![enter image description here][1] Figure 1: (a) Location of the different Adriatic Sea wave measurements along the Italian and Croatian coastline and (b) selected 36 one-day extreme wave events during the 1979-2019 period – depending on the wind conditions (bora or sirocco) schematized by arrows in the map, used for the SWAN model evaluation. The notation + 1 (panel b) means that the 01/01/2015 event is also selected To better understand the behavior of extreme Adriatic Sea wave storms under projected climate change, 36 characteristic events – 22 bora and 14 sirocco storms occurring between 1979 and 2019, were selected and ran in evaluation mode in order to (1) estimate the skill of the ultra-high-resolution Adriatic Sea and Coast (AdriSC) modelling suite used in this study and (2) provide baseline conditions for the climate change impact. The pseudo-global warming (PGW) methodology – which imposes an additional climatological change to the forcing used in the evaluation simulations, was implemented, for the very first time, for a coupled ocean-wave-atmosphere model and used to assess the behavior of the selected storms under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 greenhouse gas projections. The findings of this experiment are that (1) the AdriSC model is found capable of reproducing both the Adriatic waves associated with the 36 storms and the northern Adriatic surges occurring during the sirocco events, (2) the wave significant heights and peak periods are likely to decrease during all future wave events but most particularly during bora storms and (3) the northern Adriatic storm surges are in consequence also likely to decrease during sirocco events. As it was previously demonstrated that the Adriatic extreme wind-wave events are likely to be less intense in a future warmer climate, this study also proved the validity of applying the PGW methodology to coupled ocean-wave-atmosphere simulations at the coastal and nearshore scales. Additionally, the sensitivity of severe bora dynamics in the northern Adriatic Sea to atmospheric model resolution is tested. In this spirit, simulations of the Adriatic Sea and Coast (AdriSC) atmospheric models – i.e. the Weather Research and Forecasting (WRF) model at 15-km, 3-km and 1.5-km resolution, as well as ERA5 re-analysis at 30-km resolution are compared for the same ensemble of 22 severe bora storms spanning between 1991 and 2019. First, each model is evaluated against hourly ground-based atmospheric station data (wind speed and direction at 10 m, 2-m air and dew temperature, mean sea level pressure) for the ensemble of extreme events. Then, baseline conditions – defined as the median over the ensemble of peak conditions of each bora storm, are derived from the WRF 3-km model and used to describe the bora dynamical features captured at this resolution. And, finally, the differences between the remaining models (WRF 15-km, WRF 1.5-km and ERA5) and WRF 3-km are used to quantify the capacity of each model to reproduce the known bora dynamics. The comparison is also performed at the process level, i.e. hydraulic jumps and trapped lee-waves known to occur during bora. The findings of this study are that (1) sheltered ground-based stations as well as ERA5 re-analysis strongly underestimate extreme bora wind speed, (2) WRF 3-km model generally reproduce the bora dynamics except for the rotors which require a resolution of at least 1.5 km and (3) neither ERA5 nor WRF 15-km – and consequently, none of the regional climate models used in the Mediterranean Sea with a resolution of the order of 10 km, can be used to reproduce properly the wind-driven dynamics driving the dense water formation in the northern Adriatic Sea and thus the thermohaline circulation of the Adriatic-Ionian basin. [1]: https://files.osf.io/v1/resources/7d6jq/providers/osfstorage/5ec4df83f3e87e0089579200?mode=render