The monster at this weekend's box office has nothing to do with the movies.

It's Hurricane Irene, and it's threatening to shave several percentage points off what already was expected to be a feeble box office take.

The storm, which the Weather Channel is calling an extraordinary threat and potentially devastating, could affect more than 50 million Americans from North Carolina to New England. A state of emergency has been declared in New Jersey, North Carolina and New York, and New York City mass transit is shutting down this weekend.

As one studio executive noted drolly, That's not exactly movie weather.

A hurricane is a whole lot scarier than the massive snowstorm that kept Avatar from breaking box-office opening weekend records in December 2009. And a few percentage points can make the difference on a weekend that's traditionally weak -- and one in which the No. 1 movie at the box office almost certainly will be The Help, the DreamWorks hit now in its third week.

Even in good years, the last few weekends of August tend to be box-office bummers, but Irene and a trio of new releases that offer low expectations may be the perfect storm.

Even before Irene threatened to keep the eastern seaboard away from the movies, no new picture was expected to take in even $15 million this weekend.

The three new films, the Weinstein Co.'s R-rated comedy Our Idiot Brother, FilmDistrict's R-rated horror Don't Be Afraid of the Dark and Sony's PG-13 thriller Colombiana, are all battling for second place, with no one expecting anything huge. Or even big.

The Weinstein Co. is betting that the low-cost Idiot will nonetheless pay off handsomely.

And there's reason to believe it will.

R-rated comedies have been hot this summer -- The Hangover Part II, Bridesmaids, Horrible Bosses and Bad Teacher all were legitimate hits, and Friends With Benefits was a modest success. The more recent The Change-Up and 30 Minutes or Less flopped.

Trailers have been in theaters since April, and tracking shows the movie doing well among both men and women, particularly those younger than 25.

Then there's the cost. Weinstein acquired the movie at Sundance for around $6 million, but has been spending heavily -- by Weinstein standards -- on marketing.

Weinstein, which hasn't had a big hit since The King's Speech, will cheer for any take in the double digits for Our Idiot Brother, which opens in 2,555 locations.

The movie, directed by Jesse Peretz and starring Paul Rudd, is aptly titled. It's about an idealist who barges into his three sisters' lives. Outside projections have it taking in anywhere from $9 million to $12.5 million.

Don't Be Afraid of the Dark is a remake of the 1973 TV movie.

Troy Nixey's R-rated horror, which FilmDistrict acquired and is releasing, has a fancy pedigree: Guillermo del Toro wrote the film, which had a budget estimated at around $28 million. Katie Holmes stars.

Horror comes with a solid fan base, and there has been strong internet awareness and search engine tracking. It's particularly strong among women younger than 25, with African-Americans and Latinos.

The movie, which opens at 2,716 locations, is projected to bring in anywhere between $10 million and $13 million. It's about a young girl who moves in with her father and his girlfriend, only to discover terrifying creatures in her new home.

But while this has been a good summer for R-rated comedy, it's been a frightening summer for horror. Final Destination 5 underperformed in its August 12 opening weekend, grossing a weak $18 million -- good enough to be No. 3 at the box office. The next weekend, Fright Night opened with an unimpressive $7.7 million -- No. 6 at the box office.

Finally, there's Colombiana, a PG-13 movie about a girl who witnesses her parents' murder and grows up to be an assassin.

The movie, directed by Olivier Megaton, had a budget estimated at $40 million and opens at 2,614 locations. Projections range between $7 million and $8 million on the low side to $14 million.

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