Are West African Heat‐Lows Analogous to Dry Tropical Cyclones?

ABSTRACT Heat‐lows are low pressure systems that past idealised modelling work has noted qualitatively resemble dry tropical cyclones (TCs). This is because of their low‐level cyclonic circulation co‐located with strong surface sensible heat fluxes and deep dry convection. Direct quantitative tests of this resemblance are lacking, which is the focus of this work. We compare the climatology of summertime West African heat‐lows from a pre‐existing data of tracked dry low pressure systems against that of the traditional tropical cyclone potential intensity (PI) calculated from ERA5 reanalysis, generalised to apply over land with known sensible heat flux and variable land surface roughness. We find that the spatial distribution of heat‐low tracks correlates well with mean PI and the magnitude of peak near‐surface wind speeds (~10 m s −1 ) are reasonably well predicted by PI. However, heat‐low intensity shows minimal diurnal variation despite strong diurnal variations in PI. This suggests that they are not strongly driven by surface heat fluxes necessary to support a TC‐like system. Moreover, the composite structure of heat‐lows are found to be highly asymmetric and baroclinic, even when focusing on a small subset of the strongest cases. These results together suggest that West African heat‐lows are likely not analogous to pure dry TCs. Surface heat fluxes may still help contribute to their generation, and instead are likely sustained by the dynamics of traditional easterly waves or hybrid systems.