Neither liquidating instantly like the Wicked Witch of the West, nor receding over centuries like the glaciers that once covered New England, the snows of winter have been disappearing.

As the vernal equinox arrives at 6:45 p.m. today, the winter that dumped a total of 61 inches of snow on the region is expected to deliver one last sucker punch as it retreats, dropping 3 to 6 inches to bury all those lawns and sidewalks yet again. But amid the lingering ghosts of this cruel winter, there is reason for cheer. What it's leaving behind are the conditions for a lush, if late-blooming, spring.

"The groundwater and all our drinking water supply reservoirs are getting replenished," said Lori Mathieu, chief of the drinking water section of the state Department of Public Health.

Snowfall is expected to begin between 1 and 3 p.m., and may turn to freezing rain or sleet at night before ending between 1 and 4 a.m., Gary Lessor, meteorologist with The Weather Center at Western Connecticut State University, said Thursday.

"It'll be in the low to mid-40s on Saturday, then back into the 30s on Sunday and Monday, still much colder than normal," Lessor said.

Reservoir levels statewide had fallen below normal in August through November, but are now above the historical average, over 95 percent capacity, according to the health department. Groton Utilities' five reservoirs are at 98 percent capacity and expected to reach 100 percent soon, so the spillway into the Poquonnock River has been opened, said Rick Stevens, manager of the water division. The aquifer that feeds the utility's one production well - pumped only in the summer months - is at its maximum level, Stevens said.

"It's totally recharged," he said.

New London's public water reservoirs, which also supply Waterford and parts of East Lyme, were at 80 percent capacity on Tuesday, compared to 65 percent capacity at the same time last year, said Barry Weiner, chairman of the Water and Water Pollution Control Authority. He expects levels will approach 100 percent, and owing to the system's ample storage capacity, will be able supply plenty of water through the dry summer months.

"Our levels now are excellent," he said.

Groundwater, the source of private and public well supplies, had been below normal when winter started but now has recovered, said John Mullaney, hydrologist at the U.S. Geological Survey's Connecticut office. While much of the meltwater is flowing into streams, he said, some is being sucked into the soil. The USGS' six continuous groundwater monitoring wells around the state showed a sharp rise in the depth to water - how far down the water is in the well - on March 14, a rainy day in the 40s.

"Some of it is finding its way to the water table," he said. "It's good to have high groundwater levels at the beginning of the growing season. In the summer months, you don't get much recharge, so you're riding out on the storage you put up earlier in the year. This year, we certainly won't be starting out the year with any deficit."

The melting snow has filled streams and wetlands in time for egg-laying season, and is seeping into the thawing earth, moistening the top layers of dirt and percolating to the water table. Jon Morrison, supervising hydrologist at the USGS, said the slow changeover from ice and snow to water thus far has been a good thing, giving the ground and streams time to absorb the melt without causing flooding.

"If we get a very quick warmup with 2 to 3 inches of rain, we still have the potential for some flooding," he said.

Arthur Christian, supervising civil engineer for the state Department of Energy and Environmental Protection, said the ponds behind dams around the state are filling up quickly, and some spillways have been opened, but none is in danger of flooding so far.

"As long as it keeps melting slowly …" he said.

As any high school physics teacher will attest, the reason snow doesn't melt all at once when the thermometer starts to rise has to do with all the extra energy required for water to transition from the solid to the liquid phase.

"It takes a lot of heat to melt ice," Morrison said.

So until there's a run of 50-degree days, winter's icy leftovers will still be around, scattered in shady places in the yard and packed into stubborn mountains in mall parking lots.

Dave DeNoia, public works supervisor for New London, said the crop at the city's two snow farms has shrunk several feet recently, but it's got a long way to go. The city trucked and dumped tons of plowed snow on a 2-acre lot on Bank Street in front of the Shaw's Cove office complex, and on a 1-acre empty lot in the Fort Trumbull neighborhood. At their peak the snow farm piles rose about 15 feet high, he said.

"They came down 3 feet in the last two weeks, but I would predict you'll probably still see snow there until the first or second week of April," he said.

DeNoia is also in charge of the city's athletic fields. He's expecting the fields will stay wet for several weeks, probably delaying reseeding and other work.

"It's going to be a difficult year for getting the recreational fields open," he said.

Farmers may also have to wait longer than usual to plow and plant until the fields dry out sufficiently, said Jeff Ward, chief scientist at the Connecticut Agricultural Experiment Station.

"It could also delay some of the spring wildflowers," he said.

j.benson@theday.com

Twitter: @BensonJudy