Missouri 2011 Growing Season Climate Summary
Commercial Agriculture/University of Missouri Extension
A challenging growing season was experienced by farmers this year as floods, drought and extreme temperatures impacted the Show Me state. With the exception of May and September, all months from April through October witnessed above normal temperatures, and a wet spring transitioned to a hot, dry summer creating stress on crops and livestock. Statewide precipitation averaged above normal in April and May and below normal from June through October.
The clash of air masses was frequent over Missouri during the spring of 2011 and resulted in large weekly temperature swings and unsettled weather. A very mild weather pattern dominated during the first two weeks April and was warmer than the latter half of the month. There were numerous precipitation events during the month including a week long historic rain event across southern Missouri that brought record rainfall and flooding to the region.
Most counties across southern Missouri recorded their wettest April on record. Generally, more than a foot of rain fell southeast of a line extending from Newton to Sainte Genevieve counties. Some southeastern locations in Shannon, Carter, Butler and Cape Girardeau counties reported more than 20 inches of rain for the month. Overall, average April rainfall was 7.45 inches for the state, making it the 5th wettest April in the past 117 years. The cool, wet weather during the latter half of the month halted spring planting opportunities across the state
May had below normal temperatures and above normal precipitation, but much of the month was dominated by highly contrasting air masses, leading to periods of much warmer than normal and much cooler than normal weather. Numerous rain events throughout the month led to above normal precipitation for most locations. Preliminary numbers indicate the statewide average total for the month was just over 6 inches, or 1- inch above normal.
An unusually warm air mass established itself over Missouri during the first ten days of June with oppressive heat impacting the state and several high temperature records broken. Temperatures averaged 8-10 degrees above normal during the period and it was the hottest June 1-10 period since 1934. Most locations experienced 90 degree plus temperatures on a daily basis and some locations in the Bootheel witnessed several days with triple digit heat.
A pattern change led to a more seasonable and below normal temperature regime for the remainder of June and was a welcome change for many. Overall, monthly temperatures averaged 1-3 degrees above normal across the northern half of Missouri whereas southern sections averaged 3-6 degrees above normal. Springfield, Joplin and West Plains had their 6th, 4th and 4th hottest June on record, respectively.
Precipitation was highly variable during the month with a sharp gradient extending from northeastern through southwestern Missouri. Generally, above normal rain fell across the northeastern half of the state with below normal precipitation across the southwestern half. Amounts increased northeast of a St. Joseph to Cape Girardeau line, from 4.5 inches to more than 12 inches. Totals decreased southwest of this line, from 4.5 inches to less than 1-inch. Some of the highest June rainfall totals occurred in Scotland, Lewis and Clark counties where the communities of Memphis, Monticello and Kahoka reported 13.29, 15.47 and 17.88 inches, respectively. Some of the driest communities were in Christian and Greene counties. A couple observers living near Nixa and Springfield reported 0.53 inches and 0.61 inches, respectively.
Flooding along the Missouri River was ongoing for much of June due to record water release occurring from upstream reservoirs in Montana and the Dakotas. These record releases translated to major flooding downstream to St. Joseph, MO and moderate flooding along the Missouri River from Kansas City to Jefferson City, MO. Thousands of acres of cropland were flooded in northwestern Missouri where overtopped levees and levy breeches worsened the situation. Atchison and Holt counties, in the northwest corner of the state, were experiencing numerous impacts with flooded residences, closed roads and inundated cropland.
A ridge of high pressure over the southern Plains intensified and expanded northeastward in July, profoundly influencing the weather pattern across the Show-Me state. Hot and dry conditions spread across Missouri and had adverse impacts on people, animals and vegetation. Missouri witnessed its hottest July in more than 30 years. The average statewide temperature for the month was 83°F, slightly over 5 degrees above normal, and the hottest month since July 1980. It was also the 6th hottest July on record and will go down as the 8th hottest month of all time when final numbers are tallied.
