ST. LOUIS — Storm system number one is now here, and our second and more impressive wave is still on track to impact Wednesday into Wednesday evening.
Wave #1 (Tuesday)
A mix of snow, sleet, and rain has been falling overnight across the southern edge of the St. Louis region. Snow is falling in Farmington, Missouri, and Sparta, Illinois, with a changeover to sleet near Fredericktown. It is all raining farther south. A narrow band of one to two inches of snow or sleet is expected from Salem, Missouri, to Chester, Illinois. Snow will accumulate on untreated roads and lead to slick conditions.
Farther north, closer to I-44 and I-64, a dusting of snow will be possible. Both state’s departments of transportation have been treating roads, but watch for slick spots, especially on bridges.
The snow is expected to finish around lunchtime Tuesday with just a few pockets of flurries hanging around. There will be a lull between storms Tuesday afternoon, evening, and the early overnight Wednesday.
Wave #2 (Wednesday & Wednesday evening)
This is the more substantial storm and looks to arrive around sunrise Wednesday and move quickly across the area through the day. This will first arrive as all snow northwest of metro St. Louis. Expect accumulating snow from Hermann, Missouri, to Winfield to Carlinville, Illinois, two to four inches.
As we go through the morning, precipitation will build farther south. Surface temperatures will be borderline along and south of I-44 in Missouri and south of I-70 in Illinois, and warm air higher up in the atmosphere will make this more of a sleet and freezing rain event in those areas.
Wednesday Winter Storm Timeline
- Sunrise: Snow starts northwest of St. Louis.
- Mid-morning: Mix of snow, sleet, and ice spreads south.
- Late morning: St. Louis sees snow/sleet divide, ice possible south.
- Afternoon: Transition to mostly snow, roads stay hazardous.
- Evening: Storm moves out, lingering travel impacts.
Unfortunately, metropolitan St. Louis will sit right on the line between the two. A mix of sleet and snow is expected right along those interstate corridors. It will be a sharp cutoff between precipitation types. St. Charles may stay all snow while Kirkwood sees more sleet.
Farther south, the chance for this to begin as freezing rain goes up, from Cuba, Missouri to Belleville, Illinois. Very borderline temps, right around 32, will not make the best conditions for glazing, but it cannot be ruled out. Further south, from Ellington, Missouri to Pinckneyville, Illinois, this will be mostly rain. As we head through Wednesday afternoon, I think we’ll see a transition into mostly pockets of snow.
Bottomline: the farther north and west you go, the higher the snowfall totals will be. The farther south and east, the more this will be sleet and freezing rain at the onset, and accumulations will be lower because of this. No matter where you are, there will be significant impacts on travel and daily activities throughout the day on Wednesday.