Central/Eastern Illinois
A few cities include: Champaign, Joliet and Springfield.
Local tornado season: Peaks in April/May southern areas, May/June northern areas.
Terrain: Relatively flat, some rivers and forested areas.
Road network: Good in most areas.
Radar coverage: Usually fairly good.
Central and eastern Illinois is no stranger to tornadoes. In fact, it has been in middle of several historic tornado outbreaks over the years with long-track tornadoes. Most tornado events here occur in the spring, but there have been fall outbreaks as well.
While tornadoes are a common hazard, large hail can affect the area, mainly in the most intense storms. Very large hail is not common, but has been reported on occasion. Damaging winds are commonplace through central and eastern Illinois, along with storm motions that can sometimes reach highway speeds.
Terrain
Illinois ranks as one of the flattest states in the country and central/eastern portions of the state are arguably the best for storm chasing. There are patchy areas of trees and a few small bodies of water to work with, but terrain obstacles in this part of Illinois are few and far between. Trees do become more prevalent in east-central Illinois near the Indiana border, but even here the density of trees is not overly detrimental for storm chasing purposes.
Note that the thicker forests of southern Illinois are not grouped into this chase area and fall into the Ohio Valley zone.
Road network
The road network throughout central and eastern Illinois is usually favorable for storm chasing. Many U.S. and state highways take a north-south or east-west orientation and secondary road networks tend to be oriented in a grid-type pattern. Most of these secondary roads are also paved, so that makes it relatively easily to storm chase in the more rural areas.
There are plenty of freeways to help quickly navigate across Illinois. I-39 marks the approximate western edge of this chase zone, while I-55 connects Springfield to Chicago. Interstate 57 bisects the region, connecting southern Illinois with a direct path to Chicago. From St. Louis, I-64 tracks east toward the Buckeye state, while I-70 is a more northeasterly route toward Indiana. Farther north, interstates 72 and 74 can bring you either west or east.
Radar coverage
KILX, in the heart of Illinois, offers radar coverage for much of the area. KLOT covers northeastern Illinois and the triad of KSLX, KPAH and KVWX offer radar coverage for most of southern Illinois. There are no large gaps in radar coverage, but some storms in south-central Illinois can find themselves directly between KSLX/KPAH/KVWX, without lower level radar coverage. Even here, since the “gap” is so small, usually one of the radar sites can be selected for a reasonable scan of a storm.
Likewise, a narrow part of east-central Illinois near the Indiana border falls directly between KILX and KIND. Once again, the area between radars is small and will usually not cause much issue while storm chasing there.
In summary, central into eastern Illinois is a favorable place to storm chase in the Midwest. The region has often produced significant, long-track tornadoes and the combination of a favorable road network; generally flat terrain and good radar coverage make this an appealing area to chase storms.