Fog was fairly patchy along the east coast of Queensland this morning but it became quite thick in places, leading to low visibility. Visibility dropped below 50 metres in some areas yet at the same time, just a short distance away visibility was good, greater than 10 kilometres. In the Brisbane area, visibility at Archerfield was less than 50 metres just before sunrise this morning yet less than 30km away, at Ipswich and Brisbane airport, visibility was good, allowing flights to come and go as planned. The main reasons were wind speed and humidity differences. It was more humid in the east of the city but slightly windier, yet in the west it was too dry for fog. Archerfield got the best of both with fog lasting until just after 5am. Those up and about early this morning near Bayside and in the Ipswich area may not have had a clue fog had been so thick so close by. A low pressure trough which had been crossing southern Queensland during yesterday, bringing a drier change, stalled overnight as it reached the Brisbane area. It had begun drying out western suburbs in the afternoon but had not dried eastern suburbs until about sunrise. It was a similar story further north with some parts blanketed while nearby was left under clear sky. Pockets of thick fog stretched as far north as the Central Coast. Visibility got as low as 100 metres at Bundberg airport and 450 metres, 150 metres at Samuel Hill, 250 metres at Proserpine and 450 metres at Mackay before wind picked up and dispersed it just before sunrise. The low pressure trough will shift northeast during the next day or so, keeping the relatively humid air to its east. Fogs are most likely north from Capricornia on Friday and north from the Central Coast on Saturday.