Long Island's clear, sunny Sunday will give way to a week that will become increasingly unsettled, the National Weather Service said.

"Today we will have a relatively nice day," said Joey Picca, meteorologist for the National Weather Service. Clouds will increase somewhat throughout Sunday, but it will stay dry, with highs in the lower 60s and lows in the lower 40s, cooler on the East End.

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Monday will be "not too different," Picca said, with similar temperatures and partly cloudy skies.

"Then Tuesday a big low pressure system starts to move in from the west," he said.

There will be a 30 to 40 percent chance of rain starting Tuesday that will increase through Thursday. Temperatures during midweek will be cooler, with highs in the mid-50s and lows in the low to mid-40s.

Then Friday, the weather will finally clear up and dry out, with highs in the lower 60s, Picca said.