NittanyWx

When I'm talking about source region, I'm not talking about extreme arctic air. One of the challenges with airmasses from the north and west is that these airmasses can weaken over time when there isn't sufficient snow-cover. Looking at snow-cover anomalies and the Chinook showing up in the extended range...I'm struggling to find the snowpack build right now and a material change in that scenario. So that means any Continental polar airmass loses punch as it advects southeastward. A +PNA with no snowcover and cP airmass that doesn't have much of a cold punch to begin with weakens chances for snow. So what I'm looking for, and why I keep harping on the need for source, is to mitigate the risk of an empty trough and no real source for cold to accompany any coastal storm if and when El Nino forcing become a dominant driver again in the mid-lats and the seasonal +PNA trend re-establishes.

We're thinking alike

All about source region.

There's a source region problem. Perhaps that Kara-Siberia ridge starts dislodging some cooler air towards AK/NW Canada that can be tapped into at a later date when +PNA base state returns.

By the way, the VP200 Hovmollers are already in 'favorable' territory inside the 15 day. So the models are already 'seeing' the MJO

I will continue to harp on about the source region until it's resolved. It's the biggest inhibitor to anything other than a transient cool period right now. Kara Sea ridge developing 11-15 day should shunt some cooler air on this side of the pole, primarily focused over Alaska and hopefully some of NW Canada. For significant storm odds to increase along with a helpful airmass with it, this period would hopefully include some cold air draining into W Canada. At that point you'd look for a baseline Nino +PNA to re emerge which would, in theory, be the timing when things would line up for something more significant.

Thinking is for a transient few cooler days around mid month sandwiched around warmer ones. I still don't see permanent blowtorch, though I do think the post cool period could produce several much above normal days.

CPC did/does some work on ENSO and snowfall. The problem is the composites haven't updated since 2010, so it's a bit outdated.

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.