Midwest Weekly Highlights - August 22-31, 2012
Portions of the central Midwest and Missouri received significant precipitation during the last ten days of August, while the rest of the region received less (Figure 1). A band of precipitation measuring at least 1" stretched from western Iowa to eastern Indiana. The greatest amounts of 3" to 4" were found at the border of western Iowa and Missouri. Locations in southern Missouri also received 1.5" to 3" of precipitation throughout the last ten days of the month. In other parts of the Midwest precipitation was much less, measuring only 0.01" to 0.5" in some portions of the northern and southeastern Midwest. Overall, the end of August brought below normal precipitation to much of the region, with the exception of the central Midwest and portions of Missouri (Figure 2). There were several daily precipitation records set during the last ten days of August.
As August was coming to a close, the remnants of Hurricane Isaac were making their way to the Midwest. This tropical system brought significant rainfall to southern parts of the region. The precipitation totals from this system will be discussed in next week's report.
Above Normal Temperatures Return
After an unseasonably cool couple of weeks, above average temperatures returned to much of the region during the last ten days of August (Figure 3). The greatest departures were in the northern Midwest, with northern Minnesota and northern Michigan experiencing average temperatures that were 6°F to 8°F above normal. Portions of the southern Midwest experienced temperatures that were closer to normal, and small portions of southern Missouri and southern Kentucky experienced temperatures were slightly cooler than normal.
Maximum temperatures ranged from 90°F to 95°F in the southern Midwest to 75°F to 80°F in the northern Midwest (Figure 4), making maximum temperatures above normal across much of the region as well
(Figure 5). While minimum temperatures were above normal in the upper Midwest, they were either near- or below-normal further south in the region (Figure 6). There were several daily temperature records set during this time, including both record highs and record lows.
With some precipitation falling during the last ten days of the month in the central Midwest, there was some improvement in drought conditions on the US Drought Monitor in this region
(Figure 7), mainly across southern Iowa, north central Illinois, and northern Indiana. However, exceptional drought (D4) remains in just over 7% of the region and about 65% of the region is still being impacted by some level of drought. Next week, it will be interesting to see if the remnants of Hurricane Isaac reduced the severity of drought across the southern Midwest.
In terms of severe weather, it was fairly quiet across the Midwest during the last ten days of the month. There were reports on five out of the ten days, but they were scattered across the region and no widespread severe weather systems impacted the region (Figure 8). The most active days for severe weather were August 23rd and 31st. On the 31st, there were 5 tornado reports in Illinois and Missouri. However, none of the tornadoes appear to have been too damaging, except for some crop damage, uprooting of trees, and some minor home damage.