psuhoffman

I don’t think that tpv is the issue. It’s behind the trough axis. It’s close but so long as it’s behind it’s not compressing that much. It’s not helping unless it dives in behind and phases though. But the bigger issue is the spacing (or lack of) between the waves off the coast and Thursday’s storm. The ridge to the west is too close also.

No they don’t, and I don’t blame anyone for not giving a crap what I have to say at this point..., but here is the deal. Back on the horse. Analysis. Not using clown snow maps lol. this is the setup for day 4 and then day 8 with key features identified As I said it’s almost a replay do over. The pattern sort of hit the pause/reset button because of the amplification of the Thursday wave delaying the eventual progression. Btw it’s possible if that were to happen with each wave we get through the “reboot” period without ever having the pattern break down before what could evolve mid Feb but one step at a time and that’s rather hopeful but it’s on the table. So what are the difference that could lead to a better outcome day 8. Frankly both look good at a quick glance. It’s not like Thursday is an awful look. But when you zoom in the spacing issue becomes apparent. The wave in front has slowed significantly in the last 72 hours. The ridge behind has shifted east slightly. The combo is compressing the flow around our wave and limiting its ability to amplify. Looking at day 8 the spacing seems better. What sticks out to me is the block is weaker, it’s more just a ridge in northern Quebec by then but that’s fine it’s done it’s dirty work and set up the suppressed flow across the Conus and the 50/50s. The 50/50 is exiting though and there is more space between the waves here on both sides! Don’t mind the lesser amplitude of the wave that’s mostly due to the longer lead time washing things a bit. All features are more muted on ensembles at range. Flashing ahead to the critical moment we need amplification as the wave crosses our longitude you can see the difference with the spacing. All that said...the issues to be careful of here are that the spacing could change. It looked better for Thursday around day 8-10 too then the wave in front slowed down. Also like I’ve said were in a double bind so if the spacing is too great we could go the other way and get rain. But that look there is worthy of interest. It’s basically a do over of Thursday’s setup and I was in love with that look from range so I would by a hypocrite to crap on this next one. Let’s try take 2.

The Cubs and Red Sox finally won a World Series in my lifetime. We just have to keep at it.

Agree with all this. That first point is totally true. The models can only project based on the data they have at the time they initialize. If we start trying to tinker around with predictions on top of predictions chaos would take over and we would get too much volatility. So as new data comes in every 6 hours they adjust as a crucial feature gets better sampled or something they projected turns out to be an error. The second point...only having the gfs would be a problem. Only having any one model would be. None of them are so good that an error at day 5-10 is unlikely. Contrary we know they definitely do have errors. No operational is ever in any run going to nail the details globally at day 5-10. The trick is predicting the errors and adjusting for them. Only having one tool would make that harder since often the others give clues. We could still adjust for biases but the gfs was actually running contrary to its typical bias in this case. The GFS gets way too much attention Imo. It saturates us because it runs a full suite every 6 hours, it’s the main flagship tool of NCEP and its the first and most easily accessible product every run. But frankly it’s behind the other major globals. It’s on par with the JMA and we dismiss that as a joke. But honestly more times then not over the 25 years I’ve been doing this the gfs adds more uncertainty then of it simply didn’t exist. More often then not we probably could have done better had it simply not been there! Some of that is our fault. If we weighted it correctly based on its scores it wouldn’t be as problematic but we weight it too heavily and allow it to skew our perception imo. Imagine if it was only the ICON showing what the gfs was the last 2 days...and the gfs was showing the weak POS the icon was...our perception would have been completely different. But they shouldn’t be. That’s our fault. lastly (and I bear some blame here) the way we evaluate on here is not really scientifically sound and healthy. We know guidance can’t see details at day 7+ but the problem is all we care about is one detail...snow in our yard. And so we try to pull that detail from guidance we know can’t possibly get that right at long range. If I had an actual job forecasting I would never do what we do here and talk about snow chances for a specific spot 10 days away. If I was actually forecasting the last few days for Thursday I would say “a threat for a storm along the mid Atlantic coast. Snow or rain possible, we will know more details as we get closer”. That’s in reality the best we can do. But that’s not good enough on here. Some get carried away. I probably feed into that because I sometimes try to be an optimist and not just crap on a threat until it’s apparent it’s not working out. The left few days I saw the flaws but I did have some hope maybe guidance was weakening the energy out west in error. Sometimes day 5-8 I’ve seen that and it bounces back. But it almost always bounces back at day 5 and we’re inside that so when I didn’t see a trend the last 24 hours I think you could see the frustration in my posts. This was my baby. I picked out this threat 3 weeks out. And in general the pattern progressed how I thought but the details matter. But I wanted it to work. I want snow. I want DC to get snow. I didn’t want to admit I was wrong and some of the discreet details just weren’t coming together. And I was probably too optimistic in my posts for those reasons. Even now it’s not 100% over. Maybe guidance is dampening the feature too much. But we’re getting to the point I’m not going to stick my head in the sand anymore wrt the obvious issues showing.

