psuhoffman

I know I seem really confident here... I am not. And I have no special insight. But I do know if the trend across guidance of the last 2 weeks or so, ever since the current pattern started of severe -AO and a retrogressing longwave pattern, this will look nothing like what people think of when they say "miller b". Does that mean this hits...probably not, most of our threats fail, even in a year like 2010, we remember the big hits...we don't remember the 2 storms in December that failed before Dec 19, or the one around New Years, or the one in mid January that made Ji go thermal nuclear and blow up the thread, or the 2 later in February or the one in March that made Ji say the season was ruined. Even in the absolute BEST possible patterns we fail more than we win...but if we get a good pattern and have it lock in for a significant period of our cold season...we do usually eventually win...and I think we will this year also. What I can say about this threat specifically is that unless guidance is way off on the depth of the trough this is not similar to our typical miller b setup. Could it trend towards that...yea, if the NS wave starts not digging as far south...if we start to see it start to trend northeast...then yea this becomes a typical NYC to Boston storm and yes that could happen. But...know what else could happen...if the seasonal trend continues and the whole trough ends up another 200 miles west 5 days from now...this ends up closer to January 1996 than a typical miller b. That was a northern stream wave that dove in and captured a weak STJ wave also...but it dove in through the Dakotas and right now guidance has this diving in through Wisconsin. Shift this west a bit and its almost identical to the 1996 setup. It's also coming as a previous -3stdv greenland block dissipates as it retrogrades into central Canada, which was the setup in 1996 also! I am NOT saying this is a 1996 repeat...just that its a lot closer to that type of thing than I think many realize. If we only get a slight west shift it becomes similar to January 1966, take a look at the h5 in the KU book for that one...its damn close just that one the NS wave dove in around the WI/MN border...slightly west of where guidance has this one. It could go the other way, past does not always predict future. Maye the trend this time is north...or east...or south and the deep south gets clobbered...but if whats been the most common guidance error were to play out...we would end up with a serious threat here from this...that's all I am saying. Oh and BTW 1996 looked almost identical to what the models are showing right now when it was 3-5 days out...it didn't morph into a huge storm for us until 24 hours out. Remember when Bob Ryan cam back on the 11 news after his actual weather segment to say "we're getting a blizzard" at the end of the broadcast. They didn't even have graphics yet...but the 0z guidance all came out during the 11 news and showed it shifting north. Until then it was a richmond to NC blizzard. Yea the guidance is better now...so maybe that correction would happen around day 4 instead of day 1-2 but it's not so much better that a similar error can't happen 5-6 days out from the storm.

So sorry but glad everyone is safe, that is the most important thing

Holy snowy balls Batman Mitch you’re the only one I ever see post those, most don’t have access. There are no free outlets I know of and most pay ones don’t even offer it, so this is your responsibility lol

People keep saying this. But SWFE/WAA events have issues too. Sure there are less moving parts but that doesn’t mean easier. You need the perfect thermal boundary placement. We still need the cold to be south of us. If the low Amplifies to our west we will still flip. If it’s under amped or the boundary presses south we get suppressed. We’ve barely had any coastals the last 9 years. We’ve had dozens of SWFEs and yesterday was the first warning level snow I’ve had from any of them and it was anything but easy and ended up half sleet and only worked because of an anomalous cold wave! Meanwhile my hit rate on coastal is way way way higher. We’ve barely had any frankly but the handful we have had make up my only decent snowstorms since 2016, which was a coastal btw. I just don’t see all this evidence that SEFEs are easier way to score big snowstorms here. Frankly imo the biggest reason we’ve not had much snow (other than it’s been warm, although these 2 things are related because I’d the thermal boundary is way to our NW we aren’t getting coastals) is that we’ve had almost no coastal storms the last 9 years.

So frustrating it trended better in several ways but worse in the one that might matter most.

Yea I switch from h5 to surface and I don’t see what I expect

The ridge is slightly better oriented imo. It’s getting closer to what we want to see

Through 90 it’s better. Might not do it but it’s heading the right way

For me the big thing is keep seeing that NS wave digging south of us and amplifying. If that’s true we have ways to win that don’t require unusual and unlikely model adjustments.

