psuhoffman

Blocking patterns aren’t always cold. Often they are quite mild north of the storm track. This year has been to the extreme though.

Shockingly this would make the 3rd time this cold season the EPS caved to the GEFS wrt long range longwave pattern. The op GFS has been awful with synoptic details in the medium range lately but the GEFS since it’s major upgrade has been extremely good with pattern recognition.

Not that uncommon for a high lat blocking pattern. What’s uncommon is there wasn’t the snowy response further south. There was the response in the storm track but it was just rainstorm after rainstorm.

Keep it up and we’ll be shoveling something...

I like the end of the EPS run. That NAO/50/50 configuration is ideal. I couldn’t draw it up better. Would make it really hard for anything to cut. Yes the main trough is west but the SE ridge is suppressed and flat and enough cold should bleed east under the block in that look. That trough will also help eject energy that can slide under the blocking Look at the temperature and pressure profile Thats really good. The gradient is to our south but it’s not suppressive and the polar boundary is just to our north. Plenty of cold to tap. The mean SLP is screaming this kind of result imo!

I actually like the end and about to show why.

Yes..took a step back from the ledge. Also better NAO block and that wasn’t even a problem to begin with.

I think the EPS took a baby step towards a better look for the threat window around the 20th much better ridging into the west and more depth to the eastern trough as well as a better alignment. Only snag is it still washes the wave in front of it out and so the WAR is still there. If that wave can amplify into a 50/50 that’s a really good look. But 2/3 factors moved in the right direction. Meatloaf approves.

It’s a beast signature and centered almost perfect across all guidance. But if that degrades we’re screwed no matter what happens w EPo given how far west the pac ridge is.

Definitely but I guess that part I just took for granted since the -NAO is there across all guidance. The difference is the GEPS/EPS lost the EPO ridge and develops a flat pac ridge.

Yes. It all comes down to that. The GEPS is fully on the EPS side now. Both lose the EPO ridge and the pac jet gets directed right into the CONUS. It’s all down to that one feature because everything else is identical across guidance (except for features that are a direct effect of that difference).

I mean worst case people post in the wrong thread and so it’s the same as now lol. I think people can figure it out. Don’t disappoint me people.

Just in case anyone wasn’t in on the joke the gefs didn’t cave. Even out to day 16 it was pretty similar if not slightly better then the 0/6z runs. Model death match still on.

I’ll wait

@frd @CAPE @WxUSAF there is a dichotomy long range. The strat crew keeps hinting Feb could rock. The MJO/AAM/GLAM gang thinks we torch feb. There are conflicting signals. The progression of the tropical forcing and angular momentum favors a warmer canonical Nina Feb. The SSW progression favors Feb as when we see the greatest impacts on the TPV and subsequent blocking and cold intrusion into the mid latitudes. The question is which driver wins that fight or if it’s a stalemate does that end up favorable enough for us?

People who only want to hear what could go right and not what could go wrong.

Yea “long range pattern thread” and “medium range storm thread” thread.

That too...with a flow straight off the pole the STJ gets shut off and even if the cold does come east we can go dry.

I would bump the GEFS to a 8 long range and the EPS isn’t good but it’s not a 1. It does still have a -AO and there is at least hope with that. Last year with that pac and a +AO was a 1. I’d give the EPS a 2/3

It has some correlation to cold. It definitely correlates to cold in the US but that correlation becomes weaker the further east of the Miss you get. Almost every arctic outbreak does coincide with a -EPO because it produces cross polar flow. But most of our Arctic outbreaks don’t feature significant snowstorms. Details matter but in general an EPO ridge will focus the cold too far west of us and unless there are mitigating coinciding factors like a -NAO or displaced TPV in SE Canada the storm track will be to our west. The gradient often isn’t that far away so the cold can get in behind each wave but with the longwave trough axis so far west anything that amplifies will usually cut. You get a little NW of us or into New England and that can be a great pattern with storms riding the gradient. But we usually end up SE of the track here. Only in very rare cases like 2014 and 2015 does it work out and they took some rare combinations of a displaced TPV and an extremely positively tilted poleward EPO ridge. Looking at all our warning snowfalls the EPO was almost evenly split. The EPO alone just doesn’t correlate much to our snowfall. I will end with this since some have pointed this out...if we need true arctic air going forward to get snow then the EPO probably will become more correlated to snow. But that would be a VERY BAD thing!

Wrt the GEFS v EPS... hope this illustrates the difference better features 1-4 are the same on both. But 5/6 are there on the GEFS and not EPS. GEPS is kind of in between. Feature 5 there is crucial. That extension of the pac ridge into the high latitudes taps true polar cold and directs it down into the Conus. That creates a broader colder trough in the US that presses the thermal boundary into the east allowing storms to amplify further east under the block which leads to feature 6. The SE ridge (2) can be mitigated by 5/1/6 in that look. It’s a critical mass thing. Get a cold enough profile to set off the chain reaction we want and that all starts with that ridge up near AK. The strong 50/50 signature along with a cold enough airmass will stop storms from cutting end the SE ridge could even end up helping us to stop suppression. But if that ridge near AK fails and not enough cold gets into the pattern the trough won’t press, it will pull back fully into the west and storms will cut and then wash out when they hit the blocking ridge. The NAO block will be rendered useless. ATT I favor the GEFS look. The high latitudes have favored ridging this year and the pacific progression favors that. But I’m not ruling out the EPS. I’d like to see it flip back. Hopefully I’m not driving everyone nuts with this stuff. Just trying to explain what could make the pattern go one way or the other.

It’s more about potential energy. An increase in water temps from 80 to 85 will add a lot more heat/energy then an increase from 35 to 45 in the higher latitudes. Same with the air. Warning in the tropics will add a lot more heat then the warning in the Arctic does.

My source is only updated to day 13 so I can’t say what happens at the end but day 9-13 looks much better on the GEFS still with a more elongated trough that extends into the Atlantic vs dumping it all into the west right after the initial dump around the 15th. 0z EPS 12z GEFS same time

I agree with that. We shouldn’t be discussing details with a storm more then 7 days out anyways. I was thinking more for stuff day 3-6. We used to have threads before we decided that was bad luck.

@CAPE one last point wrt the pac issue. To simplify the relationship with the N PAC vortex...the warmer base state of the PAC has enhanced the jet and that in a nutshell means there is going to be this big firehose of warmth directed somewhere. And unfortunately we are downwind of it. But where would we rather it directed? Across the mid latitudes (directly at us) and enhancing a screaming zonal flow around the mid latitude northern hemisphere that also enhances the PV to its north! We have seen what that looks like plenty recently right? Big ring of red around with a blue ball of death over the pole. Good luck! Or do we want a vortex in the north Pac to take the fire hose and direct it up into the high latitudes and at least disrupt the PV and create chaos! Either way the whole base state is warm. But one seems to give us more of a fighting chance. Again this is just a 10,000 foot view observation.