More than 1,800 flights have been cancelled in preparation for Winter Storm Juno – a snowstorm expected to be one of the worst to ever hit the Northeast of the US.

The worst effects of the "potentially historic" storm will be seen in New York, with Boston, Connecticut, New Jersey, Pennsylvania and Rhode Island all expected to see blizzard-like conditions.

"This is a major, potentially historic snowstorm for the Northeast and easily the biggest of the 2014-15 winter season so far," said weather.com meteorologist Chris Dolce. "Expect extreme impacts from eastern Pennsylvania and New Jersey through New England, peaking Monday night through Tuesday. Avoid all travel, as it will be extremely dangerous with blizzard or near-blizzard conditions likely."

Flights cancelled

Airlines that have been forced to cancel flights include American, Delta, JetBlue, Southwest and US Airways.

From the UK, both Virgin Atlantic and British Airways have also advised passengers flights have been cancelled as a result of Juno.

"On Monday 26 January heavy snow is forecast to fall over the East Coast of the USA. We anticipate that some flights to and from the US will be disrupted," BA said in a statement.

"Many flights may need to have de-icing treatment on their wings, engines and fuselage, before they are cleared for take-off and this might also lead to some flight delays throughout the day."

Virgin said its services to New York JFK and Newark, Boston and Washington are all affected. Passengers can change their ticket free of charge before 30 January, it added.

Worst in New York's history

New York Mayor Bill de Blasio said they are predicting up to three feet of snow in the city and warned people to "prepare for something worse than we have seen before".

"This could be the biggest snowstorm in the history of this city," he said. The National Weather Service called Juno a "crippling and potentially historic blizzard".

The heaviest snowfall ever seen in New York City took place in 2006, when 2.2 foot of snow fell between 11 and 12 February.

De Blasio advised drivers to stay off the roads and asked residents to check on neighbours, particularly the elderly. "Whatever normal precautions you take in advance of a storm, take even more," he said. "Stay safe."

Where is Juno coming from?

Winter Storm Juno was initially a clipper-type system – a fast moving low-pressure area that normally takes place between December and February in Canada and the Upper Midwest and Great Lakes areas of the US.

However, it is now set to turn into a major coastal storm after intensifying off the Atlantic Coast.

Winter Storm Juno is known as a nor'easter (or northeaster), a macro-scale storm that normally affects the Upper East coast of the US. It is an area of low pressure that normally passes just off the US and Canadian east coast. They have the potential to cause severe coastal flooding, hurricane force winds and blizzard conditions.

The National Weather Service said: "Unlike the system this past week which had limited access to cold air, a pronounced surface ridge to the north will supply sufficient subfreezing air to the Northeastern US. This will allow snow to be the dominant precipitation type with hefty totals expected given the anomalous slug of moisture hitting the New England coast.

"It appears many of the major metropolitan areas will be affected anywhere from Philadelphia through New York City and into Boston."

When will it hit?

Winter Storm Juno is expected to hit from Monday afternoon (26 January) and last until Wednesday.

"As the surface low deepens rather markedly late Monday night, the pressure gradient will increase resulting in very windy conditions across the north-eastern states," the National Weather Services said. "In particular, forecast wind gusts may easily reach the 40 to 70mph range resulting in near-zero visibility given the abundance of snow on the ground. This has resulted in blizzard warnings being issued from south-eastern New York/north-eastern New Jersey up the coastline to north-eastern Maine."

According to the Weather Channel, Monday evening and overnight will see the worst of the storm, with travel being "very dangerous or impossible". On Tuesday, the storm will continue with intense snowfall throughout the day, but this will begin to peter out by the evening in New York.

New England will continue to be hit by snow and rain in the early hours of Wednesday, but the storm should have come to an end by the morning.

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