Lack of normal precipitation in northern Corn Belt
Using simple statistical analysis, the average likelihood of erasing 1-inch of accumulated deficit since October 1 is 38 percent. For a 2-inch deficit, the likelihood is 28 percent, and for a 3-inch deficit, it’s 20 percent. Conversely, there is a 36 percent chance that the deficits could increase another inch, a 19 percent chance they would increase 2 inches, and a 5 percent chance they would increase by 3 inches.
One of the major differences between this winter and last winter has been the absence of snowfall across the northern Great Plains. Storm systems have remained well to the south and north of the region. Last year most locations in North Dakota were approaching 50 inches of snow for the winter, while this year you would be hard pressed to find many locations that have received 12 inches so far this winter.
The disappointing snow totals across the northern Plains have definitely reduced the flood risk for the Missouri River basin. Unfortunately, the miserable snow season has extended westward to include most of the central Rocky and Sierra mountains. With 40 percent of the snow season yet remaining, there is time to benefit from late snow storm activity, but current streamflow estimates don’t paint a rosy outlook.
If normal moisture is received through the remainder of the winter, streamflow estimates for the Platte watershed indicate flows of less than 80 percent of normal (Figure 4). More concerning is that the average snowpack in the central Rockies is under 85 percent. When it drops below 85 percent, it may likely disappear before mid-June as it did in 2000, 2002, and 2006. This would increase the odds that heat and dryness would build eastward until the Monsoon season begins across the desert Southwest during the second half of July.
The next couple of months are critical for cutting into precipitation deficits that have accumulated since the end of the last growing season across the northern Plains. If there is below normal mountain snowpack and March storms don’t substantially cut into these moisture deficits, a drought alert will likely be issued for northeastern Nebraska by early April.