Boston’s public schools closed in advance of a Friday storm that is expected to dump 8 inches of snow on the city.

Winter storm warnings were in effect for Boston and a majority of Eastern and Central Massachusetts from late Thursday until 3 p.m. Friday, according to the National Weather Service.

“The snow levels are expected to increase throughout the school day and we believe it is in the best interests of our students’ safety to close schools on Friday,’’ School Superintendent Tommy Chang said in a statement.

Mayor Martin J. Walsh, in a statement, added, “With expected accumulations of 4 to 8 inches over the next 22 hours, we are acting out of an abundance of caution for the safety of our residents, especially our children. Our Office of Emergency Management will continue to monitor the storm throughout its duration. I’m asking residents to remain vigilant during this snow event and keep an eye out for our neighbors, especially our seniors during this time.’’

The Public Works Department will have 500 trucks salting streets by 6 a.m, with 40,000 tons of salt on hand, the mayor’s office said. Two truck-mounted snow blowers will also be available for snow removal to clear main roadways.

Cape Cod and the islands, which were previously thought to receive the brunt of the storm, are now only expected to get 1 to 2 inches and are under a winter storm watch.

“Moisture and the colder air will mean a period of snow after midnight and through the [Friday] morning rush hour,’’ forecasters wrote. “The snow may mix with or change to rain.’’

Snowfall was expected to begin around midnight and continue through the morning commute Friday.

Snow could fall at a rate of one inch per hour in some ­areas.

The Massachusetts Emergency Management Agency said in a situational awareness statement that the snow will likely lead to hazardous driving conditions.

“This will be wet snow and the accumulation on trees and power lines could result in isolated power outages,’’ the agency said.

A snow emergency has not yet been declared, Boston officials said, so residents should not use space savers on streets.

The region already had more than 1,760 power outages as of Thursday morning, according to outage information provided by Eversource and National Grid, because of overnight rainstorms.

John R. Ellement of the Globe staff and Globe correspondent Mina Corpuz contributed to this report. J.D. Capelouto can be reached at jd.capelouto@globe.com. Follow him on Twitter @jdcapelouto.