Sailors in this week’s Sydney to Hobart were planning to break race records, but instead they may be facing a different kind of wreckage, with a dramatic weather front set to strike only hours after the race begins.

Downpours, abrupt wind changes and thunderstorms have all been predicted, with fast and favourable winds at the start of the race turning sour as the largest yachts approach the Bass Strait.

“At the moment, we’re expecting strong winds to be likely for the race. There’s the chance that we could be seeing some gale wind warnings,” Gabrielle Woodhouse, senior meteorologist for the NSW Bureau of Meteorology, said at a pre-race briefing at the Cruising Yacht Club of Australia.

“There’s also the chance we could be seeing the risk of some lightning or some thunderstorms.”

Woodhouse offered positive news for the Thursday’s race start, saying winds in the harbour would sit at around 15 knots, increasing to 20 knots once yachts turn out of the heads, with sunny weather. However by Thursday afternoon, further south on the NSW coast, sailors can expect to be hit with destructive 35 knot winds and gloomy skies.

The full force of the trough is expected to strike in the early hours of Friday morning, just as the most competitive 100-foot supermaxi yachts hit the Bass Strait, where a southwesterly change could bring winds of up to 40 knots. For some, like race favourite Master Lock Comanche’s co-skipper James Mayo, this is all par for the course.

“It’s better than waking up on Boxing Day and knowing you’re facing a southerly,” Mayo said. “For us, it’s about keeping the boat in one piece.

“There definitely looks like there [will be] some difficult periods that you’ve got to transition through.