WxUSAF

Started this evening (while still working, yo @Yeoman!) with a Flying Dog Tropical Bitch.

For our region, the journey to climo NEVER involves pure-snow events only. Well, only in magical fantasy years like 2009-10. You got to take the slop with the snow. We had 2 pretty lovely all snow/mostly snow events last week. So I'll take my medicine, eat the slop, and tack on another couple/few inches to my annual total.

Was it the 12/2020 storm that @Cobalt reminded me of yesterday where we had a somewhat similar discussion? NAM went nuts with the warm layer intrusion way inland. As I recall, it was "right" in the sense that a warm layer did go much farther inland than we had been thinking up until that point, but it did end up underdone with the front end snow? The Euro has very good vertical (and horizontal) resolution as well, so got to give that credence also IMO.

I never do!

I'm skeptical DCA gets below freezing this weekend at all.

DC has a watch and I don't??

We are very much still in business after Sunday. I honestly think this could end up a very memorable winter month.

One small detail I've been wondering about seems to have appeared on the 0z Euro (at least). The annoying/helpful/disastrous northern stream shortwave makes a pretty good pass for the metro areas late on Monday. And it's strong obviously. Euro spits out some light snow with it. I think that's very plausible and could add C-1" later on Monday.

Eh...I don't think that's as big a deal as it might seem. That WAA is fierce. The radar will probably get the DC snow hole look by like 15-16z on Sunday and it will start snowing on time around 18z.

I kind of think it's not worth paying really much attention at all until tomorrow's 12z runs when we'll be within 3k NAM range and between it and the Euro, we can probably get some good fidelity on the changing thermal profile Sunday afternoon/evening. Otherwise, things seemed pretty locked in place.

Everybody is clearly tired of tracking this storm lol. 2.5 new pages overnight.

HH GFS is close. DCA might need fresh snowcover in addition to an arctic airmass to get a low of 21F.

You’re far enough west that any warm layer you get will probably be really short lived. But that sounding shows that (at least) the 800-875mb layer is warming rapidly and a higher resolution model probably would indicate a warmer layer. It’s still going to snow in the metro corridor and it still will accumulate. But I think there will be SOME sleet for many/most east of 81.

I mean, yes, verbatim it’s snowing meteors to beat the band right there. But I do think the euro and NAM are going to find some warmer layers in there and it’s going to be pounding sleet.

Yikes

The HoCo jackpot is a plot twist I did not see coming!

Not at all, assuming you have proper expectations. Now if you’re going all in on the 18z 12k NAM, best to look ahead to D7+.

We've talked a lot about 2/14/14 with this storm and there are certainly similarities. Even down to a northern stream s/w over the Northern Plains. But there was more spacing between them and the northern stream s/w didn't dive south and partially phase with the coastal storm, and the coastal storm stayed offshore. It had a decent antecedent airmass, but the high also wasn't locked in and the 850 temps and surface temps warmed quite a bit during the day. http://www.meteo.psu.edu/fxg1/NARR/2014/us0213.php

It is. GFS/Euro blend is a solid front end for the metro corridor with 3-6". Hard to tell how much rain still, but obviously a huge dry slot. Less surface reflection west of the Apps helps concentrate the WAA right into our area, so we get a really solid 6-8 hours of snow. Hard to see that we'll get a GEFS mean like offshore track, but even one that goes Richmond-->lower DE-->ACY could be a big improvement with limited non-frozen precip while also giving us the best WAA snow.

Icon and GGEM both hit us next Friday. GFS is much more suppressed.

This GFS track probably is good enough for you to add 1-2" of snow as it pulls away Monday. Maybe C-1" for me.

We've gotten a small, but noticeable shift east/south, but it's still well short of putting the metro corridor in the CCB/deform band. So the sensible weather outcome is not much different. Probably results actually in slightly less WAA thump, but gives us better odds of limiting rain before the dry slot. Also we are getting pretty close to getting a little coating back on top at the end Monday as it pulls away.

Just a note...that capture/tuck/stall that the Icon does in south-central VA (and all the other guidance does somewhere nearby as well) is what we dream about. When it occurs 50mi east of Norfolk/Ocean City. That's when the deform band just crushes the metro corridor.

My intuition is farther south = less northern stream interaction = slower. The pull from the northern stream shortwave is what speeds it up once it gets captured and starts moving N/NW.

Near surface could stay cold, but it would briefly torch in the 925-850mb range. That could actually limit the surface wind risk.