After a seasonable week, temperatures across Long Island are creeping up again, with a potential for a record-breaking high on Sunday.

Temperatures for Saturday are running about five degrees above normal, with highs in the mid 40s, said Jay Engle, a meteorologist with the National Weather Service’s Upton office. Usual temperatures for the season are in the upper 30s.

Clouds are expected to move in throughout the day, with a slight chance of sprinkles, until about midnight, when the chance for rain increases, Engle said. Temperatures will also drop a few degrees into the low 40s overnight before heavier rain moves in.

“The rain will become moderate to heavy at times into Sunday morning,” Engle said.

The rest of Sunday will be warm and wet — highs are expected in the upper 50s, with 59 forecast for Islip. That’s three degrees higher than the previous record, set in 2000, Engle said.

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“In addition to that, we’ll have gusty winds,” said Matt Hammer, a meteorologist with News 12 Long Island. “Rain will taper off to scattered showers during the afternoon hours.”

Sunday night, the temperatures should drop significantly into the lower 30s for a chilly Monday, Engle said.

Hammer added that there’s even a slight possibility we’ll see some snowflakes, though nothing is confirmed.

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“Yes, there is the threat for a few flurries or a light snow shower Tuesday night into early Wednesday morning, but nothing significant on the horizon just yet,” he said.

There may also be some wind in coastal areas, the service advised. A small craft advisory is in effect until 6 a.m. Sunday, and a gale advisory will be in effect from Sunday to 6 a.m. Monday.