An amazingly strong high pressure system located over the arctic during the past month has brought wave after wave of colder-than-usual air into North America. The cold coupled with some periodic precipitation events has resulted in a greater-than-usual amount of snow on the ground from a part of the central U.S. Plains and lower Midwest northwest into the Canadian Prairies.

The cold and snow then worked together to produce some bone-chilling cold temperatures in the southern U.S. Plains, Lower Mississippi River Basin and Tennessee River Basin in the last days of March, resulting in freeze damage to wheat grown from western and northern Texas through the lower Mississippi River Basin.

An unusual snowstorm developed in the central Plains during the weekend of March 23-24 before moving across most of the lower Midwest. The storm produced 3 to 6 inches and local totals to 8 inches of snow across the region from Colorado and Nebraska to Ohio. Locally large amounts of snow fell in northeastern Colorado and central Illinois where 15- and 16-inch amounts were reported, respectively. The precipitation event extended the continuous snow field out of Canada’s Prairies and the northern U.S. Plains into the central Plains and lower Midwest. The large area of snow on the ground then helped to limit airmass modification as a surge of arctic air came southward into the United States.

Snow not unusual, but cold impressive

The snow was not all that unusual for this time of year, but the cold air that followed the storm was more impressive. Frost and freezes reached their way southward into all of West Texas and a fair amount of northern and central Texas on March 25, and then across most of the lower Mississippi River Basin on March 27. Damage was done to wheat produced in all of these areas, although the region is not known for its wheat production. Nevertheless, World Weather, Inc. has estimated wheat production losses in the United States from the week’s cold weather to be around 2% to 3%.

Little to none of the wheat impacted was of the high quality bread making variety that is produced in the central U.S. Plains, which leaves a large portion of the U.S. hard red winter wheat production region unaffected by last week’s cold and snow.

Much of the recent cold weather that has affected the United States has been associated with a much larger phenomenon called “Arctic Oscillation” (AO). Arctic Oscillation is determined by the strength of a prevailing high pressure system anchored over the arctic. When the high pressure system is exceptionally strong — as has been the case this late winter — it has a tendency to produce colder-than-usual temperatures from the Canadian Prairies through the heart of the U.S. northern Plains and upper Midwest into the lower Midwest and central Plains.

One year ago, there was virtually no snow on the ground and temperatures were at record warm levels. The anomalous winter weather of 2012 also was associated with Arctic Oscillation, but this time the arctic high pressure system was extremely weak allowing warmer air from the lower latitudes to reach much higher in latitude than usual resulting in greater amounts of warmth and little coolness.

Weather’s impact on Europe

Today’s strong arctic high pressure system is considered to be the negative phase of AO and it has implications of significance for many areas around the world, one of which is Europe. Temperatures across the European continent also have been colder than usual this year along with some greater-than-usual precipitation.

The wetter and cooler biased conditions across Europe, Canada and the United States have been tied to the Arctic Oscillation and the odds are extremely high that weather changes in the next few weeks largely will be determined by this dominating weather feature.

The larger-than-usual high pressure system aloft has been present over the arctic since early December, but has it only evolved into a significantly anomalous event in the past few weeks. Those are the same few weeks in which so much snow and cold has been reported across Europe, the western Commonwealth of Independent States and much of North America.

Forecasts see a weakening

Computer forecast models have suggested that the strong arctic high pressure system will weaken over the next two weeks and that should bring on less frequent and less significant precipitation for Europe and the United States. However, until the AO gets back to near normal there will still be bouts of notable cold weather.

Winter wheat development will begin to increase across the United States and Europe as the arctic high pressure system shrinks back down to a more reasonable size and that should occur over the next two to three weeks.

In the meantime, this winter’s abundance of snow in Canada’s Prairies, the north-central United States, Eastern Europe and the western Commonwealth of Independent States has been and will continue to be responsible for delayed early spring farming. The planting of corn in some areas either has been delayed or soon will be delayed because of slower warming than usual. The development of winter wheat, barley and rye also is evolving much slower than usual this spring in North America, Europe and western Asia.

India and China are the two most important wheat production areas in the Northern Hemisphere that will not be waiting on weather pattern changes before crop development and fieldwork may advance normally. China does have need for some rain in northern wheat and corn production areas while India is seeing its winter crops fill and beginning to mature. Harvesting of winter grain in India is expected to occur from now through May and the weather outlook is favorable for that purpose.