Shah, who has been authorised by Prime Minister Narendra Modi to preside over the exercise of nominating the chief minister, will make the announcement at 4pm at "Kamalam", the party's headquarters in Gandhinagar, state unit chief Vijay R. Rupani said on Thursday.
Rupani met the media this evening after Shah held a meeting with him and other senior state leaders including Nitin Patel who, party sources in Gandhinagar said, had emerged as the front-runner, unless there was a last-minute surprise.
Patel, a veteran legislator and senior minister, was by Rupani's side when he spoke to journalists. Asked later about his prospective elevation, he said: "The party's central leadership will decide who will be the CM."
Informed sources claimed he has begun accepting congratulatory messages and telling MLAs and BJP office-bearers he would function in a "spirit of consensus" and make himself accessible to them.
Patel apparently emerged as a "consensus" candidate for two reasons: Anandiben, who reportedly shared with her media confidants her "bitterness" over the circumstances in which she had to demit office, made it clear to the Prime Minister that neither Shah nor his "surrogate" Rupani would be acceptable to her.
"If, despite her objections, for some reason Shah is chosen as the CM, it means Modi no longer listens to Anandiben," said a Shah loyalist in Gujarat.
A source in Delhi close to Shah said: "I cannot divulge the name but Amitbhai is not going as the CM. This is final."
Secondly, the Patels, who form the BJP's political spine and have been upset with the party over the crackdown on the Patidar (Patel) agitation for reservation, had to be "mollified".
"I don't know if bringing in Nitin Patel is the best way of placating them but the BJP has no other option," a source said.
The name of another minister, Saurabh Patel, the finance, energy and petrochemicals minister and a Modi favourite, had also cropped up briefly as Anandiben's successor. But he reportedly ruled himself out.
Shah arrived in Ahmedabad this morning and promptly held a meeting with Rupani, Nitin Patel and the others. "Taking everybody's inputs was necessary because the Gujarat BJP is faction-ridden and every MLA holds a strong opinion on everything," said the source close to Shah.
He was welcomed at the airport with a slogan that the Gujarat BJP had coined for Modi: "Dekhi, dekho kaun aaya, Gujarat ka sher aaya (look, look who's come, Gujarat's lion has come)."
In the past too, leadership changes in the BJP have had a messy prelude and, sometimes, an unhappy ending.
Shah has directed all party legislators to show up at the BJP headquarters at noon today for a last session before announcing the name of the next chief minister.
Central minister Nitin Gadkari and BJP general secretary Saroj Pandey will be around as special observers to see the process through.