psuhoffman

I’m telling you when the HRRR is dry and under amplified sometimes it’s onto something. Not always but I pay it more attention when it’s doing that then when it’s wet and amped. Also I don’t like the trajectory. When waves are projected to be this west to east at our latitude on guidance 24 hours out make up all the times I can remember when things sunk south at game time. The early March 2014 storm was the kind of that. Took a 6-10” storm down to 3” across northern MD. I know the trajectory is just a symptom of the true cause, wave that’s not amplifying enough to overcome the cold press but I’ve found guidance tends to underestimate the northward progress of the moisture transport when a wave is amplifying and over estimate it when it’s not and the trajectory is a good simple way to see it. These things aren’t universal. I’m still watching. I’ve not given up. But I don’t have good vibes. ETA: this is for MD north of 70. I think DC is fine. I’d be excited if I still lived in VA.

On the day of those storms yes numerically the NAO was neutral to positive. But there had been blocking and I consider the loading pattern days before more important. Second most don’t consider the nao by the numerical metric. If they see ridging near Greenland over a vortex under it near 50/50 they call it a -NAO, but numerically it’s actually a -AO. But I’m not interested in a semantics argument about terms. My point is that’s a good pattern for a snowstorm. I don’t care what we call it.

Yes but there were extenuating circumstances. First of all the boundary ended up set up about the same place a lot. And it was just luck that it set up where it did. I was up in central PA that one year and got a lot less snow then Manchester that winter. It was just dumb luck the waves went where they did. Also there were two very amplified storms that season in Feb and March where we jacked up here. But compared to the mean I won’t do as well up here over the long run in an epo driven wave pattern. If that was the pediment pattern every winter for example (using years with that predominant pattern like 2009, 2018, 2022) the avg snow for here would probably be like 26” instead of 40 and the avg snow for somewhere like where @CAPE lives would be like 18” which might even be above the overall avg. Yea being NW would help some but not nearly as much as it does in a more amplified blocking pattern! This area can go over 80” in a winter, even 100”! But most of those years had blocking and amplified storms not progressive wave patterns.

Chuck, first let me say you’re right about the numeric NAO, because of how they calculate it (which most don’t know) that’s probably a neutral NAO. But everything else I’m like ???? First of all that vortex is a hair off from 50/50 and because of how the heights curve on that map it’s more east not north of 50/50. If you go back a day it’s centered right over 50/50. As it is with the wave before, but it doesn’t matter because there is a huge SER that’s not had time to get beat down due to still hostile pacific forcing. And if that 50/50 location doesn’t work then now did this or this happen? The Atlantic vortex was in that same spot for two of our biggest HECS storms.

The pattern is locked and loaded. But now it’s time to cash it into snow on the ground.

Besides the fact I’m a big storm chaser and epo driven progressive wave patterns aren’t that… I also probably hate them because I moved way up here to get more snow and those patterns almost eliminate any advantage being NW gives you. It’s just luck where those waves traverse west to east and it’s typically cold enough even on coast as long as you’re north of the boundary. I’d love those patterns if I lived on the Delmarva or the northern neck. For them a wound up coastal can end up problematic because it’s hard to stay on the cold side closer to the coast.

not everyone lives where you do

I should specify I was specifically looking at MD where its DAF

It's just anecdotal but over the years I've noticed something with the HRRR when it doesn't match up with other guidance...when its more amplified/north/wetter than everything else it almost never is right. When its less amplified or south/dryer...it sometimes is right and the next run of other guidance moves towards it.

This one is not going to be the one to break your streak of bad luck. Sorry

lol its way way way down on the list of data I would weight heavily but it's showing the opposite of what I would want to see given it has tended to be way over amplified at range. I would prefer to see it showing things too far north frankly. Of course where I am I want things to be north in general. This is looking like a very similar setup to Jan 6th which is super YUCK to me but I am happy for those of you to my south who will enjoy this one.

HRRR was the first red flag in that Mar 7 2018 bust because it is almost always over amplified but the evening before when all guidance was showing 4-8" of snow across northeast MD, it starting deamplifying and shifting the snow well northeast...and a few hours later all the 0z guidance came in showing the same thing. It's generally crap at range and hard to use because you can't tell when its on to something or just on something

It is....but.... 90% of the time lately its been way off because its been over amplified and way too far north at range...so it being south and dry like that...well its not what I would want to see.

Everyone wanted the Bills to win 2 weeks ago...but I wanted KC, because I knew the Eagles could do this to them, maybe not to THAT extent, but I wanted the Eagles to be the team to put a stop to their nonsense. Washington has a much better offense than KC, but KC has a better Defense...they were keeping Philly in check somewhat in the first half until the doors came off due to the two turnovers at the end of the first half (the pick 6 followed by the int inside their own 20) which really turned the game sideways. But I think I agree that Washington has a better chance if they played 10 times to win more of those games than KC, and not just because they did win that second regular season game which was really weird and Hurts was out most of. But I think having a better offense gives you more a chance. The offense can get hot and in that kind of game anything can happen. But I don't think you can beat this Philly team in a physical defensive type game...you can't out bully the biggest bully there is.

