psuhoffman

The late week setup screams painfully close miss to me which would be the perfect way to end this season.

Yea that would be almost as bad as using the CFS to predict an mjo phase 8.

It has always been common for DC to go through multiple year runs of sucky winters. But the trend for 50 years has been for those suck years to be even worse. Unfortunately it’s bevoming quite normal for DC to go long stretches with very little snowfall. The good years are becoming better too and big storms bigger...but I think most snow lovers would prefer a more even distribution and not as long a wait between good times. But that is our current climo.

If I had to guess right now based on historical probabilities and recent trends in long term global patterns, next year is likely to suck also but not as bad as this. A 5-10” winter around DC would be my best guess right now. There is a lot of time for that to change. Maybe the warmer waters in the IO and western PAC driving the unfavorable mjo shifts. Maybe enso changes trajectory. Maybe the long term AO state flips. But that’s a lot of maybe. Better to just expect it to suck and be pleasantly surprised if it doesn’t.

I can think of something else that describes

I must look into this analog thing. Never heard of it. Sounds like voodoo black magic to me.

Yea each model keeps spitting out a snow solution here or there but it continues to be a random storm with no consistency. Until we see guidance converge on the same discreet event it all remains highly unlikely.

Wrt the op euro the SS and NS missed the phase and a major storm by 6 hours. It was as close as you can get without a major amped solution. And it would have amplified perfectly for us location wise. It was a run that suggests there is a chance. There have been enough runs with a similar look that it’s at least still a threat, if a long shot one. That’s all it’s worth.

In fairness you might be the only one of the 7 people in this sub effected by that still paying any attention. I am at the point where I check in once a day and scan everything but not wasting any more time than that. I don't really have that much time right now anyways.

I know the thread is a dumpster fire joke at this point but it can snow even into late March here, and some of the years it did were god awful seasons like this one. Now...does that mean it’s likely? Hell no. It’s a long shot. And we’re not getting some 20” cold smoke HECS. A small slushy accumulation is more likely if anything at all. But some would be happy with that and would want to track it. So if you’re one of the people who has totally checked out (I’m mostly checked out) fine but leave those that want to track every lottery ticket chance to the bitter end alone. It’s no skin off your back. Posts whining about other people tracking low probability snow chances is more annoying than the posts tracking them.

Lol with some luck 2018 could have been a good year. Every so often you can get a good Nina but that might have been the year and we just got screwed. Most places around us had above normal snow that year. Frankly in the last 40 years our odds of a big year in anything other than a moderate nino are very low. It used to be a neutral was a pretty good enso state also but lately they mostly end up crap too.

Winters like these happen once a decade where everyone outside the northern mountains get screwed.

Unfavorable pac forcing combined with a strong PV. Years where there was a significant pattern flip from warm to cold during winter 1958,1960,1966,1972,1987,1993,1999,2000,2005,2007,2014,2016,2018. There are plenty of flips from cold to warm also. But by New Years the combo of a strong phase 5/6 mjo wave in conjunction with a strong PV coupling with the tpv hinted that this year was at risk to be a total dud. That combo is the leading cause of our total wasted years. This result isn’t a big surprise.

I doubt anyone actually expects it to snow

Any hope of that factor changing left the building a while ago. At this point whatever minimal chances at snow remain hinge on getting a lucky wave track from short wavelength induces chaos.

