The National Weather Service predicts dangerously cold temperatures and likely some snow this weekend, but meteorologists say they will not know exactly how much snow St. Louis will get until the storm is closer.
The National Weather Service on Wednesday placed the St. Louis region, as well as much of southern Missouri and Illinois, under a winter storm watch from Friday night until noon Sunday. Meteorologists forecast wind chill as low as 10 degrees below zero Saturday morning, with an 80% chance of at least an inch of snow that evening. The winter storm alert states total snow accumulation could reach four to six inches.
National Weather Service meteorologist Marshall Pfahler said dangerously cold temperatures are a concern this weekend, regardless of snowfall.
“It is going to be so cold that even if it just ends up being around one inch, it should have a pretty easy time adhering to roadways and virtually all surfaces,” Pfahler said. “Even light amounts of snow will probably cause impacts across the area.”
Pfahler said meteorologists have been watching two storm tracks this week: a northerly track that would bring widespread snow to St. Louis, and a southerly track that would keep the area relatively dry. He said the current guidance is trending toward the northerly track, making it more likely that St. Louis will get heavier snowfall.
Pfahler told STLPR that storm systems like this one are unpredictable because meteorologists are tracking a lot of moving parts from far away. The National Weather Service relies on weather balloons across the country to gather samples used to build forecast models. Since this storm system remained over the Pacific Ocean and parts of Alaska into Wednesday evening, he said it’s difficult to get a precise forecast.
“Each day we will be able to get a little bit more detail and provide that with a little bit more confidence,” Pfahler said. “Each storm is a little bit different (depending) on how quickly that confidence increases.”
Bracing for impact
The Missouri Department of Transportation plans to hold a briefing on Thursday afternoon to discuss the storm and its expected impact on road conditions across the state.
MoDOT Director Ed Hassinger will be joined by NWS warning coordination meteorologist Kevin Deitsch, Capt. Scott White from the Missouri State Highway Patrol and Missouri State Emergency Management Director James Remillard.
This storm is also expected to affect much of central and southern Illinois. Joseph Monroe is a District 8 operations engineer for the Illinois Department of Transportation. He said subzero temperatures and high winds could mean IDOT will choose not to pretreat the roads.
“If the storm would move south and we get lesser amounts of snow, you may not actually want chemicals on the pavement,” Monroe said. “The wind and the traffic will essentially act like a snow blower and knock the snow off the pavement.”
He said Illinois residents can expect to see plows on the road early Saturday morning if the current forecast holds. In the meantime, he recommends drivers top off their gas tanks and check their tires and windshield wiper fluid in case of an emergency.
“If there’s a very important trip you need to take, that’s our job to get you there,” Monroe said.
