Northern Hemisphere Warm Fronts Are Less Efficient at Precipitating Ice Than Their Southern Hemisphere Counterparts

Using satellite observations, ice water path (IWP), liquid water path (LWP), and surface precipitation across warm frontal regions are examined in the Northern (NH) and Southern (SH) Hemispheres, accounting for the life stages and characteristics of extratropical cyclones (ETCs). Focusing only on oceanic ETCs over a 4‐year period, composite transects of the observations reveal that most hemispheric differences in warm frontal IWP, LWP, and precipitation align with variations in precipitable water, cyclone strength, and storm maturity. However, for similar cyclone strength and environmental moisture, NH warm fronts during early development contain more ice but are less efficient at precipitating than those in the SH. Higher dust concentrations in NH might explain the greater ice amounts, while higher sea‐salt concentrations in SH might explain the greater precipitation efficiency in their respective warm frontal regions. Plain Language Summary This study investigates cloud and precipitation properties in warm frontal regions of extratropical cyclones (ETCs), focusing on how they evolve through different stages of the cyclone life cycle. Using global satellite observations of oceanic ETCs, we examine transects across warm fronts of vertically integrated ice and liquid amounts, along with surface precipitation, and compare these variables between Northern and Southern hemispheres. The observations reveal that ice, liquid and precipitation amounts depend strongly on the environmental moisture and cyclone strength, regardless of cyclone age. However, when selecting the Northern and Southern Hemisphere cyclones to have similar environmental factors such as environmental moisture, storm intensity, and maturity, Northern Hemisphere (NH) warm fronts in the early stages of cyclone development contain more ice but produce less precipitation than their Southern Hemisphere (SH) counterparts. One hypothesis is that higher dust concentrations in the NH storms may suppress ice fallout, contributing to the observed precipitation inefficiency. In contrast, SH cyclones may have more efficient precipitation due to sea salt enhancing hydrometeor removal.