Unseasonably warm weather is on the way for Long Island this week, National Weather Service forecasters said Sunday morning, a day when much of the Island awoke to dense fog and slack winds that are expected to keep the shroud in place until midday.

"It's basically a cloud on the ground," said Joey Picca, a Weather Service meteorologist in Upton. "When winds are calm, it can't really mix drier air from above to help this fog burn off and it settles in place."

advertisement | advertise on newsday

A dense fog advisory was in place for Nassau County and western Suffolk and visibility was reduced to a quarter mile or less at Kennedy Airport and some smaller area airports. But police said they'd had no indication of any collisions due to reduced visibility and there appeared to be few flight delays because of it.

Picca said that highs during the next few days could reach the 50s and even 60s, about 10 degrees warmer than normal.

Cooler air from the west is due to arrive Wednesday and Thursday, he said, with lows once more dipping into the 30s and rain possible.