Highs on Sunday will be in the mid- to upper 60s, with mostly sunny skies for the rest of the day, according to David Stark, meteorologist with the service's Upton bureau.
But a cooler air mass moving in from the northwest will drop temperatures Sunday night into the lower 40s, with the pine barrens reaching into the low to mid-30s, Stark said.
"It's definitely a little bit cooler than what we would expect for this time of year," he said.
Monday and Tuesday will continue with the cool trend, with highs on Monday only going into the upper 50s to near 60, and lows on Monday in the upper 30s to low 40s, he said. Tuesday's highs will be in the low 60s, with lows in the lower 40s.
Wednesday will begin to warm up, with highs in the mid- to upper 60s. Wednesday afternoon brings a chance of showers that could last into the evening and overnight into Thursday, Stark said. Going into Thursday, low temperatures will be in the lower 50s.
Thursday will mark the start of several warmer days, with highs in the upper 60s to lower 70s, and lows in the low to mid-50s. Friday's highs will be in the lower 70s.
"We may even be slightly above normal by the end of the week," Stark said.