ORH_wxman

It’s an empirical fact we’ve seen more of the huge SE ridge linking with a -NAO the pst few years but just because that part is true, it doesn’t mean it’s true going forward or that a warmer climate caused it. Im always cautious in attributing largely stochastic features to a particular variable. So much of our snow blitzes in the 2000s/2010s came from that -NAO/-PNA couplet despite heights being noticeably higher than the 1960s when we saw a bunch of similar snow blitzes on that couplet.

Why would it make it more common for ridge linkage? You’d need the heights in the mid-latitude band to be rising faster than the heights in the arctic to make that true….otherwise you just get the same exact pattern as 1996 except everything is just up 10 or 20dm if the heights are rising together in similar magnitude. We’ve had excellent -PNA/-NAO patterns relatively recently (portions of 2016-17 come to mind and even the massive Mar 2018 snowgasm was -PNA/-NAO)

Well both times it failed we were snowing in the Rose Bowl so it’s kind of a limited example there. Your more classic RNA with the trough into WA/OR and maybe N CA would typically do very well with that pattern.

Yeah the NAO itself is stochastic enough and variable enough in it's own episodes that it's hard to generalize. You can have a very strong block but if you don't have a very strong TPV pinned under it, then you aren't going to get as much suppression. So the block isn't the only variable in that case....the strength and size of the TPV plays a role. REplace a monster TPV with a much smaller TPV lobe pinned underneath, and now maybe the same block is perfect for Boston snowstorm instead of DC. I do agree with @Typhoon Tip that we probably shouldn't take too much beyind D6-7 seriously at the moment (not that we ever should, but especially in this case) because that TPV/NAO coupling behavior is definitely notoriously bad on guidance. You have spokes of energy rotating around and other piece of energy diving down in the northern stream all interacting with it and it can change quickly.....hence why sometimes we'll see a monster bomb running due north near the BM on one run near 1/10 while the next set of runs might have nothing within 500 miles of that spot.

Big NAO blocks tend to be the most helpful during -PNA patterns. Much of the epic stretch in Feb 1969 consisted of that type of pattern and the first half of January 2011 did as well with that huge block. During +PNA, I'd rather have the NAO block centered toward Iceland or at least central Greenland....we saw sort of an Iceland block in the Feb 2003 pattern during that +PNA. Feb 1978 did have a west-based block and +PNA, but orientation was slightly different so that the PV wasn't sitting on top of our head. My biggest fear is a January 1985 repeat which I have mentioned a few times. We lost probably 2-3 legit threats that month due to overpowering NAO block with PV too close to us in SE Canada.

And that was 00z....12z barely gets 0.1" to Kevin's backyard. 00z got it almost to Canadian border. So those bigger northward members have probably almost all been eliminated.

At least you cleaned up in 12/20/09. Retro storm was pretty good too around New Years.

Yeah I'm pretty much ready to punt 1/6-7 after today's 12z suite. It was decidedly the opposite trend we wanted to see. Status quo would've been manageable at this lead time, but trending worse with the confluence just about closes the door. We'd need to see a quick reversal which is unlikely. I might keep an eye out further southwest near NYC but even there is starting to look bleak.

Dec through the New Years retrograde storm was actually a solid period....really shat the bed after that though west of you we did get the epic WINDEX event plus the MLK storm that caused Kevin to have a top 3 meltdown in the history of the forum.

Ukie is still amped....was the most amped at 00z too. It still has confluence problems though at the last second. Does get maybe 2-4" into most of SNE....less further northeast abd maybe a bit more in SW CT.

We want that PV west. Having it sit over us would basically be 10-14 days of cold/dry. Epic pond skating.

Except the confluence was decidedly stronger on the GFS....ICON is was weaker. Canadian was a bit stronger with confluence.

Too bad we can't phase in one of the PV spokes to get this north....prob the only realistic way to overcome such a stout TPV pinned there.

Canadian has an awesome shortwave which tries to push it north, but still too much confluence.

Way more confluence this run...total opposite trend of the ICON

ICON scrapes the south coast and Cape for 1/6-7....better than 00z but obviously the rest of us need more than that. But good to see a little less confluence this run.

06z GFS was using that follow up wave to push precip into SNE for 1/6 (really 1/7). Euro suite still shows a more consolidated shortwave for that threat but differing on the amount of confluence in the ensemble members.

Still a lot of spread for 1/6 on EPS. The mean is still spreading QPF well up into NNE. Plenty of whiffs on the table too. But we’re still not all that coherent on this one yet.

Well you are the most shamelessly IMBY on here, lol. I’ll tell you, another 3/5-7/01 storm would erase some of those extreme NE MA and SE NH deficits really fast. Some people forget that 2 days after the end of that storm was a late bloomer Miller B that dumped another 6-12” of paste in that same area (might have been more up in Maine). What a ridiculous stretch.

Yes I think it works well in that scenario because the second one has a relatively undisturbed baroclinic zone due to the first getting ground up. Typically, when there’s two close together, that first one will sweep the baroclinic zone out to sea which screws us…but not if you can grind the first one into a pulp before it does that. I’ve been looping a lot of the longer range ensembles and it’s remarkable how stable the longwave ridge out west is on so many individual members right to the end of their runs…it’s one reason I’m really not all that worried if the 1/6-1/7 threat doesn’t work out. This looks like one of those patterns that could produce a lot of chances even beyond the two we’re pseudo-focused on right now. A lot easier to get a hit if you have 4-5 at bats versus just one.

Just wait until guidance hones in on a couple of eastern MA/RI specials. That will really rejuvenate Luke.

That look near Jan 10-11 is really a powderkeg. Could easily end up as nothing but the longwave support on that is immense. You have this giant PNA ridge pushing everything so far south.

I actually don’t mind the second shortwave coming behind the other one on the 18z GFS because it allows amplification into the block somewhat. Im not sure it will look like that though given the euro is quite different with a much stronger consolidated shortwave. Either way, needing the confluence to relax a touch isn’t the worst spot to be at D7

Not in this thread. Weenie-ing out over April weather is why we have the December thread.

Def a lot of spread on 1/6…the mean has like 0.1” to the Canadian border but 0.25” down into parts of SNE. So prob a lot of big ones and total whiffs when you have a diffuse look like that on the QPF shield. This is to be expected though considering we are 7-8 days out. It feels like closer because we’ve been talking about that as the first potential event for days now.