Delays reported at area airports

Snow in Dallas. "Life-threatening" weather in Chicago, according to the National Weather Service. A winter storm warning for most of Long Island.

All affected air travel Tuesday, canceling almost 20 flights at Long Island-MacArthur Airport and causing several major airlines to issue travel alerts for MacArthur, LaGuardia, Kennedy and Newark.

At MacArthur, Southwest canceled nine arrivals and nine departures, all between 11:30 a.m. and 6:45 p.m., airport spokeswoman Catherine Green said. USAirways canceled an arrival due in at 9:50 p.m., Green said.

Southwest operates 20 to 24 flights daily at MacArthur. USAirways operates 10 daily flights at the airport.

The 7:10 a.m. Southwest flight to West Palm Beach left on time, but was delayed en route. The 11:05 a.m. departure is on time, but the 11:30 a.m. flight is canceled.

Green said conditions will be evaluated as the day progresses and each airline will determine whether to cancel more flights.

Meanwhile, major airlines, among them American, Delta and USAirways, have issued travel advisories for the northern U.S., including travel into and out of Newark, Kennedy, LaGuardia and Islip between now and Thursday.

USAirways is advising travelers they may be able to rebook their flights without a fee up to seven days before or after their original travel date during the affected period.

"Winter weather is expected to impact travel to, from and through 20 states" in the northern U.S. between now and Friday, according to a message on the Delta website. The airline advised ticket holders to check their flight status "frequently."

Most airline officials are recommending customers do just that and rebook flights when possible.