psuhoffman

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

I thought I controlled myself pretty well considering what they run did to me...I made like 3 posts after the euro then went to bed. lol. I still like where we stand, especially 95, I just don't like the introduction of that feature in New ENgland adding uncertainty. Uncertainty sometimes doesn't work out the way we want and damnit I want this snow curse broken NOW.

would you agree that if we do get a more tucked capture stall like the GGEM/UK we also likely get the typical NW deform band that guidance almost always misses with amplifying mid atlantic coastal systems. Seems to me, and please correct me if I am wrong, that guidance from range tends to focus the deform band along the best fgen associated with the moisture transport from the coastal where it intersects the CCB and the instability from the upper low. And there will be a band there...but what it often misses is the increased forcing along the NW fringe of the CCB where the moisture transport hits the "brick wall" of confluence to the north. That resistance typically seems to add lift and while its not to the degree as further south you also tend to get really high ratios there. IMO those 2 factors contribute to that deathband we often see that guidance totally misses on the northern fringes of the CCB.

Not as bad as on the RGEM/GGEM. My area kind of is in a screw zone of subsidence between bands but that is not something I am going to worry about at this range...and we all know that if the southern PA/northern MD area gets into the actual CCB good banding will set up here due to oragraphic influences. Mappy's area gets absolutely crushed with one of those bands but the UK has some weird dry pockets mixed in that screw over some areas (me) lol. Even if that were true it wont nail that from this range.

IF (huge mega if) we do get the further southwest capture/stall option guidance will underdo the snowfall in that deform bad. That is a 90% given. They also will miss the NW deathband...we all know that. But that only works out if we actually get the close to the coast capture stall option...if the storm swings out too wide due to a positive tilt precipitated by the flow too suppressive in front...the area will be robbed of the moisture transport we need off the coastal as the upper low swings through and it will just be instability disorganized areas of snow.

UK is a picture perfect capture/stall location for our area. Hopefully the euro follows.

I don't know but its obvious from the drastic shifts in guidance run to run and how closely those shifts correspond to the handling of that feature in New England, that its volatile and delicate. The guidance is having a really hard time getting a handle on what that little vort is going to do and it has a great effect on our system.

There are 2 obvious camps emerging in the guidance... and it involves how they are handling the upstream feature in New England. Those that are diving the vort there further southwest are suppressing the flow (NAM/Euro) and causing the trough to remain more positive with a more suppressed east solution WRT the coastal. Then a camp that is less suppressive with that feature (GFS/PARA/ICON). The GGEM/RGEM are kind of in between and so we see probably the ideal result for 95. There is honestly no way to know for sure what is going to happen with that feature in New England, but it holds the key here IMO.

no..true it was north then south then north and now south again...but we are getting closer now...its one thing to be jumpy at 150 hours...but this is now 5 consecutive runs it has trended south. The bigger issue is it aligns with what I always thought was the bigger threat...that the flow to the northeast would suppress. I never for a second bought or worried at all about the runs that were north. The pattern doesn't fit that. But I am open to being convinced I am just being paranoid and this euro run was garbage and it will correct back north. lol

Even the Navgem looks like THIS... Maybe it was just one hiccup but the trend is VERY disturbing. And not just for me. Like I said after the last run...I am one more adjustment of the exact same maginitued of the last 4 runs from being on the outside looking in....well that is now Baltimore, Columbia, Leesburg...one more after that and its DC... are we sure the south trend is over? That wave over New England squashing the flow in front keeps trending south every run! So part of me says....ok EVERYTHING else is north even the typically super suppressed NAVGEM, it was just a bad run. But on the other hand...this...is hard to ignore

The rest of the 0z guidance looked so good then the euro ruins my night. Lol

It’s a 12-15” snowstorm in DC proper. Yes with a period of mix/rain. But why is the period of mix getting as much attention as the 15” of snow?????

DC loses about .35 to mix/rain on the UK. Still gets 1.2 qpf as snow

@yoda on the 10-1 map DC is 12” but the first part of the waa and the deform world be high ratios so that looks like 12-15” to me These are all 10-1 and I would adjust up. Deform will have high ratios as depicted so would the first part of the WAA IAD 16” Leesburg 17” BWI 13” winchester 13” Westninster 17” Mappy 20” EZF 11” Frederick 13” Towson 17” Columbia 15”

Look at the icon and Ukmet...even the gfs somewhat. We can ALL win with a more amplified solution so long as we can stomach a few hours of sleet or drizzle.

Ukmet is a great run. DC about 5” from the WAA thump them dryslot and some light mix then about .7 qpf as snow from the deform. That would probably be another 8-10” or so. N VA through Central MD jacks. Likely some 20” totals there.

The northern guidance came south. The southern guidance came north some. I’d like the euro tonight to look more like the NAM/rgem/icon/gfs/Ukmet then the ggem and para.