For the first time since November the Madden Julian oscillation is activated and intensifying in the equatorial Pacific Ocean into early February. The result is increased risk of excessive precipitation in the East-central U.S. and a mild climate pattern east of the Continental Divide as the final month of meteorological winter arrives.

Beginning midweek the northern hemisphere jet stream will trough on the U.S. West Coast and re-strengthen in western Europe. In-between the two vigorous trough patterns a third trough resides south of Greenland. By late January the pattern still remains although with slightly less amplitude. These features shape the last third of January 2021 climate for the northern hemisphere.