Our long duration winter storm is slowly inching closer and will begin to make its presence known across the Midwest and here in Illinois later tonight with snow moving into portions of the state. This system will be affecting us here through Saturday morning so even though there could be some breaks in activity across some areas, other areas could see continuous precipitation, possibly in the form of snow for over 48 straight hours. As you'll see below, this system is going to produce a widespread area of shovelable snow.
Per usual, let's take a look at where our system is this morning and the track it's going to take. At this time, it has pretty much fully come ashore and is kind of unorganized at the moment across portions of the Pacific Northwest and into southwest British Columbia in Canada. It will continue mostly east, crossing the northern Rockies and then diving more southeast into the northern and central plains tomorrow morning and afternoon, organizing and strengthening as it heads in our direction.
Just to start off, below is expected start times of precipitation across the state with the slow moving precipitation as it comes eastward with an animation of it following below.
The loop below runs from 6am this morning till noon tomorrow, showing the gradual spreading east of precipitation (mostly in the for of snow for Illinois). Much of the state today will be quiet and dry but look for mostly light snow to cross the river and enter Illinois later this afternoon and more so tonight into the overnight hours. Then, look for light snows to continue across a wide area into tomorrow afternoon and evening, favoring the northern half of the state with rain more likely downstate. Areas that remain all snow will receive 1-2" locally 3" of snow by late tomorrow afternoon and evening.
The above is just about the first half of this event as the animation below then runs from noon tomorrow through noon on Saturday, showing the very slow movement of this storm as it meanders across the Midwest. Areas of light to occasionally moderate snow will continue into Thursday night and Friday morning with some accumulations possible. As we head into Friday morning and afternoon, some model guidance, including the one below warm up the surface and low levels enough to make it so it changes to rain for a time. If that occurs, expect it not to be long lasting with rain changing back to snow Friday evening and continuing through overnight Friday into Saturday morning. This is the period we are watching for the heaviest snowfall rates and period that could produce some higher snowfall totals.
As mentioned yesterday, the expected snowfall totals below are what falls from late tomorrow night through Saturday morning and unlike the last system where all the snow fell in a short amount of time, this will be more drawn out with periods of light snow being the norm. It is also possible that the roads remain just wet and now snow covered given the marginal surface temperatures and all the accumulations will be on grassy and elevated surfaces.
Stay tuned for continued updates as the map below is subject to change as we continue to watch this system evolve.
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