October 2010 Weather and Its Impacts on Missouri

Pat Guinan
State Climatologist
Commercial Agriculture/University of Missouri Extension

Pleasant fall weather reigned supreme across Missouri during October with above normal temperatures and below normal precipitation. Preliminary temperature data indicate the statewide temperature averaged 2.2 degrees above normal with monthly average maximum temperatures in the lower and middle 70's and monthly average minimum temperatures in the middle 40's. High pressure and low humidity contributed to numerous cloud-free days and few opportunities for precipitation across the region.

Precipitation reports were indicating a statewide average total of 0.70 inches, which is 2.66 inches below normal. It was the 4th driest October on record and the driest since 1964. Heaviest monthly totals were confined to some northwestern counties where Maryville and Grant City reported 2.62 and 2.31 inches, respectively. Alternatively, many locations in south central Missouri and the eastern Ozarks received less than 0.30 inches for the entire month. Lowest October rainfall totals were reported in the south central communities of Marshfield and Hartville, where each location reported a scant 0.03" for the month.

One notable severe weather event occurred on October 25-26 and was associated with a cold front trailing from an unusually strong low pressure system in the upper Midwest. During the evening hours of the 25th, a squall line developed ahead of the front in western Missouri and strengthened as it swept eastward through the state. Numerous straight line wind damage incidents impacted the southeastern half of Missouri, but fortunately no serious injuries were reported.

The growing season effectively came to an end across much of the Show-Me State on the morning of October 29 when widespread freezing temperatures occurred for the first time across much of the Show-Me State. With the exception of urban locations and far southeastern sections, most areas dropped to the middle and upper 20's.

There was significant progress in row crop harvesting due to the extended dry and mild conditions. By the end of the month, 94% of the corn and 90% of the soybean crop were harvested, 2 to 3 weeks ahead of normal according to the Missouri Agricultural Statistics Service. Topsoil moisture conditions were reported short to very short in 50% of the reporting districts with especially dry soils in the south central and southeastern districts where subsoil moisture was reported 83 and 85% short to very short, respectively.

The dry weather also led to deteriorating pasture conditions across the state where south central and southeastern sections reported 71 and 86% in poor to very poor condition, respectively. Drought has been plaguing the Bootheel region since early July and was beginning to result in low stock water supplies. Nearly 80% of stock water was reported in short to very short condition compared to 18% a month earlier according to the Missouri Agricultural Statistic Service.

There exists a decent chance for soil moisture recharge over southeastern Missouri this winter. Currently a moderate to strong La Nina is in progress and is expected to continue through the winter season. Typically, moderate to strong La Nia winters bring above normal precipitation to a corridor extending from Lower Michigan to Arkansas. The highest probabilities for wetter than normal conditions extend along the Ohio River Valley and include far southeastern sections of Missouri. Normally, more than 11 inches of precipitation occurs over the Bootheel during the December through February period.