ST. LOUIS – We’ve been warning about the likelihood of extreme winter weather in late December for a couple of weeks now. The next several days will finally see those prognostications come to fruition.

We know it’s coming; but when, exactly?

The day to focus on is Thursday, as the powerful storm moves into the region. This will all unfold very rapidly on Thursday. We may start very briefly with a mix of rain, snow, and sleet, maybe for 15 to 30 minutes at most, then kick over to snow entirely.

This all happens in the late morning hours into the early afternoon.

It’s all snow Thursday afternoon into Thursday evening. For a couple of hours, that snow may be intense, with rapid accumulation possible. Accumulating will rapidly wind down between 6 p.m. and 8 p.m., with lighter snow and flurries thereafter.

The dramatic drop in temperatures will begin around noon as well. Temperatures will dip from the mid-30s mid-morning to just above 0° by 6 p.m. Winds will rapidly increase from the northwest, with 30 to 45 mile-per-hour gusts likely, causing blizzard-like conditions for a while Thursday afternoon, with extensive snow drifts that evening into Friday.

Roads will get terrible quickly with this flash freeze and likely stay quite dangerous through Thursday night into Friday. We expect some improvement by Saturday, at least on the main roads. Accumulations will range between 2 and 5 inches across the viewing area, with the higher totals more likely to the north and northeast of St. Louis.

This winter storm will have a much more dangerous impact than its snow accumulation totals would imply, because of the strong winds, extreme temperature drop, and bitterly-cold winds. Travel is not recommended from Thursday afternoon until at least mid-morning Friday. Alternate travel plans should be seriously considered. As for travel plans Christmas Eve and Christmas Day, the weather will be dry, but temperatures will remain bitterly cold, particularly Saturday, with some moderation expected by Sunday.