Daryl Ritchison said he really doesn't forecast the weather. Rather, he analyzes long-term weather trends and current conditions and, based on what he finds, projects what's most likely to occur in the future.
Now, Ritchison, director of the North Dakota Agricultural Weather Network, thinks this is the best bet for the state in 2021: Dry, though probably less so than the exceptionally dry 2020, and warm, though probably not quite as warm as the much-warmer-than-usual 2020.
His data "really suggests the Northern Plains, much of it, in 2021 — especially the summer months, say the middle of May to the middle of September, the core of the growing season — will be above average (in temperature)," he said.
On the moisture side, North Dakota probably will be "a little drier than average," he said. "I think there are many reasons to think 2020-2021 being dry" and fewer reasons to think that "it will be wet next year and that we have a complete reversal going forward," he said.
Ritchison spoke Thursday, Dec. 10, at the annual Prairie Grains Conference in Grand Forks, N.D. The event, hosted by a number of North Dakota and Minnesota commodity and general farm groups, was held online this year, with all the sessions on one day instead of the normal two.
His presentation was aimed primarily at North Dakota ag producers. But it's relevant to adjacent areas in surrounding states, too.
Area farmers play close attention during the winter to what weather experts predict for the upcoming crop season. Different crops are affected differently by precipitation and temperature, so the winter predictions influence which crops are planted in the spring.
Potential conditions in April and May, when planting typically begins, are of particular importance at this time of year. Ritchison predicted the two-month period will start off relatively cold, but turn around in May.
Ritchison emphasized that North Dakota began a wet cycle in 1993 which continued, for the most part, through 2019. Late year, autumn was particularly wet.
"In fact, last autumn was the wettest autumn on record in North Dakota," he said. "It was way beyond the (previous) wettest."
In contrast, 2020 was extremely dry. For example, Williston, N.D., suffered through the fourth driest year on record, Ritchison said.
Over roughly the past 300 years, the area had several other wet cycles that typically lasted 20-25 years. Given that, it's reasonable to assume that the 2020s will turn drier, reverting to more common precipitation patterns. The coming decade probably won't be as dry as 2020, but annual precipitation totals generally will be lower than they were during the wet cycle, Ritchison said.
"I really think North Dakota is in the slow process of transitioning out of this wet cycle and moving into a slightly drier pattern going forward," he said.
This year also brought warmer-than-average temperatures. By one measure, most parts of the state "were 1 to 1.5 degrees above average. It doesn't sound like much, but it's a lot of extra growing degree days" (which accelerated the development of growing crops), he said.
That level of temperatures is unlikely to be repeated in 2021, with slightly above-average temperatures a more realistic possibility, he said.
Precipitation forecasts are tricky
Annual precipitation is difficult to forecast because thunderstorms produce erratic rainfall totals that vary greatly even in small areas.
"We're highly dependent on thunderstorms. We all have seen it. That side of the road, wow, they got an inch over here. But this field over here got nothing. It's just the nature of thunderstorms and why making a precipitation forecast, in particular," is difficult, he said.
"You can get the general flavor, as I like to call it, but you can't get everybody right — or very, very rarely," he said.
Overall, however, "There are reasons to think more dry than wet for 2021 which would be devastating if true in western North Dakota" which suffered through a particularly dry 2020, Ritchison said. "But it would be a question of how much drier than usual. If it's 10-15% (less), that probably would be doable. But if it's another year of 50% , then we're realistically talking strong drought."