Summary: January in Illinois finished out at 26.7 degrees, 0.3 degrees above average. Both precipitation and snowfall were below average. The statewide average precipitation (rain plus water content of snow) was 0.85 inches, 1.22 inches below average. Snowfall was below average across most of the state.
The temperatures in January in Illinois showed some very large swings that tended to cancel each other out in the end since we finished 0.3 degrees above average. The first 9 days were above average, followed by 4 days below average, then 3 days above average. The second half of January started out much below average, but steadily warmed and by the end of the month was 20 degrees above average.
While the magnitude of the swings were impressive, the pattern of warm and cold stretches is typical of winter in Illinois and represents the passage of warm and cold fronts across the region. Because it may take a day or more for a system to pass through Illinois, the dates and size of the temperature departures at a particular station may not correspond to the statewide numbers, especially in far southern Illinois.
The January precipitation (left) and departures from average (right) show that precipitation was uniformly light across Illinois, just under an inch in most places (light green) and just over an inch below average (shades of yellow).
The January snowfall (left) ranged from 2 to 5 inches in most locations. Western Illinois saw 5 to 7.5 inches. However, as the panel on the right indicates most of Illinois received below-average snowfall (shades of beige and yellows).
In an earlier post we examined the NWS Climate Prediction Center forecasts through next summer that included the statement, “Illinois has a higher risk of being both warmer and drier than average through mid-summer. There is an increased risk of being warmer than average in late summer and in fall.”
Taken at face value, the NWS forecast would suggest that we have an increased risk of drought this year. Six months of warmer and drier weather can certainly do that.
However, the key factors in this forecast will be how the El Niño winds down and if La Niña shows up. The chart below is the forecast showing the odds for how things may play out in 2016. The red bar represents the odds of El Niño. The odds are now at 100% and slowly decreased for the next several 3-month time frames. By May-June-July (MJJ), there is only a 40 percent that El Niño will still be around. At that same time, there is an almost 50 percent chance that we will return to average or “neutral” conditions (green bar).
In the meantime, there is a small, but increasing chance that La Niña could appear (blue bar) and the odds reach 40 percent in August-September-October. Take my word for it, you don’t want La Niña showing up. In Illinois we have a pattern of warmer and drier conditions in the critical July-August time frame during La Niña. A return to neutral conditions is more favorable with near-average conditions in July and August.
Another thing to consider is that El Niño and La Niña are not the only two players in town. Indeed, other weather patterns can overwhelm the influence of these two. For example, we have had several springs in recent years with short periods of a very active storm pattern, resulting in very wet conditions.
What does history tell us?
The NOAA Climate Prediction Center (CPC) released their seasonal outlooks today. Illinois has a higher risk of being both warmer and drier than average through mid-summer. There is an increased risk of being warmer than average in late summer and in fall.
CPC also stated in a January 14 release that the “strong El Niño is expected to gradually weaken through spring 2016, and transition to ENSO-neutral during late spring or early summer.”
In addition, there is a chance that La Niña conditions (the opposite of El Niño) could develop in the summer or fall time frame. Unfortunately, the appearance of La Niña in summer or fall in Illinois typically means hot, dry weather. I will discuss this more in a separate post.
This is the first time I can remember CPC forecasting an increased risk of warmer and drier conditions so far out for Illinois. If the forecast comes to pass, this could be a challenging summer.
February: Illinois has an increased risk of being both warmer and drier than average.
February – April: Illinois has an increased risk of being both warmer and drier than average.
May – July: Illinois has an increased risk of being both warmer and drier than average.
August – October: Illinois has an increased risk of being warmer than average. No forecast on precipitation.
The National Centers for Environmental Information (NCEI) reported that the US experienced the second warmest and third wettest year on record, based on records going back to 1895.
What is amazing to me is that all of the lower 48 states were warmer than average. From the report …
The 2015 annual average U.S. temperature was 54.4°F, 2.4°F above the 20th century average, the second warmest year on record. Only 2012 was warmer for the U.S. with an average temperature of 55.3°F.
Here is what US temperatures look like over time. While the linear trend is 1.4 degrees over the last century, the pattern is more complex with much cooler temperatures in the early 20th century, followed by warming in the 30s and 40s, before cooling slightly in the 60s and 70s, and then warming since the 1980s.
Annual temperature for the US from 1895 to 2015. The blue line is a linear trend showing a 14 degree warming over the last century. Plot courtesy of NCEI.
The old statistical joke is that a person with one foot in the fire and one foot in a bucket of icewater feels comfortable – on average. That describes Illinois for January. In round numbers, the first 9 days were 7 degrees above average. The next five days were 6 degrees below average. So we are a little warmer than average for the month, but you wouldn’t know from this week’s weather. Here is how it looks in a chart:
According to the National Weather Service, the cold weather will continue through the middle of next week before warming. Here are the forecasted lows for Monday, showing the lows dropping below zero for northern and central Illinois, and in the single digits for southern Illinois. That will probably be the coldest morning of the week.
So far this winter, central and southern Illinois have seen little or no snow. Here are the totals through January 6 for this winter. Areas north of I-80 have seen amounts in the 10-15 inch range, which is close to average. However, the snowfall totals drop off dramatically southward with much of central Illinois reporting only 1 to 4 inches. And south of Interstate 70 no measurable snow has been reported so far this winter.
Here is the snowfall departure map for the same period. Far northern Illinois is in green, meaning that they are at, or slightly above, average on snowfall. Areas in the light beige are up to 2.5 inches below average; areas in yellow are between 2.5 and 5 inches below average; and areas in the darker yellow or orange are 5 to 7.5 inches below average.
Why are the snowfall totals so low? Thanks to the El Niño pattern, warmer-than-average temperatures in November and December meant that most precipitation fell as rain rather than snow. We have seen this tendency for below-average snowfall in several past El Niño events.
A recent Champaign-Urbana News-Gazette story outlined the impacts of the nearly snowless winter – money saved by the cities from lower salt usage and snow plowing, no school closings, easier road maintenance. On the other hand, the sale of shovels, snow blowers, and winter clothing have all suffered.
And if you really miss the snow, just think back to this time in the winter of 2013-14 when we had already experienced several winter storms and a visit from our friend, Polar Vortex. At this point in that winter, much of central and northern Illinois had received 20 to 30 inches of snow (dark green), while the rest of the state had received 15 to 20 inches of snow.
Illinois experienced record or near-record conditions in 2015. Here is the breakdown by category. Overall, Illinois started out 2015 on the cold side but finished with the warmest December on record. However, to me the outstanding feature of 2015 was the wet weather with the wettest June, second wettest December, and sixth wettest year on record.
- The warmest December on record: 40.6 degrees, 10.7 degrees above average.
- The second warmest September – December on record: 53.2 degrees, 4.9 degrees above average.
- The 8th coldest February on record: 19.4 degrees, 11.5 degrees below average.
- Annual: 52.8 degrees, 0.4 degrees above average (not ranked, but of interest)
- The second wettest December on record: 6.70 inches, 4.01 inches above average.
- The wettest November-December on record: 12.30 inches, 6.15 inches above average.
- The wettest June on record: 9.44 inches, 5.23 inches above average.
- The 6th wettest year on record: 48.49 inches, 8.53 inches above average.
Statewide records go back to 1895.