Is a resident of Jeddah who performed Umrah in Dhul-Qa'dah and intended to perform Hajj obligated to offer a sacrifice during Hajj, and what is the required ritual for him?

Your 'Umrah on 14/11/1426 AH falls within the months of Hajj. If you remained in Makkah, the sacrifice of Tamattu' would be incumbent upon you. However, if you returned to Jeddah, then, according to a group of scholars, no sacrifice is due from you, because the distance between Jeddah and Makkah is a distance for shortening prayers (qasr). And whoever travels after 'Umrah during the months of Hajj to a distance of qasr or more, then performs Ihram for Hajj in the same year, no sacrifice is due from him. And even on the view that it is less than the distance for qasr, no sacrifice is due from you either, because you are among "the residents of Al-Masjid Al-Haram" who are not required to offer a sacrifice, based on the statement of Allah Almighty: "That is for him whose family is not among the residents of Al-Masjid Al-Haram."