December Medium/Long Range Discussion

[Solution Man]

6 minutes ago, WxUSAF said:

Last Friday's storm almost disappeared for DC-north within 36 hours?  So I don't expect much consistency on a weak vort in fast flow until like 0z Thursday.

Voice of reason

[Maestrobjwa]

8 minutes ago, jayyy said:

For sure. Models seem pretty lost on how to handle everything in such a fast flow, especially given how weak all of these waves are. Guess we’ll have to keep expectations at nothing and be surprised if we get more

Fast flow always seems to confuse the models for some reason (probably just not advanced enough yet).

[BTRWx's Thanks Giving]

1 hour ago, NorthArlington101 said:

Funny enough though, the AIFS hates Friday and likes Sunday better.

That model is horrible!

[mitchnick]

20 minutes ago, Solution Man said:

Voice of reason

Or insanity

[jayyy]

Fast flow always seems to confuse the models for some reason (probably just not advanced enough yet).

A lot of moving parts to try to resolve in a given window. Makes sense I suppose

[IronTy]

2 hours ago, PrinceFrederickWx said:

I have watched a many a snowstorm get chewed up by mountains lol

Allegheny plateau is to winter storms as Hispaniola is to hurricanes.  

[CAPE]

I think I like Sunday for a 1-3 type deal. Cold HP moving in from the NW and a decent shortwave that might dig a bit more. We shall see.

[bncho]

The weekend is too far north for most except maybe TSSN and mitchnick but the 18z Euro has Friday. A general coating for the area.

[nj2va]

34 minutes ago, CAPE said:

I think I like Sunday for a 1-3 type deal. Cold HP moving in from the NW and a decent shortwave that might dig a bit more. We shall see.

The CAPE storm

[87storms]

1 hour ago, Maestrobjwa said:

Fast flow always seems to confuse the models for some reason (probably just not advanced enough yet).

The Friday system is moisture starved and the Sunday one is basically a cold front with most of the energy further north: https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=us&pkg=z500_vort&runtime=2025120918&fh=114

I guess we can find a way into a light snow event from both systems, but the real snow producers are when we get some southern stream influence which has been really hard to come by in these neck of the woods.

[CAPE]

Latest Natty Blend.

[WesternFringe]

35 minutes ago, bncho said:

The weekend is too far north for most except maybe TSSN and mitchnick but the 18z Euro has Friday. A general coating for the area.

More than a coating out here!  Hope it juices up more for the metros though and/or you all get a decent hit Sunday.

[bncho]

18z EPS is the strongest signal out of the last several runs.

[Ji]

phase 8 this. 

[BristowWx]

2 minutes ago, Ji said:

phase 8 this. 

You had to know this was coming. No way we just roll along with below normal temps and snow chances every few days.  RIC getting nearly half their annual snowfall before 15 Dec.  insanity. 

[Ralph Wiggum]

4 minutes ago, Ji said:

phase 8 this. 

Not that we've ever seen it before (sarcasm), but I wonder if the LR MJO forecast phases could be incorrect? Seeing alot of posts over the past 36 hrs "mjo says cold phase so its gotta be cold". It doesn't gotta be anything if the MJO forcing is incorrect. 

[mitchnick]

By the end of the Gefs 18z run (Christmas Day), the ridge across the country has been squashed far enough south to result in normal 850 temps and BN surface temps. Coincidentally, just like the Cansips was showing for the month of January I mentioned earlier today in this thread.

[nj2va]

2 minutes ago, mitchnick said:

By the end of the Gefs 18z run (Christmas Day), the ridge across the country has been squashed far enough south to result in normal 850 temps and BN surface temps. Coincidentally, just like the Cansips was showing for the month of January I mentioned earlier today in this thread.

Goes with the pattern of late where LR warmth is muted.

[jayyy]

We live in the mid Atlantic. We all know we won’t see wall to wall cold from November onward. But there has also been a very clear pattern over the past few months of models vastly overdoing long range warmups. Modeled warm ups end up being either muted or are not occurring. We will 100% see periods of warmer weather in a niña, but I’m gonna take the under on it being 70+ on Christmas.

This winter is different than the previous few in that there’s a ton of cold air nearby in Canada with a healthy snowpack to our north. Even the more relaxed zonal flow some models are hinting at in a few weeks shouldn’t be torchy. May end up just having normal temps. 70+? Call me skeptical.

There will likely be a reload of the pattern around Christmas. It will probably hit 50+ some days. But idk about 70+ or this winter being over after December like some are suggesting

[Chris78]

Nam holds together a little better but loses alot of juice coming over the mountains. Hopefully we can beef this thing up a bit.

[TSSN+]

4 minutes ago, Chris78 said:

Nam holds together a little better but loses alot of juice coming over the mountains. Hopefully we can beef this thing up a bit.

I vote we blow up the mountains. 

[Maestrobjwa]

5 minutes ago, TSSN+ said:

I vote we blow up the mountains. 

Lol. I was just sitting here wondering what our weather would be like if the mountains weren't there...

[TSSN+]

1 minute ago, Maestrobjwa said:

Lol. I was just sitting here wondering what our weather would be like if the mountains weren't there...

Probably no more CAD events, but lot more lake effect bands, light events that get chewed up etc. 

[nj2va]

11 minutes ago, TSSN+ said:

I vote we blow up the mountains. 

Let’s just get rid of PA and turn it into a Great Lake.

[bncho]

20 minutes ago, TSSN+ said:

I vote we blow up the mountains. 

DC would average 20" lol

[MillvilleWx]

4 hours ago, BTRWx's Thanks Giving said:

That model is horrible!

Actually, the model in the 500mb progs has been pretty decent overall, but it's not a normal dynamical model, so it doesn't follow the same exact principles and biases that other models do. It is basically one giant analog that uses historical variance and comes out with a progression that makes sense given recent patterns. The issue with the AIFS and AIFS ensemble is it doesn't account for those dynamical inputs that provide more detailed QPF distributions and more advanced ptype algorithms. I use it for a proxy in QPF (Spatial) and the mean 500mb pattern. The rest you have to use your meteorology and some real time context for what could transpire given the forecast pattern evolution. You have to be careful with the AI at long leads as the model will still be subject to variability due to temporal regulation and the idea of chaos increasing in a dynamical fluid (Atmosphere) as we move out in time. 

[jayyy]

By the end of the Gefs 18z run (Christmas Day), the ridge across the country has been squashed far enough south to result in normal 850 temps and BN surface temps. Coincidentally, just like the Cansips was showing for the month of January I mentioned earlier today in this thread.

Looks workable. Would rather there be cold air looming around nearby with room for the southern stream to juice up than be in a suppressive / fast NS dominated pattern all winter. When cold patterns / blocking relax is when we tend to get our biggies

[Warm Nose]

16 minutes ago, nj2va said:

Let’s just get rid of PA and turn it into a Great Lake.

 

29 minutes ago, TSSN+ said:

I vote we blow up the mountains.