There is a bit of a lag though

EPS Setup...50/50, west based block, energy diving into the midwest amplifying into the TN Valley 3 day snowfall centered on......Feb 20

Probably not, but you're assuming there is no 50 miles north jump the last 24 hours as we've seen a couple times this season. Or that there isn't some surprise not surprise banding on the northern fringe that puts down 5" with barely and QPF as we've seen at times...then if we tack on 2-3" of snow/sleet from wave 2 suddenly we had a really nice event. And those things are not crazy impossible. But yes if I had to put money on it the most likely outcome is we get fringed with 2" from the first wave and 1" of slop from the second and its not a fun time for us.

Sorry for the double post everyone, the initial post was missing something and when I tried to edit it accidentally deleted it and had to re-post.

@Stormchaserchuck1 has focused on the location of the block rightfully pointing out it originates as a AO not NAO block...but not sure I see why it matters in the long run. Here at day 5 the issue isn't the blocking IMO, we have a low right at 50/50 which is the important thing. The reason blocking is important is getting that reaction. PD2 for example didn't have blocking in a classic sense but a PV displacement into the 50/50 space created the same effect for our snow purposes. The issue here is because the tropical forcing is still in the western pacific we have a SER and a hostile PNA. The next wave is getting better but might still have a little too much SER but again the blocking worked the next wave crosses 50/50 also. Finally the next wave will enter this setup With the tropical forcing now into the central pacific phase 8 the trough axis is in the east with a favorable PNA and again we see lower heights across 50/50. Plus even though the block started out north it retrograded to the same spot a greenland block typically ends up, Baffin Island, where west based blocks go to sit and rot and where we typically see them for our big snowstorms. It got there from a slightly further north trajectory initially from a merging of an EPO and Scandy blocks, but as long as it ends up the same place with the same impact on the 50/50 domain I fail to see why it affects our snow chances. The issue with the first 2 waves is the pattern has not matured. Blocking typically starts to set up in Phase 7 but the SER takes until 8 to get beat down. Its a little frustrating that the operationals continue to show thermal issues even once we get the perfect longwave configuration out around day 10+ but I want to wait a few more days and see if they adjust before worrying too much. All 3 major ensemble guidance shows the absolute perfect 100% what we want in every way h5 pattern for a big snowstorm day 12-16 right now. If that doesn't work I don't even know what we are looking for anymore.

My area might have the highest boom/bust potential for this event. If the initial wave trends north some I could get hit good from both part 1 and 2, on the other hand it is equally or maybe even more likely I get fringed by both and get stuck in a snow minimum in between.

What a 7 day look

That wave 3 weeks ago and the waves this week are a perfect example why we need blocking to work. It’s so freaking hard to get a flush hit from these progressive boundary waves. There is nothing to lock them into a track. They can go to our south or north based on insignificant changes in amplitude. They have a relatively narrow area of heavy snow west to east that will only give a small portion of the east coast a win. But with a block and 50/50 if there is enough cold in the pattern you just need any strong wave to come along and crash into the confluence. The win zone is huge. It can try to cut and it will be turned east and we get a ton of snow to ice. It can take an imperfect track and will be forced under us. The precip coverage will be huge compared to these petty boundary waves because the wave is trying to gain latitude and throwing moisture up over the cold air locked in instead of these frustrating west to east waves where we’re at the mercy of a ton of variables any one of which can screw us over. sure we might get lucky this week. But over the long run this is a hard way to try to get a lot of snow. Throw a juiced up amplifying wave into cold with a blocked flow is simple with a huge margin for error where a minor amplitude shift won’t screw us out of snow!

We’ve had a decent number of snowstorms from a block where this one ends up. It’s a bit odd how it starts so far north but it retrogrades to Baffin Island which is where a block that starts centered over Greenland typically ends up. So in the end the effect should be the same but it starts out less than ideal which is why I’m not more optimistic for the wave next weekend. I think around the 20th and after we will have legit threats. Also we can get a AO driven snow but we need some help from either the PNA or EPO and we have that nice to around the 20th.

@Ralph Wiggum before you start a panic can we wait and see. I’m on the record sharing your concern. But if it’s true that strong high latitude blocks will continue to link to a SER the whole time we might as well just give up and stop tracking because that’s how we get 90% of both our HECS storms and BIG snow seasons. So what are we even doing here if you think it won’t work anymore? Let’s see how it plays out.