NEW YORK (BLOOMBERG) - A one-two punch of bad weather and longer airport security lines mean it will be a miserable weekend for many travellers in the United States.

Winter storm Harper, a blizzard that the National Weather Service expects to travel from the Midwest through New England and the north-east, may leave up to 45cm of snow. In addition, severe thunderstorms with damaging winds and isolated tornadoes may plague the Deep South, along with heavy rain and flash flooding from the Mid-South to the Mid-Atlantic.

Governors in Pennsylvania, New Jersey and New York have declared states of emergency even before the brunt of the storms hit the region.

Delta Air Lines, Southwest Airlines and American Airlines waived rebooking fees this weekend for travellers impacted by Harper.

As of 2.20pm in New York, 1,818 flights had been cancelled within, into or out of the US, the majority from Chicago, Boston and New York, according to FlightAware, a Houston-based airline tracking service. Another 1,739 had been delayed. Some 936 flights have been cancelled on Sunday (Jan 20), mostly in Boston, New York and Philadelphia.

The Transportation Security Administration on Sunday (Jan 20) reported an 8 per cent national rate of unscheduled absences on Saturday, compared with 3 per cent a year ago. Some workers said they aren't able to report to work due to financial limitations, TSA said in a statement on Saturday.

Though TSA workers are furloughed due to the US government shutdown, they're still required to work without pay.

Temperatures expected in the Kansas City area on Sunday - where the Chiefs will host the New England Patriots in an AFC Championship game - will be in the bone-chilling minus 2 to minus 7 deg C range.