Missouri 2019 Growing Season Climate Summary

Pat Guinan
MU Extension/State Climatologist
Commercial Agriculture Program

November 11, 2019

Exceptional wetness and prolonged flooding defined the 2019 growing season making it another challenging year for Missouri farmers. Official precipitation data indicate it was the fourth wettest April-October for Missouri since records began in 1895.

Historic Missouri River flooding in March continued impacting parts of northwestern Missouri through April. Some areas remained flooded and were vulnerable to future flood events where levee systems had failed. Interstate 29, between St. Joseph and Omaha, remained closed through the end of April.

Unusually wet April conditions and flooding also impacted southeastern Missouri, especially in the Bootheel where more than 25-inches had fallen since the beginning of the year and year-to-date surpluses were approaching a foot. Numerous fields in the Bootheel were submerged during the month.

According to the Missouri Agricultural Statistics Service, for the week ending April 28, corn planting was 45% complete, 10 percentage points behind the 5-year average. About half of the pastures were in fair condition. Topsoil and subsoil moisture supplies were mostly adequate to surplus statewide.

Seasonable temperatures accompanied exceptional and unprecedented wetness during May in Missouri. Daily temperatures were variable with erratic temperature swings and warmer weather during the latter half of the month. Regionally, temperature departures were variable across the state with the northwestern half of Missouri averaging near to cooler than average and the southeastern half of the state averaging near to above average.

May is climatologically Missouri’s wettest month and 2019 broke records. Historic wetness impacted the Show Me State with a statewide average total of 10.31 inches, double the normal. It was the wettest May in 125 years of records and the sixth wettest month of all time.

May amounts varied across the Show Me State, but most locations received more than six inches for the month. Much of northern and southwestern Missouri received more than 10-inches with several counties receiving more than 15-inches. Lighter amounts ranged from 4-5 inches and were confined to a small portion of east central Missouri.

The unprecedented rainfall was due to a persistent southwesterly flow upper air pattern that brought unstable weather and frequent periods of showers and thunderstorms to the region. This pattern combined with antecedent wet soil moisture conditions resulted in major flooding over large parts of the Missouri, Mississippi and Arkansas River basins.

Persistent flooding and rising waters were too much for already stressed levees and numerous systems were overtopped or breached in May. Hundreds of road closures were reported in Missouri and thousands of bottomland acres were flooded, including farmland, businesses and residences. Many residents were forced out of their homes as rivers remained above flood stage for much of the month and levees continued to fail. It was the state’s worst flooding in a generation where watermarks approached levels in some Missouri locations along the Missouri and Mississippi Rivers not seen since the major flood events of 1993 and 1995.

The saturated conditions limited fieldwork activity and planting opportunities across the state. According to the Missouri Agricultural Statistics Service, as of June 2, 2019, 69% of the corn and 18% of the soybean crop had been planted; the 5-year average is 97% and 63%, respectively. The wet weather generally benefited pastures with 64% of them reported to be in good to excellent condition.

Seasonably cool June temperatures accompanied mostly wet conditions for Missouri. It was the first cooler than average June in 15 years, and coolest June since 2004. Most of the state reported above average rainfall in June with a statewide average of just below six inches. The past two months ranked as the 3rd wettest May-June period on record, and wettest May-June since 1943.

Flooding continued to be a problem during the month with many rivers and streams remaining near and above flood stage. A widespread heavy rain event during the latter half of June resulted in another crest for many rivers, which re-flooded roads and bottomland acres and stressed levees further.

Frequent June rain events made it challenging for farmers to finish planting and cut and bale hay. According to the Missouri Agricultural Statistics Service, for the week ending June 30, 95% of the corn had been planted compared to a 5-year average of 99%. Soybean was 79% planted, compared to a 5-year average of 90%. Topsoil and subsoil moisture supplies were rated 98% and 100% adequate to surplus, respectively. Corn and soybean was rated mostly fair at 45% and 42%, respectively. Pasture conditions were mostly good at 56%. The majority of hay supplies and other roughages were adequate at 67%. Stock water supplies were reported to be in adequate (86%) or surplus (14%) condition.

Seasonable temperatures impacted Missouri in July with the exception of a 4-day hot spell in mid-July when high temperatures climbed into the middle 90’s. No triple-digit heat had been reported for the year and there were more days when daily minimum temperatures were above average due to above average dew point temperatures during the month.

July precipitation was variable across Missouri but the overall total was above average with preliminary data indicating a statewide average near 4.5 inches. Heaviest rainfall occurred over portions of west central, south central, east central and southeast Missouri where more than five inches were common. Wet and dry pockets were also notable over the northern half of Missouri. Another dry area was found over some far southwestern and south central counties in a corridor extending from McDonald to Douglas and Carter Counties.

According to the Missouri Agricultural Statistics Service report from July 28, 2019, 16% of the state reported topsoil moisture supplies in short to very short condition with 75% of the state reporting topsoil moisture in adequate condition. Statewide subsoil condition was reported 11% short to very short, and 78% adequate. Corn, soybean and pasture conditions were reported at 24%, 17%, and 7% in poor to very poor condition, respectively. Corn and soybean were reported in good to excellent condition at 34% and 41%, respectively. The majority of pasture was in good to excellent condition at 72%. The majority of hay and other roughages were adequate to surplus (84%), as well as stock water supplies (98%).

No official drought status was reported in Missouri by the end of July. Only portions of Nodaway and Worth Counties were identified as abnormally dry according to the U.S. Drought Monitor.

