With the Ontario provincial election campaign still in its early days, the race remains Doug Ford's to lose. His Progressive Conservatives continue to hold a commanding lead in the polls.

But now Andrea Horwath's NDP has the momentum. It needs it. The party has a lot of ground to make up.

The CBC's Ontario Poll Tracker, an aggregation of all publicly available polling data, shows the Progressive Conservatives ahead with 41.1 per cent support and on track for a solid majority government.

The party has been leading consistently in the polls since shortly after the 2014 election. Not even the turmoil over the PC leadership appeared to have much of an impact.

But for the first time, the New Democrats have moved into second place and ahead of Kathleen Wynne's Liberals. The NDP now stands at 27.2 per cent support, with the Liberals trailing in third at 25.7 per cent.

Doug Ford (left) and the Ontario PCs continue to lead in the polls, while Kathleen Wynne's Liberals have dropped to third. (Frank Gunn/Canadian Press)

This represents a nearly four-point gain for the NDP since Apr. 30 and much of it has come at the PCs' expense; the Liberals have dropped only a point since then, while the PCs have slid 2.5 percentage points.

Six of the last seven surveys have put the NDP in second place (either alone or in a tie with the Liberals) and the increase has been recorded by multiple polls, with Abacus Data and Forum Research showing a five and six point gain over the last few weeks. Ipsos/Global News has put the NDP up a single point while Pollara/Maclean's, in the field publicly for the first time, pegged the NDP at 30 per cent.

PCs likely would win majority if election held today

But despite the NDP's gains in the run-up to the campaign launch, Ford's PCs are not yet in a position where they need to worry.

The Poll Tracker estimates the PCs would win around 87 seats with current levels of support. Their likely range of seats spans from 62 to 98 — almost entirely across the 63-seat threshold for a majority government. It is estimated that the PCs would have a 90 per cent chance of winning a majority if the election were held today.

The party leads in every region of the province. The PCs are ahead of the Liberals by about 12 points in eastern Ontario and one point in Toronto, while they are edging out the NDP by nine points in northern Ontario, 10 in the southwest and 19 points in the GTA-Hamilton-Niagara region.

The New Democrats likely would form the official opposition at their current level of support, winning about 27 seats or between 16 and 42 of Ontario's 124 ridings. The odds of the NDP finishing ahead of the Liberals in the seat count are better than three-to-one.

The Liberals, with just 10 seats in the projection, likely would be relegated to third party status, though the projection range for the party is between two and 34 seats.

Why the NDP's odds of winning are low — so far

The New Democrats have a number of things working in their favour as the campaign kicks off. Horwath is more popular than either of her rivals — Forum gives her a net +17 approval rating, compared to -15 for Ford and -51 for Wynne — while the party also has more voters available to it. Abacus says that 62 per cent of voters either will vote NDP or would consider doing so, ahead of the PCs' 54 per cent and the Liberals' 46 per cent.

Liberal and PC voters also rank the NDP as their preferred second choice in polling by Ipsos and Forum, suggesting that the party has the most potential for growth.

But the Poll Tracker model still only gives the NDP a 0.5 per cent chance of winning the most seats in an election held today, while the Liberals are awarded a 4.2 per cent chance.

How can that be the case when the NDP is projected to win more seats than the Liberals, and the party's upper range is also higher?

The problem for the New Democrats is that their support is not well distributed across the province. They are in play in fewer seats, while the Liberals and PCs are battling over a higher number. A drop in support for the PCs puts more seats into play for the Liberals than it does for the NDP, while the NDP needs to make more substantial gains before seats outside of its traditional bases of support begin to fall their way.

The error bars in the Poll Tracker take into account 80 per cent of potential polling errors; within that bar, the PCs win 100 per cent of the time. But outside of that 80 per cent confidence interval, the Liberals are projected to have a higher seat potential than the NDP — they simply have more seats than the NDP within their grasp if the polls are significantly overestimating PC support.

That's unlikely at this stage. If these numbers hold through to June 7, the polls would need to be off by an enormous amount to rob the PCs of victory. But if the New Democrats continue to make gains, Ford may need to keep a wary eye on his rear-view mirror.