Barcelona roof top

We will be spending a Saturday night in Barcelona during the Festes de la Merce at the El Palace hotel. I am looking for suggestions for a roof top bar or restaurant that may have a good view of the festivities.

Our flight out on Sunday is early, so we won't be having a "late" dinner.

Perhaps the The Grand Hotel Central in Via Laietana might be an option.

http://www.nextstop-barcelona.com/top-5-rooftop-bars-in-barelona/

or the Chill Out Terrace at the Ohla hotel

http://www.ohlahotel.com/en/#/gastronomia/ohla-terrace-chill-out/

I think the Mercer Hotel terrace is only for hotel guests at Plaça St Jaume.

There aren't any hotels near Placa Sant Jaume where the real action is. The parade procession snakes its way through the Gothic Quarter at a relatively rapid pace. It's a pretty crazy event in terms of crowd size....everything is really packed. Wish there were more locations for you, but unfortunately, you are limited. An option is using an apartment rental service that allows you to rent an apartment in Placa Sant Jaume for one day.