The most common upper level jet pattern with snowstorms that produce a large area of 10”+.
From Kocin and Uccellini, 1990
The lower branch of the direction circulation associated with the northern jet streak helps to provide an northerly component to the low level ageostrophic winds
The lower branch of the indirect circulation supplies a southerly component that helps enhance the low level jet.
The two branches act together to enhance low-level frontogenesis and upper level divergence