psuhoffman

BTW I think you can still do pretty good with a more amped solution...I think a decent front end is likely and then so long as the storm exits more east then north (likely given the blocking) that deform axis will be shifting southeast as it exits and can clip you on the way out. March 2018 was a good example of that.

That NS vort over New England that was trending south every run for 36 hours before reversing course was giving me shades of every great setup we have wasted in the last 5 years. It seems we've been screwed several times by something like that recently. Likely a correlation to the dominant NS patterns we've been in. Que someone with #remindsmeof2018

that is REALLY hard to do on the coastal plain with a miller b hybrid where the primary is coming across west to east at about our latitude. Doesn't mean it can't end up a good storm...but there is almost always going to be a period during the transfer/secondary process where you end up in the dry slot and some of the warmer air riding across ahead of the wave sneaks in and without the dynamic and convective cooling and heavy precip to help mix out mid level warm layers...and to keep the surface saturated...its just hard. It's possible...and there was that one euro run (besides the runs many days ago when this was still in fantasy land range and models tend to mess up more major aspects) that struck the perfect balance, but you are playing with fire with that. To get all snow with a miller b coming across this far north you kind of need it to be de-amplifying and sinking southeast. But then you risk something like March 2013. If you hit the jackpot perfectly you can get something like that one euro run where it de-amplified the perfect amount then the coastal started to amplify just in time to give DC a 12" cold smoke outcome...but like I said that is walking a high wire and its playing with fire. You get SLIGHTLY more suppression and the coastal doesn't amp up in time with that scenario and suddenly you have a dying WAA wave and its a pathetic nothing burger for everyone. That said I am not ignoring the challenges of your geographic location. But you can do pretty good from the WAA thump still...4-6" is very possible...and then you need to have that deform band sink south on Monday and give you some love on the way out. If we can get this storm to tuck into the VA capes then fade ENE from there that is very much on the table.

That hole is an area that got unlucky twice. Ended up between bands during the WAA then again during the deform. Subsidence can be cruel. Btw euro started to pick up on that duel banding structure on the NW side that happens EVERY time. There will always, in EVERY storm, be unlucky little pockets like that. I actually ended up in one in 2016. I got 28”, and no I’m not complaining one bit I’m not crazy, but all around me got 30-36”. I ended up in a couple dead zones between banding and oh well. But no model can get either the meso banding or the associated screw zones between them right from 24 hours let alone 72 so I wouldn’t sweat it. That’s something for the now cast.

Agree it ended very well. Trough was less positively tilted. Low started to get going further west and tucked a bit more which had the desired effect on the deform zone across our area. I’m happy with it. It was a very acceptable run but left some room for improvements. I do think we see a full tuck like other guidance on tonight’s run.

Full tuck at 1am

Baby step

Slightly more ridging in front and a slightly more amplified h5 at 33 hours. Heights to the NE maybe a slight smidge less suppressive

@Bob Chill welcome back!!!!! Missed you

18z gefs really ramped up the deform Monday!

If it slides ENE from there you will.

Ok it’s been fun but it’s time for the euro to tuck this biatch right up against the Delmarva and end the suspense.

it moistened up some though...the 3K sometimes does whacky stuff outside 36 hours.

NAM took a significant move towards the other camp this run. Gets DC better with the deformation zone and is still snowing at 84.

I think we can add the JMA to the majority tuck camp. Its super hard to tell from 24 hour timestamps and super low resolution, and the key time period is kind of missed in between hour 72 and 96 hours...but it looks identical to the GFS/CMC at 72 and from the precip and making reasonable inferences I estimate the JMA adds about .35 qpf from the CCB after about .4 qpf from the WAA wave. That is pretty good btw for the JMA which is low resolution. Even if it was only .35 that would imply a 4-6" snowfall across the area (on top of the 3-6" from the WAA part) given typical high ratios in the deform axis. But that qpf is likely conservative. And that is the most analysis I have ever done or ever care to do again of the JMA. But that was for @Ji. Take care man!

