According to my grandfather's 1957 St. Joseph Daily Missal, this is the season of Septuagesima with tomorrow's Sabbath being the Sexagesima Sunday. This
begins the pre-lent period which comprises Septuagesima, Sexagesima, and Quinquagesima Sundays. These three weeks form a transition from the joy of Christmastide to the austerity of the Penitential Season of Lent. This is the season when the Church most earnestly invites her children to prepare properly for the Feast of Christ's glorious Resurrection. She urges them to rise from and expiate their sins; to practice prayer and charity with greater zeal; to become indeed new men through God's grace.
From Septuagesima to Holy Saturday, the "Alleluia" as well as the "Gloria in excelsis" are omitted in "Masses of the Season." Purple vestments are used to signify penance.