When I give talks on climate and climate change, I often get questions about volcanoes and their impact on our climate. The Washington Post had a recent article on the subject, mentioning the famous eruption of Tambora in 1815, which in 1816 led to the year without a summer in the eastern US. It probably had impacts on Illinois but we had no widespread observations in place at the time.
Climate.gov just posted an interesting video on Charles David Keeling and his ground-breaking measurements of CO2 levels in the atmosphere. The observatory was located on Mauna Loa, on top of the second highest peak in the Hawaiian Islands.
The idea behind the site was to keep it far removed from any nearby sources of CO2 resulting from human activity. Because of it’s location and longevity, it is our best measurement of the background CO2 levels in the lower atmosphere. Here is the link to the Mauna Loa Observatory records and trends.
Dr. Keeling received his undergraduate degree here at the University of Illinois in 1948 and his Ph.D. in Chemistry at Northwestern in 1954. There is a brief bio here.
Here are maps showing how April so far has been warmer and wetter than average across Illinois and the Midwest.
Temperature Departure from Average
Right now, most of the eastern two-thirds of the United States have experienced above-average temperatures for April (first map). The Midwest has been 1 to 6 degrees above-average, depending on the shade of orange (second map). Click on any map to enlarge.
In the near-future, the 6-10 and 8-14 day forecast indicate that colder-than-average conditions will prevail for the next two weeks. For precipitation, there is an increased chance of drier-than-average conditions in parts of northern Illinois for the next two weeks.
There is not a lot to report for Illinois at the medium range. We are in equal chances (EC) for above-, below-, and near-average temperature and precipitation for both May and the 3-month period of May-July.
According to the National Weather Service report on the April 9, 2015, tornadoes, the tornado that tracked through Fairdale was rated EF-4 on the Enhanced Fujita scale. This would be the first EF-4 tornado in April since 1981 for Illinois and only the 33rd in Illinois history, regardless of month, since reliable records began in 1950.
According to the NWS Storm Prediction Center database, only 33 F/EF-4 tornadoes have struck Illinois since 1950. Even more rare, only 8 have hit Illinois in April. Of those eight in April, six struck in the 1960s, one in 1981, and one in 2015:
Here are all the F/EF-4 tracks for Illinois from 1950-2014, from the MRCC tornado tracker tool. Unfortunately, we cannot screen out just the April events at this time. While this is a screenshot of the tool, the actual tool allows you to zoom in and out. If you point to a track then you get a pop up window with the details of that track. Check out the tornado tracker tool – it’s free.
Today is the 62nd anniversary of the first documented case of a tornado detected by radar. Illinois State Water Survey staff, at Willard Airport in Champaign, IL, captured the historic event on film on April 9, 1953. This discovery helped lead to the first national weather radar network in the United States.
First recorded radar hook echo associated with a tornado, April 9, 1953, near Champaign, IL. The radar was located to the south of Champaign-Urbana at Willard Airport. The tornado was located north of Champaign-Urbana. Photo by Illinois State Water Survey, Prairie Research Institute, University of Illinois.
The statewide average temperature for March was 38.2 degrees, 3.1 degrees below average. This follows on the heels of a slightly colder-than-average January and much colder-than-average February. As a result, the year-to-date temperature for Illinois was 27.8 degrees, 5.1 degrees below average and the 16th coldest on record. In comparison, the same period in 2014 was 24.4 degrees and the 4th coldest on record.
According to the latest NWS forecasts, the first two weeks of April are expected to be warmer-than-average.
The statewide precipitation for March was 2.44 inches, 0.52 inches below average. However, it was not evenly distributed (left). Northern Illinois was dry with less than 2 inches of precipitation in many locations. Central Illinois was close to average with 2 to 4 inches widely reported. On the other hand, Southern Illinois was much wetter with 4 to 8 inches of precipitation (shades of blue). The largest reported total for the month was in Belknap (far southern Illinois) with 8.43 inches.
The heavy rains in southern Illinois contributed to moderate flooding on tributaries of the Wabash and Ohio Rivers.