Back-to-back storms Saturday and Sunday could bring up to a foot of snow to Boston, but it’s uncertain how much of the second blast will be icy and how much will fall as rain, forecasters said Friday.
The National Weather Service issued a winter storm warning for parts of Bristol and Plymouth counties — areas expected to see 4 to 8 inches of heavy, wet snow — from 1 a.m. to 7 p.m. Saturday.
The service issued a winter weather advisory for the same 18-hour period across a swath of northern Connecticut and much of Massachusetts, where forecasters expect 2 to 5 inches of snow.
A storm moving up the East Coast was expected to reach Massachusetts around 2 a.m. Saturday and linger through the morning, but move through the region quickly enough to that it will bring limited snowfall, forecasters said.
This storm will probably drop a wintry mix of precipitation across much of the area, with 4 to 6 inches of snowfall expected in Boston but mostly rain along New England’s southern coast, according to the weather service.
Saturday’s snowfall should be heaviest between 4 a.m. and noon, forecasters said, and wind gusts could measure 20 to 30 miles per hour along the Massachusetts and Rhode Island coasts, with gusts of 30 to 40 miles per hour on Cape Cod and the Islands.
Light snowfall could continue into Saturday evening, but skies should clear overnight, as the region sees a brief respite before another winter weather system arrives.
The coming storm caused Boston Public Schools to cancel all Saturday activities, as the city braced for dangerous travel conditions. Mayor Martin J. Walsh stressed in a statement Friday that he is not planning to declare a snow emergency or parking ban in the city, and that school is not canceled for Monday.
“Officials will continue to monitor the forecast and notify students and families over the weekend if the weather will impact school being open on Monday,” the statement said.
Boston Public Works planned to use 70 pieces of equipment to pretreat roads and to have 560 pieces of equipment working at the height of the storm, city officials said.
The Massachusetts Department of Transportation also prepared Friday to deal with the storms, with up to 700 workers and about 3,900 pieces of equipment available for snow and ice removal.
“Our snow and ice crews are closely watching the weather forecast and planning upcoming deployments of plows and other equipment,” MassDOT Highway Administrator Jonathan Gulliver said in a statement Friday.
“We encourage anyone who will be traveling throughout the weekend to check roadway conditions and weather forecasts before getting behind the wheel,” Gulliver continued, “and exercise safe driving behavior at all times including reducing speeds and giving plenty of space to plows and other vehicles.”
Following mostly dry weather Sunday, the weekend’s second storm is expected to hit the region that night and last into Monday, forecasters said. That system may drop significant snow inland, but the precipitation will probably shift into rain near the coast, the weather service said.
Overnight into Monday, inland snow could fall at 1 to 2 inches per hour, dropping 4 to 7 inches of accumulation along the Interstate 95 corridor and 6 to 10 inches further west, but only about 1 to 2 inches near the south coast.
Boston is expected to get about 6 to 8 inches of accumulation.
The winter weather could bring some power outages, forecasters warned, especially in the sections of Northern Connecticut, Northwest Rhode Island, and Northeastern Massachusetts, where more than half of foot of wet snow is anticipated.
Snow will end Monday morning but will probably impede rush-hour commuters, especially in the interior of the state.
Walsh asked that property owners shovel their sidewalks and walkways, as they are required to do, as well as fire hydrants and catch basins. He also asked that no one throw snow into city streets, impeding cleanup and potentially leading to a fine.
“We are encouraging residents to use caution when traveling, assist older neighbors and those who are disabled, and keep up with the shoveling of their property throughout the storm,” he said in Friday’s statement.
Walsh asked that city residents who see homeless people in need of help during winter weather call 911.
For the rest of the workweek, the weather is expected to dry out but get colder, forecasters said, with temperatures well below the normal range. Highs are expected to be in the 20s for much of the week, with lows in the teens.
Abbi Matheson of the Globe staff contributed to this report. Jeremy C. Fox can be reached at jeremy.fox@globe.com. Follow him on Twitter @jeremycfox.