The borough council members will choose and appoint a new mayor and deputy to serve for the remainder of the civic year, which runs until May.
The East Anglian Daily Times understands that the mayor's role will be taken by Conservative councillor Nicolette Chambers, although this has not been formally announced.
Ms Chambers is currently deputy mayor and a councillor for the Chelmsford Rural West ward.
Her replacement as deputy mayor will also take place at the meeting.
Fellow Tory Mr Lee resigned on November 9 following claims illegal pornography had been downloaded onto his council laptop.
The father-of-three, who has not been arrested, also resigned as a councillor for the Moulsham and Central Ward.
He has been told he will not be able to continue his role as vice-governor of the Boswells School in Chelmsford until a police investigation into the allegations against him is completed.
Mr Lee's laptop was seized from his home earlier this month and specialists from Essex Police's high-tech crime unit are analysing it.
The investigation is expected to take months rather than weeks as police try and work out when any images were viewed and how many people had access to the computer.
Chelmsford Borough Council and 44-year-old Mr Lee, who worked in the banking and IT sectors, issued a joint statement at the time confirming his resignation.
It said: “This follows an ongoing police investigation in relation to alleged inappropriate use of computer equipment belonging to Chelmsford Borough Council.
“Full co-operation is being given to the police by the mayor and the council in an investigation, which is likely to last several months.”
Essex Police confirmed there had been an allegation from the council that one of its computers had been used to access “sexually explicit images”.