Thank you. 2 thoughts wrt what you noticed (I noted it also). First it's hard to draw conclusions about that because what those numbers don't show is the frequency of those patterns. If a pattern is more rare it might be the best pattern but have less instances of snow simply because there were less opportunities compared to a more common but less productive pattern. That said, I do think there is also a bit of "too much of a good thing" going on with a -EPO/+PNA full latitude ridge. In a vacuum a -EPO/+PNA/-AO/-NAO are the best phases of each of the 4 major indexes. But when in combination it's not always that simple. When we have a really strong -NAO for instance, some of our biggest snowstorms happened with an unfavorable PNA/EPO combo, but in reality that "unfavorable" pattern out west trying to force ridging into the cold locked into the northeast is what created the big storm. Without that we would have been cold/dry with a weak wave running off the southeast coast. Time of year also matters...we typically need the epo/pna more early in the season and the nao more late. Without any NAO help...by far our best look is that east based EPO ridge nosing over the top creating a broad flat trough under it across the lower 48. The NAO changes the equation. The more blocking (especially later in winter) the less we need EPO/PNA help. Enough blocking later in the season and we actually dont want a big wester ridge. So there really is no one perfect look that is universal across the whole winter season. That study I did was just step one is a larger plan. Right now I have no time for anything. My less frequent posting lately is not just because the weather sucks... its more that this is a busy time of year for me. December/January I have a lot of free time. Between Holidays, end of semester and PD breaks there, and testing I have a solid 2 months with not much going on other than my normal teaching duties and even those...I only have a normal class to plan for or stuff to grade about half the time. Right now is one of the times of year I am slammed with observations, curriculum planning meetings, summer school planning, bridge project scoring, Test prep planning, debate events... I just don't have time. But I have way more in the plans. I just found out I might be getting a rather significant increase in my responsibilities wrt to my summer position so I may not get to all of this but I should still have more time to at least start this list. In addition to what I did in December, I want to do a similar study for our area. Then I also want to look month by month and break down the dominant patterns from 1950 on to see the frequency of each pattern. I also want to break down those splits by month to confirm which patterns work best by each month. Once done I would be able to determine what the odds of snowfall in any given pattern are (roughly) by month. That would make what I posted here a lot more useful. But that will take a lot of time I don't have right now. If I don't get it finished this summer I probably will next December during my next "down time" period.

@Maestrobjwa CCB refers to the cold conveyor belt. I think to fully explain this I should do a quick overview of how most mid latitude cyclones work First of all low pressure typically forms along the boundary of cold and warm air...as air moves across the boundary to try to bring equilibrium to the imbalance. This movement of air creates lower pressure where the air is vacating faster than it is filling in. A low can really intensify when an area of divergence in the upper levels crosses over the surface area of lower pressure. These areas of divergence are typically found in front of either long-wave troughs or Rossby waves or smaller shortwave troughs embedded in the flow. This divergence aloft creates lift below it to "fill" the void and this lift (rising air) from the surface lowers the pressure as the lift outpaces the rate air is filling the surface void. On top of that the rising air cools and condenses causing precip but that process creates latent heat release which causes more lift (warm air rises). This creates a feedback loop that intensifies low pressure. Early in the life cycle of a developing low pressure area they are typically just waves along the temperature boundary Precipitation breaks out along the boundary where the flow ahead of the developing low pressure begins to cross the "boundary" to the north of the wave. The warmer air crossing the boundary has to rise over the denser colder air and this lift creates WAA (warm air advection) precipitation. (rising air cools and condenses creating precip) Showery precip usually exists along the cold front to the south of the low where cold air is undercutting the warmer air cause it to rise...but since this displacement happens much faster the precip there is sometimes more intense (thunderstorms or convective showers) but short lived. Many waves never make it beyond this stage if there are factors inhibiting their intensification. But if a low can amplify and deepen it will develop a circulation at several different levels As it develops this structure...the cold conveyor belt begins to bring moisture that is to the east of the low from the warm conveyor belt to the west of the low. As this happens the storm will begin to develop the classic comma head structure seen below. That precip to the west of the low track is often commonly called the "CCB" since it is a function of a healthy system developing precip in response to the cold conveyor belt transport of moisture west of the low track. Additionally the precip to the west of the surface low track is not driven by WAA as much as other forces and so can have a colder thermal profile, especially in marginal events. Seen above there the dry conveyor belt begins to cause the "dry slot" that you often get near the track of the surface low pressure. Below I have zoomed in on what is going on in the "CCB". This region in the "CCB" develops a deformation zone...a region where the atmosphere is being pulled in different directions at different levels. The convergence of the DCB, CCB, WCB, as well as the sheer at different levels created by the mid and upper level low pressures creates instability in this area. Where the moisture convergence from the CCB bringing moisture in off the WCB meets this instability you can get intense snow bands. This is what they call the "deform" band. One of the best examples of a deform band was from the February 2006 storm. This radar is from the NYC area but this same band impacted our area...I think the Columbia MD area got 20" because they were under this band for several hours. You can see on the radar loop the forces I described above at work. Later in the life cycle of a mid latitude cyclone, because the cold air often outpaces the advance of the warm air...the cold catches up and the low ends up cut off from the warm air advection...at this point we say it has occluded and it looks like this. At this stage the intensification period is over and the storm typically begins to weaken. But during this stage you can often see snowfall wrapped up even under the surface low instead of displaced to the NW of it. Hope this helped some. You can ask any follow up questions also...others feel free to add anything to this.

