December 2019 Med/Long Range Disco

[CAPE]

In this type of pattern the best case scenario is a 1-3/2-4 deal from a modest wave sliding underneath. Anything too amplified is going to take a west track, and ends up mostly rain for I-95 and east, esp in mid December.

[frd]

2 minutes ago, C.A.P.E. said:

I liked what I saw on the 0z GEFS. More than one opportunity in this period-

I will get  excited when the highest snow amounts in the ensembles are South of us. Seems like the last 2 years the ensembles paint a rosy picture of 4 to 6 inch amounts ( several times in the season ) and they never happen. Worse yet, the 46 day snow total off the ECM, that also seems never to work out.  I cringe when I see folks like JB or even Maue post these sometimes. I admit it is entertaining, but hardly ever works out.   

[CAPE]

Just now, frd said:

I will get  excited when the highest snow amounts in the ensembles are South of us. Seems like the last 2 years the ensembles paint a rosy picture of 4 to 6 inch amounts ( several times in the season ) and they never happen. Worse yet, the 46 day snow total off the ECM, that also seems never to work out.  I cringe when I see folks like JB or even Maue post these sometimes. I admit it is entertaining, but hardly ever works out.   

I am not big on snow maps, but it does indicate that the majority of members are hinting at an event(or 2) with some frozen potential in the MA.

[PDIII]

Is this good:

 

how about this:

 

 

 

[Wonderdog]

1 hour ago, Weather Will said:

Clown map Kuchera 6zGFS WB through next weekend.  Would be great if we reach the total snowfall most long range forecasters are predicting for DC by mid December.  I love the pattern.  If not this one,  I think it will be fun this winter.  Lots of potential.  We just need a little luck which no model or forecaster knows how to calculate.  That is one reason why this hobby is so fun.

That would be quite the front end thump. I like those types of storms. Fun tracking coming up!

[WxUSAF]

 I haven’t looked yet myself, but from reading elsewhere it sounds like the overnight ensembles (GEFS and Eps) were more bullish on the mid week anfrontal wave. 

[frd]

I am not really sure about what HM is focusing on in regards to the vulnerability of the vortex.  When I read Isotherm and a couple others whom really focus on the strat they paint a not so rosy picture. Little to be hopeful about for a while. Even the QBO is not going to be a player until maybe Feb. from some sources. 

Regardless of whether the QBO is following the linear progression of 2002 most closely, this fall does not have the feel of 2002 and certainly the Nino aspects are not the same.  Enter a recent warmer backdrop globally, that comparison losses value, as we are talking 17 years ago.  

Even though the GFS has short-term skill and is predicting wave 1 attacks on the vortex, the result seems to be more movement of the vortex, displacements if you may, versus a real weakening trend versus what was happening, or starting to happen last year at this time, as Simon mentioned that this morning.  This development more closely matches what Isotherm was looking for I believe for the mid month period.  

 

 

[CAPE]

8 minutes ago, WxUSAF said:

 I haven’t looked yet myself, but from reading elsewhere it sounds like the overnight ensembles (GEFS and Eps) were more bullish on the mid week anfrontal wave. 

[CAPE]

And this..

[Scraff]

6 minutes ago, C.A.P.E. said:

The “cold enough” is close by, but can it time up right for white vs wet? 

[Ralph Wiggum]

Noticed some subtle but important changes in the GEFS mean irt the day 10ish storm evolution at 500mb. Figured maybe they were worth noting. Still progressive look in the N Atl but there is slightly more ridging ahead of the storm but more importantly imo is the separation between the stj disturbance and the NS/PV. That look of less phasing and more sliding is something that favors more white and less wet for you guys. So many options but looks like with this setup we either root for a heavy thump with the inevitable changeover and phase to the West OR root for all white but maybe sacrificing totals as it moves/'slides' quickly.

[CAPE]

Just now, Scraff said:

The “cold enough” is close by, but can it time up right for white vs wet? 

The general idea is there. It absolutely will come down to timing, and as we know, odds are better these things don't work out many more times than they do.

[Ralph Wiggum]

4 minutes ago, C.A.P.E. said:

The general idea is there. It absolutely will come down to timing, and as we know, odds are better these things don't work out many more times than they do.

How many members have this trailing wave irt Dec 11? I see the GGEM is still on board? Just curious what the spread looks like and if we are seeing any increases in the tendency for this development. As you said, these have more a tendency to fail. A progressive Atl flow doesnt help matters much.

[frd]

The same old story with Decembers and the NAO. 

Seems no break in this pattern. According to bluewave this goes back to 2013.   (see below ) 

I know there was talk of a wave break and possible interval of a -NAO during mid-month, but I don't see it.  

Those calling for a -NAO in December of any magnitude might need to reconsider. ( The caveat is no one really can be confident in the outcomes of the NAO far into the future so, my comment is  geared to the next couple of weeks ) 

Bringing up the common seasonal idea is that the most robust - NAO is in Feb and the most robust -EPO is in Jan.

However, starting to wonder  whether HL blocking shows up eventually,  and whether we get a -AO averaged winter. Reading some folks whom tie in the tropics with the HL, they state tropical forcing including AAM and GLAAM are lacking in terms of promoting the  mechanisms needed  to achieve  durable HL blocking, 

They also state HL blocking precursors will be fading starting now and may last for a while. An additional concern is the warming in the Eastern ENSO region. 

So make of that as you may, it appears as others have stated, a high probability of not knowing what is going to happen along with a roller coaster of temps here in the East in the coming three weeks.  

