BOSTON -- These are the nervous hours for the NHL, the moments leading up to the Winter Classic when eyes are turned skyward and weather forecasts are close at hand and the threat of a winter disaster lurks in a drop of rain or flake of snow.
As much as the Winter Classic has become a staple on the NHL calendar, a monster event that has been far more successful than anyone could have imagined when the first one went off in snowy Buffalo two years ago, it will always come with a certain amount of uncertainty until the final whistle ends the game.
Indeed, part of the intrigue and charm of the event is waiting and wondering what side of the bed Mother Nature will wake up on come Jan. 1.
The weather forecast for Friday's game between the Philadelphia Flyers and Boston Bruins at Fenway Park has improved somewhat, lessening but not eliminating entirely the anxiety that goes with taking the game outdoors. Earlier in the week, the forecast called for rain showers, which would have presented a problem for the league's state-of-the-art mobile ice-making truck and endangered Friday's game.
Now, the forecast suggests cooler temperatures and a mix of snow and rain, although a significant accumulation will also be problematic, as it was late in Buffalo.
Still, part of planning the Winter Classic includes planning for the event not to go off, or rather have it start a day later. Both the Flyers and Bruins had an off day built into their schedules in case the game had to be moved to Jan. 2.
"We'll continue to monitor the weather," Don Renzulli, the NHL's senior vice president for events, told reporters at a briefing this week. "We're prepared for a number of different issues, and when we get to Thursday, we'll make a call based on that current weather forecast. But right now, it looks like we'll be good to go and play the game."
One of the considerations for NHL commissioner Gary Bettman, chief of business affairs for the NHL Players' Association Mike Ouellet and ice guru Dan Craig will be the potential to get the full game in and whether they are better off rescheduling the game before 40,000 fans jam into their seats if the weather doesn't look like it's going to cooperate.
"In a perfect situation, we wouldn't want to bring them into the stadium if we knew we couldn't get the game in and we really have to think hard and really look at the forecast to make that determination," Renzulli said. "It's not like baseball where you can get in 5½ innings and it's a full game. We want to play three full periods and we're going to do everything to make a decision based on that."
So far, the league has avoided what NHL COO John Collins calls the "inevitability of weather," and there is nothing but optimism that the Fenway game will join the previous two installments as an unmitigated success. The league has reaped only huge benefits, both financially and optically, from the bold plan to take the game back to its roots.
In many ways, the Winter Classic is Collins' baby, part of a multipronged strategy he designed to improve the NHL's profile when he came to the league from the NFL.
"It has been the best example and the biggest example of what we're trying to do," Collins said Wednesday.
From an unknown quantity when the ice and boards rose up in the middle of Ralph Wilson Stadium in Buffalo, the event has become a signature event for the league and a cash cow for the teams that have hosted it.
Both Chicago and Boston tied tickets to the game to their season-ticket marketing. In Boston, it translated into about 5,000 additional season tickets this season. Corporate sponsorships for the event are also through the roof.
"It is amazing how far it's come," Collins said. "On a national level, the thing's been a beast."
In the past three years, the league's corporate advertising revenue has jumped 66 percent and the Winter Classic is at the heart of that leap. Sports Business Daily recently reported that sports business executives ranked the Winter Classic fifth among major sporting events they were looking forward to in 2010, ahead of sporting staples like the BCS National Championship, the World Series, the Masters and the Daytona 500. The survey was taken in December and included reports from more than 1,100 senior-level sports professionals.
The event has become so successful, it will spawn a second outdoor game in Canada, likely around "Hockey Day in Canada" in February of the 2010-11 season. Collins downplayed any idea that a second game would dilute the success of the Winter Classic, which has enjoyed huge television ratings.
For the first time, the league is accepting bids from teams which want to host the Winter Classic, and it's believed virtually every NHL team has expressed at least a passing interest in hosting the game. The bidding process begins next week and will conclude around the Olympic break.
Collins said there isn't a formula for where the game will be held in the future, but it won't stray too far from traditional hockey markets.
Regardless of where it ends up -- how about Heinz Field in Pittsburgh with the Washington Capitals visiting Sidney Crosby and the Penguins? -- rest assured, the event will continue to walk the tightrope between classic and conundrum.
Scott Burnside covers the NHL for ESPN.com.