Drier, cooler air unfurls over Long Island on Friday as high pressure and gusty northern winds ride in from southern Canada, the National Weather Service said.

The service's Upton office said clouds will develop starting Saturday afternoon, but the weekend overall should be dry.

News 12 Long Island meteorologist Rich Hoffman said Friday conditions will include "mostly sunny skies" and daily highs across Nassau and Suffolk counties just shy of 60 degrees. That's a considerable drop from the 70-degree temperatures the past couple of days.

Hoffman called Friday a "jacket weather" day; the forecast also calls for a breezy north wind from 9 to 16 mph.

The weather service has issued a frost advisory from midnight to 9 a.m. Saturday. The advisory covers eastern Suffolk County and warns of temperatures dipping into the mid-30s.

Also, the service said favorable conditions exist on Long Island Friday for the spread of wildfires.

Low humidity and dry ground conditions mean an "enhanced threat of wildfire spread," the service said. "If a fire were to be ignited . . . conditions are favorable for that fire to spread."

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Hoffman said that in addition to the frost advisory for Saturday morning, there's a slight chance of showers from late Saturday into Sunday morning.

Expect high temperatures from 55 to 60 on Saturday, with more sunshine and slightly warmer conditions on Sunday.