WxUSAF

HoCo closing early. Thank goodness my overworked kids get a break after 1.5 days of schooling!

Reminder just in case anyone forgot that nam bias is too wet (12k especially) and too amped. When NAM’s track agrees closely with the global guidance (18z tomorrow?), then using it for thermals/mixing/banding is the proper value-added use.

Anyone who gets a squall is going to see temps drop very quickly.

I think @psuhoffmanis probably doing the “guy peaking out from behind the tree rubbing his hands” gif thing once he sees the overnight runs. I think you’re good. If the max ends up along the VA/NC border, then that’s probably too far.

I’m leaving some of my outdoor Xmas decorations up specifically because I want to see them in the snow

Yesterday I was thinking that the “real” north trend probably wouldn’t show up until the storm is really forming over the plains and convection, etc. is giving it that strong diabatic heat release. So then the guidance would start to “see” the strength of the WAA and shift things a bit north. So even though I figured the GFS was out to lunch, it moving north all day yesterday already did make me a little nervous. Put those two north shifts together and it really could be a congrats NYC thing. With 60-72 hours to go until snow starts and the system not yet really developed, I’m quite happy to be on the north side of the modeled jackpot zone. I would still expect a modest shift north on guidance tomorrow-ish.

None of the darker blobs are ever over my yard

That is really looking like a nice end scenario in the last 24 hours. Hope that continues to juice up.

Gfs has been moving more southern stream energy out each run the last 24-36 hours. Euro still mostly burying it.

So dang close to an absolute monster

I know it’s useless, but I’d appreciate if everyone preemptively promised not to jump when tomorrow’s 12z 12k NAM at 84 hours shows the storm in Detroit. Thanks much!

This is a good question for @dtk or @high risk

Wow, WWA for me too. I'm skeptical I see anything more than a quick dusting. As for schools, tomorrow is giving "all after school activities are cancelled" and then it snows with nothing accumulating on the road for 10 minutes around 530pm.

I believe a few snowflakes are falling

Guidance being so good at identifying storm windows like 15+ days out is a serious blessing and a curse. Just wait for the King to come in and drive this bastard to Buffalo.

This is something I was noticing over the last 24 hours and 12z runs so far really demonstrate it. The slightly northward shifted solutions are also much wetter generally. This goes hand-in-hand with a stronger shortwave and/or less confluence allowing more vigorous moisture transport. So with the tracks that put RIC-Baltimore on the edge of ever flipping p-types also have greater totals. As long as it doesn't get much stronger/norther from these types of solutions, this is probably a trade most of us (north of RIC or Fredericksburg) would be willing to make since both that front end thump is more intense and there's a more coherent CCB snow shield on the back side Monday.

In the red! #blessed

@mappy I like seeing euro back to “where is started”. If we get a normal north shift in the last 72 hours, that puts the metro corridor right in the central swath. And you know the northern end of that where ratios are maximized.

So 0z euro went back to about where it was at 12z? I think a slight north shift close to game time is quite possible, but not one that’s going to make this a congrats NYC/SNE event. More like congrats @psuhoffman @mappy and @mitchnick. Which we all knew was probably coming anyway. And I think some of the banding structure, as @MillvilleWx alluded to, might give the impression of a north shift when in reality it’s just the in-storm dynamics creating a non uniform snow swath. Anyway…nice consensus. Going to be thread time after 12z runs.

That’s sleet for sure. 18z EPS looking solid allegedly?

I’m ready. I think by tomorrow evening we could also do a dedicated thread. Your call

I know we always sweat little 20-50mi wiggles, even down to game time. But I haven't seen anything in at least 48 hours, and maybe more, that I would count as an actual "trend". Euro especially has been near rock solid.

Hard to put any stock in the gfs solution for the 10th given how bouncy it’s been for the 6th, but it’s illustrative for the ingredients of a classic miller A. Here’s the setup at 500mb. Strong southern shortwave (green) and northern shortwave diving in (blue). To turn the coast, we’d want this all shifted west by a couple-few hundred miles. Not a major shift at D10. Then on the next panel, you can see that they don’t quite phase completely. If they did, that would also help pull it north. Still pretty close for d10.

Probably too early to look at this really, but I’m skeptical of ratios much higher than 10:1 in warm sector snowfall.

BWI exactly normal for December and DCA and IAD fractionally above normal. Warm seems to always win out in the end.