Ag Weather Forum

Greenland Block Threatens Planting

Bryce Anderson
By  Bryce Anderson , DTN Senior Ag Meteorologist
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With all the chatter about the state of affairs in the Pacific Ocean (El Nino/La Nina prospects), there has not been a lot of attention given to what's happened lately in the far northern latitudes. But, the past week has changed that dramatically.

Here's what went on: After the entire winter season featured mostly west-to-east upper air flow across North America, with very mild temperatures as a result, the configuration suddenly changed during the last few days of March, when a large upper-air high (ridge) developed over Greenland in the northern reaches of the Atlantic Ocean. The development of that Greenland ridge meant that the polar vortex (this entity is always around the Arctic) took a different slant. Rather than basically be confined to the high latitudes, the polar vortex instead adopted a north-to-south trajectory. And, we know what has happened since: bitter-cold air for the season swept across the eastern half of the U.S. Freezing precipitation and snow formed over much of the northern and eastern Corn Belt. Spring field work reverted from being an activity to just an idea, to the frustration of producers.

Blocking high pressure is not a new feature, of course. During the winters of 2013-14 and 2014-15, dominant highs set up camp along the west coast of North America, and brought on the polar-vortex dominated winters of bitter cold. The 2014 feature lasted well into the spring, whereas the 2015 pattern relaxed earlier and thus allowed at least the western Corn Belt to do quite well on spring planting.

Where we go from here is, frankly, up to the block. We have seen time and time again that forecast models have issued with these high-latitude blocks on both ends of the event--the models have problems in forecasting the development of these features, and the models also have issues in predicting their modifying and ending. Quite often, it seems that the models break these features down too early and then have to play catch-up in subsequent productions.

Because of the forecast models' lack of skill in handling the evolution of the blocking high pressure entities, the prospect of further slowdowns in field work and planting in the Midwest has to be taken seriously. We're certainly looking at another week to ten days of limited progress in most areas.

Another point to keep in mind is that, going back to 2009, we have had some springs with significant planting delays: 2009, 2011, 2013, and 2014. 2015 was highly variable, with very favorable conditions in the northwestern Midwest, and heavy rain and very slow progress in the southern and eastern Midwest. Only in 2010 and 2012 was planting a wide-open season, and we all remember what happened in 2012 with heat and drought reducing yields. So, history is certainly on the side of issues with spring planting. Add in the development of the enigmatic Greenland block, and this issue's potential for causing progress headaches becomes a prominent feature once again in 2016.


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