It should be no surprise that this winter was one of the mildest on record for Illinois. “Winter” refers to the three key months of December, January, and February. This year the average winter temperature was 34.2 degrees, 5.2 degrees above normal, and the third warmest winter on record. Here are the top four warmest winters. As you can see, we had a two-way tie for second place.
First place, the winter of 1931-32 at 37.1 degrees;
Second place, a tie between 1997-98 and 2001-02 at 34.5 degrees;
Third place, this winter at 34.2 degrees.
Not only was it warm in terms of the average temperatures, but this winter lacked the really cold weather. Only a few place had temperatures drop below zero. The coldest reading for the winter was a mere -6 degrees at both Galena and Elizabeth in the far northwestern corner of the state.
Winter – Precipitation
The statewide average precipitation for winter was 6.73 inches, just 0.24 inches below normal. Much of that precipitation fell as rain and not snow. Snowfall totals were 50 to 75 percent of normal across much of northern Illinois and 25 to 50 percent of normal in central and southern Illinois. The snowiest spot in the state through the end of February was Woodstock with 27.9 inches, followed closely by Stockton with 27.6 inches and Mt. Carroll with 27.3 inches.
The statewide average temperature for February was 35.1 degrees, 4.6 degrees above average. The statewide average precipitation was 1.55 inches, 0.4 inches below normal. Snowfall ranged from less than an inch in southern Illinois to 3 inches in central Illinois. It was a little snowier in the northern third of the state with amounts ranging from 3 to 8 inches.
The statewide records go back to 1895.
In a news release yesterday, we reported that this December/January was the 6th warmest on record. Here are the other years in the top ten list. The list includes the average temperature of the two months combined and the year for January.
36.8° F in 1932
34.7° F in 2002
33.8° F in 1950
33.55° F in 1934
33.45° F in 1933 and 1983
33.4° F in 2012
32.7° F in 1989 and 2007
32.5° F in 1960 and 1992
32.3° F in 1941
32.1° F in 1939
Remember last winter, the evil twin of this winter? The average temperature of that December/January was 23.2° F. That is 10.2° colder than this winter and was the 10th coldest on record.
NOAA has revised their winter outlook for the U.S, according to a recent post on their ClimateWatch Magazine. An earlier outlook had northern Illinois with chances of well below normal temperatures. The new outlook (below) has pulled the colder outlook out of Illinois as well as expanded the area in the southern half of Illinois with an increased chance of above normal temperatures. So overall, a milder winter is expected in terms of temperatures.
The precipitation outlook for this winter remains unchanged for Illinois. Most of the state, except for far western Illinois, has an increased chance of above normal precipitation. Unfortunately, NOAA does not do a snowfall forecast. Research indicates that the Great Lakes region has better chances for above normal snowfall during past La Niña events. However, the weaker than expected La Niña event this winter and the slow start to the snowfall season suggest that the pattern of increased snowfall during La Niña winters may not pan out this year.
The winter outlook covers the period of December-February, the heart of the winter weather season in most of the U.S.
For the second winter in a row, La Niña will influence weather patterns across the country, but as usual, it’s not the only climate factor at play. The ‘wild card’ is the lesser-known and less predictable Arctic Oscillation that could produce dramatic short-term swings in temperatures this winter.
Overall, northern Illinois is expected to have increased odds of being colder and snowier than normal – similar to last year. Here are the details. Below the forecast is a refresher on the winter of 2010-2011 that we all knew and loved.
For Illinois, the northern third of the state is expected to have an increased chance of below-normal temperatures. The southern two-thirds of the state has equal chances of above, below, or near-normal temperatures.
Almost all the state, except for far western Illinois, is expected to have an increased chance of above-normal precipitation. Far western Illinois has equal chances of above, below, or near-normal temperatures. Although NOAA does not offer a winter snowfall forecast, increased precipitation in the winter months usually means increased snowfall.
Winter of 2010-2011
Here are the temperature map and snowfall map for the Midwest for the winter of December 2010 to February 2011. Both maps are expressed as departures from the 1971-2000 averages. The winter was both colder and snowier than average across the Midwest. Meanwhile, precipitation (rainfall and the water content of snow) was right at average for the winter.