A historic event is expected to unfold in mid-Missouri, and in fact in most of Missouri tomorrow and Wednesday. Having grown up in Missouri, I have seen snow storms come and go. Most of the 'big' storms have been such that provided a nice blanket of 6-10" (as we just experienced on the 20-21st), and I can count on one hand the times we have had extreme snowfalls of 12-15". Nothing comes close to what has been churning for the past few days, and what may possibly come through in the next 12 hours.
A split flow in the jet stream has merged dropping down a large polar air mass that is expected to bring sub-zero temperatures by Wednesday night. At the same time, a huge storm will be ejected out of Texas bringing an enormous amount of moisture tapped from the gulf. Below is a graphic showing the projected path of the surface low that will cause this storm.
Here is the 2-day Quantitative Precipitation Forecast valid Monday night:
These amounts are extreme, even during spring torrents that visit the area. But to have a snowstorm bring such rain is unprecedented during this generation.
On the right side of my blog, I show the NWS STL graphical snow forecast. This changes with each cycle of the model runs, and this image was captured at 6:00 am Tuesday morning. Amazing totals.
Finally, a first has happened in the history of the NWS STL. Never before have they issued a Blizzard Warning for their CFA. As you can see below, much of Missouri is under a blizzard warning from 6 am Tuesday till noon Wednesday. Blizzard conditions include heavy snow, 35+ mph sustained winds, and 1/4 mile visibility for at least 3 hours.
Of course, this storm is not affecting only our area. Many people will be affected by this dangerous system across the country. A crippling ice storm is expected for southern Illinois into Indiana, and the heavy snow will continue northeastward into the already battered New England states. The warning map below was captured early this afternoon.