Midwest Weekly Highlights - October 15-21, 2003

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Indian Summer returns to the Midwest.

The third week of October was generally dry and mild across the Midwest. Average temperatures for the week ranged from 3F degrees below normal in eastern Ohio to 7F above normal in western Minnesota (Figure 1). High pressure over the western United States pushed into the Midwest on October 18-19, setting up a strong southwesterly flow of air over the region.  Temperatures soared to 15-20F above normal on the 19th and 20th, before a cold front knocked temperatures back down to near normal levels.  Maximum temperatures reached as high as 90F over the western portions of the region (Figure 2 and Figure 3, Unisys).  At least 121 high temperature records were set across the central and western United States on October 19, and additional records were set on the October 20.

A series of weak frontal systems moved through the region, but precipitation was mostly limited to scattered light showers.  The exception was in Ohio, where a wave moving along a stationary front October 16-17 produced an inch of rain in many parts of the state. Precipitation this week ranged from 200 percent of normal overparts of Ohio to under 10 percent of normal across northern Iowa, much of Minnesota, and the northern half of Wisconsin (Figure 4).  While a dry October (Figure 5) has favored harvest activities, the lack of rainfall in the upper Midwest in particular is worsening drought conditions there.  The latest U.S. Drought Monitor (Figure 6) indicated increased intensity of drought in northern Minnesota, and the extreme drought area in southeastern Minnesota expanded into Iowa and Wisconsin.