Missouri 2016 Growing Season Climate Summary
MU Extension/State Climatologist
Commercial Agriculture Program
November 9, 2016
Mild temperatures dominated in Missouri at the start of the growing season with April averaging 2.5 degrees above the long-term average. Precipitation was slightly below average with an average statewide total of 3.8 inches. Regionally, wetter April conditions were reported across far western Missouri where 4-5 inches were common; several locations between Kansas City and St. Joseph reported 5-7 inches for the month. Driest areas were confined to parts of north central, northeastern and south central Missouri where less than 2-inches were observed.
The mild and generally dry April weather was welcomed by farmers for planting opportunities. According to the National Agricultural Statistics Service, Missouri led the country in percentage of corn planted (89%) for the week ending May 1st, 42 percentage points ahead of the five year average. Nearly 90% of the pastures were in fair to good condition according to the Missouri Agricultural Statistics Service. Topsoil and subsoil moisture supplies were mostly adequate statewide.
For the first time in eight months the monthly temperature in May averaged below normal in the Show Me state. The average statewide temperature for May was nearly 1.5 degrees below the long-term average. From the onset, temperatures were variable during the month with alternating cool and mild periods. Precipitation data indicated a statewide average May total of 5.8 inches, or a little more than one-inch above the long-term average. It was the first wetter than normal month for the year.
May rainfall was variable across the state with heaviest totals reported across southeastern and northwestern sections, where 5-8 inches were common. Another area of higher rainfall, 5-7 inches, was located in southwestern Missouri, from Nevada to Joplin. Below average rainfall, with amounts ranging from 3-5 inches, were typical over north central, northeast, central and portions of southwestern Missouri.
Heat and dryness intensified during June and drought concerns and impacts were beginning to emerge. Missouri reported its 9th hottest June on record, similar to warmth experienced in 2010. The statewide average temperature was 77°F, or 4 degrees above the long-term average. For the northern half of Missouri, it was the warmest June in decades. St. Joseph, Kansas City, Columbia and St. Louis recorded their warmest June since 1953. The mercury climbed into the 90's on a majority of days, with only a few days reporting below normal temperatures. Columbia broke a June record for reaching the 90's on 19 consecutive days, June 9-27.
June precipitation data indicated a statewide average total of 2.5 inches, or a little more than 2 inches below the long-term average. It was the driest June since 2012. Rainfall was variable across the state with heaviest amounts reported across parts of northwestern and north central Missouri and southwestern and south central sections, where 3-4 inches were common. Lightest monthly totals ranged from 1-2 inches, and were typical over northeastern and east central sections and portions of central and southeastern Missouri.
By the last week of June, more than half of Missouri was experiencing abnormally dry to moderate drought conditions according to the Drought Monitor map. The hot weather in combination with much below normal June rainfall translated to vegetative stress for parts of Missouri and was evidenced by brown lawns and curling corn. Columbia, Missouri experienced its 6th driest January through June since records began, and driest first-half of the year in 24 years.
According to the Missouri Agricultural Statistics Service, by the last week of June, 51% and 39% of the topsoil and subsoil moisture supplies, respectively, were in short to very short condition in the state. Corn was rated mostly fair to good at 82%, and soybean conditions were mostly fair to good at 86%. Pasture conditions were in mostly fair to good condition at 89%. The majority of hay and stock water supplies were adequate.
Dryness concerns were mitigated in July when a wet weather pattern set-up across Missouri. Several widespread significant rain events occurred with rainfall data indicating a statewide average total of 6.7 inches, nearly 3 inches above normal. It was the 9th wettest July on record. Drought-stressed vegetation was able to recover with the wetter conditions. Most locations received 5 or more inches during July with radar estimates reporting 10 or more inches in several counties, mostly in central Missouri. Even though most locations reported abundant rainfall during July, there were a few dry pockets around the state, notably in a few northwestern, north central and southwestern counties, and the southern tip of the Bootheel.
July temperatures were slightly warmer than normal, but conditions were uncomfortable during the month due to summer heat and high humidity. The statewide average temperature for the month was 78.1°F, or 0.5° above normal. The wet conditions contributed toward higher summer dew points, similar to several high heat index days experienced in 2010 and 2011. Columbia's average dew point temperature for the month was 70.9°F, and ranked as the 4th highest for July.
The wetter July conditions benefited agriculture. According to the Missouri Agricultural Statistics Service, 81% of the state reported topsoil moisture supplies in adequate to surplus condition by the end of the month. Corn, soybean and pasture conditions were looking promising with 76%, 70%, and 58% in good to excellent condition, respectively. More than 90% of hay and stock water supplies were also adequate to surplus.
The wet period that began in July persisted into August. Most of the state experienced above normal rainfall, with data indicating a statewide average of 6.5 inches, nearly 3 inches above the long-term average. It was the 5th wettest August on record and the wettest August since 1982. The July-August period ranked as the 2nd wettest on record and wettest July-August since 1915.
The statewide average temperature for August was 0.5°F above normal. The mean temperature, however, did not tell the whole story for August temperatures and was a recurring theme for the summer (Jun-Jul-Aug). The statewide average summer minimum temperature was 3.0°F above normal, compared to the statewide average summer maximum temperature, which was 0.3°F above normal. This phenomenon has been a notable trend over the past few decades for Missouri. The average summer minimum temperature this year ranked as the 5th warmest on record, and warmest since 1954.
A contributing factor toward these summer max/min temperature disparities has been unusually high summer dew point temperatures in Missouri. This summer was unusually humid, similar to 2010 and 2011, and resulted in high heat indices and uncomfortable outdoor conditions for people, pets and livestock. Gulf of Mexico air masses over the region, in combination with abundant rainfall, led to efficient evapotranspiration from soil and plants. These conditions utilized a notable amount of the sun's energy, and acted to suppress maximum temperatures, but kept minimum nighttime temperatures elevated.
According to the Missouri Agricultural Statistics Service report for the week ending August 29, 2016, 91% of the state reported topsoil moisture supplies in adequate to surplus condition. An unusually large percentage of the subsoil moisture supplies (91%) were also in adequate to surplus condition. Corn condition was reported as 76% in good to excellent condition, soybean condition was 73% in good to excellent condition, pasture conditions were rated at 67% in good to excellent condition and hay and other roughages were 95% adequate to surplus.
Warm and humid were the dominant conditions for Missouri during September. The statewide average monthly temperature of 71.9°F was 3.6 degrees above the long-term average. Dew point temperatures also remained uncomfortably high for much of September. The only notable reprieve of cool, less humid conditions occurred during the last week of the month.
The majority of rain fell during the first 2.5 weeks of September and it was the third consecutive wet month for the state. The monthly average statewide total was 4.2 inches, slightly above the long-term average. Precipitation was variable with wettest conditions over northwestern, central and south central sections, where 4-6 inches were common. Parts of northeast and far southern Missouri observed below normal rainfall, with some locations reporting less than 3-inches. Corn harvest was advancing at an average pace by the end of September due to drier weather during the latter half of the month.
Autumn warmth persisted into October with only a few areas across northern Missouri experiencing their first light freeze. Median autumn dates for specific freeze thresholds in Missouri can be found at http://ipm.missouri.edu/FrostFreezeGuide. Temperatures averaged more than 5 degrees above average and it was the warmest October for Missouri since 1971. With few exceptions, dry conditions prevailed for much of October and provided ample opportunities for crop dry-down, harvest and other fieldwork activities. According to the Missouri Agricultural Statistics Service, corn and soybean harvest was 92% and 73% complete, respectively, for the week ending October 30.