As we stare down an unseasonably cold start to the spring season the mood here in Billings seems to be one of frustration at the lack of change in the seasons. Here in the Q2 weather center the sentiment is much the same. We are ready for spring! And the numbers tell us it is usually here by now.
To give a little context into just how unusual our weather has been of late I dug into the some of the historical weather data taken from the observations made at Billings Logan International Airport.
I looked at the data for the first seven days of April going back for a period of five years, 2013-2017. I then compared the findings to our observed conditions for the first four days of the month and our forecasted conditions for the rest of the week.
The long term average for the daily high temperature here in Billings over the first week of April is right around 54 degrees. These averages are established over 30 year periods and while they do a good job of showing roughly what conditions to expect, they rarely predict what we will see on a given day. That is where some of the more specific observations come into play.
Starting with temperature we can see some pretty drastic differences in the historical pattern and what we have been living through here in 2018. In the five year period from 2013-17 we observed a total of three days where daily high temperatures were less than 40 degrees. In the first week of this year we have already had two such days and are forecasting another two this week. If this plays out we will eclipse the total number of sub 40 degree days seen in the last five years in the first week of April in our first week of April 2018.
In this same time period, there have been 9 days where the daily high temperature was great than 65 degrees. That represents 26 percent of days in the first week of April over the last 5 years. We have not had anything even approaching a 65 degree day here this week and are not forecasting for anything in that range.
Now let’s talk about daily low temperatures. In the five year period I looked at, the coldest overnight low temperature was 21 degrees. That happened back on April 1, 2014. Here in the first week of April we have already had two nights where the temperatures dipped into the single digits. In other words, we have already had two nights this week that were about 15 degrees colder than any low temperature observed in the first week of April in the last 5 years. So if you have been thinking to yourself that it has been colder than April than any in recent memory, you would be correct!
As far as snowfall is concerned, we again find ourselves on the wintry side of recent history. The observed snow depth across the days in my sample topped out at “trace” and was consistently zero inches. The official measurement from Billings Logan International Airport was 1.2 inches of snow on Sunday night and 7.4 inches of snow throughout the day on Monday. The Monday snowfall broke an all time daily record for snowfall on April 2. The previous record was 4.6 inches set all the way back in 1940. Amongst the last five years the highest daily snowfall total in the first week of April was only half an inch.
For those of you who are questioning why exactly we appear to have been cursed with a never ending winter this year, there is one reason that is being offered up as the cause of our unseasonably cool weather.
Without getting into too many details that only weather nerds like me care about, I will try tell you a little bit about the situation. There is a large scale pressure fluctuation called the North Atlantic Oscillation (NAO). This is basically the broad scale pattern of the pressure over a portion of the North Atlantic. The reason this is important is because the state of the NAO influences the pattern of the Jet Stream over North America. The current state of the NAO is such that it forces the Jet Stream to plunge south over central North America. This allows polar air from northern Canada to make its way much further south than it normally would at this time of the year. This in turn leads to the much colder temperatures we have been observing.
This is a large scale pattern, which means that we here in Montana have not been suffering through a chilly spring alone. If there is any upside to the situation, it is that we are not specifically having a bad spring while everyone else enjoys balmy conditions. Temperatures have been well below average for much of the East Coast and the Midwest as well.
The forecast for the short term is for more of the same. We can expect cool temperatures this week with a good chance for more snowfall over the next couple days.