Snow began falling in New York City early Friday morning as Winter Storm Nemo loomed over the Northeast, poised to blast metropolitan areas with heavy snow and high winds.


Blizzard warnings have been issued for cities across the Northeastern U.S., and snow totals could reach historically high levels. Up to 30 inches of snow is expected to accumulate in Boston, Mass.; Hartford, Conn., could see 2 feet of snow, while New York City could get as much as 15 inches.


"We're talking about some fierce forces coming together," the Weather Channel's Jim Cantore said on Friday morning.


The worst of the storm is expected to hit Friday afternoon and evening. In New York City, the snow will fade to rain in late morning and early afternoon, with snow returning later in the day.


Massive travel delays are expected this weekend, and residents living in areas where blizzard warnings have been issued are advised to avoid travel. Wind and snow could create whiteout conditions and bring down trees and power lines. Northbound Amtrak service out of New York's Penn Station will be suspended Friday afternoon, with the last train departing at 1:03 p.m.


Storms feed off contrasts in temperature, and the weather conditions have set up a veritable banquet for Nemo. The storm is the product of a blast of frigid Arctic air moving southeast from Canada meeting with a warm, moist system coming up from the southern Atlantic coast. Higher-than-normal ocean surface temperatures are also providing extra energy for the snow to feed off, according to Weather Underground meteorologist Jeff Masters.


“The central pressure for this storm is of the sort we see with a Category 1 hurricane,” Masters said in a phone interview on Thursday. “It's not the same as a hurricane.” Nemo lacks the defined eye and structure that such storms have. “But there will be gusts of hurricane force.”


New York City could see wind gusts of more than 50 miles per hour on Friday evening, while Cape Cod could get blasted with gusts of more than 70 miles per hour.


High snow accumulation could land Winter Storm Nemo a spot in the record books. In December 2010, a Nor'easter dumped more than 20 inches of snow on New York City, with winds whipping the snowfall into banks up to 4 feet high. The biggest snowstorm in the city's history hit in February 2006, with nearly 27 inches of snow recorded in Central Park.


Boston, on the other hand, is poised to receive record snowfall. The city's highest snowfall total, 27.6 inches, occurred in February 2003, according to the National Weather Service.