The Andes Cordillera serves as a primary source of water for ecosystems and human

populations, yet it is increasingly threatened by climate change. At the same time, it

remains one of the regions with the largest uncertainties in projected precipitation

changes among Regional Climate Models (RCMs) and Global Climate Models (GCMs).

This study examines discrepancies in projections of seasonal precipitation and seasonal

maximum daily precipitation (Rx1day) simulated by ten RCMs and their driving GCMs.

We also investigate potential mechanisms underlying the spread of projections using a

Potential Instability framework.

In this talk, I will contrast the stabilizing effect of enhanced upper-tropospheric warming

with the increase in atmospheric instability associated with greater moisture availability.

The results reveal a shift in precipitation seasonality and contrasting signals between

seasonal precipitation and seasonal Rx1day. Overall, the robustness of projected

precipitation changes across the Andes is low, in contrast to the strong drying signal

consistently simulated by the driving GCMs.