PMS tracks in the Hertzsprung-Russel diagram for solar metallicity stars with initial masses between 0.6 and 2.0 M_⊙ (classical models are shown here) and properties of the external convective layers. Colors indicate the radial extent of the convective envelope (top left panel), the temperature at its bottom (top right panel), the maximal convective flux (bottom left panel), and the thermal diffusivity below the envelope (bottom right panel). Dashed lines connect points with similar values for these quantities, and the colored axes are in cgs units. The dotted parts of the tracks correspond to the phase when the stars are still fully convective.