RCNYILWX

Big time jump in the mean. Individual member low locations show clustering is most focused on the northern and northwest portion of the mean. Sent from my SM-G965U using Tapatalk

Took a little closer look at some of the soundings on the GFS and as we figured, it's pretty bogus. More than enough lower and mid-level saturation gets up into southern WI on that run, and considering placement and magnitude of large scale forcing, if I didn't have access to QPF, I would have the northern extent of the QPF shield probably up close to MKE. Sent from my SM-G965U using Tapatalk

Need a little dose of old school meteorology on that run of the GFS. Regardless of the confluence to the northeast, the surface and h7 low track depicted would not have nearly as compact a cold sector precip shield imo. It's a close to ideal 700 mb low track and surface low track shown to get heavy snow up into the Chicago metro. Sent from my SM-G965U using Tapatalk

Appreciate your contributions on here while you're out in the area! Always enjoy your posts and those of other knowledgeable posters when lurking on the NE threads.@OceanStWx should pay us a visit on this thread if it's not too busy over there haha. Sent from my SM-G965U using Tapatalk

Oh I didn't think you were, I wanted to provide some clarification since I had done the forecast and made the graphic. I appreciate the feedback and having been a part of our social media and graphics team for a while, we do try to incorporate feedback into improvements and how we convey things. Sent from my SM-G965U using Tapatalk

I made the graphic and wasnt trying to convey overly high confidence in those amounts. It's pretty reasonable to say at this juncture that if the ingredients all come together, that a swath of 6" of snow is fairly likely given the forcing and moisture available. I was hoping to make note of the uncertainty by italicizing and underlining possible wording. The shaded areas used are pretty much WPC's Day 5 outlook (dark blue is the darker green 30-50% area and lighter blue is the lighter green 10-30% area). Of course we can see in the spectrum of outcomes, there's still a lower probability completely failure mode in this. We decided that if we're going to ramp up messaging for an event a little farther out, may as well be this one. * If* subsequent trends do support the higher end outcome, we're probably 3 full forecast package issuances away from watch issuance (Friday night/Sat AM midnight shift). Sent from my SM-G965U using Tapatalk

Yup, looked like should be partial for 12z and should be full sampling for 00z tomorrow. The PV lobe southwest of the block that's also a key player is up over NW Territories. Sent from my SM-G965U using Tapatalk

Been thinking the same thing, feel pretty confident that sans blocking this would be a much warmer outcome. The blocking could yield a failure mode, but the heights ahead of the wave are already pretty amped, with no block, they really pump and SLP track is probably over the LOT CWA. Sent from my SM-G965U using Tapatalk

I'm not seeing stronger with northern stream, if we're referring to the PV lobe over Manitoba. Unless I'm looking at it wrong it looks like it's a hair west northwest of 12z and there's subtle higher heights than 12z over eastern Ontario. To me biggest change is the shortwave is a little slower and more positively tilted. Could get to that farther south outcome anyway but I'm not sure it's due to the northern stream. Sent from my SM-G965U using Tapatalk

LOT long-term AFD out, nice and short as usual from me Sent from my SM-G965U using Tapatalk

12z EPS now centered from QCA to Chicago metro roughly. Lots of good hits on the members, would like to get rid of the remaining duds. I'm busy getting the forecast out so don't have time to post images today. Sent from my SM-G965U using Tapatalk

What's nice about this setup is that we're not relying on an exotic phase, like some of the fails the past few winters. Main sensitivity is to the magnitude of confluence from the NAO blocking and to a lesser extent the magnitude of the main shortwave itself. We're seeing the potential here if that confluence can stay far enough north. Still some failure modes, but also plenty of reasons why this has legs. Another important thing to keep in mind is that without that block, there's no event here, background pattern of plunging -PNA (which would normally yield a strongly amplifying SE ridge), La Nina forcing, and point of entry of the southern stream wave probably would be a pretty warm cutter. So there's some concern lingering for suppression, but lessening vs yesterday given trends since then. I think concern for wave coming in too far north and bringing mixing issues farther north is a valid one too. All in all, I like where we sit and we have some wiggle room.

Textbook for the Chicago metro. Sent from my SM-G965U using Tapatalk

Oh my at the UKMET. Plus LES on the back side. Gotta try to not get too excited lol, will be doing the grids and AFD for LOT. Sent from my SM-G965U using Tapatalk

Yep, the NAM performed very well with that event, probably the overall best with UKMET. Sent from my SM-G965U using Tapatalk

Definitely a bump north vs 06z. If the ECMWF and EPS don't change drastically, I'd give more forecast weighting to the ECMWF suite than the GFS/GEFS. Would like to see the UKMET jump more fully on board today. Sent from my SM-G965U using Tapatalk

It's good to use some caution, there's no guarantees the ECMWF locks in and we'll have to see the rest of the 12z suite. Model adjustments don't necessarily follow a linear caving trend. It's just interesting to see a linear-like trend on the GFS and having similar experiences in the past. For the December 17th storm I've referenced, the GFS did not really budge from its incorrect solution, it only stepped that way in the near term, and honorary New England sub thread guest@weathafella can comment more on that. I've brought it up because it's fairly analogous in that the GFS for that setup struggled mightily with the effect of confluence from the north. Sent from my SM-G965U using Tapatalk

For the lulz, go on Tidbits and do a run to run of the GFS going back to 12z yesterday. Sent from my SM-G965U using Tapatalk

The classic GFS baby stepping we know and love. Sent from my SM-G965U using Tapatalk

Our event page for the snow squall: https://www.weather.gov/lot/2021jan19 Includes a short presentation put together by one of our forecasters that I tweaked for public consumption. Really fascinating event. Looking back, it's clear that at a busier time of day we would've needed to issue our first SQW, and there was some consideration put toward it as the event unfolded. The last snow squall event of this magnitude I can recall, brief whiteouts and roads going to trash, was late January 2014 with an Arctic front. And multiple instances of thundersnow associated with a Clipper type system is rare, if I'm not missing any events, I think have to go back to December 2010 for that in the LOT CWA. Disappointed I missed out on personally experiencing impacts where I live, but glad others got to experience this unique event, and was cool to look back on again while putting together the event page. Sent from my SM-G965U using Tapatalk

00z EPS mean and individual members. The mean is pretty much a carbon copy of the 18z run. Looking at member low locations, if anything a slight north lean. Still some clunker members but a majority favoring heaviest snow swath from I-80 and north to WI. Didn't see a jump toward the suppressed solutions. Good to see multi-run consistency from the EPS in favoring a significant event. Sent from my SM-G965U using Tapatalk

UKMET was still a slight improvement. Cold sector precip gets squashed by the confluence but a 995 mb low riding the Ohio River on Monday-Monday night. If all you had was the surface map for your forecast, that surface low track would usually portend solid snow at least up to I-80. As is, UKMET indicates a moderate event from central IN northeast across northern half of OH. Sent from my SM-G965U using Tapatalk

Baby step at 500 mb on the 18z GFS, northern stream slower/not as potent/farther north. Sent from my SM-G965U using Tapatalk

That's one of our newer meteorologists, on a training shift. I'm working tomorrow and Friday on the day shifts. Not sure who will be doing what. Sent from my SM-G965U using Tapatalk

I think it was supposed to be addressed and the size of the GEFS was increased which theoretically helps. However anecdotally it still appears to be too non-dispersive. Since we don't have many big events to go by this winter, the December 17th event I mentioned earlier, GEFS did suffer from being too close to the op.