Terpeast

If going by the 3:1 dp/temp adjustment to wet bulb temp, IAD currently at 36/24 will meet at 33 at saturation. Rain. Could get colder with more CAD, but not with a light wind from the SE.

Nice link! Thanks. I was looking at the NWS 3 day history

The fall line in the recent run appears just west of my house. Probably once you gain elevation after passing Leesburg you’d see something.

IAD dropped from 37 to 32 in the last hour, with a 22 dp.

Only if we get a legit STJ. I don't see it yet.

Looked at the models and trends today. I’m not buying into the anafront, but it wouldn’t surprise me to see a brief snow shower or two (no accumulation) just as precip shuts off on fropa. I’ll take that.

I agree with this for 2 reasons: 1. A lot depends on the antecedent airmass and the high pressure position & strength prior to a storm. If you take one specific storm and put the exact same track into a slightly different airmass and a slightly different high up north, then you'll see different results, and you can't solely blame AGW for it. 2. We've seen cold 33 degree rainstorms before. I grew up here, and we've had them every winter. They're nothing new. EDIT: adding a 3rd reason: 3. We seem to be forgetting that in the last several years, the delmarva / coast made out like bandits in their own heater. They had, what, 3 or 4 "bomb cyclones" dumping 18" give or take right on those beaches, right?

I remember that storm. That was the only legit snow we had that winter. We got other storms where it snowed in NC/SC but rained here at 33-36 degrees.

Crazy how cold it is this week so far and how much colder it's going to be buy rain is still our main precip Cold, then warms up to rain, then cold after. Story of my life in the mid atlantic since the late 70s

Low 19

Just woke up. Did I miss anything?

Welp. Thanks anyways.

Not sure when NAM gets into its range, but it seems to be trending colder at precip onset. Only checked 850 temps, not ptype

I was checking daily temps and precip data for IAD and DCA for the 85-86 winter, which was - and still is - my top analog for this winter. It was very back loaded, and it didn’t really get going until the end of February, when it got most of its snow. It was quite cold wall to wall, but had so little to show for it Dec-Jan. I can only imagine what this forum would have been like in a winter like this.

I think the bigger culprit than chaos or lack of 50/50 is the pna being too far west. Models initially had it centered over the western rockies, then pulled it back westward just offshore into the eastern Pacific. I’ve said it before and I’ll say it again - without a western US ridge, we have a snowballs chance in hell of getting a good snowstorm here. Especially if it’s December. OTOH, if we had a 50/50, plenty of cold air, and a block of just the right strength and position, then MAYBE we can get away with a neutral PNA.

Dipped to 23

Looks like a clipper. But someone told me they’d gone extinct in recent years.

Posting a 500mb map longer than 2 weeks out should result in 3 day ban That’s actually a good idea. Especially if it’s an OP run.

FWIW, LWX mentioned the possibility of a brief period of anafrontal snow in their recent AFD.

So it looks like around 18-19z when the front crosses DCA?

I'm back after a decade's hiatus, so yeah I might as well be new here.

It'll be interesting to watch for sure. I'll be right by the window for this.

I still wouldn't get too excited about this. I mean, we can't even trust the models beyond 3 days right now, and anafront snows are very rare here.

I remember it well, too, obviously. I was in Vienna at the time, and I was coming back home from swim practice in torrential rain. My mom was driving and she was white knuckling it the whole way because we could hardly anything in front of us. Then just as we got home, it changed over to snow and a brief blizzard of thundersnow ensued. We would see purple flashes of lightning through the snow. My cousin, who was staying with us at the time, and I jebwalked through it... it was awesome. The most memorable 2 inches I've ever seen in my life. P.S. after that event, the entire month of December totally sucked donkey balls... by the end of the month I was whining "it never snows here anymore". Then we all know what happened a week after that.

November 1995. It was THAT long ago.