Midwest Overview - October 2009

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A Month of Records

Persistent cold and wet weather resulted in numerous temperature and precipitation records across the Midwest during the month, including the wettest October on record for the region, based on preliminary data.

It was much cooler than normal across the Midwest in October, although there was a distinct west to east gradient. Temperature departures ranged from 8°F below normal in western Iowa to only 2°F below normal in the far eastern portions of the region (Figure 1). The first half of the month was the coldest with temperature departures ranging from 12°F below normal in the far west to 2°F in southeastern Kentucky (Figure 2). More than 900 low maximum and low minimum temperature records were set in the Midwest the first two weeks of October. For the entire month there were 1485 low maximum and 198 low minimum temperature records set or tied.

Based on preliminary data, this was the 7th coldest October on record in the Midwest region. In Iowa, it was the third coldest October on record. Temperatures reached 70ºF on only four days during the month with Iowa City the warm spot with a 74ºF maximum on October 21.   Never before in the historical record has the temperature failed to exceed 74ºF somewhere in the state during October (old record ‘lowest’ maximum was 78º in 1985, 1959 and 1925).  

State	October Temperature Rank*
Illinois	7
Indiana	10
Iowa	3
Kentucky	12
Michigan	11
Minnesota	5
Missouri	5
Ohio	17
Wisconsin	8
MIDWEST	7

*Based on preliminary data and subject to change
 

Impressive October Precipitation

Precipitation was frequent in October, and frequently heavy. Precipitation was much above normal across all but far eastern Kentucky and in extreme northern Minnesota, where it was close to average (Figure 3). Precipitation was 300 to 400 percent of normal across the southeastern half of Missouri and the southern half of Illinois, and 300 percent of normal across a portion of western Minnesota.
 

Records Tumble

The heavy rain that occurred the last ten days of the month pushed October rainfall totals to record levels at many locations in the central Midwest. Of 965 stations with 30 or more years of records, 192 locations had their wettest October on record, and another 351 locations had their second through fifth wettest October (Figure 4).

Based on preliminary data, this was the wettest October on record for the entire nine-state region. October precipitation ranked in the top five wettest in all states except Ohio.

State	October Precip Rank*	Maximum Station Precipitation Reported (in)*	Location	Station Type
Illinois	2	14.20	Granite City 1.4 ENE	CoCoRaHS
Indiana	4	10.30	Merrillville 4.5 E	CoCoRaHS
Iowa	1	9.13	St. Ansgar	NWS Coop
Kentucky	3	11.56	Clinton 4 S	NWS Coop
Michigan	4	10.42	South Haven	NWS Coop
Minnesota	3	10.29	Grand Meadow	NWS Coop
Missouri	2	17.28	Winona 2.8 SW	CoCoRaHS
Ohio	17	6.36	Van Wert	NWS Coop
Wisconsin	2	7.71	Peshtigo	NWS Coop
MIDWEST	1	17.28	Winona 2.8 SW (MO)	CoCoRaHs

*Based on preliminary data and subject to change
 

October Snow

The northwestern third of the region received the first snow of the season rather early this year, and snowfall was above normal at the end of the month (Figure 5). Snow fell in northwestern Iowa and in Minnesota on October 9-10, with one to four inch amounts common along the Interstate 80 corridor from Council Bluffs to Des Moines, IA on the morning of the 10th, including a 6.7 inch total at Underwood, IA. A second event followed on October 11-12 and brought more light snow to Iowa and higher amounts to eastern Minnesota. On October 23-24 one to five inches of snow fell across northern Wisconsin and the Michigan Upper Peninsula. Minneapolis-St. Paul, MN received 2.8 inches of snow in October, the seventh highest on record and the most in October since 1991.
 

Not a Good Month for Agriculture

Freezing temperatures wear recorded across the northern half of the region by the middle of the month, and a hard freeze had ended the growing season across the northern half of the region by October 21. At the end of the month only substantial portions of Missouri and Illinois had not yet experienced a hard freeze. Producers had been hoping for a late freeze to allow the corn crop to mature. However, the bigger weather issue was the wet weather. Precipitation occurred on a majority of days in October, leaving few days adequate for field work. At the end of the month soybean harvest was behind schedule in all nine states, and corn harvest was only complete in Kentucky (Figure 6). Elsewhere, corn harvest ranged from 67 percent behind normal in Illinois to 36 percent behind normal in Missouri.

For more details on weather and climate events during October 2009, click on the individual weekly report links on the upper right.

-SDH-