Updated at 9:45 a.m. to correct weather advisory ending at 4 p.m. today, not Monday.

A winter weather advisory is in effect until 4 p.m. in St. Lawrence County, according to the National Weather Service.

Several St. Lawrence County schools closed today due to slippery road conditions brought on by freezing rain, snow and sleet.

Snow accumulations of 1 inch are expected along with some additional ice.

Maximum snowfall rate is up to a half-inch per hour. The wintry mix will taper off into snow this afternoon and into Thursday night.

Many schools and afternoon activities have been cancelled, including the Sheard Litteracy Center''s Family Literacy Night and North Country Tai Chi classes in Heuvelton and Canton.

For more other cancellations visit http://northcountrynow.com/cancellations-delays

Drivers are urged to used caution while the advisory is in effect.

For up to date weather in your area visit northcountrynow.com/weather

A seven-day forecast follows:

• Today: Occasional snow and sleet before 10am, then occasional freezing rain between 10am and 2pm, then occasional rain after 2pm. High near 35. Northeast wind 10 to 16 mph. Chance of precipitation is 100%. Total daytime ice accumulation of less than a 0.1 of an inch possible. Total daytime snow and sleet accumulation of less than a half inch possible.

• Tonight: Rain. Low around 35. Northeast wind 9 to 17 mph. Chance of precipitation is 100%. New precipitation amounts between three quarters and one inch possible.

• Thursday: Rain. High near 42. East wind 6 to 13 mph becoming west in the afternoon. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

• Thursday Night: Rain and snow likely before 7pm, then snow. Low around 11. Northwest wind 10 to 16 mph, with gusts as high as 28 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 2 inches possible.

• Friday: A 30 percent chance of snow showers before 7am. Mostly sunny, with a high near 18. West wind 11 to 15 mph. New snow accumulation of less than one inch possible.

• Friday Night: Partly cloudy, with a low around 7. Southwest wind 5 to 10 mph.

• Saturday: Mostly cloudy, with a high near 33. Southwest wind 8 to 18 mph, with gusts as high as 30 mph.

• Saturday Night: A 40 percent chance of snow showers. Mostly cloudy, with a low around 20. West wind 10 to 18 mph.

• Sunday: A 30 percent chance of snow showers. Partly sunny, with a high near 31. Southwest wind 6 to 8 mph.

• Sunday Night: Snow showers likely, mainly after 1am. Mostly cloudy, with a low around 20. Southwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%.

• Monday: Snow showers likely. Cloudy, with a high near 24. West wind 5 to 13 mph. Chance of precipitation is 60%.

• Monday Night: A 30 percent chance of snow showers. Mostly cloudy, with a low around 5. Northwest wind 6 to 11 mph.

• Tuesday: Mostly sunny, with a high near 23. West wind 7 to 10 mph.