The best day for outdoor plans over the Memorial Day weekend is probably Sunday, when clear, sunny skies and temperatures in the mid- to upper-70s are forecast, the National Weather Service said.

The start of the extended weekend on Friday is expected to be partly cloudy, the service's Upton office said, with daily highs in the low- to mid-70s and northwest winds increasing to 12 to 17 mph.

There's a slight chance of showers in the range of about 3 p.m. to 7 p.m. as a quick-moving cold front spreads across Nassau and Suffolk counties, forecasters said.

High pressure builds over the weekend and remains in place through much of next week, generating mostly clear skies and dry conditions through Sunday night.

The service issued a special statement on an enhanced risk for fire conditions on Friday and Saturday.

Dry ground conditions, low relative humidity and wind gusts of 25 to 30 mph are likely, which could "be conducive to the growth or spread of any fires that develop," the service said.

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Friday night remains breezy, with some gusts from the north of up to 21 mph.

News 12 Long Island meteorologist Rich Hoffman said any chance of rain through the extended weekend is small.

He expects mostly sunshine and said a high UV index means those spending lots of time outdoors should supply themselves with sunscreen, sunglasses and hats.

Hoffman also said beachgoers should be aware that "water temperatures are chilly at ocean and sound beaches, from 53 to 58 degrees."

Temperatures in bay waters are slightly warmer, from 58 to 63 degrees.

The cold front pushes out late Saturday, but lingers long enough for cool daytime temperatures; sunshine and daily highs in the mid-60s are forecast, with southwest winds 7 to 14 mph.

An incoming warm front means daily highs Sunday in the mid 70s with west winds between 8 and 14 mph.

Clouds move in late Sunday and overnight Monday, generating partly cloudy skies and a chance of showers and thunderstorms starting in the early afternoon.

Chance of rain for most of Monday is 30 percent. Daily highs are in the low to mid 70s.

Starting Tuesday, warmer temperatures appear likely for a stretch. Daily highs in the upper 70s are expected through Thursday.

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In its marine forecast, the service said a small craft advisory is in effect for Long Island waters from Friday afternoon into Saturday morning.

Winds should diminish later Saturday, with the advisory likely to give way to sub small craft advisory conditions for much of the extended weekend.