RCNYILWX

Since I think it's meant to be for this thread, the 12z GEM has a really nice event starting Sunday evening and continuing through Monday. Probably would've been better to group together the 7th through 9th because there's a way you can get a longer duration round out of this setup, such as shown by the GEM. The ECMWF runs I cited in medium long range thread had some wave spacing between Sunday and Monday, though it's too soon to tell if we could get one longer event or two shorter events or specifically most favored areas. All we can say is that multiple short-waves that won't be sampled for a couple days lends to lower predictability than last weekend's event. Don't think the threat has really trended downward, gotta take a wait and see approach. The pieces are there for a nice event because of the tight baroclinic zone expected to be in place. Sent from my SM-G965U using Tapatalk

You wrote that before the 12z GEM rolled out haha. Looks really nice for Sunday evening/night through Monday. I think ultimately the later Sunday-Monday period has a decent chance to work out for a solid event. Saturday PM should snow in most of the CWA but needs work to be anything more than a 1-3" type event. Sent from my SM-G965U using Tapatalk

I didn't see any zzzz overnight. The 00z Euro looked really good on Sunday and it had good support from its ensemble and the signal for Monday is still good with GFS/GEFS the most excited. Edit: I see the 06z Euro shifted south on Sunday, but that's not really a big deal in a pattern like this. Could easily come back north, as the guidance is going to struggle with exact positioning of the baroclinic zone and the influence of the PV being to the north.

Expect a good amount of run to run variability on the op runs. 00z GFS is still decent but not nearly to the extent of its previous runs, while GEM is more suppressed and sheared. Meanwhile the 00z UKMET is juiced for the system with QPF up to 0.4 to 0.7 across the LOT CWA. Sent from my SM-G965U using Tapatalk

Aside from the extreme NAO block, the pattern this weekend through next week is the closest looking to 2014 that we've had since 2014. The initial ridge spike dislodges the PV lobe which then gets trapped underneath the block. Whereas in 2014 there were constant reloads of the EPO ridging that brought down PV lobes. Either way, it gets to a fairly similar look in the CONUS, with a strong polar jet directed right into the subforum and a train of Pac hybrid shortwaves. Sent from my SM-G965U using Tapatalk

Looking forward to another fun shift tonight. MTF will be doing the grids and AFD. Certainly an interesting setup to get accumulating snow in the area. In addition to the support for dynamic cooling, it helps that the surface high is not too far off to the east so lingering dry air aloft helps the process. Sent from my SM-G965U using Tapatalk

For those up tracking, we will be ramping up our winter weather messaging for Thursday in collab with WPC. Still concerned for freezing rain within the CWA earlier and now with trends of a lot of the guidance and strong ensemble support with a decided shift southward we're liking idea of accumulating snow, strong winds and blowing snow across northern IL Thursday night. Flash freeze scenario still in play as well since it does look like all areas should briefly rise above freezing. Sent from my SM-G965U using Tapatalk

If I may jump in on the Chicago snow talk stuff, I have no problem with posting historical context about low snow starts or even simply just expressing frustration about a cruddy pattern; after all we're posting on winter threads because most on here want as much snow as possible. I get more peeved at the persistence pattern posts, that it's sucked so it will continue to do so. The pattern is persistent until it changes. We've had plenty of recent examples that what happens in December the rest of winter does not remember. I personally wasn't overly optimistic about this winter, was fairly bearish about it until unexpectedly persistent blocking materialized. I always go back to the mantra all it takes is one, or two, or at our latitude, we get chances. Our middle 50th percentile for seasonal snow in the Chicago area is near 30" to low-mid 40s", so it's much more common to get a bit above normal snow than to dabble with futility. What I did feel confident about in this winter is that we would realize an active stretch where those chances would become possible and that even in the warmest Nina winters, usually get a few opportunities for a favorably tracked southwest type system. Glad that the blocking gave us a chance to get into a stretch where we got two solid systems in a week, as it appeared quite possible it could. Sent from my SM-G965U using Tapatalk

On the range of possible outcomes, certainly an interesting solution to add into the mix. That run has a sharper digging northern s/w able to phase with more southern routed energy and the whole thing quickly goes neutral to negative tilt. I'd place it on the lower probability end of the spectrum to get that well timed phase, though we'll see shortly on the rest of the incoming 12z operational and ensemble cycle if that idea gets any more than minor member support. Sent from my SM-G965U using Tapatalk

See overnight AFD for my thoughts on this one. No longer concerned about a snowpack nuke which is nice. Would certainly prefer a snowpack net gain like NAM/RGEM and last night's GEM solution. Not putting my eggs fully into that basket yet with so much ensemble spread and NAM and RGEM rather far out in their range, but tend to favor the colder outcome which could include light-mod snow accums in parts like above mentioned solutions. Think that even in a change to rain outcome there would be a freezing rain risk in the morning. Probably a decent chance we end up needing an advisory for parts of the area. With sloppy non snow ptypes possible into parts of the area and support for post polar front precip with crashing temps could also see a rare flash freeze type setup materialize. Models like the GFS commonly overdo surface warming when southeast surface winds are pulling from a lower dew point air mass and we have extensive deep snow pack. Also think it's possible previous runs have not been accounting for wet bulbing aloft enough. Sent from my SM-G965U using Tapatalk

