(12:30AM - 1/12/19) Friday night update on the ongoing major snowstorm that is currently affecting the state, and will continue to through the weekend...
An area of snow overspread much of West, Southwest and Southern Illinois this afternoon an evening, and continues at this time as it also spreads across Central Illinois. Hardest hit areas of Southwest Illinois have already received 4-8" of snow, including the St. Louis metro area. Snow will continue to spread across all of Central Illinois and portions of Southern Illinois tonight through Saturday night, at varying intensities. As mentioned in our earlier forecast from today, the one exception will be far Southern Illinois...Across this area there may be brief lulls in precipitation, as well as precip turning to rain or a mix for a while later tonight into Saturday night, before turning to a bit more snow on Sunday morning into Sunday afternoon. Due to the aforementioned, this will set up a gradient across Southern Illinois, with higher snowfall totals north/norhwest to lower south/southeast.
Further north, snow will also push into portions of Northern Illinois later tonight and Saturday morning. This activity will continue into Saturday night, before becoming scattered and diminishing Sunday morning. As mentioned in our earlier forecast...Northern Illinois is another area to point out, where there will be a gradient in snowfall totals.. Dry air advecting in from the northeast will help create this gradient. This gradient does not look as sharp as it once did on some guidance, which has trended towards the consensus...thus will continue with a more relaxed gradient as was shown in our previous forecast.
Snow will be moderate to heavy at times across the state during the weekend, especially across Central and and portions of Southern Illinois tonight into Saturday night. One good bit of news is that winds will remain relativity light during this event, which will help limit blowing and drifting. However, this will be a heavy/wet snow for portions of South-Central Illinois. Additionally, significant travel disruption has already been seen this evening, and will continue to be likely across the state this weekend, so travel is discouraged for many areas.
With all of that said, final snowfall totals over a good portion of Central and Southern Illinois will be in the 6-12" range. Across a portion of Eastern Missouri on into West-Southwest Illinois, amounts of 12-15" are possible. Amounts taper across far Southern Illinois and across Northern Illinois.