Direction also helps determine the fetch . This fetch must typically be at least 80 km to ensure that enough heat and moisture fluxes into the boundary layer to initiate significant convection. Stability Static stability affects the depth through which mixing and convection will occur. Deeper mixing allows deeper, more intense convection. Subsidence inversions almost always coexist with cold anticyclones.
Stability also plays a role in determining cloud band structure.
The relative humidity of the upstream air determines the amount of moisture required to saturate it. Drier airmasses require longer residence times over water to saturate. Without a saturated airmass, cloud formation and moist convection is inhibited. Furthermore, no latent heat is released. Aerodynamic surface roughness increases turbulent exchange from the lake into the boundary layer.