It's looking more and more likely that a snow storm will seriously impact Toronto and surrounding regions heading into the holiday weekend, with weather forecasts evolving quickly to paint a messy picture ahead. 

In a special weather statement issued for the City of Toronto on Monday, Environment Canada warned of what it called (at the time) a "significant winter storm" closing out the work week.

The federal weather agency changed the wording in its alert late Tuesday afternoon to warn not of a "significant" storm but a "major winter storm."

"Major winter storm expected late this week into the holiday weekend. Precipitation may begin as rain or snow late Thursday before transitioning to rain in many areas Thursday night," reads the update, published just after 4 p.m. on Tuesday.

Be weather aware if you're travelling for the holidays. Here's our Significant Weather Outlook for Ontario valid for Friday and Saturday. #ONstorm #ONwx pic.twitter.com/qLr6cXEt49

— ECCC Weather Ontario (@ECCCWeatherON) December 20, 2022

"Temperatures are expected to plummet on Friday leading to a potential flash freeze for locations that receive rainfall. Rapidly falling temperatures will be accompanied by strong to potentially damaging winds along with snow that may be heavy at times."

Meteorologists warn that "blizzard conditions are possible" later on Friday and into the weekend for areas downwind of Lake Huron and Georgian Bay, and they're not kidding around.

"The sheer size of this storm, the flash freeze potential and blizzard conditions with powerful winds and impressive snowfall totals are what has forecasters attention," said The Weather Network's Kelly Sonnenburg in a Tuesday afternoon update that calls the incoming system a "beast."

SIGNIFICANT WINTER STORM: Thurs night into Sat, Dec 24, 2022 with 80-110km/h Gusts, Flash Freeze, Rain, & Blizzard Conditions #onstorm #ontario #ontarioweather #Ontario #OntarioWeather #ontariotravel #ontariocanada #toronto #barrie #windsor #london #sarnia #kitchener pic.twitter.com/Bvn3lyabOY

— Instant Weather Ontario (@IWeatherON) December 20, 2022

By Friday, if everything goes as predicted, "southwesterly wind gusts exceeding 80 km/h will blanket the 401 corridor, and could even surpass 120 km/h along the Lake Erie shores."

Temperatures will drop rapidly, by as much as 15 C overnight, as a cold front arrives Friday morning.

"Consider altering plans through the holiday weekend as travel conditions may become dangerous," advises Environment Canada.

"Extensive utility outages are possible. Temperatures Friday night into the weekend will likely be the coldest of the season to date."