Increasing Future Precipitation in the Southwestern US in the Summer and Its Contrasting Mechanism With Decreasing Precipitation in the Spring

It has been known that the southwestern United States (US) experienced a drying trend during spring as climate warms. Less is about projected increase of summer precipitation in region and its physical mechanisms. By using model simulations moisture budget analysis, we show contrast to spring, changes gradient wind convergence both cause increasing summer. The change featured by larger water vapor along western coast than inland, thus causing enhanced advection future climate. caused maximum jet weakening over continental US near latitudes region, which leads convergence.