Significant North Atlantic Blocking is sometimes preceded by a very clear, dominating, southern stream over the Atlantic Basin. Below is a latitude by height u-wind plot for 1/1-1/10 in R1, 2021 vs. climo. This grid is between 0-100°W and 0-90°N from 850mb-10mb. pic.twitter.com/v7fdlJxxQq

— Anthony Masiello (@antmasiello) January 12, 2021