Midwest Overview - October 2011

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East-West Split for Precipitation

There was a pronounced split from west to east across the Midwest in October. The western half of the region was drier than normal and the eastern half was wetter (Figure 1). The contrast was significant with precipitation totals ranging from less than 25% of normal in parts of Missouri and Iowa to more than 200% of normal in parts of Ohio (Figure 2). The rainfall pattern largely explained the Drought Monitor depiction near the end of the month (Figure 3) with drought conditions in the western half of the Midwest.
 

Cooling Trend

Temperatures typically cool considerably during October. This year the trend was enhanced as warmer than normal temperatures to start the month gave way to cooler than normal temperatures late in the month.

Daily temperature records reflected the shift with lots of record highs early in the month trending to mostly record lows later in the month. Temperatures averaged near normal for a swath from Missouri to Ohio with below normal temperatures in Kentucky and above normal temperatures from Iowa to Michigan (Figure 4).
 

Windy Conditions

Windy conditions, especially in the upper Midwest, were tied to two strong low pressure systems that affected the region. The first system moved into Canada on the 14th (Figure 5) but lingered with strong northwest winds behind the system. Small boats were capsized in Wisconsin and Michigan but everyone was rescued in both incidents. The second system moved across Ohio on the 19th (Figure 6) bringing strong northeast winds to the upper Midwest. Chicago and Milwaukee each reported damage on Lake Michigan and on shore. Boats anchored along the shoreline were sunk or blown ashore and windows were blown out of high-rise buildings in both cities.
 

Missouri River Flood Repairs

With the Missouri River back in its banks, repairs continued in October. Throughout the month roads were fixed and reopened to traffic for the first time since early summer when flooding inundated them. Among the roads reopened were miles long stretches of Interstate 29 in western Iowa and northwest Missouri. The river itself was also reopened to boat traffic early in October. Repairs continued on Interstate 680 in western Iowa and on the scores of levees in Iowa and Missouri that were weakened or breached in the months long flooding.
 

-MST-
The Indiana State Climate Office and the Iowa Climatology Bureau also contributed to this report.