ST. LOUIS, Mo. — The big story this week is the impending winter storm. It has all the classic earmarks of a solid snowmaker. The only aspect of this system that is marginal will be the temperatures, which will hover close to freezing through the event. That is important to the eventual impact on roads, which may not be as bad for as long as the snowfall totals would typically indicate.

The system arrives late Tuesday evening and likely will begin as a cold rain after 9 p.m. A transition to snow will occur sometime just after midnight, with the heaviest snow expected to fall between 2 a.m. and 8 a.m. Wednesday morning.

The heaviest snow totals will generally be along and south of I-70. Snowfall totals in this area, including metropolitan St. Louis, will range from four to eight inches. The chances that St. Louis would see eight inches of snow are fairly low. The National Weather Service says that it has around a 5% probability of happening. The average amount of snow expected to fall around St. Louis is five inches. However, towns south of St. Louis, such as Farmington, have a 25% chance of receiving eight inches of snow.

St. Louis storm timeline:

Rain starts around 9 p.m. Tuesday

Heaviest snow expected between 2 a.m and 8 a.m. Wednesday

The heaviest snowfall is expected south of I-70

The snow could impact the morning rush-hour Wednesday

This will be a heavy, wet snow with temperatures near or just above freezing. That means after the snow has ended, roads should improve rather quickly during the day as it will melt very quickly when temps warm into the upper 30s Wednesday afternoon. However, the roads are likely to be in rough shape going into the morning drive Wednesday and up until the snow tapers to flurries just before midday.