November was a busy month for me and so ridiculously warm (as was all of fall) that I haven’t though much about the upcoming winter. But with our first measurable snow forecasted for this weekend, I finally was inspired to take a look!
Climate-Temperatures: Indiana Winters have become warmer over time, but the last few years have been highly variable with some extremely warm or cold winters occurring in the past 5 seasons (2013-2014 was the coldest winter in about 30 years!).
Climate-Snow: Indianapolis averages 22.0″ of snow during winter (Dec-Jan-Feb) but last year just under 11″ fell. That was down from 2014-2015 (17.0″) and much lower than the record 52.2″ from 2013-14. 2009-10 and 2010-11 were also among the top 10% of snowiest winters, but you can see on the above chart that 2009-10 was not all that cold, and there lies part of the challenge with snow — it depends on both the overall precipitation amounts (dry = less snow) and the air temperatures at time of precipitation. A cold but dry winter could be less snowy than a warm and wet one if most precipitation falls during cold periods.
Teleconnections: These are large circulation patterns such as El Nino (warm temperatures in the Equatorial Pacific) or the North Atlantic Oscillation (pressure patterns). El Nino is pretty far away and tends to only matter if it’s strong, like last year. This year a weak La Nina (cooler than average temperatures) is forecasted. A weak La Nina is useless as a predictor. How about the NAO? A negative NAO typically causes cold weather in the eastern U.S., but this index can vary weekly, even daily, and predicting it on a seasonal basis is hard. So teleconnections aren’t very helpful in this case.
Climate Prediction Center: As you might expect, given the lack of strong signals they are hedging their bets and going with “equal chances” of above, below, or near normal temperatures for Indiana. They are also predicting above average precipitation.
Summary: Given the large variability we’ve seen in recent winters and lack of strong signals, this winter is challenging to predict. Simple averaging of recent years suggests slightly warmer than average temperatures, but we haven’t experienced “near normal” temperatures since 2007-2008! So I could see almost any scenario — thus I’ll default to the long term average temperature for winter: 30.5 degrees Fahrenheit.
Precipitation: If we assume that precipitation will be above average, it stands to reason that snowfall is likely to be above average. This is because temperatures that are either near normal or below normal would both cause above average snowfall, while only warmer than average temperatures would lead to below average snowfall. So, I’ll predict 30-35″ for the season with one notable (>6″) storm likely.
Even if my forecast is wrong, as long as I get to go sledding with my kids this year (last year we couldn’t even do that!), I’ll be happy! Otherwise, we might have to take a family vacation to White Sands National Monument in New Mexico, where I went sledding last May.