Figure 4. Schematic representation of reverse shear polar low development. Dashed lines are low-level isotherms, stippling denote the main cloud areas. Polar low formation occurred on the warm side of the confluence zone between the cold-air at the rear of the synoptic scale cyclone (indicated by large “L”) and the warm sector.

Adapted from Bond and Shapiro, 1991; ©American Meteorological Society. Used with permission.