THICK fog at Ulmarra made for poor visibility on the highway and the river yesterday morning, obscuring the Ulmarra-Southgate ferry for much of its journey.
Weatherzone meteorologist Kim Westcott said although no fog was recorded at Grafton Airport, local conditions in low-lying areas were ideal.
"Clear skies and light winds with high level humidity...fog likes shallow places and the river helps with the humidity," she said.
Looking ahead to the weekend, Ms Westcott said cool mornings would hang around, but the days would be warm and sunny.
"Temperatures will reach 25 on Thursday and 26 on Friday but daytime maximums will drop on Saturday to a top of 20 degrees and this is due to the wind changing direction to come from the south."
She said there was a slight chance of showers for Monday.
Meanwhile the Bureau of Meteorology has this week released an update on the El Niño Southern Oscillation (ENSO) index, reviewing the likelihood of an El Niño event in 2014 down to 50%.
According to the report, if El Niño were to occur, it is increasingly unlikely to be a strong event.
"Despite the tropical Pacific Ocean being primed for an El Niño during much of the first half of 2014, the atmosphere above has largely failed to respond, and hence the ocean and atmosphere have not reinforced each other," the report says.
"As a result, some cooling has now taken place in the central and eastern tropical Pacific Ocean, with most of the key NINO regions returning to neutral values."
3 day forecast
Today 5-25 Patchy fog early in the morning. Sunny day. Light winds becoming NW 15-20 km/h in the middle of the day.
Tomorrow7-26 Sunny. Winds NW 20-30 km/h becoming light during the afternoon.
Saturday 6-20 Sunny. Winds SW 15-20 km/h tending SE to SW during the morning.