October 15-21, 2023

Below- and Above-Normal Temperatures Observed

Temperatures were up and down during the third week of October, and it generally depended on the location. Average temperatures were above normal across the western and Upper Midwest, especially Minnesota, where parts of the state were as much as 9°F above normal for the period (Figure 1). This was relative, especially since Illinois, Indiana, Ohio, and Kentucky were generally near or below normal. Kentucky observed an average temperature of 54.8°F, which was 0.9°F below normal and the most below normal in the region. In Minnesota, the average temperature of 49°F was 4.7°F above normal and the most above normal for the region.

Daily minimum temperatures were above normal for most of the region. Minnesota, Wisconsin, Michigan, and Ohio all saw minimum temperatures 3-6°F above normal (Figure 2). Only Missouri saw average minimum temperatures that were overall below normal, and even there it was limited to at most 2°F below normal in the far southwestern corner of the state. Temperatures rose later in the period for the region, with minimum temperatures on October 19 in the low 50s as far north as Sault Ste. Marie, where the normal minimum temperature is 37°F.

Maximum temperatures were above normal to the west and below normal to the east. In parts of Minnesota, maximum temperatures were as much as 12°F above normal; in parts of Ohio and Kentucky, temperatures were 6-8°F below normal (Figure 3). While temperatures were uniform across the region early in the period, the upper 50s in northern Minnesota were quite a bit above normal, while similar temperatures observed further south on the same day were actually well below normal. In the wake of a cold front that pushed through right at the beginning of the week, temperatures were as much as 19°F below normal in Kentucky on October 16, while in northern Minnesota, where high pressure was beginning to build, temperatures were 10°F above normal in spots. In fact, a maximum temperature of 52°F was the coldest maximum on record for October 16 in Scottsville, Kentucky. A record low maximum of 55°F was also set in Cynthiana, Kentucky, just north of Lexington, on October 16. On the same day, it was warmer in St. Cloud, Minnesota, where it was 64°F, which was 8°F above normal. By October 21, temperatures were rebounding in Kentucky. Louisville observed a maximum temperature of 76°F, which tied for the 3rd warmest on record for October 21.

Ohio Valley Rain And Little Elsewhere

The week was defined by up to 2 inches of rain in parts of Ohio, and nearly none in Iowa and Minnesota (Figure 4). Two separate cold fronts moved through the region October 20-21, both of which hit Ohio with the most rain in the Midwest. Parts of eastern Ohio saw over two inches of rain, mainly from Canton south and east to the West Virginia border (Figure 5). Most of the rest of the state saw 1-2 inches, with the Greater Toledo and Cincinnati areas seeing less than 1 inch. The only other areas that observed over one inch of precipitation were southwest Michigan and the Upper Peninsula.

On the flip side, isolated pockets of Iowa and Minnesota saw little to no rain. Des Moines observed less than 0.02 inches of rain all week, and Waterloo observed 0 inches. The southeastern part of Iowa saw the most rain for the week, with points south and east of Ottumwa observing up to 0.3 inches of rain. In Minnesota, Mankato observed a trace of precipitation on October 15, and nothing for the rest of the week. Most of southern Minnesota was the same, with the Twin Cities seeing, at most, 0.1 inches for the entire week. In northern Minnesota, rain was slightly more abundant, with totals generally in the 0.3-0.75 inch range (Figure 6).

Drought Gradually Waned, Record-Breaking River Lows

Drought continued losing its grip on the Midwest. A more amplified fall pattern brought more rain to the region, albeit scattered. The largest decreases in drought were in the abnormally dry (D0) and moderate drought (D1) categories. At the beginning of the period, 50 percent of the Midwest was in D1. Less than 50 percent of the Midwest is now experiencing moderate drought conditions, as coverage decreased to 46.94 percent. Even so, there were no percent changes in severe (D2) or extreme (D3) drought, which continue to cover 17.81 percent and 4.66 percent of the Midwest, respectively (Figure 7).

The greatest improvement was in Ohio, where much of the eastern half of the state is no longer in D0. Significant improvements were also noted in northern Indiana, where drought no longer exists. However, the western Midwest observed little rain this past period. While no increases in drought coverage were noted, extreme drought persisted in central Missouri, eastern Iowa and a small pocket of north-central Wisconsin. Much of Iowa and Missouri remained in either moderate or severe drought as of the end of the week (Figure 8).

River levels also rose slightly after months of severely low water levels. The Mississippi River Basin has been arguably the most below normal. On October 16, the Mississippi River at Caruthersville, Missouri set the record for lowest water level ever recorded at -2.98 feet (Figure 9). The low water stage for Caruthersville is 4 feet, and by October 21 the river rose to -1.86 feet. The Mississippi River at Tiptonville, Missouri recorded the second lowest water level ever observed there, coming in at -2.58 feet on October 15. By October 21, the river had risen to -0.25 feet at Tiptonville (Figure 10).