High-pressure transcritical turbulent flow regimes enhance the mixing and heat transfer rates with respect to atmospheric pressure conditions [1]. The two characteristic states of supercritical fluids, gas- and liquid-like, are differentiated across the pseudo-boiling line. In this regard, their thermophysical properties in the vicinity of the pseudoboiling region can be leveraged to significantly increase the Reynolds numbers and destabilize the flow. The underlying physical mechanism responsible for this destabilization is the presence of a baroclinic torque, which is formed by the combination of rapid density gradients across the pseudo-boiling region (wall-normal direction) and the force driving the flow. As a result, the enstrophy levels are enhanced by 100× compared to equivalent low-pressure cases. Consequently, the flow physics behaviour deviates from standard boundary layers [1]. Therefore, the nature of this instability is broadly analyzed by means of linear stability theory. In isothermal wall-bounded transcritical conditions the presence of a secondary mode accelerates the turbulence transition, which is non-existing in super- and subcritical states [2]. Nevertheless, this transition is anticipated for non-isothermal flows. To this extent, these effects are characterized for Poiseuille flows using linear stability analysis. In particular, neutral curve sensitivity to Eckert numbers and perturbation profiles of dynamic and thermodynamic unstable modes, which trigger the early flow destabilization.