Based on preliminary numbers*, the statewide average precipitation for October in Illinois was 4.5 inches, which is 1.2 inches above average. It was the 15th wettest October since 1895. The wettest October on record for the state was 1941 with 9.06 inches of precipitation.
The largest precipitation totals were in the central third of the state where 6 to 8 inches were common. Greenfield had an incredible 9.94 inches of precipitation. Medora, Girard, and Carlinville also reported over 9 inches of precipitation. Precipitation totals were more moderate elsewhere; 4 to 6 inches in southern Illinois and 2 to 4 inches in northern Illinois. Also, several locations in northeast Illinois reported seeing traces of snow for the month.
The statewide average temperature was 54.0 degrees, 0.1 degrees below average.
*I updated these numbers on November 2 with only a 0.2 degree change in temperature from 54.2 to 54.0 degrees.
MAPS AND PLOTS FOR OCTOBER
The plot of past October precipitation for Illinois (below) shows that things have become slightly wetter over time, about 0.64 inches in the last century. The outstanding October’s of 1941 and 2009 are easily seen as well.
Probably the most frequently asked question I get these days is “Will this winter be as bad as last winter?” I discussed this a bit in an earlier post. The National Weather Service forecast does not show a repeat of last winter based in part on winter trends and the possible arrival of El Niño.
Another way to look at this is through the historical data. I looked at the 20 coldest winters for Illinois since 1895 and what the next winter was like (table below). “Temp” is short for temperature and “depart” is short for temperature departure from average.
Since this last winter was #9, that leaves us with 19 other winters where we can look at the next year. Of those 10 of the following winters were below average. In fact, we see the three-peat winters of 1976-77, 1977-78, and 1978-79 in the line up as well as the repeat winters of 1903-04, and 1904-05.
Or if you are an optimist, 9 of the following winters were at or above average. If you look at the plot below the table, you can see that with the exception of the late 1970s and the early 1900 episodes, our colder winters have been followed by a winter more moderate – maybe not warm but at least not as cold. Also we have seen a warming trend of about 1ºF in the historical record. For the record, I’m hoping for a milder winter.
Top 20 coldest winters (December-February) and the following winters.
So far, we have had 30 tornado reports in Illinois for 2014*, according to initial reports from the NOAA Storm Prediction Center. Nearly half of those were from the tornado outbreak of February 20th. Our five-year average is 59.
*Of course, 2013 was a quiet year until the November 17th outbreak that struck Illinois.
Normally, our core tornado season is March-June with about two-thirds of our tornadoes occurring then. This year was very quite during that period, I think in part due to the colder spring weather. Here is the tornado count by month:
Here are the event reports from the National Climatic Data Center through the end of July. This database contains some edits to the initial data from the Storm Prediction Center so the totals may not line up between the two sources. You can recreate this report with working links to each event at: http://www.ncdc.noaa.gov/stormevents/
US Tornado Statistics
Here is the distribution of the tornadoes for 2014 and the graph of accumulated tornado totals by year for the past 10 years, according to the NOAA Storm Prediction Center. Right now the national count is 998 tornadoes, which is below the ~1300 average through this date. The number of tornado-related deaths this year is 45, compared to 55 in 2013 and 70 in 2012.
Here are the patterns of precipitation and temperature departures across the Corn Belt for October so far. The eastern half of the Corn Belt experienced both wetter and cooler than average conditions for the month. Meanwhile, the western Corn Belt was both drier and warmer than average.
Today the NWS Climate Prediction Center has released their latest outlook for November and this winter. Below are the maps for November temperature, November precipitation, December-February temperature, and December-February precipitation.
For Illinois, November temperatures have equal chances (EC) of being above, below, or near-average. November precipitation is rated as EC except for the northeast quarter of the state, which has an increased chance of below-average precipitation. This is part of a larger area with increased chances of below-average precipitation across the Great Lakes region.
The category of EC is a little hard to interpret. Basically, it means that there are no consistent indications that conditions could be too warm/cold/wet/dry. Sometimes I call it a neutral forecast.
For December-February, the traditional winter months, Illinois has equal chances (EC) of above, below, and near-average temperatures. However, Illinois has an increased chance of below-average precipitation.
NOAA has released a new 2-page fact sheet on El Niño and the Midwest (links below). Several people in the Midwest had input into this, including myself. El Niño typically results in warmer and drier than average winters. Confidence in these patterns is higher during stronger El Niño events.
Right now the NOAA Climate Prediction Center states that El Niño is favored to begin in the next 1-2 months and last into spring of 2015. The current thinking is that the odds are 2-in-3 in favor of it arriving and that the event will likely remain weak throughout its duration.
The statewide average temperature for October so far in Illinois is 56.5 degrees, 1.4 degrees below average. The statewide average precipitation for October so far is 2.5 inches.
Here is the map showing how the precipitation has fallen in Illinois and surrounding states. The heaviest amounts in Illinois were the 3 to 5 inches between Interstates 70 and 74. Amounts of 1 to 3 inches were common in the northern and southern thirds of the state. The largest total so far is 8.38 inches reported at Greenfield in Greene County
Traces of snow were reported in Chicago and Rockford on October 4. A few years ago I did a post on the earliest and median dates for the first measurable snowfall of the season. Measurable means at least 0.1 inches or more. Snow flurries or traces of snow do not count since they have not been tracked closely in the historical weather records.
No real surprises for anyone who has experienced winter in Illinois. The earliest dates of measurable snow are in the late October, early November time frame. And the median dates range from late November in northern Illinois to the second half of December in southern Illinois. Even so, the dates can vary considerably between nearby sites since many of the early season snows are sporadic and not very widespread.
Here are the monthly temperature and precipitation departures for 2014. September joins January, February, March, and July as much cooler than average months. For precipitation, we noted last month that we were regularly alternating between wetter- and drier-than-average months in 2014. That changed in September with two months in a row of wetter-than-average conditions.
October is off to a wet start and the wet weather is expected to continue over the next 14 days for Illinois. This could have an impact on the already slow fall harvest season in Illinois. The USDA NASS report on Monday noted that 14% of the corn crop in Illinois was harvested, compared to a 5-year average of 34%. Also, 10% of the soybean crop was harvested compared to the 5-year average of 18%.
Here is the precipitation over the past 24 hours. Amounts of 1 to 3 inches were widespread across central Illinois. This was the same area that received much above average precipitation in September, according to the post on September.