Remember in 2018 after the first several threats in that March Blocking pattern fell apart and that March 14 storm epically screwed us by being suppressed then reforming and crushing New England I had had promised and made an epic blow the world up rant. Then we got a big snowstorm a week later. Maybe it works twice lol.

it was supposed to be figurative...like a mic drop but point taken

Was cleaning out my old post graphics... How did DC not get any significant snow out of THIS... lol

We’ve been tracking. It would be nice to start hitting. Wrt that I touched on it a bit yesterday, it’s there but it displays the same limitations our other threats have. Limited depth of cold so if the flow relaxes it cuts but if the flow is suppressive enough to keep us supporting of snow the wave starts to look sheared and weak and like a minor event. You might not mind since you sometimes get excited over a snow shower or a few sleet pellets but it’s got the same inhibiting factor wrt chances it’s a significant legit snowstorm. That said it seems everything is going to have to be that kind of thread the needle so if we keep poking at the needle eventually you would think the thread would go through just by chance.

I took issue with your reason not the prediction. The high location was a result of other drivers not a cause. The compressed flow in front in the Atlantic and the amplitude of the wave are the real issues. The wave needed to be stronger or the flow more relaxed in front. Some combo. 2 days ago for a bit those things were trending our way across guidance. Since they have gone the other way.

You would have NO idea there would be a wave anywhere along along the east coast producing a snow threat somewhere between NC and PA Thursday from 10 days away without using NWP. There is no way to extrapolate that far out using old school methods. It’s a miracle of science we saw this threat along the east coast from day 15!!! You’re using an example of a success as if it’s a failure!

Dude put up or shut up. All you do is complain yet I NEVER see you make a prediction on anything past a couple days. And frankly over the years your short range predictions based on the pressure in Pittsburg aren’t any more reliable then what the NWS has going using NWP along with classical methodology. Earlier this winter your method was completely useless and I had to explain to you that the lack of a “suppressive high” had absolutely nothing to do with why the storm was suppressed because it was the compressed flow in the Atlantic. The pressure was irrelevant. If you can predict the long range better without technology please show us. If you can’t then these bitter “old man yelling get off my lawn” posts are way past amusing. Oh and save us your “how dare you respond to me in a public thread” crap too.

It seems anecdotally that spread has decreased days 5-10 on ensembles on both the gfs and euro. They almost always agree with the op now. That is less helpful Imo.

Don’t confuse user error with tool error. That poster has no clue how to use nwp. The purpose of ensembles is to tell us what a reasonable range of variability is according to THAT models physical interpretation. So they can tell us if a situation is highly volition by spread. Or they can tell us if the op likely had a bad run (even by its own physics). But an ensemble can’t correct for the parent operationals biases and core mistakes because it is a derivative of that model. You have to look at other guidance. Furthermore the guidance didn’t fail here. It’s done pretty good. From like 200-360 hours it identified this general setup. And it keyed on a possible event on the mid Atlantic coast. But from that range they cannon accurately predict the discreet details, like a weak wave that lingers and lowers heights some in front of it or a vort cut off under a block meandering around in Canada, that will determine exactly how amplified and exactly where a storm hits. If you’re judging NWP by details on synoptic events at day 7+ then that’s like grading your QB only by his completion rate on 50 yard Hail Mary passes. As we got within 7 days the preponderance of evidence started to show warts that threatened this event. The gfs showing a snowstorm doesn’t mean “guidance says a snowstorm”. The best guidance we have the euro has been saying hold on for days now. The second best the UK was never on board. The ggem was the next most amplified but it was further south and its ensembles were even less enthused. Most of the JV models were south. Taken in totality the evidence suggested the gfs was over amplified. We expected this to happen. We all knew the gfs all alone was likely to cave. I had hoped maybe the guidance across the board was dampening the wave coming out of the west too much but the last 24 hours the lack of why move that way in the euro and UK and the slow degradation in the gfs and ggem had me realizing where this was likely headed. Not for sure yet but don’t look good. Imo guidance has been incredibly good giving us a good idea how this threat was evolving at a good range if you know how to be unbiased and use them.

