NittanyWx

Agree with this and was making a similar point yesterday. Lotta ways to skin a cat, tropical forcing being one of them, but would prefer it be some form of combination of influences to overcome background interference.

The model itself is forecasting the variables that are plotted into an MJO plot. Please explain how a model can catch up to its own forecast?

This is a good way to think about it. There's plenty of blocking right now over the pole and NAO regions, but the Pacific is very much non-cooperative. The net result is this pattern that isn't a prolonged torch, but any cold spell is pretty short lived and doesn't pack much of a punch here in early Dec. Week 2 trends look quite mild. Now if you have a cooperative Pac, you're aided by this blocking. So I'm not by any means throwing in the towel on winter. But 10 year normal temps in Dec aren't doing much snow wise right now. The playbook is Pac improvement, whether that be through the RWT, wave breaking, some strato influence, the MJO assisting with these things or some combo of all of them. Then the blocking can really help. And that's not to say Dec is a shutout, but I think the focus should be 90% Pacific right now

I'll go one further. Models have gotten a lot better at forecasting the MJO and subsequent RWT over the past 15 years. Part of the challenge is figuring out 'are you better than the model at forecasting the MJO?' And more importantly, are you better at diagnosing the downstream pattern than the model. I think a lot of folks treat the MJO like it's still 2009 and you had clear skill advantages and especially so in certain patterns. Not sure that's the case as much anymore given the improvements in the NWP space. It's a tricky game of when you're actually adding skill vs when you're actually taking decent modeling and making it worse with your own tinkering.

Well you were talking Holiday week in your post and my point is 'what air are you advecting'? If you're saying more towards January, I think you'd have a better case for it since there's potential for retrograde into EPO regions if you take that model verbatim. That Alaska look last week of December isn't what you want though.

If you're talking about the EC Weekly 500, it's missing any material source region and that trof is pretty empty. Essentially transporting mediocre Pacific air amid some storminess. Again, for the purposes of this winter you're looking for a source region build with Nino tendency to ridge out west. So in those breaks synoptically between ridges (you almost always get them), gonna really look to see if anything decent drains into W Canada. That's 90% of my focus right now. I liked the trends today a bit towards the end of the run today for that happening. But I need to see more synoptically for me to believe in a loading pattern that could deliver anything Christmas week. I don't have enough of a feel for what any +PNA or whatever would be transporting. Risk is a +PNA is just bringing in some modulated weak air and any potential system wouldn't have much to work with. My advice to this forum is focus on the source and less so the MJO. MJO 8 isn't the be all/end all for snow. Doesn't magically give you a source region.

I'd prefer Canadian prairies and upper Midwest, personally. Now thats not to say it CAN'T snow without those areas, but more often than not your source region is north and west and gets modulated and weakened without snowcover. More important to me is a loading pattern that at least brings in some cold into western Canada to tap into. We're lacking that currently. Models today towards the end are starting to show some signs of that, but that's really step 1 in the process.

Also, for the life of me I don't understand all the fighting about which phase the MJO is in and how phase 8 fixes everything. You need a loading pattern for a source, you need a source region regardless. That source region can come from wave breaking, stratospheric fluxes, etc etc. Feel like in winter everyone thinks the MJO is the solution to all problems and I don't think that's necessarily true. December's are tough in Nino years as the continent is often flooded with Pac air. We're seeing that play out right now.

I see a lot of Nino standing wave here. Which isn't terrible in most circumstances and you can get some Kelvin waves to leak east out of that. But, and I'm gonna keep saying this, we need some help with source region and building some snow pack to the west still, in my view before I can start to take storm risk seriously. It's not an all out torch, but it's still relatively mild.

It's gonna take several steps for this to improve enough where you'd trust a pattern to have any meaningful cold with it. That's the issue with these setups and its the issue with any coastal next week. You don't have much of a source to work with.

We're in an El Nino, a strong one.

I've seen weather vendors amplify this idea on the energy side too and they're getting run over right now because they're all too cold. Some people live solely inside the VP space as if it's the god particle that solves all weather.

Sitting in some heavy subsidence. Very tiny dendrites. 18 and windy.

I'll be sure to tell my cloud microphysics teacher. Look, I'm kidding a little bit. I've basically gone 'this is a Hatteras to benchmark low, it's gonna be a sizable storm for many east of 287' since Wednesday. But the northwestern component is an absolute nightmare with this and the comms around that are super difficult. I'm glad I don't do TV for events like this.

I have a stupid job. Do the weather they said!

I just want to caution folks on aiming too high on these ratios again. I think 12:1 is a solid middle ground and reasonable right now. Just too much wind. That said, this is a clear warning criteria storm east of 287 and a monster for SNE, Suffolk and some of the jersey shore.

I dont know yet, but my instinct says I can't totally toss out a gradient line starting at just west of 287 in Jersey yet. This is a very tough forecast.

Same issue with the dendrites getting beat up. Perhaps even more so. You'll just have way more liquid to work with.

Using 12-1 ratios because the wind is gonna beat up these dendrites. 10+ island and much of coastal NJ and coastal CT seems fair. It's that sharp gradient keeping me up right now. I'd love this to tuck 20 miles further west just to make this a bit more straightforward

So not the 12 hours of snow 15 miles inland then?

Most of the downstream changes are a knock on effect of subtle differences occurring inside hour 72 with regard to that northern stream piece. It's becoming a bit less theoretical today. Still some time for it to change again, but inside 72 you tend to look at it as a bit less theoretical vs trend tracking.

That shift in warm nose at 925/850 made a huge difference up there. Nice job by Albany on seeing that early yday.

Precip timing was fine at the 10z cycle, it has 0.1LE a little after 9 in the city and S Westchester closer to 10. So pending SWE it could end up a bit too dry if anything. But as far as temperatures go and the coastal front, that was handled well.

You were repsonding to a post of mine talking about the performance of the model with the coastal front. From there went on about how the 21Z HRRR 'showed no snow', which is just flat out wrong. It also kept Ptype as snow through 9pm, or roughly 2 hours. LE may end up around 0.1", which is where the 21Z HRRR may end up underperforming. If you would have said that, I would have agreed with you...

Depends on which model. Here's what the HRRR had this morning for right now: I'm a big stickler on revisionist history in this field and will call it out every time.