Mid/Upper Mississippi Valley
A few cities include: Davenport, Dubuque and Hannibal.
Local tornado season: Peaks between May and June.
Terrain: Rolling hills and forests, Mississippi River bisects.
Road network: Manageable, but there are some gaps.
Radar coverage: Good, except in northeastern Missouri.
The mid to upper Mississippi Valley area has been affected by several tornado events over the years. Many strong, long-track tornadoes have moved through the area, particularly over eastern Iowa and western Illinois. Severe thunderstorms can often produce damaging winds and large hail in the area. However, it is tornadoes that will be the most likely hazard to lure storm chasers here.
Terrain
The terrain of the mid to upper Mississippi Valley can be challenging. Either side of the river has forested areas, some that are thicker than others. The worst terrain seems to be from northeastern Missouri and far southeastern Iowa into west-central Illinois. In this area, forests can be dense.
Another area with thick forests can be found from northeastern Iowa into adjacent Wisconsin and far northwestern Illinois. In general, the greatest density of trees tends to be areas close to the Mississippi River. West of the river, the terrain tends to be rolling hills.
Road network
Much of the area has a reasonable road network, but due to rivers and trees, the road network is not a perfect grid. Primary roads tend to have curves and move at angles. Sometimes this can work to your benefit while storm chasing, but other times it will not.
Between the main roads are secondary roads that are sometimes, but not always, laid out in a grid-type pattern. Keep in mind that these roads could be dirt. Combined with the potential for flooding near the river and it can be difficult to venture off of primary roadways. Bridge crossings over the Mississippi River are also limited. If potentially chasing a storm on both sides of the river, be sure to plan ahead.
Interstates 74, 80 and 88 are the main freeways across this region. I-74 is a route that extends southeast from the Quad Cities into central Illinois. I-80 brings one west to east across Illinois and Iowa, while I-88 tracks northeast into northern Illinois. If your route takes you through the Quad Cities, you may want to check traffic conditions first. This, or referring to a GPS can help you find the fastest route around the city. Sometimes it can be I-280, but not always.
Radar coverage
For radars, KDVN covers much of this area and offers good radar data for eastern Iowa and northwestern Illinois. KARX covers the Iowa/Wisconsin border area, but storms approaching here from the west will be coming from an area with limited radar coverage.
There is a pronounced radar hole in northeastern Missouri, where storm chasing can be quite difficult, especially considering the heavily forested terrain. Some limited radar coverage extends eastward into far western Illinois, before KILX, and to a lesser degree, KLSX, provide better radar coverage.
It should be noted that there is a glaring gap in cell/data coverage in west-central Illinois. This can be problematic for anyone trying to review updated radar data while storm chasing.
In summary, storm chasing can be managed in the mid to upper Mississippi Valley with some careful planning and patience. Hills and forested areas can be a challenge and the road network is not perfect. Be sure to plan ahead to find a place to cross the Mississippi River and be prepared for no reliable radar data if you are chasing in northeastern Missouri.
Notes
Terrain and road networks become more favorable for storm chasing farther east, into central and eastern Illinois.