One last thing...After my last “emotional” post I should admit I’m clouded by location and expectation. If I was DC south this probably would still hold more interest to me and a lot in here are. And if I was just chasing a few inches I certainly wouldn’t give up. But I was kinda big game hunting and just found out there are only some rabbits and squirrels left in my area so I’m going home to drink a beer instead. If an elk just happens to wander by though....!!!!!

Guys I’ve done the whole “reason with yourself” thing but better to just rip the bandaid off. The trends are all the wrong way. And we’re hitting the 100 hour mark where guidance typically doesn’t make huge adjustments to major factors anymore. Today was a crucial day to hold or see improvement and it went the wrong way. It’s not OVER but it’s on life support Imo. let it go. That doesn’t actually have any effect on if this pulls off the rare comeback. Then it’s still gonna feel great. But don’t torture yourself anymore. Don't prolong the suffering. I’m gonna go find something fun to do. Peace.

The ensembles are only as good as the operational they are based on. They can’t help if the core model is wrong. Their usefulness is in telling us of the operational had a fluke run and went off on a tangent due to some discreet error even by its own physics. They offer a scope of variability within the physics of that model. But if the model is wrong about something due to a core bias that flaw will infect the ensembles also. All the ensembles agreeing with the op said was that the op wasn’t a fluke within its own physics parameters. But ensembles don’t ensure the models physical representations are sound. You need to compare to other guidance to determine and guess at that.

Less cold less resistance to WAA less lift less healthy precip shield to the north. We’ve seen that all year with every wave. The path to overcoming that here was when it was an extremely amplified bomb. It’s a balance. A weak wave with a weak WAA flow can create lift by having a deep hard to move cold airmass that resists the WAA creating lift. With less cold you need the flow from the wave to be stronger to compensate. Of course that opens the door to rain lol. See!

It was giving me 8” along the PA line yesterday. Trend.

No this setup is bleeding the wrong way. Has been for the last several days honestly but somehow the gfs continued to amplify the h5 way more then all other guidance anyways. But the trough in front is slowing down more and more, that tpv in Canada is diving south more each run and the combination is compressing the flow a lot more. Frankly had the h5 flow looked the way it does now when I got excited 10 days ago I probably wouldn’t have. Imo the bigger failure is the wave Monday. The progression sped up. That wave is happening during our best window wrt the Rex block and trough retrogression. But frankly the pathetic lack of cold F’d that up. No nice boundary for the wave to focus along, and that’s hey because it’s a surface driven not upper level wave. So it’s washing out and we weren’t even cold enough anyways if it hadn’t to maintain heavy snow. But simply from a pattern progression that was our best shot to get a simple overrunning snow in DC. The timing has changed for the next wave. The trough amplifies too much off the east coast and the ridge stops retrograding behind it. The wave after has a better chance to amplify but by then what pathetically little cold there is has eroded even more since the polar source is cut off. Imo the root of the fail was we had 5 days of epo ridge that opened a direct air feed off the Arctic straight down into southern Canada and the northern US...but that air quickly modified and mixed to become just an average blah airmass. That limited the potential of EVERY discreet threat within the blocking window. Created the double bind. Less potential energy from a weaker boundary. Made us need more suppression to stay cold. But less likely to get amplified waves. It’s not 100% over. Weirder things have happened. But I’m past the point of expecting it.

If this fails the lingering of the early week system which decreases the spacing and prevents ridging from really going up behind it is probably the biggest culprit. It’s the biggest change in the overall pattern from when I looked at it a week ago and really like it. The spacing isn’t as good now. Of course as the system approaches we are barely on the cold side and temps crash as the coastal forms...so whose to say had ridging gone up more this doesn’t cut and jump to the coast too far north like a lot of the gefs members that rained on us the other day. Our “win zone” with every storm is so narrow with the current temperature profile.

Another run that’s close enough not to give up. If it’s going to make a move my guess is we start to see it in the next 24 hours.

....falls apart just as it gets to us. I want off this loop

Storm after the storm....(ducks and runs)

The bombing Atlantic low combined with the blocking suppressed attempts to ridge out in the east. I’m still skeptical we get a big snow threat in the Feb 4-10 window but I could see some mix/icy scenarios and that look towards mid February is potentially very good.

Geps as predicted lost that weird split wave look. Back to looking like other guidance. It’s south of the gefs and significantly weaker though. But at least it’s back to the right progression. Targets central VA.