Only days after refusing to issue odds because of weather uncertainty, Afloat's Mystic Meg has finally nailed her colours to the mast ahead of Saturday's Round Ireland Yacht Race.

The latest forecast, combined with routing and tidal analysis, has persuaded Meg to move from caution to conviction, producing a full set of predictions for overall honours and every IRC class.

Leading the forecast is Guy Gillon's Botin 56 Khumbu, tipped for overall IRC victory ahead of Venomous and Loinnir Girl.

Khumbu is also selected to win IRC Zero, with Venomous second and Spirit of Shackleton completing the podium.

The change of heart comes as the weather picture begins to clarify. Forecasts indicate high pressure building across the region for Saturday's start, bringing generally fine and dry conditions with light westerly or variable winds, good visibility and a slight sea state off Wicklow. Early routing projections suggest a beat to Tuskar Rock before a period of very light winds on Saturday night. Winds are then expected to fill from the south before veering south-west, potentially producing a fast run along Ireland's south, west and north coasts.

Crystal Clear? — Saturday's forecast indicates high pressure over the Celtic Sea and light winds at the Round Ireland Yacht Race start, conditions that have prompted Mystic Meg to revise her predictions for the 704-nautical-mile contest Credit: weatherdotnet

Meg's analysis suggests the bigger boats could gain a crucial advantage if the forecast south-westerly fills in as expected along the west coast.

The thinking is that Khumbu and Venomous may be able to exploit the stronger breeze and extend away from the fleet before conditions become lighter later in the race, leaving the smaller boats facing a different weather scenario altogether.

That thinking helps explain the selection of Khumbu and Venomous, the two highest-rated boats in the fleet, for overall honours. Khumbu carries an IRC rating of 1.438, with Venomous rated 1.333.

Yet the forecast is far from a simple rating exercise.

In IRC One, Tom Kneen's Sunrise is tipped to win ahead of Andrew Hall's Pata Negra and Johnny Treanor's Cristina despite carrying a lower IRC rating than both Cristina and Courageous.

Similarly, John Malone and Sam Hall's Loinnir Girl heads Meg's IRC Three forecast despite not being the highest-rated boat in the class, while Ian Hickey's Cavatina is selected as a leading contender in IRC Four despite being among the lowest-rated boats in the race.

Those selections suggest that weather, tides and race duration may prove more decisive than raw handicap numbers.

One tidal gate in particular could become critical.

"Getting the tide at Rathlin could mean three or four hours difference to not making the tide, depending on wind," one experienced competitor suggested during pre-race routing discussions.

Meg believes Khumbu could finish as early as Tuesday, with much of the fleet expected home on Wednesday and the smaller boats arriving later.

Among the other class predictions are Gery Trenteasaux's Courrier Pogo in IRC Two, Loinnir Girl in IRC Three, Cavatina and John Murphy's Outrajeous at the head of IRC Four, and VSF Sports to lead the highly competitive Class40 fleet.

As ever, Mystic Meg is careful to add a disclaimer.

"These predictions are based on many variables, not least wind and tides. Use them as you see fit, but the risk is with the consumer."

With 704 nautical miles ahead and a forecast that remains capable of springing surprises, few competitors are likely to take that warning lightly.

Mystic Meg's full Round Ireland Yacht Race predictions are listed below. As ever, weather, tides and routing could yet make fools of everyone.