As a reminder a El Nino winter is thought to bring a milder winter with less snow fall.
Last week I took a look at La Nina winters and found that during the more recent La Nina winters (1950 to 2020) here at Grand Rapids the mean temperature was 24.3 and the average mean average snow fall was 76.2” the current 30 year mean here at Grand Rapids the mean temperature for (DJF) is 26.7° and the mean average snow fall is 75.2”. This year I am looking at the El Nino years. According to Stormfax there were 14 El Nino winters between 1900 and 1947. (1900/01.1902/03.1905/06.1911/12.1914/14.1918/19.1923/24.1925/24.1925/26.1930/31.1932/33.1939/40.1941/42.1946/47) Of the early(1900/1947) El Nino winters the mean snow fall was 56.2” and the mean average temperature was 26.7. In the 1900 to 1947 El Nino winters coldest winter was in 1911/12 with a mean of just 20.9° the warmest was the 1918/19 winter with a mean of 31.0. The snowiest was 89.5” in 1925/26 and the least snow was 20.0” reported in the winter of 1905/06. The mean temperature for all winters between 1900 and 1948 was 25.6 and the mean average snow fall in that time was 52.8” so in the years between 1900 and 1947 El Nino years were a little warmer than average with just about as much snow as average.
The later El Nino years can be broken down between weak, moderate, strong, and very strong. I will break the El Nino years down accordingly.
The weak El Nino years as stated in https://ggweather.com/enso/oni.htm there are 12 weak events listed. (1952/53. 1953/54.1958/59. 1969/70. 1976/77. 1977/78. 1979/80. 2004/05. 2006/07. 2014/15. 2018/19 and 2019/20) The mean snow fall for the 12 weak El Nino winters at Grand Rapids is 74.1” with a range of 39.7” in 1952/53 to a high of 104.7” in the winter of 1958/59. The 1950 to 2020 mean snow fall at Grand Rapids is 75.9” The mean DJF temperature at Grand Rapids in the weak El Nino winters is 24.8 and the 70 year mean is 26.3. So the snow fall in a weak event is just 1.8” less then the 70 year average. The mean temperature is 1.5° colder.
Between 1950 and 2020 there are a reported 7 moderate El Nino winters (1951/52. 1963/64. 1968/69. 1986/87. 1994/95. 2002/03. And 2009/10) the mean temperature during the 7 winters is 27.4 (range 22.4 in 2002/03 to 28.3 in 1986/87) and the mean snowfall is 77.7” (range from 132.0 in 1951/52 to 47.6 in 1986/87) now if you take out the record snow fall winter of 1951/52 the mean then falls to 67.6”. But in the long run the winters are a little warmer than average and have more snowfall.
There are a reported 5 strong El Nino winters between 1950 to 2020 (1957/58. 1965/66. 1972/73. 1987/88. And 1991/92.) The mean snow fall in the strong El Nino winters at Grand Rapids is 70.1” with a range of 87.8” in 1991/92 to 65.5” in 1972/73. The mean temperature of the 5 winters is 25.9 with a range of 29.0 in 1991/92 to 24.3 in 1987/88. Once again the mean over the years in not all that far off from the average.
There has been a 3rd category of El Nino winters added and that is the very strong El Nino winters. There have only been 3 such winters since 1950 (really since 1980) and here is where there is a big difference as to how the winter turns out. The very strong winters are (1982/83. 1997/98 and 2015/16) All three winters were mile and had much less snow fall then average. The mean snow fall was just 53.3” (35.9” in 1982/83. 59.8” in 1997/98 and 61.1” in 2015/16) and the mean temperature was a mild 31.5° with 31.5 being the average in 1997/98 and 2015/16 and 31.6 in 1982/83.
So it looks like for most winters a good starting point is for guess “near average” and with a small sample size one could say mild with less snow for a strong El Nino winter.