Monday, December 25, 2017

MikJournal Monday 12/25/2017...Winter's Past vs. Winter's Present

Good Monday morning. Many people are spending time with families today. I will be working later, since this is still a busy time of year where I work.

Well, I have snow on the ground this morning. It only amounted to about 0.1". But, that is my first measurable snowfall of the season.

That got me thinking. How harsh and how snowy have the winters of this century compare to the winters of decades ago? I did some research and came up with some interesting statistics.

Let's start with the 2000's. Since 2000, here in Louisville, it has snowed every day of meteorological winter. That's right. At least a trace of snow has been reported for every date of December 1 through February 28 (29 for leap years).

The next statistic is maximum snow depth for any given day. During the 2000's, the most snow on the ground at any one time in Louisville was 10" on March 5, 2015. The next closest maximum was 8" on December 23, 2004.

What about the coldest temperatures during the 2000's here in Louisville? I counted 6 days when the temperature was below zero. The coldest reading was -6 degrees on February 20, 2015.

So, here is your summary:

Louisville (2000's):
Days of snow during Met Winter: all
Max snow depth: 10"
# of times below zero: 6
Coldest Reading: -6

Louisville (1980-1999):
Days of snow during Met Winter: all but February 19
Max snow depth: 18"
# of times below zero: 25
Coldest Reading: -22
 
Louisville (1960-1979):
Days of snow during Met Winter: all
Max snow depth: 18"
# of times below zero: 37
Coldest Reading: -20

Here is a summary of total snowfall for the same periods for Louisville:
2000's -       255.1"
1980-1999: 269.7"
1960-1979: 439.5"
(based on snow season (Jul-Jun) beginning 1959/1960)

Of course, the current time period will not end until December 2019. So, there is still quite a bit of winter left, but it is safe to say that the period of the 60's through the 90's have been much colder than the 2000's, at least here in Louisville. I have also shown that the period ending with the 70's was colder and snowier than even the 80's until present.

Could this be an example of climate change or Louisville's increasing heat island effect? I cannot verify that one. However, I can use another example. Let's try Lexington, who does not have as much of a heat island effect, though that seems debatable anymore.

Using the same criteria as above....

Lexington (2000's):
Days of snow through Met Winter: all
Max snow depth: 12"
# of times below zero: 14
Coldest Reading: -18

Lexington (1980-1999):
Days of snow through Met Winter: all but December 5
Max snow depth: 17"
# of times below zero: 35
Coldest Reading: -20

Lexington (1960-1979):
Days of snow through Met Winter: all
Max snow depth: 14"
# of times below zero: 61
Coldest Reading: -21

Summary of total snowfall for Lexington:
2000's -       256.5"
1980-1999: 275.9"
1960-1979: 423.5"

So, I still have to say that the 60's and 70's were a much colder and snowier period than today. Although the 80's and 90's were colder than today, snowfall amounts are about the same by the time you prorate the amounts.

In conclusion, we are living in warmer times, as characterized by the year end global reports. Yes, it's not just here. But, we are seeing much more volatile, extreme weather events as well. So, don't be fooled by a year of not much snowfall. It has happened in the past. Some years would see 3 or 4" only to be hammered by 20-30"+ amounts the next year. Expect to see more of that kind of weather and climate in the years to come.

Have a good week everyone. Snow chances are elevated. So, enjoy it.

MS


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