November 2014 – Illinois State Climatologist

November 21, 2014

Friday Wrapup – Illinois Very Cold and Dry in November

So far, November has been much colder and drier than average. The statewide average temperature is 34.6 degrees, which is 9 degrees below average.

The statewide average precipitation (rainfall + water content of snow) was only 0.6 inches, about a third of the average through this date.

There have been astounding snowfall totals in places like Buffalo, NY, and some significant snowfall in Minnesota and Wisconsin. However, Illinois and most of the surrounding states have had far less snowfall (first map) in November. Many sites in the state had 1 to 2 inches except for a stretch between Quincy and Chicago with less than an inch.

The modest snowfall totals in November so far are not that unusual. Average snowfall totals for the month are generally less than an inch south of I-80 and about 1 to 2 inches north of I-80 (second map).

November 20, 2014

Latest Outlook for Winter in the US

Today the NOAA Climate Prediction Center released their latest winter forecast. First, there are two important notes about the winter forecast. One is that El Niño has not arrived yet, and if it does, it is expected to be mild.

The other point is that the current conditions are not always a reliable predictor of future conditions. In other words, just because we are having a cold November (9 degrees below average), that does not doom us to another cold winter. To give a recent example, November of 2012 was 1.3 degrees below average, while the following winter of 2012-13 was 3.0 degrees above average.

The first panel shows the temperature odds for December-February, our core winter months. Southern Illinois has a slightly elevated chance of colder-than-average temperatures as does most of the southern states. There is a stronger chance that temperatures will be above-average on the West Coast and Alaska.

The second panel shows the precipitation odds for winter. The outstanding feature for us is the large area around the Great Lakes with an increased chance of being drier-than-average that covers all of Illinois.

November 19, 2014

Cold Week for the US

It has been a very cold week in the US with temperature departures in the central US at 15 to 25 degrees below average. Yesterday, Champaign-Urbana was 26 degrees below average for the date and just 2 degrees shy of the record low of 6 degrees set back in 1891.

Here is the temperature departure for today from the site Climate Reanalyzer showing the bitterly cold temperatures in the eastern half of the US, while once again Alaska is well above average. We saw this pattern most of last winter, starting in late November.

Here is the plot of the jet stream (high winds at upper levels of the atmosphere – shaded in yellow and red) showing its dip down into the southern US. That means we pretty much have an open door to cold Arctic air in the Midwest.

November 17, 2014

Cold and Snowy November in Illinois

Here is the scene out my backdoor last night, not just frost on the pumpkin but real snow. And the poor annuals in the flower-pot are done.

As of this morning we had 0.5 inches of snow in Champaign-Urbana. The snow over this weekend was widespread across Illinois but heaviest in the far north and far south (map below). In fact, the heaviest amounts were in southern and eastern Illinois and included Shawneetown with 4.0 inches, Newton with 3.1 inches, and Beecher City, Paris, and Salem all with 3.0 inches. Nationally, 50 percent of the US is covered in snow this morning (second map). The statewide average temperature for Illinois for November is 37.7 degrees, 6.5 degrees below average. Both Chicago and Rockford have experienced 5 days in a row with temperatures not rising above freezing. And the National Weather Service forecasts for today and Tuesday show that highs will stay in the teens in northern Illinois and in the 20’s in central and southern Illinois. Those are temperatures more typical of January than November. Temperatures are expected to slowly warm up towards the weekend.

nsm_depth_2014111705_National — Fifty percent of the lower 48 states covered in snow.