We need the same adjustment. If the longwave features adjust west the same way they did last week that energy diving into the Midwest that becomes the storm will trend west also. Right now it’s coming in too far east for what we need. Shift that west and watch. Do I know it will no. A trend can reverse anytime. But this isn’t significantly more complicated. There is going to be a major wave amplification off the east coast. The pattern argues for it. It’s been identified as a period to watch for a long time. The question is where exactly. We don’t need some crazy adjustment in the phasing being shown. We juts need to shift the whole thing west. Some are applying the typical miller b thing here but the reason miller bs always fail for us is rarely does the NS dig south enough. That isn’t the issue on guidance right now.

Adjust the AIFS exactly the same way and…well

This is what it ended up actually looking like

BTW everyone is praising the AIFS and it did do really well but it was southeast at day 5-6 also juts not by as much adjust what it shows now the same way this adjusted and we’re good

Not grading my last minute adjustment as the storm started for many by then. This is the one I put out 2 days before. I think 90% ended up within the ranges. BWI busted high by 1”. I was too high along the southeast fringes. I’m ok with this.

Btw a super non scientific thing to keep an eye on. I’m way more ok with guidance being a miss to the southeast than if it’s to the east or worst northeast. If the axis of snow is to our south or southeast we have the best chance of a positive trend. East is more iffy. Northeast and don’t waste your time. It’s next. There are scientific reasons behind this regarding which model errors we need to correct each of those and which are more likely but I’m not in the mood to write 5 pages so for now I’m ok with the fact the major ensembles are all showing the snow max to our south. That’s not a typical miller b representation and one that’s more likely to adjust in a positive way.

Yea people don’t realize that the difference between 6” and 12” in your yard doesn’t impact the verification scores of a global model. Missing a mid level warm layer by a few hours and 30 miles might effect our ground truth but it’s an insignificant error in the global scheme.

Depends. If the longwave ridge trough axis stays where the guidance projects right now it’s likely a miss east. But it’s been trending west and last week it did the same thing right up to the end. If you apply the same idea that NS wave will dig in further west. Into the MS valley instead of the TN valley. Usually with a miller b our issue is the NS wave doesn’t dig south enough. Without some serious -AO help it’s rare to get a NS wave south enough for a major amplification to work for us. We need the upper low to track across southern VA really. Getting the NS to do that is hard. But this setup that actually doesn’t seem to be the issue. Damn some of the runs dig too much and cut off into a NC storm. The bigger issue I see now is the NS is diving in too far east to capture whatever STJ wave there is in time for us. Adjust the whole evolution west 200 miles and we would be in amazing shape! Keep an eye on two things. 1) the whole longer ridge/trough axis. Is the western ridge keeps adjusting west watch the NS wave dive in further west and boom. If it doesn’t then missing southeast (like the AIFS) is the likely outcome. 2) the depth of the NS trough. If we start to see if not dig as deep then a more typical miss to the northeast where Boston is happy and we smoke cirrus becomes a more likely outcome. if the depth of the trough remains the same and we get the westward trend of the longwave pattern to continue as it has the last 10 days then we will get a snowstorm.

the guidance was too slow on retrograding the longwave pattern last week which lead to this past storm going from a TN Valley/NC blizzard to eventually a OH Valley to New England blizzard. And the same trend is continuing right now, if it does continue the same exact error….well we’re all thinking it! The whole pattern is retrograding and reloading. Just as the current block is retrograding into the west and dissipating the next Scandinavian ridge is about to retro into Greenland next week! Think the last 9 years when we were often stuck in a feedback loop of never ending suck. This time we’re stuck in the feedback loop we want with the consistent being a permanently weak AO all winter that looks to continue frankly likely the whole cold season. We’ve slightly underperformed to this point but we have a whole half (and the snowier half) of snow climo left to correct that!

Oh I’m paying attention. I’m just exhausted.

RRFS held from its previous run showing a general 6-8" across most of the area before the flip

I posted a forecast 2 days ago...it's likely going to bust a little high...this was just a last minute update on what I am thinking...I won't grade this. And it hasn't started for me yet lol

Final Thoughts, these totals include sleet accumulation. Things really started to tighten up the snow/ice gradient the last 24 hours. I see a path for this to bust low...if we do have really heavy precip in the morning between 10-16Z like the RGEM/Euro/GFS/UK show

Naw DCA will report 3.8” no matter what

I’ll put a final map out in a min but some over unders in my head right now DC: 5” IAD: 6.5” BWI: 6.5” Winchester 10” leesburg 8” Frederick 9” Westminster 9” Owings Mills 8”

DC is just…I dunno it’s like they have some snow dome right there. And even when we get southern sliders they often end up missing the real big totals on those to the south.