Ag Weather Forum

We have been talking since the spring about the development of high pressure (blocking) in the higher latitudes (Alaska, Canada and Greenland) and its impact on the weather pattern in the central US (cool and wet).

Now on the verge of midsummer we can add a few comments on the expected weather pattern during the month of July. First-- there are no indications of an end to the blocking pattern in Canada. This will continue to allow the jet stream to move southward into the US, at times promoting episodes of cool, wet weather. Second--there are now clear indications that the summer subtropical ridge that promotes hot and dry weather will mostly be confined to the western US. In general when we see a ridge set up in this region during the summer, it tends to persist with no signifcant penetration into the Midwest. This is even more likely to occur in a summer with high latitude blocking forcing the jet stream further south than normal.

It appears that as we enter the month of July the greatest concern with crops in the Midwest will be a lack of sunshine caused by too much rain, the impact of this rainfall washing nutrients out of the soils and a lack of growing degrees days.

Mike

(CZ/ES)