Midlatitude storm tracks are stronger over ocean basins than continents, and also stronger in the Southern Hemisphere than in the Northern Hemisphere. It is still not clear how Earth's land-ocean distribution, ocean heat transport, and orography, set up this structure. We use an intermediate complexity moist general circulation model to reveal substantial non-additivities in the response to these inhomogeneities, and then diagnose why.

The doldrums are regions of light winds and relatively clear skies found in the tropics. They often occur during severe coral bleaching events on the Great Barrier Reef yet remain poorly understood. This study examines why the doldrums form and persist, identifying how both tropical and extratropical weather systems align to first form the doldrums and how the stalling of these weather systems prolongs the doldrums over the Great Barrier Reef.

Most convective storm losses occur in urban areas, raising the question of whether cities can intensify severe storms, such as supercells. We found that cities can weaken an approaching supercell by reducing low-level moisture, but can also trigger a new one downwind. More urban vegetation reduces city effects on storm evolution, while building height has little impact. This conceptual model improves understanding of supercell–city interactions and supports advances in early warning systems.

The study analyses how atmospheric river characteristics change in relation to warm conveyor belt ascent and how these changes evolve over the extratropical cyclone lifecycle. Using reanalysis data, we show that the ascent intensifies both the moisture content and precipitation values within the atmospheric river, and that this intensification occurs around the maximum deepening point of the extratropical cyclone. These can improve weather forecasts and early warnings for floods in Europe.

Despite steady improvements in forecasting skill, episodes of low forecast skill, called forecast busts, still persist. Using global ensemble simulations at different grid spacings, we show that coarse-grid simulations fail to resolve key mesoscale diabatic processes, and that errors upscale and propagate downstream, leading to large forecast errors. Fine grid spacing simulations better capture scale interactions in strongly diabatic flow, highlighting the potential of kilometer-scale models.