October 17-23, 2001:

The period of October 17-23 was quite dry in most of the southern and northern thirds of the Midwest. A swath from Iowa to southern Michigan received 1-3 inches of rain (Figure 20), and was the only part of the Midwest receiving above normal precipitation during the week (Figure 21). The portion of the region south of the rainy belt remained 2-4°F above normal temperature, while Wisconsin and some of the northern edge of Midwest were a few degrees below normal (Figure 22). A strong Canadian high pressure area dominated the region for the first 3 days of the week, with temperatures cooler than normal, especially in the north-central Midwest. However, as the high pushed eastward to the Atlantic coast, warm, moist air re-entered most of the Midwest from the south. A weak cold front kept parts of the northern Midwest cloudy and cool, but then returned northward as a warm front on the 21st. A weak low progressed along the quasi-stationary front, bringing a narrow band of intense rain during the 21st and 22nd through northern Illinois, Indiana, and Ohio. On the 22nd, a stronger low entered the region through Iowa, causing an outbreak of severe weather in several states on the 22nd and 23rd. Strong thunderstorms formed in Iowa (Figure 23, NWS) and progressed rapidly eastward, dropping heavy rain near Chicago (Figure 24, NWS). More rain fell in the central latitudes of the Midwest, where high stream flow levels in Indiana (Figure 25, USGS) where maintained for much of the week following the previous week's heavy rains. The Wabash River near the Indiana - Illinois border flooded considerably in places, ruining crops that had not been harvested in the flood plain (Figure 26, USGS). Farm activities were curtailed again in Illinois, Indiana, and Ohio due to rain continuing to the end of the period.