Hoosier

HRRR may be having some sfc temp issues as its known to do, especially in its longer range.

Solid map given current data. I'd say if somebody could overachieve, an area to watch would be the south burbs into part of northwest IN. It would help if tomorrow night thumps pretty good there prior to rain.

Pretty good

Can't help yourself, huh? Wouldn't be that concerned about cc and lake effect snow for now. Some of the modeling actually suggests amounts could increase for a while (this has already happened in the past several decades) as the lakes being warmer/ice free for longer helps to counteract warmer airmasses in the means. But you still do need to meet a minimum threshold to trigger les and the pattern hasn't just been a little warmer than avg, it has been very mild in the means for the past couple months.

Yeah that is kind of what I'm talking about. But they can really sound goofy when you add in the possibility of sleet/freezing rain.

Decent signal for some uptick in precip around here late morning/early afternoon, right around the time that temps become marginal.

That was a hell of a writeup for a non major storm. Appreciate the detail RC.

I'd be shocked if you got to 38. No offense to RC and the other NWS mets, but never been a big fan of the point and click. I will glance sometimes but I tend to go for the zone forecasts. The point and clicks can throw out some real gems sometimes in multi precip type situations especially when it'll break things down into 2 or 3 hour blocks.

10:1 may be best case scenario. Too many hours of marginal temps to think that will be the ratio over the duration.

What are your thoughts on this one? I do think it will likely change to rain in the city and some distance north/west of there. For how long is the question.

HRRR seems to be picking up on the cold water temps near the shore. Look at that narrow strip. Kind of funny

Tonight into the first ~half of tomorrow may very well have the coldest temperatures for the LOT region out of this entire storm. Too bad precip amounts will be pretty light in that timeframe.

I know some models had a strip of freezing rain near the front edge. Let us know when it changes to snow.

NAM does overamp sometimes.

Trend toward a stronger system, especially on the NAM, is not helping around Chicagoland because it helps to wrap in warmer air. Granted we are talking about the difference between like 1005 mb and 1010 mb, but it could end up mattering.

If anything is going to torch the sfc-925 mb layer, it's the RAP. It loves to do that, but even it generally has the 925 mb 0C line south of the GFS.

Storm is even more dragged out on the Canadian.

Hopefully 00z runs don't throw a curveball (or it's a good one if they do) but am currently leaning toward a total of 4-6" around here. I'm not sure why since everything has seemingly underachieved imby and this storm is going to be plagued with temp issues. But to be clear, I don't expect to actually see 6" on the ground and maybe not even 4". Other than the slop aspect, it should be a pretty picturesque snow on the trees.

Couple things on the 00z NAM... Stronger system which wraps in some warmer air Look how far west it still is at 12z Sat

00z NAM is pretty diggy with the upper level low so far.

Start the marathon

Was just thinking about how screwed the city would be in a marginal setup like this if it were earlier in the season. Flow is pretty much offshore until Friday but then when it does turn onshore on Friday, it is not that strong and shoreline temp is now down to 33 and the crib is all the way down to 29. Everybody is going to struggle to accumulate at times in this setup with how marginal it is but shouldn't end up with a big inland to lakeside gradient.

Nasty. The people that are near or above average snowfall to date should feel fortunate.

There really isn't a compelling reason to believe the GFS thermal profiles. Always have to be skeptical of outliers... maybe a little less so if it's the ECMWF as the outlier but that is not the case this time. What kind of track record does this upgraded GFS have to put a lot of faith in it? Like you said, it doesn't mean the snowier models are going to nail amounts either because we are still dealing with questionable 2m temps. This discrepancy with the temps aloft has been interesting to watch. I have never been more curious to look at actual observed 925 mb temps in the coming days lol

Comparison of 925 mb temps at 72 hours. The 925 mb low is basically in the same spot on both models, but there is the noticeable difference in temps.