Travellers face continuing delays at Tullamarine as airlines work to clear a backlog in services caused by thick fog today.A Qantas spokeswoman said passengers on some routes would face waits up to half an hour this afternoon after three-hour delays to a number of domestic flights earlier today.Qantas diverted five domestic and two international flights to other airports as fog shrouded Melbourne Airport this morning.Virgin Blue diverted four domestic flights and cancelled three hours. A spokeswoman said a knock-on effect would create waits up to one hour until close of business.Passengers on other airlines also faced disruptions.According to the Melbourne Airport website, both domestic and international services had been affected by the fog, with at least one in-bound flight from Bali diverted and numerous arrivals from Sydney, Perth and Hobart either cancelled or delayed.The website was still showing cancellations and delays to domestic arrivals and departures this afternoon.
Terry Ryan, senior forecaster at the Bureau of Meteorology, said visibility was earlier been cut to about 500 metres by thick cloud, which was hovering only 100 metres above the ground.The situation had improved by about 2pm but the cloud was still very low, which would affect operations until at least 5pm, he said.‘We’re expecting it to be pretty murky still for a few more hours,Mr Ryan said.Tullamarine head of corporate affairs Carly Dixon said flight delays could extend into the afternoon as airlines worked to clear backlog of affected services.‘We’ve still got minor delays but certainly planes have been landing and taking off this afternoon, she said.Delays are primarily due to catching up the network now as opposed to  the fog.’Mr Ryan said the grey and damp start to today was a sign of things to come, with recent warm weather giving way to heavy rain, strong winds and plunging temperatures over the second half of the week.We’ve got a strong front coming up from the west which will go through in the early hours of Friday morning, he said.Tomorrow will be a shower or two and then fine, but on Friday we’ll go straight into showers and gusty, south west winds.We’re saying 13 to 16 degrees, so quite a cold day Friday. Potential for hail, maybe a thunderstorm. And then further showers around Saturday, with the temperature ranging from seven degrees to only 15.Mr Ryan said the unstable weather was typical for spring and could continue right through until Christmas.He said the bulk of this week’s rain would fall in the north and north-east of the state, but metropolitan Melbourne could expect some rain from Friday.