psuhoffman

Mitch is gonna come along any second and tell us that 12z it lost the storm lol

To put this in perspective, I remember one of the events in early Feb 2014 I was up in Pine Gove PA that year...but still participating in this forum, and at about 72 hours out you were all rooting for a north trend on a wave that was supposed to be suppressed south of you...and it ended up giving me 8" of snow up in central PA and was mostly rain for DC.

I bet back in 2014 and 2015 the spread would have been even worse...so bad actually that we had no clue there was even this kind of potential at these ranges... none of our snow those years was really clear on guidance past about 72 hours. These types of patterns are not good for long lead tracking. The issue I think now is the guidance is better so we actually do have some idea what the period will look like and the threats...so now its frustrating that these waves move around every run and model to model...because we want some clarity. 10 years ago we would have no idea at all what was coming and what the specific threats were so we didn't get bothered by the crazy swings at 100+ hours.

At least you're not 13 anymore JK

I agree this is more productive discourse. Just so you know, honestly, I was just trying to make a light hearted joke yesterday and you went off. I realize we have had tense exchanges in the past so I will admit that I probably should not have tried to joke around, but it was not meant to start a nuclear exchange. Honest!

It's fine there for now... as I've said above, the most likely outcome at this range is still a miss south...but not by so much that we are out of the game. This has more chance to trend north than the waves did with that block in the way.

@WEATHER53 You use the guidance correctly all the time. You make posts where you see what the guidance shows and you say "this is not common, with the high there it will be colder" or "that SLP track would actually produce this". That is the right way to use the guidance...not to just take what it says and issue a forecast...but to adjust the guidance based on experience and probabilities and in a way to "predict how the guidance is wrong" and adjust for it. And at long leads like for next weeks storm...the operational runs are not to be taken with much weight...its about taking the full run of guidance including ensembles and get an idea of what the most likely outcome is based on the consensus of all that guidance adjusted with your experience from historical examples. Your critique of how the guidance is used seems geared towards how the weenies online use it, but who cares what randos do for fun. That isn't how profesionals do it. I ignore the noise from facebook and twitter weenies and hype merchants.

They are tools. And yes they are models showing possible outcomes, or permutations. Since we are not able to predict with 100% accuracy and each of the models we have is flawed in some way, every one will show a slightly different outcome as you increase the time range of the prediction. And that outcome will change every 6 hours as we get new information. It's up to us to make this useful. I find them useful. IF we didn't have the model guidance we would have no idea there was the risk of a major winter event over the southeast next week! Whether it comes further up the coast is less known, but we can say right now its not the most likely outcome but its possible. That's better than nothing which is what we would know without the guidance.

There are going to be multiple waves starting with Sunday. Euro misses with 4 straight, 3 south and then one north. Could we get that unlucky, sure, but I still feel optimistic something hits during this coming period...maybe not the first one but it would take some bad luck to miss every wave.

That was the GGEM that had the crazy 2 ft solutions, and its still the most amplified of the operationals at 12z but its more like 4-8" for the cities with more SE. However, we are not supposed to use operational runs at this range. The ensembles are meant for this, and the most common solution across the ensembles has been a miss to the southeast with that wave. Doesn't mean it cant hit, its not so far off that there is no chance, but seeing one run of one model show some 2ft storm does not mean "THE MODELS ARE PREDICTING 2ft" when 90% of the guidance when taken holistically as a whole show nothing.

The TPV slides by pretty quick to our north and as of now it looks like the pattern relaxes some after without another immediate shot of arctic air. But its a long ways out. But more importatntly that is not my main concern. I am hunting snow, could care less about getting frigid below 0 temps.

It’s going to be cold no matter what. Whether we get snow depends on how the TPV behaves during its elongation and split and the amplitude of the waves out west.

Just looking at the way the whole pattern evolves looping the h5 across guidance I think the second wave next week (the one the gfs is keying on) has the best chance to ride the coast north, but the first wave have the bigger upside in terms of snowfall for 95 (colder antecedent airmass). But fun times. The Sunday teaser is totally dependent on where the boundary sets up exactly and the track of that vort. It’s a narrow win zone so that won’t be nailed down either until the final 48-72 hours.