Hot temperatures and high humidity in July and early August combined to produce very uncomfortable and life threatening conditions. There were lengthy and continuous periods of various heat advisories and warnings impacting the state and, unfortunately, heat related fatalities were reported. Another feature of the prolonged heat wave was high minimum temperatures. The average July minimum temperature for most areas of Missouri was between 72-74°F, or five to six degrees above normal.
Most areas of the state reported dry conditions in July and preliminary data indicated a statewide monthly average of 2.34 inches, or more than 1.5 inches below normal. The majority of precipitation events were scattered and highly localized, but there were a few instances of significant rainfall. Heaviest monthly precipitation was confined to northwestern, north central and east central sections, and the eastern Ozarks region. Several northwestern counties reported four to six inches of rain whereas three to four inches were common over north central Missouri and parts of the eastern Ozarks. Less than two inches were typical over northeastern, central, west central, southwestern and far southeastern sections. Some exceptionally dry pockets were found in parts of northeast, west central, southwest and southeast Missouri where less than 0.75 inches were reported for the month.
The southwestern district was especially hard hit by the heat and lack of precipitation during July. According to the Missouri Agricultural Statistics Service, 84% of the corn and 91% of the soybean crop was in very poor condition by the end of the month. Complete crop failures were reported in southwest Missouri and burned up pastures were forcing livestock producers to feed hay in some areas.
Above normal summertime temperatures persisted throughout much of August, wrapping up another hot summer for the Show Me State. Preliminary numbers indicate average June-August temperatures for the state were slightly under 79°F, and rank the summer of 2011 as the 7th hottest on record, 0.1°F warmer than the summer of 2010. The hottest temperatures for the month occurred during the first and last week of August with more seasonable temperatures occurring during the second and third weeks.
Precipitation events were more numerous, and heavier, across parts of Missouri during August than the previous month, bringing some relief to the state. Preliminary numbers indicate a statewide average of nearly 3.7 inches, which is near the 30-year normal. Specifically, totals across the southwestern half of Missouri were near to above normal and averaged between 3-6 inches, whereas rainfall totals were below normal, less than 3-inches, across the northeastern half of the state.
Heaviest monthly totals were confined to some south central counties where more than 8-inches were reported across parts of Dallas, Laclede, Phelps, Texas, Dent, Howell, Shannon and Oregon counties. Driest conditions were reported across the northeastern border counties where some locations reported less than 1-inch of rain.
A significant weather pattern change in early September translated to cooler conditions for Missouri where monthly average temperatures ranged 2.5 to 3.5 degrees below normal for many locations. Some parts of the Ozarks and far northwestern Missouri had cooler departures running 3.5 to 4.5 degrees below normal for the month. A fairly active and progressive weather pattern dominated much of the month as several frontal boundaries swept through the state and brought periods of precipitation. Most rain events, however, were not widespread, nor heavy, and preliminary data indicated an average statewide total of nearly 2.90 inches, more than 1-inch below normal for the month.
According to the Missouri Agricultural Statistics Service, the generally dry weather during September hastened fieldwork activity over much of the state and allowed producers to harvest nearly two thirds of the corn by the end of the month. Soybean harvest was going at a normal pace and nearly 10% was harvested by the end of the month.
Nearly 50% of the pastures were in poor to very poor condition at the end of the September due to lingering effects of summer heat and drought that impacted much of state, especially across west central, southwestern and northeastern sections. There were numerous reports of farmers feeding hay as well as hauling water due to dry ponds, springs and creeks. Pasture deterioration was also noted across north central and northwestern sections due to unusually dry September weather.
Generally, mild and dry conditions were the rule during October with temperatures averaging near normal across southern Missouri and one to two degrees above normal across northern and central sections. All locations reported below normal rainfall with some unusually dry conditions in northwestern and west central Missouri. Several counties in northwest and west central Missouri received less than 0.25 inches for the month and a couple precipitation observers in Atchison and Harrison counties reported no measurable rainfall for October. Preliminary data were indicating it was the driest October in nearly 50 years across northwestern sections and extreme west central Missouri.