6"

For now, one can only wait. While one waits, it's a good time to look back a decade ago. Then, the Blizzard of 1996 was beginning to climb the East Coast with its blinding snows.

[Stephanie]

I have a feeling that we're going to pay for the relatively calm and warm weather we've been having so far.

Thanks for the stats!

[donsutherland1]

You're welcome, Stephanie.

I'm sure that's the kind of "payback" many would look forward to.