The nationalist first ministers of Wales, Scotland and Northern Ireland held a summit in Cardiff last month where they signed an agreement, which is not legally binding, that said no Westminster government had the right to “block democracy”.
Swinney will tell his party’s supporters that “one by one, the stars are aligning in our favour”.
He will say that if the SNP lost May’s Scottish Parliament election, the case for independence “would have been set back decades”.
While the SNP won the Holyrood ballot, the party failed to win the overall majority Swinney had set as a target for trying to force a second referendum in the face of Westminster opposition.
Despite that, Swinney will declare that “there is no turning back”.
He is expected to say: “The SNP is making the weather.
“And make no mistake – the wind is now firmly in the sails of Scotland’s independence movement.”
The first minister will go on to claim that the unionist parties at Westminster are “weaker than they have ever been”.