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Pattern The Great December Dump

Really nice to see the warm pattern continually being kicked down the road on successive EPS runs. Doesn't begin to turn legitimately mild until after mid month.
Wow, I notice warm air keeps getting pushed back.. it’s been pretty chilly the last month in the SE except for just a few above/near average days.
 
EPS goes with the Dec 2009 look here in the US w/ widespread cold anomalies nearly from coast-coast. Obviously, there's no huge -NAO this time as there was then but as the old saying goes "there's more than one way to skin a cat".

Dare I ask, are we actually going to see a below normal December for once? Still not terribly likely but have to like our chances if we get a few big shots of arctic air the next few weeks and the vortex stays around in SE Canada.

I definitely thought we'd be warming relative to normal up by the 2nd week of the month. I'll be more than happy to be dead wrong because I've grown sick & tired of mild Decembers

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Geez, haven’t seen the gefs ensembles this lit for wintry precip in the SE in a long time, many have a icy signal and some have snow around that 180-300 hr timeframe, mostly Ice tho, most show a anafront or even some overrunning with the first system, then after shows another system with many solutions (miller B/CAD, overrunning, cutters with wintry precip that starts out with CAD) interesting signal for sure, makes sense tho if we have leftover strong high pressure and a SW decides to kick into that 6D8431D7-AB3A-44FC-97F9-425EF4A29BAA.jpeg
 
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Yeah, this isn’t a warm pattern. Awesome to see in December.

Models aren’t done with this one. And a forecaster asked me if I was “a fan of fiction” tweeting on this pattern on 11/28...having that attitude when both ensemble models had a strong signal at the same pattern is what’s wrong with folks...


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Verbatim there isn't a whole lot of support for the system at day 9 on the EPS, but certainly beyond ~ day 12 ish on the tail end of this big cold shot there's some snowier solutions.

Member 21 would be nice, 2-3 separate winter storms in 5 days.

In all seriousness though, it's hard not to get at least a little excited here given the active storm track we'll already have in place

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Verbatim there isn't a whole lot of support for the system at day 9 on the EPS, but certainly beyond ~ day 12 ish on the tail end of this big cold shot there's some snowier solutions.

Member 21 would be nice, 2-3 separate winter storms in 5 days.

In all seriousness though, it's hard not to get at least a little excited here given the active storm track we'll already have in place

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Lol I just tweeted the same. The 13-17th period, if being modeled correctly, should deserve some excitement and hopefully we will grab one to track. I was thinking yesterday when graupel was falling...this winter feels different.


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Now, is this a woof or a womp or a oof or a gah? I can't keep track of all of the official terminology. :) Anyway, I'm glad to see warm patterns keep pushing back in time and the warm Euro starting to maybe cave in a bit. I am still not ready to go all in on a winter storm pattern yet, but getting deeper into the month, seeing the PV over on our side, seeing the WAR displaced north of where it usually is, and seeing a strong STJ continuing is encouraging. As some of you have said, this kind of pattern can pop a storm threat pretty quickly. But I'd feel a bit more confident in a specific period if I saw signs of a west-based -NAO developing. Maybe it will, at some point down the line.

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I definitely thought we were going to take a hiatus beginning around Dec 10 & lasting thru most of the month even just several days ago. You can basically throw that idea in the trash.
I'm wondering if the models are struggling with the mjo and the forcing there?
 
I'm wondering if the models are struggling with the mjo and the forcing there?

The evolution of these planetary-scale features is often driven by upscale growth from individual synoptic-scale events whose predictability is often limited to several days to a week or so. This basically seems like a case where a few minute details in the way the wave breaks were represented over the North Pacific have dramatically changed the outcome. The broader scale planetary waves didn't change much.

Errors in those synoptic-scale events are being amplified by the fact that we have the main lobe of the tropospheric polar vortex in our own backyard. Even minor modification to the North Pacific pattern evolution means massive alterations in sensible weather as we're now beginning to realize.

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Warning: As great as the models are trending (I especially like the EPS trend to less warmth in the SE near mid-month), don’t get your heart too set as the recent past tells us that the trend could continue too far to the point where the SER takes back over in future runs and the runs warm back up. Don’t get too complacent as the models have and will again break your heart. But hopefully not this time.
 
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