Midwest Weekly Highlights - October 22-31, 2014

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Widespread Below Normal Precipitation

The Midwest saw widespread below normal precipitation during the last ten days of October (Figure 1). Areas with significantly below normal precipitation (ranging from 0% to 10% of normal) include portions of northern Illinois, southeast Iowa, and northern Missouri. There were a few areas with above normal precipitation, with the greatest departures of 100% to 175% of normal in Upper Michigan. Accumulated precipitation totals ranged from 0" in eastern Iowa/western Illinois to 1.5" in Upper Michigan (Figure 2).

Snowfall totals for the end of October ranged from 0.1" to 0.2" in south-central Wisconsin to 2" to 5" in Upper Michigan (Figure 3). Snowfall totals in these areas were near normal, however with no snowfall, portions of Minnesota and northern Michigan were 0.5" to 1.5" below normal for this time of year (Figure 4). While not considered measurable, there were several stations across the region (as far south as central Illinois) that reported traces of snowfall, much of which fell on October 31st (read more about the wild and wintery Halloween below).
 

Near to Above Normal Temperatures, Freezing Temperatures Extend South

Temperatures were above normal in western portions of the region during the last ten days of October, while the rest of the Midwest was near normal (Figure 5). Greatest departures of 7°F to 8°F above normal were in northern Missouri, northern Iowa, and northern Minnesota. While a majority of the last ten days of the month was near to above normal for the region, temperatures cooled off the last couple days of the week and temperatures were significantly below normal (Figure 6).

A majority of the region has now received its first 32°F freeze of the season, with many of the southern Midwest states occurring during the last ten days of October (and first few days of November) (Figure 7). For many stations, this freeze actually came slightly later than the median date for the first 32°F freeze (Figure 8). With widespread freezing temperatures, it has been reported that the growing season has officially ended across much of the Midwest.

Wild and Wintery Halloween

Unfortunately Halloween was cold, windy, and snowy for many trick-or-treaters across the upper Midwest. Average wind speeds and gusts were significant in the Great Lakes region, with wind gusts over 60 mph reported in some areas (Figure 9, courtesy of The Weather Channel). These high wind speeds created some impressive waves in and along shorelines of the Great Lakes. In Lake Michigan, waves reached heights of 21.7 feet at the NOAA mid-lake buoy east of Kenosha, Wisconsin (Kenosha County). Since buoy observations of Lake Michigan began in 1981, there has only been one other occasion with higher waves (September 30, 2011). In Chicago, the strong waves managed to push the waters of Lake Michigan onto the northbound lane of Lakeshore Drive, just in time for the evening commute. Chicago's O'Hare International Airport had to cancel more than 700 incoming and outgoing flights by Friday night because of heavy winds, rain, and snow. For more information and impressive pictures from Chicago, visit the WGN Chicago Weather Center blog post.

-MW-
Extension Climatologist for Illinois-Indiana Sea Grant and the Midwestern Regional Climate Center