Ensemble members will struggle to show HUGE totals because they are lower resolution and the snow maps are 10-1. It's very likely an 8" ensemble member is really a 12" snowstorm...maybe even more honestly. That said...the crazy huge totals of a few day's ago are probably off the table because the flow to the northeast has trended more suppressive which has caused the trough to remain more positively tilted then it was when we were seeing those 30" type solutions. It's not impossible to get back to that...but we have some work to do. I think setting the bar at a solid MECS is more realistic.

Be careful using the mean on the EPS because there are two still 2 distinct camps wrt where they capture the secondary. The good news is the improvement on the mean is because about 11 members jumped ship from the eastern escape camp to the tucked in camp. The majority camp went from a slight 55/45 lean towards OTS at 6z to a 60/40 lean towards a quicker capture and tuck. The OTS option is still there and there is a not insignificant camp that support the OP but it was a clear move towards the other guidance.

we have a conundrum... the GFS/UK/GGEM/RGEM/ICON/NAVGEM all agree on phasing and tucking the low off the VA capes which places our area under the deformation axis. The Euro/NAM jump the upper low further northeast and have the capture happen further north and OTS which misses us with most of the effects from the coastal. Obviously the preponderance of evidence suggests the south solution but we have the EE rule saying no. Tough one. The euro moved in the right direction 12z so I am going to favor the closer to the coast solution ATT.

@MillvilleWx good catch. I think the h7 and h5 issues are linked. The runs that do not open up the h5 and amplify it from the OH valley across VA to the coast jump the h7 in and phase "clean". The runs that stall the h5 then jump to off the coast do not because the storm is not "phasing" yet. The phase gets delayed (which for our area is a killer) as the H5 makes the jump. We want the h5 to stay closed off and start to phase as it crosses VA not jump to off the coast...and we probably get the h7 feature you pointed out to respond. They are symbiotic imo.

It has been a compromise but the GFS didn't even see the coastal at all for our area until recently. At this point yea they are converging and run to run the euro might cave to a detail on the GFS at this point...but lets not forget from 5 days the GFS was totally clueless as usual.

This was so close in so many ways to something much bigger... We don't even need it ALL to come together we just needed either some combination of slightly more backing off of the feature in New England or faster with the feature diggin in behind, and probably only slightly, and that H5 doesn't open up and instead amplifies across to our south which links up with the mid level moisture feed off the coastal and activates the deform axis over our area.

yes but the euro trended a little better this run. It was the first time it nudged the "other way" in 36 hours. The trend is USUALLY (not always) to relax features up there a little at the last minute. Not a ton but usually once you get inside 48 hours you see some relaxation of the flow to the northeast as the next wave approaches. This isn't any great insight just stating typical model bias over the years...of course every situation is unique. I was happy to see the euro start to back down with that crushing feature even if just a little. If you loop the H5 trend at 72 hours from the last 3 runs its a little closer to a better phase for us imo.

@stormtracker...illustration... look how the h5 jumps over us...we need it to stay closed and phase over VA not jump too off the coast like that. But it was VERY close...the track is perfect just need it a little more amplified and the trough less positive so it doesn't open up. But look at the trend the last 3 runs...one more adjustment like that and it will.

looking at h5 this run was actually closer to a tucked solution...but it just missed. The confluence backed off some and it almost but the H5 opened up at the last minute instead of phasing in with the coastal which cut off the moisture transport from the coastal into our area and failed to really activate the deformation zone. Instead the focus became the fgen region to the north of the developing coastal. But its a delicate thing...its not like there was no deform zone...it just wasnt the beast it could be if we get a better transfer/phase which we will if that feature in New ENgland can BACK OFF just a bit more. This is one of those runs where the clown map says it was worse but it was closer to something BIG. Unfortunately it did show the "fail" relatively (it still would be a decent snowfall) option for DC with the split where the best lift from the WAA stays south of DC and the lift associated with the FGEN ahead of the h5 and from the developing coastal stays north. That is often the "DC split" miller b thing. But get the h5 to not open up and phase in and suddenly that weak band is dumping on DC Monday.

come on capture and tuck....do it...you know you want too...just do it