CHICAGO (CBS)– Airlines at O’Hare and Midway airports have canceled more than 1,000 flights amid snowy conditions.

The National Weather Service has issued a winter weather advisory, which was in effect until 2 p.m. Total accumulations are expected to reach 3 to 6 inches, with the heaviest snowfall expected over the northern and central parts of the Chicago area. Snow totals were expected to amount to 2 to 4 in the city. A daily record was set for snowall at O’Hare by midday with 3.4 inches of measurable snow.

O’Hare reported a ground stop for all planes until 8:30 a.m. Monday.

As of 9:50 p.m. Monday, 1,277 flights had been canceled at O’Hare. Officials said earlier that 98 flights had been canceled at Midway.

Average delays are approaching two hours at O’Hare and and less than 15 minutes at Midway.