As we enter winter, it’s time to analyze whether this fall’s climate trends are likely to continue through winter (Dec-Feb) and what regions of the country are susceptible to production problems in 2012. This is the second consecutive winter with La Niña conditions in the Equatorial Pacific and there appear to be as many dissimilarities as similarities to the same time in 2011.
Source: U.S. Climate Prediction CenterFigure 1. Three-month temperature outlook for January to March 2012. Review of National Weather Trends
During fall 2011, drought began to rapidly develop across the southern U.S. Texas bore the brunt of drought which developed into one of, if not, the worst agricultural disasters in history. This drought has now expanded northward and includes Oklahoma and the southern two-thirds of Kansas.
In contrast, the eastern Cornbelt was extremely wet from fall 2010 to spring 2011, leading to planting delays and poor root development. The shallow rooting depth left crops vulnerable to dry conditions during the summer, resulting in significant production declines from Illinois east through Ohio. This fall excessively wet conditions redeveloped and are forecast to continue into spring.
Source:; U.S. Climate Prediction CenterFigure 2. Three-month precipitation outlook for January to March 2012. The northern and western Cornbelt turned excessively dry during late August through mid-November. This mostly duplicated conditions a year earlier, with one exception. Heavy rainfall that dropped up to 7 inches of moisture across southern Minnesota and northern Iowa in fall 2010 wasn’t repeated this year. A broad area of southern Minnesota, northeast Nebraska, eastern South Dakota, and northwest Iowa has received less than a quarter of its normal precipitation during the past 90 days.
This fall the Dakota’s didn’t receive the abundance of snow they did in early 2011 when record runoff led to flooding in the Missouri River basin. At this point, many locations across eastern Montana and western North Dakota have not received two inches of snow this winter. By this time last winter, 20+ inches of snow was the norm and the average snow depth ranged from 10 to 20 inches.
With the redevelopment of La Nina conditions this fall, there was considerable banter between climatologists as to whether 2011 winter trends would return in force this winter. So far the answer is no. First and foremost, equatorial sea surface departures are averaging about 1.5° C below normal, while last year the basin was nearly 3° C below normal. The current La Nina is rated as a weak to moderate event, compared to last year’s rating of exceptionally strong.