WESTPORT — A nor’easter at midday Tuesday was buffeting Westport with driving rain, howling winds and sporadic flooding.

At noontime, there were about 100 power outages reported in Westport, while school officials canceled all after-school programs and at least one major road was closed to traffic.

And the National Weather Service predicts the storm will continue pounding southwestern Connecticut through the rest of the day.

As a result, a flash flood watch is in effect locally until at least 6 p.m. today, and a coastal flood advisory is in effect from 2 to 6 p.m. Concerns about potential flooding are greatest about 3:45 p.m., when the high tide crests along Westport’s shoreline.

Heavy rain — 2 inches already had fallen in Westport as of 11 a.m., according to the NWS — is likely to continue, whipped by wind gusts as high as 34 mph, the weather service predicts.

Although approximately 100 Westport customers of Eversource had lost power about 12:30 p.m., according to the electric utility, it warns more outages could occur as the storm drags on.

A stretch of Post Road West — between Wright and Cross streets — was closed to traffic about 11:30 a.m., according to a police alert.

All after-school activities in the town’s schools were canceled by the ongoing safety threat posed by the storm, according to an announcement shortly after 11 a.m. Tuesday from Supt. of Schools Thomas Scarice.

“Due to concerns with early evening issues associated with the nor’easter, all after-school activities scheduled for today” are canceled or postponed, Sacrice said in an emailed message. “Participants in any events being postponed will receive updates from the organizers about rescheduled dates when they become available.”