But it will be fun watching the nervous breakdowns some are going to have if they live and die with each model run over the next few days!

They are all doing this...its too many moving parts at a long lead time for them to handle. We are several days away from getting a better idea on the options next week...there are 2 threats BTW.

Good morning Quick summary of what I see The first threat Sunday is actually simple, but the cause for divergence across guidance is that its delicate. There is a vigorous SW over western AK right now. It's going to split over western Canada with a piece going east and merging into the TPV and another part diving into the trough, rounding the base and becoming our snow threat Sunday. This energy activates the boundary. It's pretty simple, how much energy and what track does this wave take. But its delicate, its a relatively weak minor player in the overall flow so models will struggle with it, but this delicate weak piece of energy holds our fate wrt snowfall sunday. The next bigger threat involves major players on the hemispheric longwave scale, but it involves lots of them in a delicate intricate balancing act so its complicated. The main TPV (1 and 2) is going to elongate and eventually split. How much energy resides with 1 and 2 and where 1 ends up and how quickly it clears out of the way to our north is a major factor. How much energy trails with 2 and how it interacts with 3 is a major factor. What 4 does and how it influences the tail of the trough is a factor. And finally what the next major wave 5 does and whether if flattens or amplifies the downstream trough is a factor. There is no way guidance is going to lock all this in at this range, especially absent blocking to set firm guides in the flow for all these features. But in general we want more energy to reside further west with 2 and 3 and less with 1 and that has been the trend across all guidance over the last 24 hours. But don't expect this to be resolved quickly. Even the crazy GFS idea of holding back so much energy that it becomes the next threat 48 hours later is not off the table and shows up on some individual members of the EPS. Lastly, what comes AFTER AFTER.... EPS continues to trend towards a much more friendly look for February. It's already backing off on the crazy SER look it was suggesting. It continues to trend towards lower heights near Hawaii which is a key, that look of the pac jet undercutting the WPO EPO ridge typically suggests troughs won't get stuck in the southwest and press east more. It also pushes the WPO EPO ridge poleward and often leads to AO ridging over the top, which we are seeing more and more now on long range guidance. This also helps to deepen troughs into the CONUS. This look puts a lot of pressure for the cold to press southeast. Last nights op euro is a good example of what that pattern would actually look like because it matches the h5 of the EPS very closely. The SER is there at H5 but look at what it actually looks like where it matters We are very much in the game for boundary waves in that look. It's February and we don't need as much of a perfect pattern to get snow the first half of February as just about every other time of the year. If that is the worst look this winter has to offer (early to mid Feb was what all the analogs suggest is likely our most hostile period in terms of the longwave pattern) we are in pretty good shape.

They do but they also still show signs of the pac jet undercutting in the central pacific and now signs of the AO going negative again. It wouldn’t take much adjustment to shift cold back into the east. Even the look they show wouldn’t be hopeless as trailing waves would have potential with cold close by.

I think that’s what he is saying. There is no way that cold doesn’t make it here given where it’s directed. Maybe not to the level guidance shows. But I think he is hinting the models might be pressing the boundary too far SE which I agree with.

It was about to lay down the hammer. It was significantly more amplified than 12z. EPS trended that way also. I’ll take that trade off to lose 1” Sunday lol.

Is ncep concerned that they’ve fallen even further behind?

That is a HUGE jump from 0z

No, I think the Northern Neck is going to get so much sleet... I would hate to live there

You're point and caution are correct, but I think this setup has more of a chance then that ever did. That required a more complicated phase to pull off and it was never really on anything except the GFS, wasn't even all that close on any other guidance. The "foundation" for this storm is there across guidance. But it's still not the most likely outcome at this range...but I think its more likely then that last one was.

I just need to make sure everyone knows it shows sleet in central VA just in case they missed it

The euro shows sleet in the northern neck