weatherwiz

For such strong WAA I thought some soundings would exhibit much stronger llvl omega or vertical velocities but not seeing any of that. Also trying to picture what kinda of flakes we will be dealing with and I would imagine they're pretty tiny. These can definitely accumulate if rates are intense but...even despite the strong WAA the signals for a true thump actually seem to be lacking. I'm going to say max snow totals probably 3...maybe 4'' and that's probably into southern VT/NH

Yup...that's the huge blow here...the antecedent airmass. Given how crappy the airmass is ahead of it I'd be very weary of this still trending warmer (especially at the surface). This reminds me of a setup we had (I want to say winter of 2017-2018)...we were very warm ahead of it and there were concerns for icing (at least down here) but we hovered 32-33 and icing didn't transpire. It's probably going to be a very narrow area for the heavier snow and higher totals...that WAA aloft too is cranking. But at least the airmass isn't necessarily dry ahead of this.

wondering that too. I was looking for dynamic cooling, maybe evaporative cooling...but seeing neither. The winds are quite weak but I guess there appears to be some very weak northerly or northeasterly component to the sfc wind. And the llvls remain quite cold so maybe we just don't mix? Looks like how 925/850 evolves is drastically different too. closing off briefly then opening up and just sliding southeast and we limit WAA there

both NAM and 3k NAM actually cool the sfc during the early afternoon but pretty solid warm tongue aloft. Looks like a sleet fest south of the Pike

And further reasoning as to why the model snow maps are pure garbage. To generate a snowfall forecast by using a constant ratio is trash...and...and...and the only parameters I believe they take into account are QPF and the snowfall ratio (this is why there was the new love for Kuchera b/c it can manipulate snow ratios) but how you can come up with a snowfall forecast without taking into account variable which even supersede QPF/snow ratio is beyond me. This is very true...especially when talking about commute impacts. This is where rates are extremely important as well.

18z GFS for Keene, NH but snow ratios fall more quickly than Urban Meyer

I would be shocked even if more than 2-4'' fell farther north. I'm just not sure how great snow growth is going to be and I certainly don't see very good snow ratios. Maybe during the thump they are good...10:1...12:1 (12:1 may be a big stretch) but that is going to be super brief. I'm thinking ratios probably more in line of 8:1 or so despite it being sufficiently cold in the lowest 5,000 feet. But where snow production will occur nothing looks impressive (to me anyways)

It also looks like there has been changes to the high pressure is being modeled. I think a few days ago high pressure was sliding more southeast across Canada but now it's looking like it slides more east-east northeast. Also, if you look at 500mb (at least on the GFS) and compare heights/winds from 18z run on the 14th to 18z today...there is a slight shift west with the s/w trough axis and some higher heights over our area...this favors a more westward cyclogenesis and thus we're seeing earlier 850 low development and a stronger influx of warmer air and with the HP not where it was modeled previously, we lose the drainage of cold air. (I wish I knew how to make a gif)

I haven't seen any official clarification yet. Only thing I've seen is the NWS Paducah has determined it was on the ground for 128-miles within their forecast area. I think the question is still AR/MO/TN and then maybe where it officially lifted off to the northeast

Enough time for this to trend towards 60 with thunder

Twitter is a cesspool over the tornado being rated EF-4 over EF-5

Finally had some time over the past few hours to really dig into things. This is my thinking for Connecticut. Initially I was actually going to go 2-4'' in the northwest and northeast hills, however, upon starting to dig further there were quite a few things that caught my eye. 1. It was looking relatively warm within the clouds...had to go well up into the clouds to get temperatures even close to -10C (like 13K) and close to around 8-9K to get below -4C. So I was concerned with sufficient ice nucleation. 2. The degree of warm-air advection is leading to a pretty high DGZ. Initially, the thump of WAA provides enough upward vertical motion to likely pool sufficient moisture/ice crystals into the DGZ for snow production, but this is going to be brief and I don't think will be enough to get more than an inch or so. Even if the rates were 1'' per hour...this process may not even persist an hour. 3. Maybe I'm wrong but much of the production here is going to be driven in the llvls and they are kinda meh for good production. 4. I certainly may be over-analyzing and over-thinking this. 99.99999% pprobable

That's very interesting you see it on the EPS but not the OP...or actually maybe it really isn't that interesting. Could it be a smoothing issue? Or maybe it just indicates that there are a ton more members hinting at such a look? Also, it is interesting to note on the OP you have that cut-off low off the coast...so is that really a piece of the PV lobe there on the EPS or is it just there is enough of a weakness with that ridge to allow interaction between that deep trough into central Canada and the cut-off low?

No disagreement there. You do raise a good point with this. I've often wondered if with the various updates to the models over the past several years if there were some changes to some of these equations...either more weight being placed on a specific component, maybe not enough weight, or just a slight altering of how these are calculated. Or maybe it's just the pattern has been so complex with so many shortwaves the models get confused. I've also wondered if perhaps going into these higher resolution with more grid points is actually hurting model performance in some regards. First off, let's not confuse this with all models...obviously we have models designated for meso-scale, short-range, medium-range, and long-range. But even some of these more global models (I guess you can call it) they are being converted into these super high complex formulas with much more grid points and a much smaller spatial resolution...this may be very good for those meso-scale models and meso-scale forecasting but it might be hell for medium/long-range as any "blip" or noise that may be picked up due to the fineness of the scale can probably largely throw off the output. This can probably be very true and throw off such equations such as the zonal horizontal momentum equation, meridional horizontal momentum equation, vorticity equation, and (maybe) continuity equation.

What would be nice is if we could get a winter with a more active southern stream as opposed to just an active northern stream. I understand we can still get solid storms and such with an active northern stream but the way the hemispheric pattern has been configured in the winter months the past several years we have not had much luck with just northern stream alone. Even if you get -NAO's involved...I think when it comes to a predominately northern stream driven pattern, it becomes much more complex than just having a -NAO or -AO...this is where structure not only becomes even more important but how the NAO is evolving as northern stream energy is arriving. You'll likely to get a better support from the NAO is the NAO is transition as this will likely result in changing height configurations over the Northeast and offers a better chance to shunt a storm south. But notice how the past few...maybe even several winter we continue to see the exact same theme with modeling in the long-range. Just constant "pattern looks good" outputs and all these outputs are in a specific time range which is typically beyond D10...sometimes even as close as D6 then everything falls apart. This goes to show we need big changes and support from other domains (not just the Arctic). We have seen favorable patterns unfold but they have typically been very brief and short-lived and it's b/c the Pacific has been such garbage and the Pacific really plays a significant role in the overall pattern configuration...the Arctic can influence the structure of the pattern but a coupling of the two would really end this theme of "looking good in the long-range to becoming crap by the medium-range".

isn't MJO 8 pretty rare anyways? (I'm not much of an MJO expert)

Not only that but models don't particularly handle MJO evolution past several days out very well.

Not a chance. I've had some spiders in my car while driving...it's the scariest thing ever.

don't forget the wildfires

This was the 19z HRRR for 21z

Actually the severe weather capital has been more east of the Plains

Absolutely agreed...100%. Our weather is quite tame when you look at other parts of the country. I mean when they get blizzards in the Plains...they get blizzards. Portions of highways will be shut down and the videos are absolutely wild. Visibility is zero. These places make our snow look meh and they certainly make our severe weather look even more meh

absolutely unreal. you could be outside enjoying the beautiful December day with sun peaking through, run inside to use the bathroom for 2 minutes, and go back out and trees are down everywhere and the sun is back out

What's happening in the heart of the country now is absolutely wild. The videos are epic. I guess some wildfires going too

That's legit a carbon copy