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

MikJournal Winter 2017/2018 Preview and December Outlook

Yes, I'm a little late to the party. I believe I have an excused absence after some 'extenuating' circumstances last week. But, trying to put last week in the rear view mirror, let's get to the winter preview and a look at what could happen this month.

Let me say I wish I had a trailer, you know, like one of those movie trailers that give you a preview of what's going to happen in the upcoming film. It would be an action-packed sequence of scenes interspersed with quiet, romantic moments, and ending with a cliff hanging, holding-your-breath departing shot, leaving you wondering, "What else could happen next?"

That's the kind of winter we could be looking at. Old Man Winter could be up for best actor in a leading role.

Meteorological winter began December 1. It will run through February 28. These are the months I am primarily addressing during this preview.

As a whole, expect a barrage of weather with nearly all facets on the table. I'm talking about snow, ice, flooding, severe weather. But, what about our region?

Wait a minute. You mean to say some of these things may not affect our region? Yes and no. Remember, historically, Kentucky has proven to be a battleground when it comes to winter weather. I do believe active weather will affect our region.

If we continue to see the Arctic region enjoying relatively calm conditions, high latitude blocking along the west coast and near Greenland, and an increasing subtropical jet thanks to La Nina, Kentucky will be a meeting place for all types of precipitation. While some may see a significant ice storm, others may see a snowstorm we haven't seen in a few years. As the winter progresses, the ups and downs will lead to Appalachian runners and Lake cutters, storm tracks that affect the type of weather we will have.

It's going to be interesting. So, buckle up.

DECEMBER OUTLOOK:

Well, the one thing that stands out is a persistent forecast for below normal temperatures for a good chunk of the first half of the month. In addition, disturbances within the flow may make for some wintry weather here as early as the 8th of this month. This would be followed by a brutal stretch of cold air that could put wind chills below zero for at least a couple of days. But, will the Greenland Block hold?

I have been seeing a consistent signal that says it will be weaker. Now, the ridge in the west looks to hold, so cold air will still have access to the U.S. However, the coldest of the air may slide more north of our area, or we may be brushed with the cold air then moderate shortly afterwards. Now, don't think I'm saying we will go from below zero wind chills to highs in the 50's within a few days. We are likely to see temperatures below average for at least the first half of the month.

So, what happens the second half of the month? It appears that the Arctic Oscillation will trend toward the neutral line, which means there should be a mix of storminess and calm in the Arctic region, keeping the coldest winds where they belong. That would help our temperatures to rebound some.

However, another shot of wintry weather looks to affect the region near or just after the middle of the month. Will that be snow for some and ice for some? It is possible. After another brief shot of cold air, I think the pattern relaxes just a little bit. We may even see temperatures near or even go above normal, what we would probably call a January Thaw, but in December.

Therefore, expect some nuisance snow showers periodically for the first part of the month along with a couple more significant systems. Dress warmly. Snowfall this month may exceed what some saw all of last winter. Hopefully, any icing will be short-lived.

I will try and post my January outlook by the end of this month.

MS