The National Weather Service says thundershowers are possible this afternoon and tonight, and frequent rains won’t let up until the new year. A flood watch was in effect for all islands today and will probably be extended overnight, said lead forecaster Roy Matsuda.

But the rain may move through quickly, he said.

"That may be our saving grace," he said. "The heavy rain cells might race across a location. It might be heavy but not stay long enough to cause extensive flooding."

The Kona low raised eyebrows over the weekend, especially on Kaua'i.

"Hail!" said Kaua'i resident Clifford Ishii. "In Waimea! What next? Snow?"

Well, yes. The road to the top of Mauna Kea was closed yesterday because of drifting snow. Drifts above the 13,000-foot level were up to two feet high.

Hail also fell on the leeward coast of O'ahu.

A few places across the state got heavy rain by last night, according to Bob Farrell, lead forecaster of the National Weather Service in Honolulu, and scattered but heavy showers remain likely throughout the next couple of days, with the possibility of rain continuing well into the week.

Parts of Hawai'i Kai got more than five inches of rain between 2 and 5 p.m. yesterday, and a gauge in the mountains above Nanakuli collected nearly 1› inches in less than half an hour.

Ishii, on Kaua'i, said his wife called him to the front door at about 2:30 p.m. to watch the pea-sized hailstones fall.

Radar also picked up hail in the Wai'anae Mountains of O'ahu, Farrell said.

"The air aloft is very cold — minus 20 degrees at 20,000 feet," he said. "The water gets pushed up to where it freezes, and comes down fast as hailstones.

"We’ll probably see more of that today or Tuesday."

Farrell said a storm system moved in over the state late Saturday, streaking the skies with lightning and leaving the Islands beneath its large, cold center yesterday and today.

"It should start moving west again on Tuesday," he said. "We may have more rain on its eastern edge."