WEATHERMAN John Kettley predicts that the ground at Aintree on John Smith's Grand National day will have softened up and he expects the venue to see around 20 millimetres of rain before Saturday.
Kettley believes the Liverpool track could endure periods of heavy rain every day between now and the National.
The BBC man, a keen follower of racing, is regularly consulted by Aintree clerk of the course Andrew Tulloch and also helps the likes of Cheltenham's Simon Claisse with up-to-date weather forecasts.
He said: "We have got our finger on the pulse, and there was some rain yesterday, although that wouldn't make any difference. But there is worse to come.
"I think Aintree has fared very well over the last three or four days. Not much rain has hit the course, which has helped things to dry out, and it looks splendid at the moment.
"The danger periods are coming and I think you have got to look at various periods of pretty wet weather through today and tomorrow.
"There is a chance of another line of heavy rain coming down off the Irish Sea on Friday night, so I think we are looking, all told, at around 20 millimetres of rain to hit the racecourse
"It has dried out in the last few days, which is great, but it is going to be soft, there is no question about that, and it just lengthens the list of horses you need to look at."