RCNYILWX

If that has staying power, might need to upgrade some more counties to a WSW. I'm not at work so I can't speak to it but I do wonder if it's being considered. Would think your area, south burbs to especially northwest Indiana is prime bc they're going to be under lake enhancement and then pure lake effect for a while longer. Can see the LE under the synoptic snow into Lake County Indiana from tMDW. Sent from my SM-S936U using Tapatalk

Big dendrites here in Naperville (DuPage-Will border just north of Bolingbrook) too, noticeable uptick in flake size within past few minutes. Sent from my SM-S936U using Tapatalk

Looks like we're getting another surge of large scale forcing to hook up with the lake enhancement. Banding filling back in from the southwest. We'll see if the LES multi bands intensify even a bit more as this occurs. Sent from my SM-S936U using Tapatalk

The 00z HRRR and NAMnest initialized adequately with it. Suspiciously low QPF response given the evolution progged, although presumably it would be higher ratio than Kuchera output. Sent from my SM-S936U using Tapatalk

More recent radar frames suggest flake size may be soon or already is improving some up to roughly I-88 in the metro. Sent from my SM-S936U using Tapatalk

Oh just for full disclosure since I'm all about owning up to bad forecasts, my forecast earlier this week sucked (overnight snow the day before the evening squalls and snow bands that did work out). That was a different setup, but the dry air winning out there made me a little gunshy to feel confident the light snow would start much earlier. I did have a hunch something like this might play out, but in the 00z and 06z TAFs last night, didn't have flurries until 4pm at DPA and 5pm at ORD, MDW, GYY. Still leaned earlier than explicit guidance though based on how the soundings looked, and had a prob30 (30% prob) group starting with the flurries onset before the 1-2SM stuff in the evening. Someone should also tell many previous runs of the GFS that it is indeed snowing across much of northern IL today. Sent from my SM-S936U using Tapatalk

I tend to like 10:1 as a better first guess (in scenarios that aren't obviously well below climo ratios) and then consider the Kuchera if the Cobb output shows that the depicted Kuchera ratios are realistic. Case by case basis. Where the forcing is consistently good and well aligned with the DGZ for this event, it's a good air mass, so the Kuchera may be fairly reliable for this storm. I think up here (WSW Chicago burbs) it's gonna be mixed in terms of ratios. Looks like our better chance at solid ratios away from the lake might be tomorrow morning. Our morning AFD update mentioned that the snow at onset later today/this evening will more likely be pixies, aka Arctic dust.

This, not a fan of the brutal cold but prefer it to come with the ground covered than with bare ground. Sent from my SM-S936U using Tapatalk

How big was Feb 14-16, 2021 there? Sent from my SM-S936U using Tapatalk

Another CIPS analog here that did tick a bit northwest by go time, fairly close in to the event: https://www.weather.gov/lot/2014feb05 Sent from my SM-S936U using Tapatalk

Some of the recent CIPS analogs have included mid February 2021 and 2007. Sure, we could see suppression. As I'm sure most in here remember though, mid Feb 2021 at this lead time was pretty much a whiff for most of the Chicago metro. These juiced expansive Gulf lows seem to have a knack for trending north (maybe due to enhanced downstream ridging due to tremendous latent heat release?). So the fact that much of the guidance is already bringing accums to the Chicago metro area perhaps should give some reason for optimism here. Another big wildcard is the SLRs, which could be exceptionally high if lift is well aligned with the already modeled to be very deep DGZ in the very cold airmass. So even Kuchera ratios would potentially be too low. For reference, MDW 3SW had 0.51" of liquid equivalent in 15.7" of snow in 24 hours from 2/15 into 2/16/2021. So if we see consistency in relatively high QPF getting relatively far north, that would likely imply stronger ascent to generate the higher QPF, which itself would likely support unusually high SLRs. For this element, recommend checking out the Cobb text snowfall output via IEM or PSU (the 18z NAM Bufkit Cobb output showed 30:1 ratios at KMDW). Finally, the lake enhancement potential could be a noteworthy component of this, as occurred in the 2021 event (see MDW 3SW snow ob above), and back in 2007.

I know you know this, but using that wording inept idiots... I understood the grounds for criticism and questioning how it was done and like I said, we could have done one and probably ideally would have farther north. If I were some rando that just moved here for work and started posting, wouldn't be too excited about posting in the future after seeing that. I obviously know it comes with the territory here, us getting criticized at times. Sent from my SM-S936U using Tapatalk

For those who prefer not to bash given the challenges of these, there was a debate in the office when I was about to leave re. SQW. It's not as simple as just pushing a button. There's a specific criteria for visibility of less than one quarter mile that wasn't really being met at the ob sites as the squall moved through areas farther north. For that reason, there was active discussion including Gino Izzi (lead forecaster), our WCM, and the other lead that had just arrived on the best way to handle things. I personally weighed in on the side of issuing a SQW for downstream areas right before I left. From a lead time perspective, I'm happy I put out a SPS at 4:50am when it wasn't exactly clear how it would go and a graphic heads up. We also made a social media post last njght that gave a heads up. I thought something like this might be possible, if you read back to AFDs from past few early mornings, but this definitely overperformed and has been a top tier squall for this area. Ultimately, yes, we could have issued a SQW earlier that included the rest of the metro, but I think we gave a heads up about adverse conditions and got some lead time with the SQW for the south burbs and points south and east. For very tough forecasts, you win aspects of it, lose some, and learn and apply it to future similar scenarios. Thankfully the roads weren't too bad for most of my drive back home - only starting getting worse traction once almost into Naperville from north Bolingbrook. Edit: I guess the app really didn't like me trying to type out less than one quarter mile visibility with a less than symbol and numbers lol