Are you right in Kankakee? We could use some quality reports for the event write-up. Definitely noticed a lack of quality reports from down there. Erroneous reports like what you cited affect the NOHRSC analysis that drives the automated snowfall analysis maps. We tried to account for the reports we received in the storm total snow maps we've posted. Sent from my SM-G965U using Tapatalk

So we just spoke to overnight ORD observer and the evening shift did mess up, did not account for snow that fell between 18z and 20z in the 00z report. So actual total in that period was 1.7". 0.3" between 00z and 06z brings the storm total to 10.8". Sent from my SM-G965U using Tapatalk

We could have anything from high ratio fluff with an Arctic wave and whiteout conditions as the Arctic airmass pours in (also a great LES setup for SWMI and NW IN) or the v16 on another end of the spectrum. Doesn't look boring at least. Canadian tries for an interesting v16 like setup but pretty quickly transfers to the bombing coastal. I'm doing long term tonight, will try to give an idea on range of outcomes possible. Sent from my SM-G965U using Tapatalk

The greats have the good WCB burst and the extended defo snows with LE. This won't be historic but after mostly meh seasons downtown since GHD II, you guys earned it and it will be a fondly remembered snowstorm.

I'm alive and still awake, worked until 1015 this morning then still had to shovel at home, build a snowman and do some sledding with my son. What a storm, probably third favorite since I've lived out here. I'm guessing somewhere around 9" here but haven't measured. This stuff is deep and super heavy. Re. question above about lake enhancement, I'm surprised in the Q&A they said we weren't expecting lake enhancement. It was in most of our AFDs once we got in range to discuss aspects like that. Question in my mind was to what extent would it boost totals. The HRRR always looks overdone so it's generally hard to trust with lake effect, but in this case with synoptic forcing plus very good speed convergence and a still above normal PWAT airmass over the region, clearly enough to get it done. The 00z and 06z NAMnest did a great job with the combined defo/lake enhancement today. Congrats to everyone who tracked this event and finally scored a good snowstorm, 3 years since a solid metro hit and best overall storm since GHDII. Enjoyed every bit of this and the opportunity to share the meteorology on here. Another cool thing is to see that my former home before IL, NYC, is about to get smoked too, not super common for that to occur after we get a sig snowstorm. Edit: Raising my kids to be snow lovers like myself haha

Made it to the office safely, drive time actually wasn't too bad with less cars out but the roads were trash as you'd expect. Just before I got here, had to help push a car up a hill on the road near my office and a little bit farther along a pickup was towing a sedan out of a ditch. Was heavy snow the whole drive in. We're about to do our 06z measurement. When I left home was estimating about 4" in southeast Naperville. Glad the forecast is working out pretty well for most of the area. Sent from my SM-G965U using Tapatalk

Is that LE starting up by your or just a small meso band or both? Sent from my SM-G965U using Tapatalk

Once we get an idea on ratios and how much heavy snow is left will give a better idea of exactly where totals will end up. Interested in the evening update from my office. I think it's distinctly possible that we'll be able to pin down an area of enhanced totals. Would be happy for my forecast to bust low. Sent from my SM-G965U using Tapatalk

It seems possible the absolute heaviest returns may not quite make it but that's also partly a function of a different character of the snow underneath the highest reflectivity. Very large rimed flakes have higher reflectivity than typical dendrites. The stuff over the northeast half or third of the metro 25-30+ dBZ will be more than enough to stack.

Solid SN borderline + here with good wind, which bodes well for when the really heavy stuff lifts in. Had the kids out in it and they were loving it. Sent from my SM-G965U using Tapatalk

Since I'm a weenie at heart like everyone on here, waited to see the 12z Euro. Had a feeling models were too warm today. Without a southerly component at the surface and in a retreating dry air mass it's hard to warm much with overcast skies. I think highest I went in the CWA today was 36 degrees, maybe a few spots of 37 far southeast. Tried to do the best I could with hourly temp trends to account for evaporative and dynamic cooling at precip onset. Aside from the areas that'll have mixing issues for a bit, looks all systems go. Sent from my SM-G965U using Tapatalk

The RAP might not be terribly far off at 850 mb. My guess is it's probably holding onto >0C too long with north and eastward extent. Main issue though is the QPF, very clear dry outlier in the 00z-06z timeframe when our heaviest snow is forecast. We find that the RAP is best for trends up to 6 hours out, so it can certainly help with diagnosing the effects of the warm nose on p-type. Sent from my SM-G965U using Tapatalk

In this case it wasn't even to cheapest bidder, we had a team that was working on it for years I believe. They were ready to roll out, had a comment/suggestion period where they were supposed to incorporate feedback from within the NWS, and from every comment I saw on an extensive employees facebook group post and also talking to the radar focal point at my office, they took literally none of the suggestions. If they had just gotten someone from academia with good web design experience, may have a much better page done over a weekend lol. Sent from my SM-G965U using Tapatalk

We're not even supporting mobile.weather.gov anymore lol. It's silly that we can't have a free app, we're not competing with anyone and it wouldn't be hard to develop. Sent from my SM-G965U using Tapatalk

If you want a good pay site, I think weathertap is probably still a solid one. O/T but it's too bad the NWS radar page update was fumbled so badly. We really could've had a nice page if they had just tapped in design experts in the private sector or just asked COD or other good pages from academia to share code to roughly mirror the good stuff they have. Sent from my SM-G965U using Tapatalk