psuhoffman

12z was more amplified than the 18z 12knam. The less impressive surface outcome was actually consistent with its upper levels. BUT it’s the NAM and the 3k and HRRR went the other way so until I see more reliable guidance trend less amplified I wouldn’t take it too seriously.

The changes on the 3k are mostly noise imo. A lot of the missing snow from 12z was from that ridiculous deform band that was putting down like 3”/hr totals. Instead of one mega band the 18z has several more transient bands. The super band was kinda an unlikely outcome but synoptically I didn’t see a huge difference. The 18z is more amplified and slower. I actually like the 18z 3k better regardless of the less impressive clown maps. That deform band isn’t something it’s going to get right anyways outside like 12 hours and otherwise absent that one thing the 18z run was better imo.

Are we discussing the 12k or 3k? They are significantly different

I’d be careful using the NAM to sniff out trends. First of all which one? The 3k is still amplified. 12k shat the bed. 6z the 3k did that. Both haven’t been updated in forever and jump around even worse than most high res guidance. Frankly over the last few years I’ve found I would have been better off simply ignoring the NAMs completely. Now if the other 18z guidance comes in like that…but so far all we have is the HRRR and it went the other way and is more amplified.

Yea it’s really become a trailing wave with a perfect surface mid and upper level pass.

Hrrr 18z looks significantly more amplified v 12z. Nice trend. NAM looks a mess at 18z which isn’t uncommon it’s bouncy AF. Which brings me to…what is NCEPs high res short range flag ship model of choice now anyways??? They stopped updating the NAM and SREF years ago. Which was fine they’re ancient and probably outlived the usefulness of tweaking their core at this point. But they were never replaced. The HRRR isn’t any more reliable and seems mostly ignored. The ARW FV3 I don’t think ever became operational (unless I missed that) and is largely absent in any forecast discussion. The RRFS has been in development for years and still isn’t operational. Frankly in most discussions of short range Synoptics they still talk about the euro and gfs mostly. So…what exactly is the current preferred high res short range guidance? Any of the pros in this area want to chime in?

Day 15 the eps is showing signs of the first wave break in the Atlantic that we need. It’s a step process. But once the pacific low retrogrades given the weak tpv imo it’s just a matter of time and wave breaks to get the Atlantic where we need.

It’’s amazing how consistent the euro has been for 5 runs. There has been a slight trend to go more negative the last 2 runs (good) but overall the euros been a rock with all other guidance converging on it. This is one of the reasons I still find the euro useful in short range. I’ll use the high res to pick out meso features but this lends confidence that the general idea here is becoming pretty locked in. Of course this is a very marginal setup wrt Tempe so now cast issues with the exact Tempe and banding will have a huge impact. 1-2 degrees and where a meso band sets up is the difference between 1-2” of wet paste and white rain. But this consistency combined with the meso models converging towards it makes me confident the idea of a more amplified negative tilt wave is correct. So at least we are in the game. Like I said I use it as a baseline to judge everything else. BTW 1-3” of wet snow is better than 2-4” of dry snow imo. The wet snow sits on top the grass better and sticks to everything. Looks a lot nicer.

HRDRPS joined the party at 12z

I’m hoping it comes in just a couple hours early so as soon as the Eagles finish off their win over the cowboys I can transition to snow measurements

I need some time alone with that Fgen plot

As 12z comes in I’m keeping an eye on something. Not only do we need to worry about boundary temps, there was a trend on the NAMs and HRR to be less amplified initially and develop the wave a little slower. HRRR barely gets it going in time to clip my area with a couple inches but further south misses out. Not because it’s not cold enough but because the wave doesn’t start to amplify in time to throw heavier precipitation into the cold side of the boundary until it’s northeast of the region. Another way to see this is by what happens further north of us. The better runs of the gfs/euro/nam for us have the axis of the heavy snow across upstate NY and NW Vermont. The newer runs of the NAM and HRRR have it across southern VT and NH because the storm amplified later and this further east. We want to see this amp up earlier and further south. ETA: my analysis was of the 6z NAMs and 12z HRRR which comes out earlier. Haven’t seen the 12z NAM yet.

