July 25-31, 2003
Midwest Weekly Highlights - July 25-31, 2003
July was wet and cool across much of the Midwest, but hot and dry in the extreme west.
A persistent upper level ridge in the western U.S. and a trough over the eastern half of the country produced wet, cool, weather over all but the western portions of the region. Temperatures this month ranged from 2.5F degrees below normal near the southern tip of Lake Michigan to 1.5F above normal in western Missouri (Figure 1). Upper level waves moving across the Midwest repeatedly produced complexes of heavy thunderstorms which soaked a broad swath from eastern Iowa through Ohio. July rainfall was more than twice the average from northeastern Illinois, across most of Indiana, and northern Ohio, and well above average elsewhere in the central and eastern Midwest (Figure 2). In sharp contrast, western Missouri, Minnesota, and Iowa received only 25 to 75 percent the normal July rainfall. Kansas City, MO (Kansas City International Airport) received only 0.12 inches of rain during July, making this the driest July on record. The previous record driest July was 0.25 inches in 1975.
The week of July 25-31 was not unlike the past two weeks, although the weather did settle down after the first three days of the period. The southeastern two-thirds of the Midwest was cooler than average for the period (Figure 3). Rainfall was generally spotty during the week, although some areas did receive heavy rain (Figure 4). The far western portion of the Midwest baked in 100 degree heat before a cold front brought some relief late on July 27. On July 26 the Kansas City International Airport reached 102F, and St. Joseph, MO reached 103F (neither one a record). Duluth, MN hit 91F, the first time since August 2001. Thunderstorms rolled through northern Wisconsin in advance of the cold front dropping heavy rain. There was an unofficial report of 6 inches of rain at Pelican Lake in Oneida County (Figure 5).
As the front pushed south on July 27 thunderstorms erupted in the warm, humid, and unstable air ahead of the front from Iowa through northern Illinois into Indiana (Figure 6). Severe thunderstorm watches were issued across northern Illinois into the northern half of Indiana. The thunderstorms produced damaging winds and heavy rain. Widespread urban flooding occurred in the Will, Kendall, Lee, LaSalle, and southern Cook counties, IL into northwestern Indiana with unofficial reports of 3.50 to 5.00 inches of rain in just two hours. Major flooding was reported in downtown Lemont, IL with roads and train tracks impassable. In Palos Hills, IL three subdivisions were completely inaccessible by emergency vehicles due to the flooding. Four feet of water covered roads in Calumet City, IN. Fortunately, the storms weakened as they moved into northern Indiana and produced only scattered damage there. Additional storms developed across Indiana and Ohio from the late afternoon through the evening. On Sunday night (July 27) the storms clobbered northern Ohio, causing widespread flooding. In Canton, OH, flood damage was estimated at $13.8 million and was expected to go higher. The communities of North Canton and Louisville, OH estimated damages at more than $1 million each. All three communities declared states of emergency on Monday, and Ohio Governor Bob Taft stated he would seek federal aid for six Ohio counties affected by the storms.
The cold front responsible for the storms finally pushed south into the Ohio Valley by late on July 28th, taking most of the rain with it. Thunderstorms with heavy rain over southeast Missouri in the evening and overnight resulted in flash flood warnings being issued for two counties in southeastern Missouri and adjacent counties in Tennessee. The storms also produced hail as large as 1.75 inches and damaging winds in southeast Missouri and western Kentucky. One person was injured in Paducah, KY when the thunderstorm winds caused a building to collapse. High pressure over the Midwest on July 29 brought a respite from the stormy weather, although by late in the day thunderstorms were entering Minnesota from the Dakotas. The storms produced some ¾ to 1 inch hail and minor wind damage in northwestern Minnesota. On July 30 and 31 thunderstorm activity increased in western and northern portions of the Midwest as another cold front began to move into the region. Severe thunderstorms occurred across Iowa, southern Wisconsin, and northern Illinois, and southern Missouri, producing large hail and some wind damage (Figure 7).