The going at Cheltenham was on Sunday morning changed to soft, good to soft in places, on all three tracks.
Clerk of the course Simon Claisse expects rain and milder temperatures in the build-up to the four-day Cheltenham Festival, which begins on Tuesday week.
He told Racing UK: "It looks as if with this milder weather it's going to stay unsettled, with bits and pieces of rain which will probably keep the ground where it is.
"Friday-Saturday looks like it could be pretty wet, with 10 or 12 millimetres - half an inch of rain.
"We may have heavy in places before we start, but let's remember that there have been plenty of years when we've been soft the weekend before the Festival and have ended up good by the Friday."
Ladbrokes slashed their price on heavy going for the opening day of the Festival on March 13. Heavy is now 9-1 with the firm, from 25-1.
"Due to a flurry of bets, combined with the latest reports from Cheltenham, we have had to slash the odds on heavy going on day one of the festival," the firm's Nicola McGeady said.
Ladbrokes - what will the official going be for the first race of the Cheltenham Festival:
4-5 Good to soft, 11-10 Soft, 9 Heavy, 33 Good, 250 Good to firm.
Select any odd to add a bet