RCNYILWX

Was gonna say, in a perfect world that's how we'd draw it up to keep the southeast ridge more muted, and plenty of cold air available in the source region. Even if we're on the edge at times, at least it's a more active look. Sent from my SM-G965U using Tapatalk

Cat. 4 Nor'easter Sent from my SM-G965U using Tapatalk

Merry Christmas to everyone and this year, Merry Torchmas. If we can't have a white Christmas, I'll take this over brutal cold and dry. Sent from my SM-G965U using Tapatalk

Big change on past couple runs of EPS in the long range. Recent prior runs had parked the PV near Alaska for longer, which is obviously not a good look for us. 12z run yesterday and 00z run last night breaks that down much quicker, with ridging returning sooner to near AK and an active/colder h5 look. With how much waffling has been going on in the long range on the ensembles, not ready to say the flip on latest EPS is for real. We'll have to see how tropical forcing (MJO etc) progresses, and plays a role in NH pattern evolution. Prior to those possible changes for the better taking place later during the first week of January, we'll have the brief cold shot behind this weekend's system followed by another warm-up due to the ++EPO from PV being over AK. Hoping@OHweather stops by with some pattern thoughts like on 33andRain. And Merry Christmas everyone. Here's to a much better January hopefully.

We didn't get lucky. The system looked promising for a band of heavy wet snow on most of the guidance and then things fell apart last minute. I issued a Winter Storm Watch for the Chicago metro and we got a FAB (flurries at best). Thankfully we made up for that debacle with GHD II. Sent from my SM-G965U using Tapatalk

I figure to be doing the same thing. So many east coast storms to relive. February 12 2006 was a great event, I actually was up in the Adirondacks skiing, and all we had up there was cirrus. Sent from my SM-G965U using Tapatalk

Weather.us has a sweet reanalysis page that they must have recently added. https://weather.us/reanalysis Sent from my SM-G965U using Tapatalk

The 12z Euro ensemble trended much colder into the first few days of 2020. Not sure if WxBell images are fair game, but here's the day 10-15 500 mb height anomaly prog.

The ensembles don't look half bad for the end of the month with both the EPS and GEFS in agreement on a -EPO/-PNA alignment. Obviously far enough out/subject to change and no guarantee of a spread the wealth snowy stretch, but reasons to be cautiously optimistic if we can get that look inside 10 days.

Thinking latest RAP/HRRR might be onto something with getting some accums farther north based off radar and observational trends over IA and western into west central IL. Amounts on north fringe might be a bit overdone but could see 1" up to a bit north of I-80 corridor. Sent from my SM-G965U using Tapatalk

I think because of technological advancement we expect more so we probably remember unusually well modeled systems in the past that were exceptions to the rule and say that it used to be better when in reality NWP is better than ever today. Sent from my SM-G965U using Tapatalk

There used to be Pacific recon missions for significant systems that may have helped. Sent from my SM-G965U using Tapatalk

The other problem we face is the ubiquity of the model data everywhere and the 'model-casts' the news stations run. So we put something out with a certain message and then for instance the 00z NAM comes out with a more aggressive solution than our forecast/forecast graphic and we get questions. Sent from my SM-G965U using Tapatalk

I'm hoping this works out up here. The fact that even the Euro has been very unstable shows it's a tricky forecast. NWP experts would say that RAOB sampling isn't that big a deal for the models but anecdotally in the past several years it seems that better sampling really does help. Sent from my SM-G965U using Tapatalk

Looks mostly dry so if Monday works out we'd probably only gradually melt it and temper the warm-up. Sent from my SM-G965U using Tapatalk

Give the GFS credit for being stubborn on this. I'd be happy to be wrong with my post yesterday trashing the GFS. Definitely a north jump on the 12z EPS for sfc low track vs 06z run, but interestingly the north trend didn't really correspond to beefing up the cold sector QPF. Only about a handful of members approach the more significant QPF/snow amounts this far north like on the GFS. About 20% get the snow swath up into the Chicago metro. Sent from my SM-G965U using Tapatalk

