Weather forecasters say it will be a doozy — probably the worst winter storm of the season is headed for Toronto and most of southern Ontario.

"This storm has the potential to be quite significant and have high impact, especially if heavy snow develops," said Environment Canada in a news release.

The national weather service says the Greater Toronto Area should be prepared for a snowstorm packing anywhere from 15 to 30 centimetres of snow in the worst- hit areas. 

"A low-pressure area over west Texas is getting organized and setting its sights on southern Ontario.

"As the low moves east across the southern states then curves northeast towards the Ohio Valley tonight, it is expected to tap into a lot of moisture and energy from the Gulf of Mexico. As a result, there is potential for this low to intensify into a significant winter storm as it moves into southern Ontario [Thursday night] and Friday."

Freezing rain and ice pellets are expected to be the leading edge of the storm. 

Toronto is revving up its snow-clearing battalions.

For Friday's morning rush hour, expect to see more than 200 de-icers and nearly 700 road ploughs attacking the snow. More than 300 sidewalk ploughs are also standing by. 

Police services are also getting prepared for the latest winter wallop.

The OPP will be calling in extra officers to help out, and with "dangerous winter weather conditions," including whiteouts, predicted by Environment Canada, they'll be needed.

A similar storm that landed in southern Ontario just before Christmas resulted in hundreds of traffic accidents. 

Police are hoping many people will heed their warnings and take a long weekend.

Officials at Toronto's Pearson International Airport, the busiest in the country, say they begin planning on how to deal with such storms 24-hours in advance, but travellers should still expect cancellations and delays.

Trish Krale, a spokeswoman for the Greater Toronto Airports Authority, said the best advice is for travellers to call ahead or check the GTAA website for up-to-date information.