ORH_wxman

Regardless of whether the Hudson Bay block forms from retrograding Greenland or building through PAC troughing (it's prob some of both since heights there are already residually very high when the PAC assists), it's very formidable for winter storms here. It's probably one of the best spots we can have a block. It's why the OP Euro gets us in the 12/14-15 storm. But I know why that is a more dangerous evolution....if it forms in SE Ontario or Quebec instead, then it torches us....which is what many of the ensemble members try to do. 1/12/11 had a nice Hudson Bay block form ahead of the PAC troughing

And here I was getting excited to see the block regenerating near Hudson Bay when I lopped the 00z ECMWF.

They look very good through early January.

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GEM/Euro/Ukie are also colder behind 12/10 than GFS is. Prob because their NAO block is not sitting on our face like the GFS.

We're looping through unfavorable forcing between now and about 12/10 or maybe even 12/12. Even GFS suite is bringing forcing into a bit more favorable by mid-month. It's a little slower than EPS, but it's probably going to happen. In the meantime, I don't think anyone should totally sell on 12/12 or 12/14. BTW here were the 12/12 individual members.....you can see some absolute whoppers (e3, e18, and e24) in there mixed with mostly nothing. Not a whole lot of "in between" type solutions.

This looks like El Nino PAC....a bit skeptical of this....but nice to look at. But even a neutral PAcific is going to be good in this pattern. You can see the PAC getting much better by around D10. Height in AK were a decent amount higher by D10 this run compared to 00z.

Not a lot of them, but there are a few big snowers on EPS for 12/12....that follow-up wave behind 12/10 threat we were talking about earlier.

Tip might have some additional fodder for his 12/13-14 thread on this run.

Yeah....whats shifting the block from Baffin to Quebec City amongst friends?

LOL at the difference in the blocking between GFS and Euro at day 6

Euro trying to focus on the follow-up wave like the GGEM was doing for 12/12. Looks a bit too flat/weak this run to get us, but may need to follow on subsequent runs if it comes in stronger.

Still has an outside shot, but you need to really thread the needle to make it interesting....if that shortwave rides up over the ridge really far north, it will then maybe be in decent position when it gets shunted southeast. But my hedge at the moment is this is a whiff.

There's been a lot of different versions of poo-pooing so hard to say how to parse them.... 1. One version was obsessing over the timing. Like if it didn't flip by Dec 8th, it was a huge bust. "we're going to lose most of early December!!!" 2. Another version was "it's a horrible pattern for the next 3 weeks". Not sure where that came other than "Feels" from but it's been posted in this thread. 3. The most reasonable pessimists IMHO have been the ones probably along the coast who understand their climo sucks in early December anyway and were worried about arctic cold being available...so that when the model guidance ticked somewhat warmer, it was game over for them even with a strong NAO block. This shouldn't really change anyone's perception in the interior, but for the coast I can see the worry. I think some of the worry has been a little overblown though even along the coast. If you get a high in the right area, even a relatively marginal airmass will prob snow to the coast except maybe right on the beaches.

He needs to confess first to the November pattern change sins...

All the other guidance keep the block and then retrograde it back into Davis Strait/Baffin area and re-strengthen it temporarily as the Dec 9-11 ridging to the north of that system feeds into it.....then it spins in the west-based region slowly decaying. GFS just disintegrates the block and never rebuilds it after Dec 10th and instead the heights fall over Greeland/Baffin and a monster ridge builds in the east.

GFS suite has been downright bizarre in how it handles the NAO block the past few runs. Def does not match the GEPS/EPS evolution. It's not even a block at all after about day 4-5.

Yeah a lot of guidance is showing that. Moisture is trapped mostly below 800mb in that look, but with 850 temps getting into the -6C or -7C range, there is likely going to be snow growth in that lower level, so could be some steady SN- inland if it sets up like that. But obviously the models seem to be really struggling with that entire evolution, so hard to take anything without a grain of salt at the moment.

Irony is that the PAC is looking pretty decent by D10 on that 12z run.

12z GGEM has a significantly different evolution for weekend/early next week....it has a little PV lobe pinned to our north and sort of focuses more on the follow up wave on 12/12 instead of 12/10. It has 12/10 initially pretty far north but then gets put through the meat grinder and we see more action from the follow up 12/12 wave. It also has Tip's 12/14 storm as a SWFE/front ender.

Every pattern has examples of taking a while to produce or producing right away. This one is no different. Models did rush the retrograding of the SE ridge by about 4 days....normally a fairly trivial error. If it weren't early season when everyone is predictably impatient, the melts would probably be about half of what we're seeing.

GFS feeling the crunch for Dec 10th....makes sense though as it was an outlier for the past 3-4 cycles. Now starting to trend toward other guidance.

Lol....yeah, making ironclad proclamations is great for sales, but not so great in forecasting. Same goes for those who are convinced we're screwed too. Seeing an awful lot of certainty in some posts while simultaneously complaining about the unreliability of model guidance.