psuhoffman

Ok I’m full tilt right now too but this is silly. Think about what you’re doing. In most waves like we’re discussing the distance between nothing, all snow, mix, all rain isn’t nearly enough to be worrying where that will be 15 days away.

The fact it’s even an option is worth noting. That’s all.

Not recently. Seems the last 7 years the “weird” only goes one way. But on a longer timescale you’re correct.

maybe, probably, but we would have to endure at least one more rainstorm before that likely as the next wave is already amplifying and the boundary is to our NW. After that maybe we're in business but my point is at that moment its still disturbing when I see a near record -AO/NAO/EPO combo and the SE ridge is still bullying the pattern. That is a BIG PROBLEM if you are south of 40.

Dunno...that's close for you..but awful for us. Unless what you are doing is "editing" the run to what you think would happen and that's fine but its also not what it actually shows. That would be a decent pattern from NYC northward but just rain down here. WAY too much ridging. I agree that upper level look SHOULD be a good pattern...but the model is saying it won't be. Normally...had I not lived through the last 7 years I would say its BS and it will be colder...but I have experienced the last 7 years and time again we have been warmer than I thought we should be given historical precedence in a similar pattern. So I have stopped doubting when I see what I would think is a "ridiculous warm" outcome from a pattern.

Yea it was the 6z for some reason. Ill edit my post. 12z actually shows how the pattern COULD fail... everything is too amplified and keeps cutting west and never pulling the boundary far enough east. But this look at the end is just infuriating. HOW is the SE ridge bullying this longwave pattern???? LOOK AT THAT. TPV trapped south of Hudson bay, huge 50/50 low, extremely -NAO/AO, HUGE EPO ridge. And a ridge to kingdom come up the east coast! Yea I see the STJ wave in southern CA and before someone yells "but the PNA" yea BUT the EPO AO NAO 50/50! There was a huge negative exactly there while we were snowing again and again in 2010! Like I've said there is an "equation" to all this...and we shouldnt need EVERY SINGLE FACTOR to be totally perfect. If we do we are FOOKED. Each thing is an independent variable and if we need 7 or 8 to all line up at some point you reach a point where the math is almost impossible. This look is going in my notes which are becoming a War and Peace length novel at this point.

6z OP GFS was relatively good for showing the details of how such a pattern could work in reality. It takes several waves to slowly establish a colder profile into our area. But eventually we get a snow to ice event and are set up for possibly another frozen event right after the run ends. But the key to that frozen event day 14 was the wave spacing. Any more space between waves and that would have been rain also. But overall a constant wave train like that and it would be unlikely we miss out on EVERYTHING, if we are looking at an extended period in such a pattern. Todays 12z op was a positive IMO and showed what the details COULD look like. Not that we want to put much stock in those details but its interesting when an OP does actually match up in general with the pattern the ensembles are showing to get an idea what the details could be in such a look.

Agree. But considering we’ve had no snow at all, if we just get a coating between now and April it’s a back loaded winter.

My guess is it ends up exactly what it looked like days ago from the type of system it is, an eastern New England event possibly. If I was in Boston I would keep an eye on this. Could we get some snow showers sure but that’s a pretty low bar.

It’s definitely going to snow. Nora gave me this and said it’s the snowman we’re going to build when it snows.

One thing I forgot to point out, don’t let temp anomalies fool you. As long as we get a temp profile back close to normal the storm track is more important. And that works both ways. We can have a high of 45-50 but if the airmass is reasonably dry and a system tracks under is it will snow. On the flip side we can see a 5 day mean (or a day 10 mean) showing cold because behind a wave it gets cold and the boundary pushes to our south but it systems are too amplified and the ridge axis it too far west on the pac side when the next wave comes it will cut west. So the pattern looks cold but it’s warm when it’s precipitating. We all know that cycle! We need to wait for the details we can’t know yet to find out whether this is actually a good look or not.

