Three less-than-terrific new releases are unlikely to dethrone “Harry Potter and the Half-Blood Prince” in its second weekend, even though Gitesh Pandya at Box Office Guru is predicting a drop of “at least” 60 percent, to around $30 million for the hormonal wizards. The consensus leader among the newcomers is the abysmal “The Ugly Truth” with Katherine Heigl and Gerard Butler, which Gitesh prognosticates will open at $21 million — a win for Sony, which reportedly spent under $40 million on this crass rom-com (and the picture looks it). I give it 1.5 stars and — caveat emptor — the reviews are a rotten 13 percent positive reviews at Rotten Tomatoes. Kyle gives 2.5 stars to the 3-D kids opus “G-Force,” which is drawing 16 percent positive notices at RT. Gitesh thinks Disney’s marketing might will bring in around $20 million over three days. Also opening wide is the Leonardo DiCaprio co-produced, femme-skewing horror flick “Orphan,” averaging a still-rotten 47 percent at RT but getting just 1.5 stars from cranky Kyle. Gitesh predicts that Warner will collect a piddling $9 million for the weekend for this variation on its classic “The Bad Seed,” co-sponsored by Robert Zemeckis‘ Dark Castle.