Atmospheric Rivers in the Eastern and Midwestern United States
Associated with Baroclinic Waves
Atmospheric rivers (ARs) significantly impact the hydrological cycle and
associated extremes in western continental regions. Recent studies
suggest ARs also influence water resources and extremes in continental
interiors. AR detection tools indicate that AR conditions are relatively
frequent in areas east of the Rocky Mountains. The origin of these ARs,
whether from synoptic-scale waves or mesoscale processes, is unclear.
This study uses meteorological composite maps and transects of AR
conditions during the four seasons. The analysis reveals that ARs east
of the Rockies are associated with a long-wave baroclinic Rossby wave.
This result demonstrates that eastern and midwestern ARs are dynamically
similar to their western coastal counterparts, though mechanisms for
vertical moisture flux differ between the two. These findings provide a
foundation for understanding future climate change and ARs in this
region and offer new methods for evaluating climate model simulations.