A prediction that Tropical Storm Arthur will rain on everyone’s parade has forced communities to postpone Fourth of July celebrations.The Lynn/Swampscott Fourth of July fireworks show has been postponed to Sunday, while Nahant and Marblehead switched their festivities to Saturday.”The city did not cancel, we were canceled on,” said Lynn Mayoral Aide Mary Fountain.Fountain, who is co-chairman of the city’s fireworks committee, said they were contacted by Atlas PyroVision officials who told them that due to the inclement weather climbing up the coastline, the barge needed for the display would not be able to make it to Lynn on time.Marblehead officials use the same barge and were therefore forced to postpone that event as well. Marblehead officials decided early Wednesday to move its Fireworks & Harbor Illumination, which had been scheduled for Friday, July 4, to Saturday, July 5 due to the forecasts.According to the National Weather Service, showers and thunderstorms are likely tonight before 10 p.m. There is also a 50 percent chance of precipitation for Friday night.Since the communities share a barge, Fountain said Lynn was forced to move its holiday display to Sunday, which worked out. Lynn has an added concern that Boston would postpone its fireworks to Saturday.”If that happened, we would lose all our state resources,” she said. “We use all the same resources.”The city and Swampscott couldn’t pull of the display it does without help from the State Police officers and the Department of Conservation and Recreation. Fountain said there was some concern Boston would switch its display to Saturday as well, but, instead, Boston moved its program up a day to today.Acting on the side of caution, Nahant officials have also shifted all of its Fourth of July festivities to Saturday, July 5. Jennifer McCarthy from Parks and Recreation said she also spoke with the fireworks company running its show, and it, too, was concerned about pending weather. McCarthy said two years ago the show was rained on and some of the pyrotechnics did not fire.”So I have seen first-hand the havoc it can cause to a show,” she said. “Saturday looks much better.”The Forbush Road Race will take off at 8 a.m. and the Town Games will start at 9 a.m. The race starts at the corner of Flash and Fox Hill roads, come early to check in. All Town Games will be held on the field behind the Fire Station.Check-in for the annual Horribles Parade will be at 5:30 p.m. at the Town Dump gate on Spring Road, and the parade will step off at 6 p.m. sharp.Families will march to the Fire Station for awards, hot dogs, Popsicles and celebration, and then the big show, fireworks at Bailey’s Hill, will go off at approximately 9 p.m.On Sunday, DCR will institute a no-parking ban on either side of Lynn Shore Drive from King’s Beach Road to 193 Lynn Shore Drive beginning at 5 p.m. That state agency will close the road altogether from Nahant Street to the Swampscott line at 7:30 p.m. The closure will remain in effect until the revelers have cleared the site.Fountain said the annual concert by Lois Lane and the Daily Planets will start at Red Rock Park at 7 p.m. as usual.”They have been doing that pre-fireworks concert for 17 years,” she said.The fireworks will begin at approximately 9 p.m.It’s not the first time the fireworks in Lynn have been delayed.”We postponed them about two years ago, they were moved to July 5 because of rain,” Fountain said. “We don’t like to cancel if we don’t have to. It’s more work to cancel, actually, than to postpone. We just want people to be safe, that’s our priority.”