Another noteworthy point is that the storm tracks placement relative to the jet stream could be a consequence of the non-zonal nature of the jet-stream, which is especially prominent in the Atlantic.
In general, the storm tracks are strongest in the winter. The Southern Hemisphere storm track has zonal variations which tend to alternate with the seasons, perhaps in conjunction with the split jet. I have also read (Trentberth, 1991) that low level baroclincity is strongest in the Southern Hemisphere during the local summer and perhaps this low level baroclinicity is contributing to the stronger than expected Southern Hemisphere storm track during their summer. There are also some irregular seasonal anomalies in the Northern Hemisphere, over the Pacific where, in the middle of the winter, low level baroclinicty and jet stream winds are simultaneously a maximum, but the storm activity is reduced. This is general attributed to the barotropic shear reducing the baroclinic eddies from fully growing or the strong winds blowing the disturbances through the zone of strong baroclinicity before the storms can develop.
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