I know you’re busy...and I’ll be having some quality time with the wife...so maybe we should let Mersky take the wheel for the weekend. I fully expect to return to phase 8 bliss... blizzard warnings and talk of new biblical classifications.

The guidance mishandling of the play between the tpv and North Atlantic vortex really mucked things up. That phasing and consolidating into Baffin vs splitting and sliding out forces the canadien ridge too far south and flipped the pattern on a dime. It was one thing...but a BIG thing. Maybe one big thing will break in our favor one of these times.

It shifted quite a bit colder. But it seems to do that partially in response to bombing the day 10 storm then squashing everything behind it. Cold/dry day 11-16. But still a better look rolling forward than 12z was imo.

In fairness the gefs was better day 10-15 but dry. But closer to workable. It was a better trend fwiw.

Now that’s bad.

Wrt the mjo and pattern...that doesn’t mean things can’t flip...but that when we do see major pattern flips it’s not purely because of the Mjo. An example is 2017/18. We had a cold phase rotation earlier that didn’t do us much good but when it rotated into cold phases again later as the permanent NAM state was flipping it had the canonical response. But that pattern then went on to persist even as the mjo wave faded and went into warmer phases. We need an actual atmospheric base state change along with the mjo. An mjo wave temporarily traversing cold phases during an unfavorable global base state pattern won’t do much good imo. Those kinds of pattern flips can happen. But the most likely time is late. The Nina like pac response favors such. Think 1999, 2009, 2017, 2018. Not all do but many years with similar pac issues feature a legit pattern change for March. and before the “that’s too late” posts yes yes I know. I’m not saying I want that. Just saying that’s what might happen.

I’ve had a thought on the MJO for a while that I’ve mentioned a few times as to why we often don’t get the response we need when it goes into “cold phases”. The whole “MJO phase 8 is great...except when it goes into 8” thing. Basically I’ve theorized that the main reason the mjo phase 8/1/2 are correlated with the H5 look we want and cold is that those mjo phases are also correlated too and amplified by the types of global patterns that produce those results. So basically a winter here with a cold base state is likely to spend more time in cold mjo phases skewing those phases that way. But when we have a warm base state winter and we wait for an mjo wave to save us it rarely does. Even when it makes it into cold phases the response is muted. It often makes things “better but not good Enough”. I suspect a cold phase mjo is not as correlated to the response we want when it happens in warm base state winters. That is probably because it’s acting alone and not associated with the typical global pattern (canonical el nino) that it is during cold winters. Instead it’s being muted by the background warm base state. On the other hand I think the same is true in cold winters. Over the years when the mjo is about to crush our dreams and JB is spinning to save his subscriptions for another month he likes to throw out examples of warm phase rotations that were cold/snowy. But they are always years like 1978 where we were in a canonical nino pattern and the base state was cold. For the same reason in a year like that the warm mjo wave is muted by the background state. When we are in a warm year and the mjo spikes into warm phases we always torch. This has just been a theory and I never bothered to research and support it. I bring this up because isotherm seems to offer scientific support for this. Isotherm From the NYC sub “Chris, and I've been ruminating on some hypotheses re: the time-lag and distorted response. One issue, in my view, is base-state resonance. Sometimes the MJO/intraseasonal signal is misaligned with the base state, and as such, when it propagates through typically conducive phases, the N HEM response may not be bonafide/favorable due to the misalignment with the background indicators. For example, 2002-03 had a much more classic AAM/GWO and hadley/walker cell structures concordant with a canonical El Nino, and thus when MJOcirculated to 8, we had a more genuine N HEM response.”

Why are you stuck on the mjo projections. This started over you comparing my analysis of the EPS to Will’s and implying they have not gotten worse for our snow chances. Neither myself or CAPE said the EPS was right. Your off on a worthless tangent because your original point was BS.