Near average temperatures impacted Missouri in August which was the trend for much of the growing season. Near to above normal temperatures occurred during the first three weeks of August followed by a pleasant 10-day cool spell to wrap-up the month.

Summer temperatures for June and August were slightly below normal with July near normal. Five out of the past seven summers have been cooler than average. Summer weather patterns over the past few decades indicate little change in maximum temperature trends whereas minimum summer temperature trends have been warming. This phenomenon has been ongoing primarily due to above average summer dew point temperatures in Missouri which act to suppress maximum air temperature and elevate minimum air temperature.

Wet summer conditions persisted into August with timely rains mitigating brief spells of dryness in some areas of the state. Rainfall data indicate a statewide average of just over six inches. Typical of the summer season, August rainfall was highly variable, ranging from less than two inches to over a foot. However, for the majority of locations, rainfall was above average. Heaviest amounts occurred over west central and a few far southwestern and east central counties. Lowest totals were confined to some far northeastern counties and few southeastern border counties. It was the 7th wettest August and 12th wettest summer (Jun-Jul-Aug) on record for the Show Me State.

According to the Missouri Agricultural Statistics Service report for the week ending September 1, 2019, 91% of the state reported topsoil moisture supplies in adequate to surplus condition compared to 52% last year. Similarly, 94% of the subsoil moisture supplies were in adequate to surplus condition compared to 34% last year. Corn was reported 38% in good to excellent condition compared to 29% last year. Soybean was reported 46% in good to excellent condition compared to 43% last year. Pastures were rated at 70% in good to excellent condition compared to 15% last year. Hay and other roughages were 84% adequate to surplus compared to 21% last year. Stock water supplies were 98% adequate to surplus compared to 50% last year.

Record monthly heat impacted Missouri in September. The statewide average temperature was 74.7°F, or 6.4° above the long-term average. It ranked as the 2nd warmest September on record for Missouri and the warmest September since 1931. The statewide average minimum temperature for September was 64.0° (+7.7°F) and was the highest ever recorded for the month.

September precipitation was highly variable across Missouri with above average rainfall in northern and west central sections and below average amounts impacting central, east central and southern portions. The average statewide monthly total was 3.22 inches, or 0.85 inches below the long-term average. It was the first drier than average month since April. Numerous pockets of unusual dryness were found over several south central and southeastern counties where less than 0.5 inches were reported for the month.

According to the Missouri Agricultural Statistics Service, as of September 29, 2019, the majority of the corn crop was in good condition at 41% compared to 23% last year. This year, 5% of corn was reported to be excellent compared to 5% last year. Remaining corn conditions this year were 33% fair, 16% poor and 5% very poor. Corn harvest was behind schedule at 26% compared to the 5-year average of 47%. Half of the soybean crop this year was reported in good (44%) to excellent (6%) condition compared to 35% good and 9% excellent at the same time last year.

The majority of hay and roughages were adequate (70%) to surplus (6%) this year with 22% short and 2% very short. Stock water supplies were mostly adequate at 91%, with 4% surplus and 5% short. The majority of pastures were reported in good (58%) to excellent (10%) condition while only 7% were in poor or very poor condition. The majority of topsoil moisture conditions were adequate (62%) or surplus (17%), while 18% were reported short and 3% very short. The majority of subsoil moisture conditions were also reported to be adequate (80%) to surplus (11%) with 8% short and 1% very short.

The summerlike September weather spilled into the beginning of October when high temperatures climbed into the 80’s and 90s, but hot weather was short-lived by a changing weather pattern and cooler conditions the rest of the month. High temperatures topped out in the 30’s toward the end of the October with a snow event impacting the northern half of the state on Halloween morning.

The statewide average October temperature was more than 3 degrees below the long-term average, making it the coldest October in a decade and the fifth below average month for the year. The first fall freeze impacted much of the state during the morning of October 12 when temperatures dipped into the upper 20’s and lower 30’s.

The beginning of October was dry in portions of south central and southeastern Missouri and for the first time this year a drought status category was depicted in some southeastern border counties according to the U.S. Drought Monitor map. Wetter conditions emerged statewide as the month progressed and Missouri was again “drought-free” by the end of October.

The statewide average October precipitation total was 5.30 inches, more than two inches above the long-term average. It was the wettest October since 2014 and the eighth wetter than average month for the year. Heaviest precipitation occurred over the southeastern 2/3 of the state where 4-7 inches were common. A few southwestern border counties reported more than a foot of rain including locations in Barry, Stone and Taney Counties.

The wet, cool weather during October limited opportunities for crop dry-down and harvest. Crop harvest was running behind normal across the region and creating other problems related to crop disease, stalk lodging, winter wheat planting, compaction, and fieldwork preparation for next year. According to the Missouri Agricultural Statistics Service, for the week ending October 27, corn and soybean harvest was 64% and 43% complete, respectively; 20 percentage points behind the 5-year average for corn and 15 percentage points behind for soybean. The majority of topsoil and subsoil moisture conditions were reported adequate at 86% and 85%, respectively. Pasture conditions were mostly good at 65% with 10% reported excellent. Hay supplies were mostly adequate (71%) to excellent (8%) with only 20% reported short to 1% very short. Stock water supplies were mostly adequate (93%).

Soil moisture conditions were unusually wet at the end of October across much of the north central and central U.S. and an elevated risk for flooding over the next several months will likely persist across the Missouri and Mississippi River Basins.