West African Heat Low Climatology and Comparison with Dry Tropical Cyclones

<p>Heat lows are low pressure systems have been qualitatively compared to dry tropical cyclones (TCs) given their low-level cyclonic circulation co-located with strong surface sensible heat fluxes. This work examines the climatology of West African heat lows and their relationship to TCs by extending the concept of potential intensity over land. Using ERA5 reanalysis, we calculate potential intensity over land from sensible heat flux and land surface roughness and orography data and use pre-existing data of tracked dry low-pressure systems to create composite West African heat lows during Summer. Potential intensity spatial distribution correlates well with that of heat low tracks and closely matches the peak heat low wind speeds. However, their asymmetric and baroclinic structure and the lack of marked diurnal cycles of maximum wind and minimum pressure in refined heat low composites suggest that West African heat lows are more likely analogous to TC-like baroclinic vortices.</p>