The National Weather Service is investigating whether a small tornado formed over land late Sunday afternoon on the northern end of Sebago Lake in Raymond.

The agency issued a tornado warning around 5 p.m. for the Sebago Lake area, but the threat passed by 5:30 p.m., said James Brown, a hydro-meteorogical technician at the weather service’s office in Gray.

Brown said he and other meteorologists were monitoring radar images at the time the warning was in effect and saw what could have been a “very small” tornado.

“We actually saw a rotation,” Brown said. “If it was over water, it would be a waterspout. If it was over land, it would be a tornado.”

After weather service staff members saw that initial radar image, they began searching social media sites to see if anyone was posting photos of what they may have seen.

“We got some pictures that we think might be something, but we need to look further before we decide,” said Brown.

Brown said the weather service may decide to send someone to Raymond on Monday to investigate further, but for now it is too soon to say whether what they saw was an actual tornado.

Thunderstorms continued throughout Sunday evening in parts of New Hampshire but did not reach as far as Maine. The National Weather Service reported that storms could continue Monday with possible damaging winds and hail in southern Maine during the afternoon.