NEWBURYPORT - Unusual weather - including punishing storms and thick fogbanks - led firefighters, members of the Coast Guard and medical providers to respond to a spate of incidents yesterday.

At around 4 a.m. yesterday the rain brought down a large tree on Broad Street, blocking the road and causing minor damage to a parked car. Meanwhile in Amesbury and Salisbury, emergency officials cleared tree limbs that had struck power lines after high winds that swept through Thursday.

Later yesterday morning, near low tide, the Coast Guard was called to assist with a 30-foot sailing vessel that had run aground just inside Seabrook Harbor. By the time the Coast Guard arrived, the boat had freed itself, and the Coast Guard determined that it was undamaged.

Later in the day the Coast Guard responded again to a medical emergency on a boat out of Seabrook.

Seabrook Fire Department Capt. Clay Fowler said the rescue was for an elderly man on a party boat out of Seabrook who suffered a diabetic reaction while at sea. The boat operators, 25 miles offshore, contacted the Coast Guard, who brought Emergency Medical Technician Petty Officer Michael Barker to them on a Merrimack River-based rescue boat before bringing the patient back in to land. The Seabrook Fire Department took the man to Exeter Hospital.

At various points throughout the day, banks of fog rolled inland off the water. It was so thick, visitors to the Newburyport waterfront boardwalk couldn't see the Salisbury shore a few hundred yards away.

"The fog is pretty unusual to see in this area," said Petty Officer Joe Richie of the Newburyport Coast Guard station. "It can cause dangerous conditions, just because people aren't used to it."

The fog also whisped through Newburyport streets, before it gave way to hard rains.

Alex Case was caught in the afternoon downpour in downtown Newburyport while walking his dog.

"Today has just been weird," Case said. "First it was really hot and humid, then we had the fog coming in off the water, now suddenly the rain. It's all just been kind of unpredictable."

The National Weather Service reported dangerous thunderstorms with hail the size of nickels moving through the southern portion of Plum Island. Warnings were issued to boaters, but no damage was reported.

"We had a secondary cold moving through, bringing cooler, drier air behind it," said Frank Nocera, a meteorologist at the National Weather Service in Taunton. "It wound up producing several storms, some of which generated some pretty-good-sized hail."

Nocera said the rest of the weekend should be pleasant and clear, with high temperatures in the low 80s today and the high 80s tomorrow.