Officials at Leopardstown are struggling to predict what the going will be when the track's high-profile fixture gets under way on Saturday afternoon.
The Foxrock venue stages a superb eight-race card, getting under way at 3.45pm, with the Red Mills Irish Champion Stakes taking top billing a little over three hours later.
Conditions remain on the fast side of good following minimal rainfall overnight, but with heavy rain forecast for later in the day and on Friday evening, things could be vastly different on Saturday morning.
Leopardstown's racing and operations manager, Nessa Joyce, said: "We had an isolated shower overnight, which was a bit of a surprise and gave us four millimetres of rain.
"We're calling the ground good to firm all round at the moment and we'll just have to see what happens later in the day. It's the great unknown.
"I think it's going to be a good few hours before we get any more rain, they are talking between 4pm and 6pm and then on through the night.
"I think the heaviest of the rain is going to be in the middle of the night and the latest forecast suggests we could get anything between 10 and 20 millimetres.
"The good thing is it sounds like by the morning we'll hopefully have had the worst of the rain, so we should have a good idea where we stand.
"Hopefully it will clear away during the morning. The worst case scenario is that it rains throughout the day, but it is very hard to predict. Hopefully it is going to be more showery than persistent rain.
"There is a crazy outside chance we won't get any rain at all, so we're just going to have to monitor things very closely."
Officials have already made provisions to stage the early races on the inside track, in order to save ground for the big events later on the card.
"There are eight races and depending on what conditions are like in the morning, we've reserved the right to run the first three races on the inside track if we need to," said Joyce.
"We hope to run the entire card on the main track, but it depends how much rain we get."