multicyclone

Multicyclone is a meteorological term that describes a storm system in which more than one cyclonic vortex develops simultaneously. The concept is most commonly applied to large extratropical cyclones that, during their evolution, split into distinct secondary lows. Each of the resulting vortices still exhibits cyclonic circulation, but the original main low and the secondary lows can interact, merge, or dissipate over time. The phenomenon is also referred to as vortex splitting or cyclogenesis of secondary extratropical cyclones.

In practice, multicyclonic development is observed most frequently over oceanic regions such as the North Atlantic, where baroclinic instabilities can generate a secondary low to the south or west of the primary low. The interaction of the two lows can intensify rainfall, wind, and atmospheric pressure gradients, leading to complex and often severe weather patterns. In the Southern Hemisphere, similar behavior has been noted in the mid–latitudes, particularly in the South Pacific and Southern Ocean during spring and summer.

Research indicates that multicyclonic events may increase in frequency as climate change alters atmospheric stability and sea‑surface temperature contrasts. Forecasting these systems remains challenging because the evolution of the secondary vortices is highly sensitive to initial conditions and the surrounding jet stream configuration. Climate models that better resolve meso‑scale dynamics are essential for improving predictions of multicyclonic storm tracks and associated hazards. The study of multicyclonic systems is thus an active area of atmospheric science, contributing to more accurate severe weather warnings and a deeper understanding of extratropical cyclone dynamics.