January 19th Winter Storm: Two Days Out

The NWS has already issued a Winter Storm Watch for this weekend. It's essentially along and north of I-70 here in Central Ohio, with some of Western Ohio getting a couple rows of counties further south included:

We're 48 hours out and all I can tell you is we're in for a classic I-70 split. If you've lived in Central Ohio for 10 years or more, you know what this is. North of I-70 the climate seems 5° colder than south of I-70. Storms plow in to Ohio and seem to use the interstate as their official rain/snow line. And sure enough, this storm won't be any different.

While each weather model has their own take on where the line will setup, we'll use the Euro to illustrate how this storm is shaping up:

Shortly after sunrise Saturday our storm will start with snow north and rain south. That split will run just about all day. Right now it looks like anywhere south of US22 for sure will stay rain throughout the day. Getting closer to I-70 it could be an absolute mess. Perhaps ice, but as of now this is looking more like a mixing event. Northern Franklin County could stay all snow while southern may stay all rain. In between? Snow, sleet, freezing rain, and plain old rain. Who knows right now.

As of now the American models like a more northern solution, with the GFS going so far north that just about all of Columbus stays rain throughout. I think that's an outlier. The Euro wants to do a complete split using I-70. I'm leaning towards the I-70 benchmark, but that's pure speculation at this point. We just won't really know exactly where this will setup until it's already here.

For a first call, this is the setup I expect to see during the day Saturday:

The biggest question mark is right through the heart of Central Ohio; what will the area of Ice do? Will it truly be freezing rain, or will we see some sleet? Will it be a rain/snow mix? The way it's looking right now, that area will be right around or slightly below the freezing mark. So any liquid that falls would most likely freeze. If we're right around 32°, maybe the icing isn't so bad.

This is for the daytime though. Saturday night we're going to have a quick switchover to heavy snow after dark. That's when the low pressure moves east and we get the backside arctic air. It'll change any rain immediately over to snow and we'll get the deformation zone setup somewhere. That's when jackpot snow kicks in. We could see high accumulation rates where ever this sets up.

Tomorrow I'll finally put numbers to all of this. For now, try not to model watch too much, it'll just drive you mad.