He can intend to fast Ramadan from the night until just before the major forenoon, as long as there is nothing that contradicts fasting after dawn. However, if something that contradicts fasting, such as eating, drinking, or sexual intercourse, occurs before that, whether intentionally or forgetfully, then the intention is not permissible afterward. As stated in the Indian Fatwas 1: 196; it was narrated from Salama ibn al-Akwa' (may Allah be pleased with him) that the Prophet (peace be upon him) commanded a man from Aslam to announce to the people that whoever has eaten should fast the rest of his day, and whoever has not eaten should fast, for today is the Day of Ashura. This is found in Sahih al-Bukhari 2: 705, Sahih Ibn Hibban 8: 385, and Al-Mustadrak 3: 608. Ashura was obligatory to fast before the obligation of Ramadan. Aisha (may Allah be pleased with her) said: "The Quraysh used to fast on the Day of Ashura in the days of ignorance, and the Messenger of Allah (peace be upon him) used to fast it. When he came to Medina, he fasted it and commanded fasting it. When Ramadan was made obligatory, he abandoned the Day of Ashura, so whoever wants may fast it and whoever wants may leave it." This is found in Sahih al-Bukhari 2: 704 and Sahih Muslim 2: 792. Imam al-Tahawi said: "This indicates that if someone is required to fast a day and did not intend it at night, it is sufficient for him to do so before noon." See: I'la al-Sunan 9: 113.