Don't change bro Sent from my SM-S936U using Tapatalk

It's legit out there underneath the narrow heavier band. On my drive home from my crazy shift dealing with 2 seasons, conditions got worse going from Bolingbrook into Naperville. Even prior to that, with the strong cross winds, especially on intersections with Weber Road, conditions were sub optimal due to blowing snow. Actually getting dendrites here under the band despite the strong winds, and a solid coating down. I'm glad I put part of the CWA in a WWA but wish I went farther south with it. Hopefully a lot less people need to drive to their offices tomorrow with it still being the holidays. Sent from my SM-S936U using Tapatalk

I'm tracking the progress of the snow since my family was able to take off on time out of ORD, scheduled for a 527pm landing at HPN. Should be a fun landing for them. Anyway, interesting to follow the terminal dopplers over the past hour since the 0.5 deg scan on both OKX and DIX was too high to account for the very dry low levels. The fact that 25-30 dBZ at 4.5-5kft AGL on the NWS dopplers wasn't quite enough to punch through for a time shows how potent that low level dry wedge was, which lines up with 25/1 ob at HPN at around 4pm/21z. Sent from my SM-S936U using Tapatalk

Anyone well versed in how flights into HPN get affected on the incoming portion of a snow system? My family is out here in the Chicago area and they're supposed to take off at 2:13pm local and land at 5:26pm EST tomorrow. It's a little tricky with how the snow will be moving in by that time, vs. well underway regarding delays and cancellations. Sent from my SM-S936U using Tapatalk

It's basically the CAMs and RAP against the globals, with the GFS the farthest northeast of these. Wouldn't be surprised at a compromise in which the better f-gen banding and accum axis is indeed farther southwest, while farther north and east we get several hours of pixies accumulating to an inch or two. Could certainly be wrong but my current lean is away from a complete whiff with the first system. Too soon to write off Saturday for adjustments back (a decent % of 06z EPS members still had solid snow up into parts of the metro).

Pretty much inevitable there would be some form of pattern relaxation. The saving grace from probably not getting into a lengthy torch is the WPO is forecast to remain strongly negative, which keeps cold air discharge going into our source region. The EPO may head back toward neutral heading into Christmas week and then perhaps back to negative thereafter. I think with the likelihood of new snow on top of the melted and consolidated snowpack through this weekend and then the deep freeze for a couple days, if we can avoid a high dew point rain event, snowpack retention should be decent before a true pattern reload commences. Also with the -WPO that means CAA behind fronts should be fairly robust. Milder more zonal patterns often end up cloudy which typically isn't effective at melting much snow this time of year, again unless you get a couple days of high dew points. Even at over two weeks out, I'd lean towards Chicago having its first official white Christmas in a while. Sent from my SM-S936U using Tapatalk

WSSI suggests that DVN upgrading some counties to a warning was a very aggressive move. Given that we had a warranted daytime warning event a week ago, it's questionable if the possibility of getting a narrow band of 6-7" of snow on a Saturday evening-early Sunday warning is sufficient to prompt a warning. Sticking with a WWA seems like it would've been fine. We'll see how it goes. Sent from my SM-S936U using Tapatalk

Call it 8.1" for me. Nearest CoCoRaHS (Naperville 2.5 ESE) had 8.5". Looks like about 8-9" was the range in this part of the southwest burbs. My largest (and favorite) November event since I've lived out here and largest overall for my area since Feb 1-3, 2022. The most recent big late November event in 2018 was slop in the southwest burbs until the very end. Sent from my SM-S936U using Tapatalk

I measured 7.3" by me, first time measuring all day though so there was definitely compaction. I don't have great places to measure since I have a big tree out front and also in back of my house. The Naperville 2.5 ESE CoCoRaHS is probably only a little over a mile from me so I'll see what they come up with in the morning. Sent from my SM-S936U using Tapatalk

Filled in nicely again, maybe another 1 to locally 2". Gonna measure later for a storm total. Has to be over 6" here too. Sent from my SM-S936U using Tapatalk

Legit SN to +SN out here in my part of Naperville (near DuPage Will border). Sent from my SM-S936U using Tapatalk

The top end range on the "official NWS forecast" graphic is the 75th percentile of the NBM distribution and the low end is the 25th percentile. Point and click is still quite high and possibly/likely overdone and our (LOT CWA) overnight forecaster did some work to rein it in a bit even. Looks like DVN made less adjustments to the initialized data so they have a large area of 12"+. I can say, speaking for my office, that we all strongly dislike the probabilistic winter page but unfortunately we don't have control over what's displayed on it.