September 22-30

Temperatures

The entire region rounded out the month with above-average temperatures. Average temperatures for the week were generally 3-5°F above normal across the southern areas, while averaging as much as 10°F+ above normal across northern Minnesota (Figure 1). This mirrors the pattern for the month, which was 6-8°F above normal in northern Minnesota and northern Wisconsin, 3-5°F for much of the rest of the region, and near normal for the far southern reaches of the region (Figure 2).

Minimum temperatures averaged much more anomalous in the east than the west, with much of Ohio averaging 11-15°F above normal (Figure 3). Much of western Wisconsin, Minnesota, and Iowa averaged 3-6°F above normal. Youngstown, Ohio observed 5 consecutive days, September 25-29, with minimum temperatures at or above 64°F, which made it the longest stretch of minimum temperatures at or above 64°F in September since 1896. Columbus, Ohio observed 8 consecutive days of minimum temperatures 65°F or above, which tied the record for the second longest stretch of 65°F+ temperatures this late in the calendar year.

Maximum temperatures were most anomalous over Minnesota where they were over 10°F above normal (Figure 4). The rest of the Upper Midwest was 6-10°F above normal. In Hibbing, Minnesota, the temperature was at or above 82°F for three consecutive days, September 26-28, which was the longest and warmest consecutive stretch of temperatures this late in the calendar year since records began in 1962. St. Cloud, Minnesota, observed 6 consecutive days of maximum temperatures at or above 80°F from September 25-30, making it the longest consecutive stretch of temperatures at or above 80°F this late in the calendar year since records began in 1893. St. Cloud also had 19 days at or above 80°F during the entirety of September, which was the second most in September since 1893, behind only 21 days in September of 1908.

Precipitation/Drought

Precipitation was abundant across the Ohio Valley, with many areas observing over 400 percent of normal precipitation for the period as the remnants of Helene affected southern reaches of the region (Figure 5). Most areas south of I-80 observed healthy precipitation totals, as did the west coast of Michigan and Greater Milwaukee. Minnesota, northern Wisconsin, Iowa, and Michigan’s UP observed less than 50 percent of normal precipitation as Helen’s remnants struggled to reach that far north. Paducah, Kentucky observed 5.33 inches of precipitation on September 27, the second largest single-day total in September since 1937. Portsmouth, Ohio observed 6.57 inches of precipitation on September 28, the largest single-day total in September since records began in 1893.

This precipitation was beneficial for drought recovery across the Ohio Valley (Figure 6). Drought was almost entirely erased from Kentucky, parts of which were in D3 (extreme drought) prior to the precipitation. There were major improvements across southwestern Ohio, as D2 (severe drought) and D3 drought were traded for just D0 (abnormally dry) and D1 (moderate drought) conditions. Drought was also eliminated from all of southern Illinois and southern Indiana. However, D1 drought expanded across the Upper Midwest and areas west of the Mississippi River. D2 conditions were introduced to northeastern Wisconsin and Michigan’s Upper Peninsula (UP).

Storm Reports

There were over 100 storm reports this week, 78 of which were wind reports (Figure 7). There were 17 hail reports and 13 tornado reports. An EF-0 tornado with 60-65 mph winds touched down in Delaware County, Indiana on September 22, damaging a pole barn. On the same day, straight-line winds overturned a camper, causing 1 fatality in Ozark County, Missouri. Another outbreak on September 24 spawned more tornadoes, this time in Indiana, where an EF-1 tornado with peak winds of 95 mph tipped over a buggy injuring two people.