ChiTownSnow

And I love it... Haha

Every year, we got 1 storm modeled that we all try to compare to 79 or 67

Cook county (city) looking like they may have the dreaded front end miss south and deform miss north.. eeek These wave 1 and wave 2 are tricky as if both under/over perform you bust

Better.. But still needs to slow down or energy will transfer to the coast

#2 please

Starting to show that brutal cutoff in NE IL

Keep n mind that's 10-1. Will be closer to 7:1 and in a tough environment

I don't buy 4-8 yet. Areas that get initial front end will either melt or miss the deform. Areas that get just deform will still struggle to accumulate due to daytime temps On paper and in models 4-8 looks reasonable but in reality I don't think it will be. If it does shift slightly northwest then areas like Rockford have the best shot at anything over. 5.

Goal posts are defined .

Which is why the smart, no fun mets wait till now

Current LOT write up seems to suggest a very localized (narrow) 3-6 type of event with less south of 55 corridor

Really detailed write up from LOT. Interesting notes on the front end/deform events LONG TERM... Issued at 256 AM CST Sat Jan 6 2024 Monday through Friday... Key Messages: * Strong storm system on track to bring a very wet accumulating snow to the region Monday night into Tuesday night * While specifics still remain a bit uncertain, we continue to hone in on two main windows of impacts: 1) Monday night mainly near and south of I-80 with a several hour burst of snow potentially intercepting some of the evening commute and 2) Tuesday midday and overnight with more widespread impacts from wet accumulating snow and strong/gusty winds. The parent disturbance set to spawn our storm system for the start of the week continues to make steady eastward progress, and is now approaching the Pacific Northwest. Water vapor loops show a strong-divergent jet streak shuttling across Washington and Oregon early this morning. This feature will begin to dive southeastward today and tonight, eventually sweeping across the Great Basin Sunday night before emerging out across the Great Plains on Monday. While individual deterministic models continue to (unsurprisingly) show run-to-run wobbles, the ensemble envelopes are generally tightening up and clustering around a preferred solution, depicting a deepening surface low tracking from near or just south of St. Louis towards Indianapolis and eventually across Lower Michigan. Historically, this is a classic track/set-up for significant snow events in our area. The limiting factor this time around, however, remains the lack of an antecedent reservoir of cold air. This has implications on a few items. First: snow-to- liquid ratios will be well under climatological values and under 10:1 on the whole. Second: The rain/snow line will probably press into our forecast area, and an eventual transition to even all rain is on the table across parts of the region, with chances increasing the farther south and east you go. Third: the gradient separating the most significant snowfall amounts will likely be sharper than model guidance depicts and relegated to a narrow corridor where the strongest f-gen/deformation forcing develops. Pinning this perhaps 30-50 mile-wide area down at this range remains a fool`s errand, but signals point to this developing somewhere in our CWA. A trend which started to emerge last night continues to develop tonight in model guidance, with two relatively distinct periods of impacts. The first, which is slated to arrive Monday night will occur with the initial burgeoning warm advection wing of the deepening surface low. Very strong ascent looks to, at least briefly, overlap the core of the DGZ as precipitable water values begin to increase past 0.6 to 0.7 inch. While it`ll be close, latest guidance suggests precip may initially begin as snow everywhere in our area before transitioning to a rain/snow mix or all rain in our southern locales. Depending on when forcing arrives, this "thump" of snow may intersect at least the tail end of the Monday evening commute with an extremely wet snow (SLRs might trend towards 6-8:1 which even with relatively modest snow amounts would likely yield challenging travel conditions in spots. Positive snow depth change output is pretty telling in this regard, with amounts essentially halved or even less compared to raw 10:1 output, indicating some degree of melting will probably occur with this first round Monday night. Model trends appear to be honing in on locales near/south of I-80 with the heftiest activity from this first burst of snow, with chances for at least two inches of snow evident. The second window looks to occur after a brief period of mid-level drying works its way across the area which may result in a temporary lull in precip rates early Tuesday morning. This window is roughly Tuesday afternoon and night as the main surface low deepens more appreciably and f-gen/deformation band forcing takes over. Strengthening north and northeasterly winds combined with the low SLRs will support a plastering-type snow. As mentioned above, the very highest snowfall amounts will likely occur in a narrow axis, with a relatively sharp fall-off in amounts either side of this. The multi-model consensus and ensemble output currently suggests the highest chances for over 4 inches of snow with this second wave essentially straddling the I-55 corridor, with rain chances increasing off to the south and east. Again, model probabilities are probably smeared out much wider than will be realized owing to (1) lingering model spread and (2) lack of modeling melting/compaction which will undoubtedly occur in this marginal temperature environment. Freshening winds off the 40 degree lake may also play a role in locally muting accumulations right at the lakefront. Conditions will ease through Wednesday morning as the low departs. Beyond this, another robust vort max looks to descend upon the region late Wednesday night into Thursday. Forecast soundings show this will probably be snow for most of the area, although noting a very quick loss of deeper saturation suggesting at least some potential for things to transition to drizzle/freezing drizzle. A signal exists in the extended guidance for yet another potentially significant winter system somewhere in the vicinity towards the end of the week and upcoming weekend... Carlaw

^^^ more analysis like this please.. it is why I come here.

1.5 here. Nice little "surprise" last minute event

Bullish huh? 3-7 final call. 4.3 imby

Sheesh..What did they drop in those recon missions? Nukes?

Some of those totals in northern iL are from tonight's system.

Any sampling with tonight's runs? Or too early still?

Lock it in. That's it...everybody go home. No more runs needed

The end of the NAM (Yes I know it's the end of the NAM) has some pretty good convection going on in Mississippi/Alabama. Meanwhile a good front end thump for a bit

Of rain?

Warm air over a luke warm lake for city.

There's room for improvement as well if it gets its act together sooner, ejecting out of the Rockies and reforming.

Thermals are a nail biter on this one

Struggling to get out of the Rockies