Top up the windshield washer fluid...a winter storm is headed our way.

A messy system is tracking towards the GTA and a large area of southern and eastern Ontario. It's set to drop anywhere from 7-25 cm of snow across the Toronto region.

Areas near the the lakeshore could see 5-10 cm Tuesday night with a few centimetres more on Wednesday. The northern suburbs around the 407 could get 15-20 cm Tuesday night with another 5 cm on Wednesday.

The storm is expected to hit Toronto between 5-6 p.m. Tuesday.

The temperature will play a major role in determining exactly how much snow falls and right now the estimates are just a "best guess" according to the Weather Network.

Any slight changes in temperature "could make it more a sloppy mess, a lot could melt as it makes contact with the ground. Or if it's a little bit colder we could see the snow really start to accumulate," says Geoff Coulson of Environment Canada.

Coulson says regardless of how much accumulation the storm brings to the GTA, Wednesday morning and possibly even Wednesday evening could be a tough drive with poor visibility and windy conditions.

The effects of the storm are already being felt in the American southwest through Oklahoma, Texas, and Kansas.

It will continue to track further north and Coulson warns there could be flight delays or cancellations at major American transportation hubs.