A large rally is taking place in Portadown to show support for the Orange Order in the wake of the Drumcree dispute.
Hundreds of Orangemen are parading through the town centre, joined by bands and a crowd of supporters who have not been deterred by the stormy weather.
The parade comes amid continuing tensions surrounding the long-running Drumcree dispute, whereby an Orange Order parade has been banned from walking down the mainly nationalist Garvaghy Road in the County Armagh town.
Northern Ireland Secretary Sir Chris Bryant has held talks with representatives from both sides in recent weeks.
What is the Drumcree dispute?
The Drumcree parade dispute began in the mid-1990s and it almost derailed the peace process at the time.
Violence related to the dispute resulted in riots, roadblocks and murders.
When the Orange Order was prevented by police from walking down the route in July 1995 there was a tense stand-off. It was the same for the next three years.
The Parades Commission began operating in 1998 to regulate parades and try to defuse tension around marches.
Its decision not to allow a march down the Garvaghy Road that summer has been challenged by the order for the past three decades.
Last month, the Parades Commission decided that the march could go ahead on 27 September with restrictions in place after its original decision to stop the march was overturned in court.
That morning, up to 1,000 people - including nationalist politicians - blocked the road, preventing Orangemen marching from Drumcree Church a mile to the west.
Since then there were repeated attempts by the Orange Order to walk the route, but they were stopped by police.
Residents maintained a constant presence on the Garvaghy Road, but that ended on 9 October when the NI Secretary Sir Chris Bryant banned the parade following advice from the PSNI chief constable.
An Orange Order challenge to Sir Chris' decision was delayed on Monday after Northern Ireland's police chief Jon Boutcher was added to the case.
Belfast's High Court heard that the case is being brought against both Boutcher and Sir Chris.
Also on Monday, the Garvaghy Road residents failed in a bid to challenge the Parades Commission's decision to allow the Drumcree parade to walk down the predominantly nationalist road.
The Court of Appeal judges said their decision was confined to the lawfulness of the decision - it was not deciding whether or not the march should occur.
Lady Chief Justice Dame Siobhan Keegan said the ruling was decided before Sir Chris banned the parade.