https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2019GL085592
The impact of the Arctic stratospheric polar vortex on persistent weather regimes over North
America is so far underexplored. Here we show the relationship between four wintertime North American
weather regimes and the stratospheric vortex strength using reanalysis data. We find that the strength of
the vortex significantly affects the behavior of the regimes. While a regime associated with Greenland
blocking is strongly favored following weak vortex events, it is not the primary regime associated with a
widespread, elevated risk of extreme cold in North America. Instead, we find that the regime most strongly
associated with widespread extremely cold weather does not show a strong dependency on the strength of
the lower stratospheric zonal mean zonal winds. We also suggest that stratospheric vortex morphology
may be particularly important for cold air outbreaks during this regime