I find the euro still useful inside 48 hours. It’s the highest resolution global. The higher res models can pick up meso features better but they also can go off on tangents. The euro can be a good baseline even at short range.

Putting this here so it doesn’t derail the storm thread. I’m also worried about surface temps. But I’m also frustrated because this SHOULD work. This exact setup has worked many times and yes this early in the season or even earlier! This isn’t like next weekend when the cold is scoured by the pac vortex. There is reasonable cold to work with. At least as much cold as were ever going to have in a string nino. The 540 line ends up south of us during the event. Not like next week when the 540 is up near Hudson Bay. That next storm doesn’t bother me if it’s a perfect track rain so much. But if we get this wave to develop like the euro and gfs are showing and it’s just a 37 degree white rain despite sub 540 thicknesses that bothers me a lot. We already had 2 events up here that I’m pretty confident would have been 1-3” in the past but ended up too warm to accumulate at all even here. Good news is if true it renders my 1” by whatever date data kinda irrelevant. Bad news is you have to subtract all those lost marginal events from your expectations for the season. But if this goes that way too it’s just another sign we are definitely losing snow on the margins. And frankly our snow climo sucked to begin with so we don’t have a lot of margins to afford to give. ETA; the boundary layer is warming faster. So seeing so many events over the last 5 years where everything went right except the boundary layer was just a couple degrees too warm is a horrible sign. I keep coming back to that storm on Super Bowl Sunday in 2021. That should have been 3-6” in DC and Baltimore. Everything went right, perfect teach in prime climo with a modified continental airmass not pac puke and it was barely even cold enough to snow here and 95 was just cold rain. That was eye opening to me. Seeing more examples like that would not be good. For my own sanity I want to see this end as some accumulating snow even outside high elevations. Maybe not in the cities but places like IAD should get 1” from something like this.

Another reason the 3knam lost the snowier solution from 0z was at 6z it was significantly less amplified with the wave. Less precip behind the front so less cooling.

I remember getting a couple minor snows in December in northern VA. Nothing major, just a couple 1-3” type events.

It’s not a legit winter storm thread until we get some SREF. You’re welcome.

True. I think there is a symbiotic relationship there though.

There is so much bad information floating around now thanks to social media. Granted there is good also but you have to be able to tell the difference.

https://x.com/psuhoffman/status/1733297807652422089?s=46&t=JDI46BeqOMUGnLaA2k6MTw

I’ll let Pittsburgh know

That was about to be a beat down here. Already 2” otg with quite a bit of precip left according to sim radar.

@brooklynwx99 frankly one of the reasons I tilted towards a huge snow season was simply how due we are…and that I’m not ready to concede our snow climo is THAT much worse. The fact is if Baltimore were to only get like 20-25” this year facing another -pdo Nina cycle after where more single digit dud seasons are likely…we could come out the other side looking at a reality where our long term avg could drop some ridiculous amount (on top of the recent drops at the end of the last two decades) that I can’t and don’t want to imagine we’re there yet.

I see both sides. Yes it’s a high bar. But…our climo here is to have 5-6 bad low snow winters then hit a couple decent and a couple huge years every decade. It’s now been 13 years since the last truly epic season and now 7 years of total utter dreg. Literally our least snowy long period on record! We are way way way past due for a HUGE winter. Frankly we could get a 40” winter this season and Baltimore would still be way below avg on snowfall over the last 8 years. And this is a nino! With all long range guidance indicating we go Nina again next year with a continuing -pdo when is that epic winter coming if not this year? During -pdo Nina’s are typically multi year. Are we waiting 3 more years? So while I’m not going to jump off a bridge if this winter ends up just ok or above avg but not great…the truth is we are due for an epic huge snow year and anything other than that will be catastrophic to our snow climo!