Forecast: Mild Saturday, wet Sunday

The last weekend of 2013 on Long Island is expected to start out mostly sunny and mild and end wet.

Temperatures on Saturday are forecast to be close to 10 degrees above normal for this time of year, with highs in the upper 40s, perhaps the lower 50s, said Joe Pollina, meteorologist with the Upton-based National Weather Service.

Weather changes are coming, however, courtesy of a low-pressure system moving in from the southwest expected to bring "a decent amount of rain" on Sunday, as much as an inch to an inch and a quarter, Pollina said.

The rain is expected to start after noon and taper off around 9 p.m., he said.

Monday is expected to be mostly sunny, "a bit on the breezy side," with temperatures topping out in the lower 40s, Pollina said.

An arctic high pressure system is expected to build in after that, causing temperatures to drop below freezing for the rest of the week, he said.

The high forecast for Tuesday at Long Island MacArthur Airport in Ronkonkoma is 31 degrees, and it "won't make it out of the 20s" Wednesday through Friday, Pollina said.

There's a chance of snow Thursday night into Friday, Pollina said, but it's too soon to tell whether it will be of the light or heavy variety.