Snow is falling Saturday in the Northeast, and the rare October Snowstorm of 2011 is expected to smash records from New York to areas inland of the Interstate 95 corridor before it ends early Sunday. Massive power outages are possible for millions in the heavy-snowfall areas of the Northeast due to accumulations of heavy, wet snow.

In New York City, where 2 to 4 inches is forecast for Manhattan, with more in the suburbs, there hasn't been measurable snow recorded in October since 1952. But with a 90 percent chance of accumulating snow, that's about to change as the record-setting October nor'easter plows up the East Coast on Saturday.

Already, the crushing early-season snowstorm is dumping heavy, wet snow across the Mid-Atlantic region, and it is spreading north -- getting stronger and moving fast. Because trees are still heavy with green leaves, the weighty, wet snow is expected to cause massive power outages where accumulations are the heaviest.

By mid-morning Saturday, rain had changed to snow in all of western Pennsylvania, and it was starting to change to snow in the Susquehanna Valley, including Harrisburg, Lancaster and York. Moreover, snow was accumulating on trees and grassy areas in Lebanon, according to AccuWeather. The same weather service gave the following snowfall reports by mid-morning Saturday:

-- 10 inches at Terra Alta, W.Va.

-- 7 inches at Redhouse, Md.

-- 5 inches at Farmington, Pa.

-- Heavy snow falling in Johnstown and State College, Pa., and in Camp David, Md.

-- About 22,300 people were without power in Maryland, Pennsylvania and West Virginia.

Even America's largest city -- New York -- won't be spared the brunt of this rare October storm. The latest models call for a 90 percent chance of four to six inches of snow in New York by Saturday night, with a low temperature of 32 degrees and blizzard-like winds bringing gusts of 40 miles per hour.

If the snowfall materializes, after beginning earlier in the day as a mix of rain and snow, it could easily become the largest October snowfall on record for New York. Previously, the largest such snowfall recorded in New York was 0.8 inches in Central Park on Oct. 31, 1925.

Inland areas of the Northeast are expected to get the brunt of the storm, with a total of six to 12 inches of heavy, wet snow falling northwest of I-95, from Pennsylvania to New York and Massachusetts. Cities in the heaviest snow forecast area Saturday include Allentown, Pa., Poughkeepsie, N.Y., and Worcester, Mass.

Tree damage and power outages are likely in the area, forecasters say, due to the nature of the heavy, wet snow that's expected to fall into warm surface temperatures.

Precipitation will start as rain in these locations, but may change over to snow. How quickly this occurs and how much snow falls is dependent on the availability of enough cold air, which is difficult to forecast early in the season.

The forecast high for New York on Saturday is 44 degrees, with rain potentially changing completely over to heavy, wet snow. A difference of just a few degrees could mean either some flakes mixing with rain for New York or four to six inches of accumulation on grassy areas like Central Park.

Also, when the low-pressure system is strong, as models indicate regarding the one approaching the Northeast Saturday, dynamic cooling can increase the odds of snow by cooling the air more than current forecast models show. Also, Saturday night's low is forecast to reach 32 degrees.

If measurable snow falls on New York, it will be a rarity. According to The Weather Channel, measurable snow has only been recorded three times in New York during the month of October. The earliest measurable snow occurred on Oct. 15, 1876. Philadelphia has a similar history, as measurable snow has been recorded in that city only five times during the month of October.