1956 U.S. weather revisited – July still following the trend
Weather patterns rarely repeat for any great length of time, but a parallel that World Weather Inc. noted a couple weeks ago seems to be in place. That parallel is with 1956, another year like this one in which La Nina had been around for much of the previous two years and a significantly negative Pacific Decadal Oscillation (PDO) was present. Both of these anomalies had been prevailing since the 22-year solar minimum occurred in 2020 (which is similar to that of 1954-1956). The rainy weather occurring so far in July across portions of the Midwest seems to be following that of 1956 after a very dry June.
World Weather reports, “June 2022 weather was quite similar to that of 1956 in the sense that most of the Plains, Midwest, Delta and southeastern states all reported mostly below-average precipitation. The pattern of June 1956 then suddenly changed in July with a wetter-than-usual pattern occurring in many of the same areas that had been drier biased in June. The same kind of pattern has evolved in the first 12 days of this month. Even though the specific details of the rain distribution in 1956 and those of July 1-12, 2022 are not exactly the same one must admit the trend change was similar and the impact was also quite the same – at least thus far.”
What happened in August and September 1956? World Weather says August 1956 was still wetter biased in the Northern Plains and Upper Midwest, but there was a drier tendency that returned to portions (not all) of the lower Midwest. The southern states remained drier than usual with the southern half of the Plains, Delta and portions of the southeastern states drier biased. September 1956 then turned more notably drier throughout the Great Plains and across much of the Midwest while staying dry in the Delta. The southeastern states, however, turned wetter – probably the byproduct of tropical cyclone activity or a trough of low pressure over the eastern U.S.
World Weather does not expect the parallel with 1956 to last through the next three months, but some flavor of these trends is expected because of the similarity to La Nina, PDO and the solar cycle as well as an upper air wind flow pattern that is quite similar to that which occurred in 1956. The weather forecaster this year’s ridge of high pressure may be a little stronger and a little farther to the east in late summer than that of 1956, which is why there may be some potential for soybeans in the pod filling stage late this summer to be impacted by late-season dryness. It is also the reason why World Weather believes there may be a greater risk to lower yields in the western Corn Belt this year relative to that in 1956 – mostly in and near the Missouri River Basin.
The forecaster concludes, “World Weather still does not believe there is any potential for a drought like 2012 this year and the evidence is building to keep all of the dryness in the Plains and western Corn Belt. Despite recent trade comments trying to parallel the June rainfall anomalies with 1988 and 2012, the parallel ended earlier this month with the significant rain that fell.” As of now, World Weather is “most concerned over Central and Southern Plains production potential along with the Delta and the southwestern Corn Belt (including Missouri, Kansas, southwestern Iowa, Nebraska and parts of South Dakota). These areas will be closely monitored for stress and late season downward pressure on production potentials. Other pockets of dryness and moisture stress may occur from time to time in the remainder of the Midwest, but recent history has shown that crop genetics have improved greatly over recent decades and timely rainfall with no extreme heat is almost better than any other pattern.”
USDA’s year-end discussion in 1956 pointed out that many crops yielded the best since 1948 (1950-55 were plagued by extended dryness). There were some record yields in 1956, despite hot, dry weather in the Plains and far western fringes of the Midwest.