PATRIOTISM! Pyrotechnics! The threat of crummy weather! It wouldn’t be a proper Fourth of July without ’em – and this year, Hollywood delivers all that in what showbiz insiders are calling the most competitive box office week in years.

This week, three firecrackers — “The Patriot,” “The Perfect Storm” and “The Adventures of Rocky and Bullwinkle” — will explode into theaters.

Each has star wattage, great advance buzz and budgets that reportedly topped $100 million.

“Rarely have we seen a Fourth of July weekend with two or three of the openers really going head-to-head,” says Paul Dergarabedian, president of Exhibitor Relations Co., a box-office tracking firm.

“This could be one of the biggest Fourth of July weekends, because we’ve got at least two behemoths opening.”

Traditionally, a studio scrambles to secure the lucrative holiday weekend with what appears to be a sure-fire hit, scaring off the competition and avoiding a face-off.

But this year, the studios opted to risk pitching battlefield bravado against crashing killer waves and some long lost favorites from ‘toon town.

“Their competition will be vigorous because there’s no clear winner. All the movies have strengths and weaknesses, which make it hard to gauge exactly what will happen,” says Martin Grove, a movie analyst for CNN who handles box-office projections.

Whatever happens this weekend, experts say all three movies will fare well in the long-run, particularly because July 4th falls on a Tuesday this year, extending the movie-going week.

“There’s going to be a lot of business because you essentially have a five-day weekend,” Grove adds.

Tinseltown is sure to welcome a goose at the box office this summer. The mid-June box-office returns are lackluster, down nearly 25 percent from the same week last year.

There are a least a few optimists who believe that three major releases can boost each other, rather that compete.

“There is a theory that good movies breed more people to go back and give another movie a try,” says movie maven Harry Knowles, who runs the film-buzz Web site Ain’t it cool news.com. “If they don’t feel burned, they’re more likely to go out and see another one.”