John Sadler is hoping forecast showers arrive to give Charmed Harmony his best chance of winning the Newmarket Handicap at Flemington.

Charmed Harmony has a preference for a track with give in it.

Warm weather with the chance of showers is predicted for the remainder of the week and the best result for Sadler would be rain on raceday.

"They are tipping rain for the next few days but the only trouble with that is they don't water as heavily," Sadler said.

"For our circumstances I would like the rain on the day of the meeting."

Charmed Harmony had a 12-run campaign last preparation that kicked off with him finishing last at Randwick in February last year.

He pulled up with cardiac arrhythmia before stringing together a consistent campaign that saw him compile four wins on end.

Charmed Harmony also contested his only Group One race, finishing fifth to Stratum Star in the Sir Rupert Clarke Stakes at Caulfield last September.

The gelding resumed at Flemington on February 20 and after leading early knocked up in the straight to finish ninth over 1400m when ridden by Sadler's apprentice son Tom.

"He was disappointing first-up, he didn't run well at all," Sadler said.

"Tom thought it was the firm ground but he can put in the odd ordinary one.

"The horse is good and hopefully he's put that bad one away.

"I would be happy if he was competitive."

Sadler said he hasn't changed anything in Charmed Harmony's training routine.

And with 53kg, Katelyn Mallyon, who has three wins and a second from four rides on the gelding, regains the mount on Saturday.