Fine….. This is the first serious pattern analysis I’ve done in a while, hopefully it’s warranted and there are more of these coming. First of all I don’t see a can kick YET. EPS at day 10 looks almost identical to previous runs. Whatever differences are incredibly minor for day 10 and noise imo. The eps was always taking longer to initiate a colder thermal regime after the longwave pattern shift but that’s simply because it doesn’t have the same cold bias as the GEFS and so it doesn’t just magically snap cold instantly the way the Gfs likes to do! The actual pattern change remains the same on the eps. Doesn’t mean it’s correct or real, we aren’t in the safe zone yet but no signs it’s a head fake as of now so I guess it’s time to take it more seriously and start a deeper look into what it could mean. This is the 5 day mean day 10-15 for reference sake I’m posting the best example of a similar pattern that worked out in a big way here Jan 2014 This is not a prediction I just want something to reference for comparison and as a what to look for. The most prominent features are a full latitude easterly centered epo ridge with a ridge bridge over the top with a -AO and a WAR. The similarities to 2014 are evident but that doesn’t mean similar results. But this pattern is fairly rare. It’s not that 2014 was a rare outcome it’s more that 2014 was a rare pattern combo to lock in for a long period. There aren’t that many good comps one way or the other. But from the few there are there are several keys to success 1) location and orientation of the epo ridge. It cannot end up any further west than it is right there. That’s already living dangerously as it is without more PNA help. So far the gefs and eps have been slowly heading towards a compromise. That’s ok so far so long as that compromise doesn’t end up any further west with the pac ridge that currently projected. 2) the orientation and depth of the CONUS trough. We don’t want it too sharp or deep. That would lead to a cutter quick cold shot and moderation pattern cold dry warm wet. We want a more SW to NE oriented trough which is what the eps shows above at the moment. We need to watch for changes there. 3) The amplitude of the WAR. In this look some war can actually help keep waves from being squashed IF it’s suppressed some. We don’t want to see the WAR building up into the 50/50 space. All 3 of these factors play off each other. If the pac ridge shifts east then we could survive a little more WAR and or trough amplitude. If the pac ridge shifted east into a pna ridge then we would actually want a deeper trough. If the epo ridge shifts west at all we would need more NAO help and a 50/50 (way less WAR) or we would be toast! It’s a interrelated equation and each factor influences the others. Lastly what made 2014 work in this look was that there was a constant wave train along the boundary but almost none amplified. There was just a constant train of weak progressive waves. It’s amazing some of them ended up dropping 8-12” in places frankly given the lack of amplitude but that might be a new normal where it takes less to create a respectable qpf event. But anything amplified would likely cut. There were only 3 truly amplified waves that winter and 2 did cut. The other in Feb tried but it initiated really far SE and there was such a cold airmass with snow cover everywhere over the top of it. It did still flip to rain in the cities though. But trust me given our total lack of arctic air lately we don’t want to try that game again. We need the waves to eject in a progressive way and not an amped up cut off system in that pattern. We won’t know those details until we’re much closer, for now we wait and hope.

The EPS isn't a can kick...it was NEVER showing colder anomalies making it into our area until after Jan 25 at the earliest. If you compare the h5 from previous runs and last night, and I am about to in a post I am working on now, the pattern at day 10 from last night is nearly identical to previous runs. The GEFS was bringing in cold a lot sooner, when isn't it, and it is starting to can kick because it is coming around to the EPS/GEPS. In reality the two are meeting in the middle, the EPS has backed off the PNA a bit in the long range and focused more on the EPO but not as bad as the GFS. A compromise here can work. I haven't seen indications of a can kick YET...but we arent within safe zone yet and even if we get this pattern change there are imperfections and issues that could still mean no snow for you if the details within the pattern don't break out way but I will get into that in my next post.

@Ji knows I’m just teasing. If there was something positive to have legit discussion I’d stop but things are so awful might as well have some fun with it. If we can get the pattern change inside day 10 and things start to get more serious my tone will change.

And it didn’t even buy us dinner first

If everything you come in contact with is a disaster what’s the common denominator?

Not overly. I’m more concerned it’s just wrong about the pattern. There is a wave around the 20th that’s going to go north of us. But it’s also very likely the next wave around the 23-25 does also. Imo it’s likely to take multiple waves to establish a cold enough regime. That puts our first good opportunity near the very end of the eps run. And by then the war is getting beat down and it looks like a more favorable setup Imo. The mean does start to increase some at the very end. I bet if it went out another 72 hours you would see something. But ya it is concerning that the pattern on the eps only seems to cool temps to near avg. It should be way colder. But we aren’t having that talk again. Personally if we get the eps pattern and it’s too warm I’d rather find that out and know. Then at least we can end the debate!

Look all we need is a -4 AO NAO EPO with a +4 PNA and a TPV exactly over 50/50 and a 1055 high over Montreal with a split flow and strong STJ. Then we might get 2-4” before the flip to rain.

Imo they are all just tools. None of them are useless but just like you can’t use a hammer alone to build a house no one of these products alone is sufficient to make a forecast. In this case the mean is skewed by outliers. But a quick look at the probabilities output identifies that. No harm to foul. Trying to use one product to base a forecast is user error. But if you look at all the evidence, including historical reference, it can be useful. We’ve known at least 10 days in advance of each pattern change this year going back to October. We even knew by 5 days out that the snow threat was zilch in most cases. I think guidance has been pretty good, it’s just not been what we wanted!

@CAPE I’m just kidding. Your concerns and preferences are legit for your location and recent history!

Careful someone will be along soon to tell us because there isn’t an epo ridge extending to Moscow it won’t be cold enough.

The eps is how you imagined prom night going at the start of senior year. Gefs is how it actually went.

Is it a can kick or is it just showing the details more clearly as it gets closer and there is less washing out due to variance and timing differences. This was always how I figured it would actually look given the gefs longwave pattern. Other than one run where it temporarily caved to the eps I never really liked what it was offering.

Must have been a typo https://m.youtube.com/watch?v=Ya2xifdO_l0

did you buy a snowblower? if so we know the problem now...