Tropical Squall has been a force in Sydney's features for three-year-old fillies so far this season and now a new challenge awaits her as she bids to add to her Group One tally.

Sydney has staged two Group One races for three-year-old fillies so far this season - the Flight Stakes and the Surround Stakes - and Tropical Squall has won both.

Adrian Bott, who trains Tropical Squall in partnership with Gai Waterhouse, is now keen to see how the filly stacks up when she takes on some older mares at Group One level in Saturday's Coolmore Classic (1500m) at Rosehill.

Tropical Squall resumed from a spell with a tough all-the-way win in the Surround (1400m) on March 2 at Randwick and Bott believes that sets her up well for Saturday's feature for fillies and mares.

"She has come through that run in tremendous order and I thought she was open to some nice improvement coming out of it," Bott said.

"It actually looks a nice progression for her.

"It will be interesting to see how she is weighted against those older mares but 1500 metres around that track I think is ideal for her.

"Importantly she's trained on and I do think she's got that ability to measure up against the older mares, particularly at the handicap conditions."

Tropical Squall will be aiming to become the 18th three-year-old filly to win a Coolmore Classic, with Typhoon Tracy in 2009 the most recent filly to win the event.

After taking out the Flight Stakes (1600m) in the spring at her fourth career start, Tropical Squall was sent to Melbourne and stretched out in distance when second in the Ethereal Stakes over 2000m and unplaced in the Group One VRC Oaks (2500m).

Tropical Squall's Coolmore Classic performance will be important in determining the rest of her autumn campaign, with the $4 million Doncaster Mile on April 6 one of the races on the radar.

"The options could be a Doncaster," Bott said.

"She would be a nice lightweight chance in that, again keeping her at the mile.

"If things weren't to measure up as we hoped, or if the Doncaster or weight-for-age against those older mares isn't an option, well stepping out to a race like the Vinery against her own age and sex could be the option.

"That's where Saturday probably gives you a perfect indication."

Tropical Squall is an $8 chance (all-in) for the Coolmore Classic having been assigned 54.5kg amongst 27 nominations, headlined by Zougotcha ($4.50) with 57kg and Saturday's Group 1 Canterbury Stakes (1300m) winner Lady Laguna ($6.50) with 58kg, who is unconfirmed. A total of six three-year-old fillies have been nominated.