September 2016
Monthly Overview - September 2016
Warm Across the Region
Temperatures were above normal across the Midwest in September. Departures above normal ranged from about 1°F in central Minnesota to about 5°F in southeast Ohio
(Figure 1). Minimum temperature departures (Figure 2) were slightly warmer than the maximum temperature departures
(Figure 3) in most areas. For the region as a whole, September ranked as the 7th warmest since 1895. Ohio statewide ranked as the warmest on record, with six other states among the warmest 10%, and all nine states ranked among the warmest 15% of their histories. Statewide departures above normal ranged from 3.1°F in Minnesota to 5.0°F in Ohio.
Heavy Rains
Heavy rains fell in multiple storms during September. Widespread areas of 5 inches or more of rain affected parts of seven states, missing only Indiana and Kentucky (Figure 4). Totals topped 10 inches where Minnesota, Iowa, and Wisconsin meet. With departures of more than 8 inches above normal
(Figure 5), totals were more than three times the normal amount (Figure 6). Some parts of each of the nine states were below normal for the month as well, with nearly all of Kentucky recording below normal precipitation totals. Charles City, Iowa (Floyd County) set a new September record with 15.83 inches, topping the old record by more than 3 inches (period of record: 133 years). The station also exceeded its annual record with 51.88 inches in 2016 already topping the old record of 51.35 inches in 1999. The new annual record will continue to increase each time it rains over the last three months of the year.
Flooding and Severe Weather
Flooding and flash flooding affected the region on more than one occasion with the most significant event in the latter half of the month
(Figure 7). Rains centered on Iowa, Minnesota, and Wisconsin from the 20th-24th fell on ground already wet from earlier rains in August and the first half of September. The result was widespread flooding which was described in detail in the week 3 and week 4 reports of the Midwest Climate Watch. Severe convective weather was reported on 16 days in September, with tornadoes on four days and large hail on six days.
Drought
Wet weather in September for the areas in drought helped to ease conditions. Most of the Midwest drought in September was in Ohio (Figure 8). Drought there dropped from about 20% of the state at the beginning of the month to less than 10% of the state by the end of the month. Regionwide numbers fell from just under 2% of the region to less than 1% affected by drought. Despite the downward trend in drought, abnormally dry areas increased in the last week of September. The dry areas were mostly in the eastern half of the region and affected about 11% of the region as of the 27th.
Corn and Soybean Harvest
Crop conditions were good or excellent for much of the Midwest corn and soybean crops. Crop maturity was near or slightly ahead of the 5-year averages according to the NASS Crop Progress report for October 2nd. Rains prevented field work in some locations, but statewide harvest was running near or just slightly behind the 5-year average in the Midwest. Median first frost dates for September include much of Minnesota and Wisconsin along with parts of Iowa and Michigan
(Figure 9). First fall frosts in September 2016 have been limited to the far northern areas of the Midwest (Figure 10).
2016 Warmth Continues
September temperatures continued the pattern of warmth in 2016. All nine Midwest states rank the current year-to-date period among the warmest 10% of January-September periods since 1895. September (7th), along with March (6th), ranked among the warmest months for the region as a whole. In 2016, five months have had at least one Midwest state ranked among the warmest 10% of years in its history: February (1 state), March (all 9), June (2), August (4), and September (7). Michigan had four such months, four other Midwest states had three such months, and Minnesota had just one month ranked among its warmest 10% in 2016.
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The Iowa Climatology Bureau also contributed to this report.
The Minnesota State Climatology Office also contributed to this report.
The Missouri Climate Center also contributed to this report.