The Fourth of July will come on the Third this year in Boston.
The annual Boston Pops concert and fireworks extravaganza on the Esplanade in Boston will be held Thursday instead of Friday because of the bad weather expected from Tropical Storm Arthur, officials said this afternoon.
“It’s not optimal. We wish it were, but we’ve got to deal with this,” State Police Colonel Timothy Alben said at a news conference this afternoon.
A rehearsal concert had already been slated for Thursday night and had been expected to draw up to 75,000 people to the Hatch Shell and the shores of the Charles River.
Alben and other officials gathered at a news conference on the Esplanade this afternoon and said that after studying weather reports and consulting with experts from the National Weather Service, they had decided that Thursday, even though there were predictions of rain, would be a better day than Friday to hold the concert and fireworks.
“We are struggling with models and projections and possibilities and so forth,” Alben said. “We’ve got to be somewhat flexible here.”
While the Fourth of July concert traditionally draws 600,000 to 1 million people, Alben acknowledged that the numbers would likely be lower with the abrupt change in schedule and the concert falling on a workday.
“I would say we’d see reduced crowds,” he said.
He also said that if the weather was bad enough Thursday, the event could be canceled.
He said that if that happens, the concert could not be rescheduled to Saturday due to musical “contracts and commitments,” but it was possible that the fireworks portion of the show could be postponed to that day.
The BSO said the show would begin at 8 p.m. Thursday. Viewers will be allowed into the secured areas of the Oval and the Lagoon beginning at 5 p.m. The remainder of the Esplanade will open during the day.
State Police advised people that Storrow Drive would be closed at noon in both directions; Memorial Drive would be closed at 6 p.m. in both directions; and the Massachusetts Avenue and Longfellow Bridges would be closed at 6 p.m.
“We certainly want to get the notice out to the business community” about the closure of Storrow Drive, said Alben.
The National Weather Service says that widespread showers and thunderstorms with locally heavy rainfall are expected beginning Thursday night and continuing into Friday as Tropical Storm Arthur sweeps through the Atlantic to the east of New England. Arthur is expected to make its closest pass to the coast Friday night into Saturday.
“Our teams have really been watching the forecasts, and they don’t look great, and we think the best day to get the show in is tomorrow,” said Department of Conservation and Recreation Commissioner Jack Murray.
“We’re keeping our fingers crossed that the weather cooperates tomorrow evening,” said Undersecretary for Homeland Security and Emergency Management Kurt N. Schwartz.
Alben said that officials recognized that there were predictions of rain for Thursday but said officials “would try to ride through that.”
MBTA Transit Police Chief McMillan urged people to take public transit to the show — and asked them to be patient with any delays.
In an e-mail to public safety officials around Massachusetts, State Fire Marshal Stephen D. Coan earlier today advised that fireworks mortars should not be loaded if heavy rainfall or high winds are forecast for the show time. He said that displays should be protected from rain, and fireworks should not be shot off during periods of high wind.
“Storm surge and swells may also be a consideration for barge-based shows scheduled through July 5th and July 6th,” he said.
Inclement weather around the Fourth is not unprecedented in Boston.
In 1992, the Boston Pops orchestra performed the concert, but the fireworks were pushed back a day because clouds hung so low over the city no one would have been able to see the sparkly detonations.
In 2012, the concert and fireworks were delayed, but ultimately completed, when a storm brought lightning to the Esplanade. The concert and fireworks resumed after the storm abated.
This afternoon, the city of Lynn postponed its fireworks show until Sunday, July 6, citing the inclement weather.
On the Cape, the town of Barnstable has canceled its July Fourth fireworks while others, such as the all-volunteer group that operates the Falmouth fireworks show, have announced they will make a final decision by 8 a.m. Thursday, which they plan to post on their Facebook page.
On the South Shore, the nonprofit that runs fireworks in Plymouth had already set July 5 as a rain date, but organizers had not yet decided what will happen on Friday, according to its website.
Under clear skies on a sweltering day earlier today, a crowd gathered outside Faneuil Hall to kick off Boston’s Independence Day festivities. Mayor Martin J. Walsh opened the 33d annual Harborfest, telling dozens in attendance in he was doing all he could to make Tropical Storm Arthur “go out to the right, and leave us.”
“There’s going to be a lot of people in Boston, I think it’s certainly going to hurt if we cancel it,” he said, noting. “Hopefully, it continues out to sea and never gets here.”
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Globe correspondent Kiera Blessing contributed to this report. John R. Ellement can be reached at firstname.lastname@example.org. Follow him on Twitter @JREbosglobe.