Two-time Sydney to Hobart winner-turned-weather technology expert Craig Smith believes it's unlikely the race record will be broken in this year's bluewater classic.
Monday's long-range weather forecast revealed uncertainty as to the 2023 race conditions, making for a nervous lead-in to Boxing Day for the fleet of 103 boats.
Four days from the start of the race, models are moving closer to consensus but there is still some doubt as to the kind of conditions boats will face on the 628 nautical-mile journey.
Crews will likely need to wait until late on Christmas Eve for more clarity.
Smith sailed on 2004 handicap winner Aera and was again aboard the winning boat on countback, Giacomo, in 2016, so knows only too well about the tense lead-up to the race.
He now works for PredictWind, an app that compiles models to predict likely weather conditions. Crews in this year's Hobart count themselves among the app's one million users.
Last year's fast conditions appeared to put the line honours record, one day, nine hours, 15 minutes, 24 seconds, under threat.
But Smith doubts whether any of the four 100ft supermaxi yachts can beat that time this year, set by reigning line honours champion Andoo Comanche in 2017.
"It just depends how they track with those light-air conditions, but if I had to put a dollar on it I'd say it's not race-breaking conditions," he told AAP.
"There's no consistent heavy, reaching and running that they'll get the opportunity."
Reigning overall winner Celestial and fellow TP52 Caro are both tipped as two of the favourites to win the race on countback this year.
Smith currently has them reaching Hobart in roughly two days, 16 hours, adding a possible change in the weather on the far-NSW South Coast may challenge the contenders for overall victory.
"It's going to be probably 40 per cent upwind, 50 per cent reaching, 10 per cent downwind - that's sort of the ball-park stuff," Smith said of the race.
"There's quite a bit of uncertainty at the start. There could well be thunderstorms, lightning at the start. That can change the dynamic at the start quite a lot.
"There's a transition zone potentially closer to Eden where there's sort of a light breeze they have in that section, using the south-bound current.
"It's going to be a real navigator's race. That transitional zone is going to be really key."
If local entrants are still scrambling to make sense of the conditions, the 10 international boats, less familiar with Australian waters, face an even tougher task.
"It's absolutely unpredictable," said German Chris Opielok, skipper of the JPK 10.80 Rockall 8.
"As far as I remember, we haven't had that situation so far. Yesterday, our arrival was about two-and-a-half days, today it's New Year's Eve."