I haven't noticed it to be a significant issue, maybe with a few events, would have to collect some verification data to know for sure. The Euro was even too wet locally with some of the early season snow systems this year. Sent from my SM-G965U using Tapatalk

The GFS has been atrocious all cool season. No reason yet to put much stock in it until more modeling supports it with next week's potential system. Today's 12z EPS has less members getting snow up this far north. Just have to hope the blind squirrel finds a nut this time. Another note on GFS/GEFS: the GEFS has always been known to be inferior to the EPS because it has less members and it's too non-dispersive (runs too close to the operational). The "upgraded" GFS and the current iteration of the GEFS aren't even based off the same physics package, since the GEFS hasn't been upgraded to the new GFS physics yet. So that probably makes it more of an apples to pears comparison between the op and the ensemble now. The ECMWF and EPS will certainly have misses (such as what it showed for Saturday just a couple nights ago) because it's still a computer modelling system, but it's by far superior and perhaps the gap has grown despite the large sums of money poured into the GFS.

I'm more interested in the Saturday threat for now. Pretty complex setup but 00z Euro with a nice outcome for parts of northern IL into IA and WI. 06z EPS seems to favor farther north but hopefully some of us could score something, with possibility the next week threat ends up farther east. Sent from my SM-G965U using Tapatalk

At this point, with the steady weakening of the band, it doesn't really meet SQW criteria. Not working now so I'm not sure the exact discussions that went on but perhaps they felt it better fit a longer lead time with possible impacts into the commute from period of snow followed by quickly falling temps. Sent from my SM-G965U using Tapatalk

Euro ensemble also with a chilly and active look at h5 out out beyond the early to mid week cold shot next week. Sent from my SM-G965U using Tapatalk

This is probably an obvious statement to make, but we did check a few years ago and there's a strong correlation between precip anomaly and snowfall amounts. CPC has essentially the entire subforum in enhanced probabilities for AN precip in the DJF and JFM outlooks. They also have a lean toward cooler anomalies for a portion of the sub in the JFM outlook. So if the above normal precip works out, that would seem to increase the odds for above normal snowfall when also accounting for the head start, unless it ends up being a blowtorch winter. Sent from my SM-G965U using Tapatalk

I did the wind forecast for the event for LOT today. We went peak gusts in 45-48 kt range. My current expectation for this event is high confidence in widespread 50+ mph gusts and we'll likely have a few ob sites reach warning criteria (58+). Not certain we'll have widespread verification of warning criteria (county based verification) assuming we go with a warning but frequent gusts in 50-55 mph range will be enough to cause tree damage and power outages and probably blow over some semis on north to south or southwest to northeast interstates. There's probably little functional difference to the public between a high end advisory event and a lower end warning event. One aspect I didn't look too closely at today is cloud base height. With strong cold advection and steep lapse rates we'll certainly develop a stratocu field. If there's something that could lead to underperforming it would be cloud bases under 3kft because the highest winds aloft are generally up around 850 mb. BUFKIT soundings are indicating that we will tap into those top of channel (mixed layer) gusts but if cloud base height is lower that could limit things somewhat to solidly advisory criteria and lower likelihood of warning criteria being met. Sent from my SM-G965U using Tapatalk

Most recent NAM is actually a bit more bullish on winds at the 850 mb level than the GFS, which is usually the other way around. Verbatim peak gusts on 06z Euro for LOT CWA are 50-60 mph. On BUFKIT, using the momentum transfer tool, usually like to see mean mixed layer gusts closer to 50 kt and top of the channel winds solidly over 50 kt to feel confident about widespread warning criteria. 06z GFS would be close for probably southwest CWA but more of a high end advisory look elsewhere in the CWA, while 06z NAM looks more supportive of warning criteria for more of the CWA. From these, high end advisory is a lock and warning criteria certainly possible. We'll see how things trend the next 2 days. Possible that the PM forecast package today goes out with a High Wind Watch or tomorrow morning. Sent from my SM-G965U using Tapatalk

And then the Euro completely backed off lol Sent from my SM-G965U using Tapatalk