WxUSAF

The farther south you are the more you’ll rely on some west coast ridging (+PNA) to force cold air and the storm track south. I think for all of us, better wintry precip chances probably come after next weeks storm. And any specific threat will be highly contingent on what happens to next weeks storm, so can’t diagnose more than that now. I’ll remain skeptical of any major frozen event from next week’s storm for awhile, but if I was north of NYC, I’d be getting excited.

Weaker ULL and redonkulous blocking produces a very unusual solution. It can happen, but wonky for obvious reasons. I’d like to see that solution after this New England weekend storm gets blown up offshore.

Well I’ll say this…I feel confident we haven’t seen the final solution yet for that storm. And crazy things happen with the kind of blocking advertised for next week.

Lol a primary low that takes an Omaha to Chicago track and then becomes a Miller B off Wilmington NC and gives us a MECS

Thanks @psuhoffman and @AtlanticWx. 1989 makes sense. Those 1967/1996 seem like too much -PNA (we hope).

@psuhoffman @CAPE @Ian or anyone else with a photographic memory or with a good database: have we ever had a -EPO/-AO/-NAO/-PNA pattern in a La Niña December? Or any La Niña winter month? And if so, what did they produce?

That low is continuing to trend south and slower as it gets shoved under the block and this weekend’s light NE event turns into a big ocean low and also suppresses the flow. So there’s some room there if we can get some precip to stretch our toward us. I think this weekend and Mon-Thurs of next week could be pretty sneakily cold.

I think there’s a long shot chance at something on the front end of that big cutter/cutoff low. Need a piece of energy to run out ahead along the warm front while we have CAD. I think the chance we get anything from a coastal redevelopment is nil.

I’m glad this pattern is finally going to change next week because I’m tired of looking at long range ensemble longwave patterns.

Kinda crazy to think, but by next Thursday the 15th, it’s quite plausible that we will only have had 3 AN in the month! The 3rd, 7th, and today. But because all 3 of those days are double-digit warm departures, the total monthly departure by next week could be pretty modest. Poor @leesburg 04. No 70F before the pre-Xmas torch

We want weaker waves that don’t cut or trailing waves that follow along the boundary laid down by a previous stronger storm. Always takes some timing and a bit of luck, but those are very typical ways we get a snow event in the mid-Atlantic.

Did I look at soundings of a 360hr chart? Maybe.

I violently endorse the 18z gfs

^thats what I was saying several days (a week?) ago about storms trending south during anomalous blocking periods. Still think we’re a bridge too far for that event, but if I lived near Philly I certainly would be watching.

Good news is that the “pattern change”, such as it’s morphed into, seems locked in on all the ensemble systems and the Op runs are generally reflecting that as well if that makes a difference to you. Next week’s big cutter plus the Siberian PV initiate this. Even earlier, this late weekend storm also seems to play a part by blowing up offshore and helping rebuild the -NAO. After the cutter, we get a -EPO/-AO/-NAO combo, but it also comes with probably a -PNA. Ironically (??), this is very much like what the pattern was supposed to be circa thanksgiving weekend. But with the -EPO, we look to get some cross polar flow and rebuild the cold in Canada. That is an overrunning/southern slider type pattern, but it can be very productive. Don’t want a big wound up low still, which could cut. Also don’t want that -PNA to dig to Baja. But seems we are getting a pattern change finally.

It’s a ways out there and we’ve had this fools gold before, but I’m intrigued at the setup as next week’s cutter gets stuck under the block and slowly walks toward the 50/50 region.

@Ji will open the Winter 2023-24 thread soon

With the storm late weekend blowing up offshore into a big 50/50 low as @brooklynwx99 showed, suddenly our “torch” period is looking pretty chilly. The Friday-Thursday period looks BN actually right now with some notable CAD ahead of the big cutter that hopefully ushers in the pattern change.

About damn time a GFS op run shows a winter pattern when we expect one. I’m sure 18z will go back to hurricanes and SE ridges.

Late December sun angle is brutal. Hopefully any potential winter wx happens overnight.

Obvs

maybe time to step away from the computer for awhile?

As @Weather Will shows there, 18z GEFS maintains more or less a similar look to 12z but more emphasizing the -EPO vs +PNA. All 3 ensemble systems have the -EPO in place by D8. D8 has more or less been our can kick point so that’s encouraging. Deeper into the runs they all get a cross-polar flow look as the EPO ridge goes across the AO domain. That will recharge Canada with very cold air if it happens eventually.

Maybe maybe not. The EPS pattern shown by @DarkSharkWX is “good” not “great”. More -EPO than +PNA and the ridging in the NAO is not a true block. But still a -AO. I’d certainly take it.