psuhoffman

My best guess looping the h5 and mslp is the nam was going to pull that low right up off VA beach or Norfolk then slide ENE based on how the flow was backing and where the upper low was about to cut off.

I am not throwing in the towel until tomorrow. One observation before tonight's runs.... Need a north trend = good shape Need a west trend = next This is because of typical model bias errors. Models very commonly are too far south in the medium range with northern stream mid and upper level features. That H5 low is likely to adjust north some in the final 48 hours. So if things start to trend towards a solution closer to the GFS, again not necessarily that extreme, but with a miss somewhat to our SOUTH not EAST... we are in the game going into the final 48 because I expect the same bleed north we see 75% of the time. Models do NOT, however, have a bias of usually amplifying too slowly in phase situations. If anything it's the opposite. Miller b storms trend east more often than west. So if the guidance converges on the more east idea with a more positively tilted upper low that doesn't close off until 6-12 hours later and we need a west trend... this is dead going into the final 48 hours. Again, I will reserve judgement until tomorrow

It wasn’t, the track was almost identical to 12z but the storm was slightly more intense but also compact. Less broad precip shield. It was noise. The overall setup improved. But within each larger scale setup there is variability to the outcome based on small scale variables. IMO this run had a better chance of a good result but we saw a worse ground truth based on some noise level variables not going our way.

I am totally fine with where the ggem is. It actually trended better with the larger features. The fact the storm was slightly east was noise

Ggem trend

A thought. There is variability within the larger scale setup. So it’s possible to get a better setup in terms of the major long wave features but end up with a worse result due to minor factors causing a slower development or less amplification. However, if the larger scale trend of backing both the NS wave and the western ridge continues at some point a better outcome becomes much more likely regardless of the small scale variables. In other words get the whole thing to back another 150 miles and it would take a much less perfect progression to get a hit. Right now we could win but it would take damn near perfect phase and amplification which is what the runs showing a hit have. Keep improving the ridge/trough axis and even a less perfect result can end up good.

I like everything about the ggem at 90 except it’s weaker and slightly easy with the southern wave. But its more amplified and detached and west with the NS and as expected the western ridge continues to bleed slightly west every run.

GFS is trending west a little with the western ridge BUT it's also flatter which is probably offsetting any gains in longitude

That is THE storm...NAM is just 12 hours faster getting it going...which I am not sure is a good thing...it opens the door to a minor snowfall v all or nothing...but it has the surface wave running out ahead of the NS upper feature such that the timing for a bigger event is probably off.

HOLY… I honestly hadn’t looked at the analogs. I was just looking at the whole H5 setup and going off memory. But DAMN

@Bob Chill 1980 was decent in DC but a fringe north of there. 2011 was a MD bullseye. But again hard to really worry about analogs when the whole setup is shifting still.

It wouldn’t show up because the CIPS are using the gfs day 5 and currently the GFS is way off. So is the euro frankly. But if they continue to adjust the whole long wave pattern west at the same rate they have been lately the next few days, 1996 might pop up. lol

You must be fun at parties jk

So you know what I’m talking about visually and not just talking out my ass. This is the trend on the eps since 0z. This is just 18 hours. Look at the position of the eastern trough and western ridge. Now imagine if this same trend continues for another 1-2 days. Or god forbid this same slow bleed were to continue for the whole next 5 days like it did the 5 days leading up to the last storm and frankly has been happening for weeks. This doesn’t mean every run. You get the hiccup run like 12z or the 0z runs last Friday night that buck the overall trend. But imagine if this overall trend continues what this would look like by the weekend!

The way the math really works…that .4 qpf mean is the product of different outcomes averages. The truth is the median snowfall for IAD is nothing! Thats because about 60% of the eps members have absolutely no snow and are too far east. The mean among the other 40% that have a more amplified solution isn’t .4 it’s closer to .8 at IAD. And if the most amplified 20% are correct it’s closer to 1” Qpf. So the math says the most likely outcome is we get nothing. But there is about a 40% chance is a storm and in that case a good chance it will be a significant one with some members already looking like a 1996 type event.

Who am I to stop a good ratio argument, but the argument assumes something about the EPS mean that isn't true. That .3-.5 qpf mean is from various clusters of permutation outcomes. There is a camp of EPS members that tuck the low into the Delmarva, and those solutions likely have 1"+ QPF. Then there are the OTS solutions which mostly have nothing. So arguing over what the ratios would be on a mean that is the compromise of two different permutations is really....well I'll be nice and say "not the best use of your time".

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