Race organisers say there'll be a three-hour delay to the racing schedule today because of heavy rain.
Roads are due to start closing from Barrule Park in Ramsey at 1.45pm, from the Bungalow at 2pm and around the rest of the course at 2.30pm.
Weather permitting, the Monster Energy Supersport Race and TT Zero electric race are due to be held today.
Organisers say they'll release an updated schedule at midday.
Bus Vannin looking for staff
Social housing rent threshold changes 'this year', says minister
Cleantech award-winner to make Island return
Island chemist to close, two others restrict hours
Friday's planned bus services listed
Celtic League hits out at Bus Vannin 'management stunt' during strike
Woman plans to break world record with Island swim
Warning over parasite causing sickness in youngsters