A gusty winter storm remains on track to batter the East Coast, threatening to tie up roads and air travel, cause power outages and dump snow from Washington to New England.

Uncertainty remains for the storm’s track, which is putting the largest cities right on the edge of the heaviest snow. A slight shift to the west could change New York from a total of 6 inches (15 centimeters) to a foot, starting Friday night, said Marc Chenard, a senior branch forecaster with the Weather Prediction Center. Confidence is high Boston will get at least 12 inches, while Washington may only see an an inch or two.

“Unfortunately, there is still a decent amount of spread, the gradient is right along the most populated areas,” Chenard said. “New York City is right on the gradient. It wouldn’t take much of a shift to bring the city itself into the foot range.”

While there could be flurries in New York Friday, the heaviest snow will strike overnight into Saturday. Boston will see its heaviest accumulations Saturday.

A storm of this size will cause airlines to cancel flights and most likely lead to reductions in commuter and long-distance train schedules. The National Weather Service has issued a winter storm watch from North Carolina to Massachusetts, and offshore ships are being warned of high winds and waves up to 9 feet (2.7 meters). The worst of the storm should hit east of Interstate 95, a major U.S. highway that links Maine to Florida and passes through many of its largest cities.

Philadelphia may receive about 5 inches, while amounts would increase across New Jersey, Chenard said.

Prior to the storm, the liquefied natural gas tanker Cadiz Knutsen anchored in Massachusetts Bay, joining the Exemplar, which has been there since late December. New England relies on LNG imports to meet heating needs. The Cadiz Knutsen’s arrival comes just as local spot prices reached $15 per million British thermal units, which is almost quadruple the benchmark U.S. futures contract.

On Thursday, U.S. gas futures climbed for a fifth day to as much as $4.451 per million Btu on the New York Mercantile Exchange. The looming nor’easter, as well as tensions in Ukraine, are contributing to the gains. Meanwhile, New York City on-peak power averaged $189.51 a megawatt-hour in the day-ahead market, keeping prices at the highest level for this time of year since at least 2017, according to grid data compiled by MCG Energy Solutions. Spot prices for the city are even stronger at $215.32 at 8:48 a.m. with demand coming in above forecasts on the state grid.

One of the problems meteorologists are having getting a clear picture of what is going to happen is disagreement between two of the major computer models, said Rob Carolan, owner of Hometown Forecast Services, which provides outlooks for Bloomberg Radio.

The European Centre for Medium-Range Weather Forecasts calls for little snow in New York for instance, while the U.S. Global Forecast System is predicting more, Carolan said. Hometown’s forecast is for 2 to 4 inches to fall across Manhattan with at least 8 to 14 inches in the Boston area. Some areas of eastern Massachusetts could see well more than 15 inches.

While the European model has had devoted adherents among meteorologists, Carolan said the U.S. GFS has done a better job this year and it’s currently calling for the storm to mirror a pattern seen by other systems all winter long.

This could be the start of an active pattern for the East Coast where numerous storms roll through bringing snow and rain, while out West, where drought remains entrenched, conditions will remain dry.

“It’s drier than dry in California for the foreseeable future,” Carolan said.