Nearly a foot more snow could accumulate by tomorrow morning in parts of St. Lawrence County, which is under a winter weather advisory posted by the National Weather Service through 11 p.m.

Several inches have fallen in St. Lawrence County communities, closing schools and forcing postponement of several planned events.

On top of what had fallen by this morning, more snow is forecast by tomorrow morning. Four to eight more inches could fall in Massena, five to nine inches in Potsdam, Canton, Ogdensburg and Gouverneur, and five to 11 inches in Star Lake, according to National Weather Service predictions.

The heaviest snowfall – perhaps as much as an inch an hour – is expected late this afternoon and tonight.

North winds are blowing at about 10 miles per hour and might gust as high as 30 mph.

Thursday and Thursday night, still more snow is expected, will the chance of snow at 70 percent in Star Lake and 50 to 60 percent in the rest of the county.

Through the period, lows in the low 20s and highs in the low 30s are predicted.

The NWS forecast for the St. Lawrence Valley and northwestern Adirondacks:

• This Afternoon: Snow. High near 27. North wind 7 to 9 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 2 to 4 inches possible.

• Tonight: Snow. Low around 22. Light and variable wind. Chance of precipitation is 100%. New snow accumulation of 3 to 7 inches possible.

• Thursday: Light snow likely. Cloudy, with a high near 29. Calm wind becoming west around 6 mph in the afternoon. Chance of precipitation is 70%. New snow accumulation of less than one inch possible.

• Thursday Night: Light snow likely before midnight, then a chance for flurries. Cloudy, with a low around 22. Light southwest wind. Chance of precipitation is 70%. New snow accumulation of less than one inch possible.

• Friday: Flurries likely. Cloudy, with a high near 31. Light west wind.

• Friday Night: A 30 percent chance of snow showers. Mostly cloudy, with a low around 22. Northwest wind around 6 mph.

• Saturday: Mostly cloudy, with a high near 30. Northwest wind 3 to 5 mph.

• Saturday Night: Mostly cloudy, with a low around 22. West wind 3 to 5 mph.

• Sunday: Partly sunny, with a high near 33. West wind 3 to 5 mph.

• Sunday Night: Mostly cloudy, with a low around 24. Southwest wind 3 to 5 mph.

• Monday: Mostly cloudy, with a high near 34. West wind 3 to 5 mph.

• Monday Night: Mostly cloudy, with a low around 23. West wind 3 to 5 mph.

• Tuesday: Mostly cloudy, with a high near 31. North wind 3 to 6 mph.