 

[Bob Chill]

Euro type solution is plausible. As leads shorten the two terms we want to avoid are "amplified" and "slower". The workable window is short. Quick and sheared will get the job done much easier than amplified and slow. I don't see our chances as any better or worse after the overnight runs. 0z Euro/EPS is in the slow/amplified camp but plenty of time for things to change. And they will every 6 hours. 

[Bob Chill]

I'd like to see ops converge on a deep CAD solution by D5. Cold supply on these types of setups is known to back off as leads shorten. We want NC/SC to be very worried about their electricity by the time we get to D5 or less. 

[frd]

Can anyone confirm these maps were just released ?  The Euro Seasonal .

Seems new to me,  and they look sort of blah with a 2 meter temp signal indicating ridging too far off the West Coast and a slight signal for a SE ridge. 

Bottom row indicates active storms and precip, but maybe on the rainy solutions along the East Coast ?  Same issue as last year possibly with a lack of HL blocking,  as I already mentioned earlier today.    Looking at this output form the Euro seems it would be similar to last year in terms of the best winter target zone, the upper Midwest and Northern Plains.   

Can the Euro seasonal be wrong, of course, but balancing things out this continues the theme of high uncertainty regarding the winter. I mean last winter's seasonal from the Euro  were so so bullish for snow and cold and then looked what happened. I continue to balance expectations.  

 

 

 

 

[WinterWxLuvr]

1 minute ago, Bob Chill said:

I'd like to see ops converge on a deep CAD solution by D5. Cold supply on these types of setups is known to back off as leads shorten. We want NC/SC to be very worried about their electricity by the time we get to D5 or less. 

I agree with this wrt the cold “retreating “ but also the actual ground temp where the cold remains is often over done meaning it gets modeled too warm and warming too fast at longer ranges.

[WxUSAF]

Normal temps and AN precip for January and February? I’d take that in a hot second. Of course the seasonal’s verification sucks.

[Bob Chill]

1 minute ago, WinterWxLuvr said:

I agree with this wrt the cold “retreating “ but also the actual ground temp where the cold remains is often over done meaning it gets modeled too warm and warming too fast at longer ranges.

Would be nice to take advantage of a pressing airmass instead of a retreating one. Surface CAD is usually modeled too warm so we can make assumptions there but if precip is moving towards us with HP to the NE then the mids almost always get roasted faster than models. Can't really parse much this far out though. The front that ushers in the cold air is still 5+ days away. 

[psuhoffman]

3 hours ago, C.A.P.E. said:

In this type of pattern the best case scenario is a 1-3/2-4 deal from a modest wave sliding underneath. Anything too amplified is going to take a west track, and ends up mostly rain for I-95 and east, esp in mid December.

 

3 hours ago, frd said:

Seems that the EPS and the GEFS are worlds apart in the eventual outcome. 

But, as mentioned already, without any significant help from the NAO or the AO regions any storm will simply cut despite how cold it is close to the event. 

Absent a favorable blocking regime EVERY storm is unlikely to work out but I wouldn't be so quick to totally discount the chance of something more significant than a 1-3" event.  There are ways it "could" happen.  The simplest is timing.  Get a trailing wave to amplify.  Time up a STJ wave with a departing system that acts as a 50/50.  A displaced TPV in a favorable location can work too.  Basically there can be temporary factors that can act to suppress a somewhat amplified system.  Anything that really goes to town and bombs will likely cut.  A very slow moving system just won't work because it would take too long and likely lose the temporary favorable setup.  But we can get moderate events from somewhat progressive but juiced up waves. Please don't take this to mean I think that is likely. Significant snow is unlikely in any base state other than a good blocking regime, but we do get moderate events from non blocking situations and this is one of the patterns that makes that possible.  Likely no, but possible.  The most likely scenario is just what you describe but there is always hope we get lucky.  

[Bob Chill]

I'm shocked that the 1052hp on the 6z gfs disappeared. Much weaker cold push = blah

[Chris78]

19 minutes ago, Bob Chill said:

I'm shocked that the 1052hp on the 6z gfs disappeared. Much weaker cold push = blah

Something in between the 06z and 12z would probably get the subforum  on the board with a 1 - 3/ 2-4 " event before a changeover. Most would probably be happy with that. Except for @Ji lol.

[Bob Chill]

6 minutes ago, Chris78 said:

Something in between the 06z and 12z would probably get the subforum  on the board with a 1 - 3/ 2-4 " event before a changeover. Most would probably be happy with that. Except for @Ji lol.

We're going through the typical shotgun medium range solutions. Solutions do seem to be slowly converging on the idea of some sort of system approaching from the SW at the same general time late next week so that's good. Still an eternity away from figuring out the important details. It's more common for the for us to fail than score on the first chance after a shutout pattern. I'm very interested in how long the winter wx window lasts down the line. Is the whole setup just a transient shot of cold before a return to blah or will there be multiple shots at something before the wheels come off? 

[Chris78]

I know its an OP run at range but I really like the  general look of the 12z GFS. Cold enough  air close by and plenty of moisture traversing the south. If we get 3 or 4 chances we may score with 1 of them.

[CAPE]

@frd

[WxUSAF]

12 minutes ago, Bob Chill said:

We're going through the typical shotgun medium range solutions. Solutions do seem to be slowly converging on the idea of some sort of system approaching from the SW at the same general time late next week so that's good. Still an eternity away from figuring out the important details. It's more common for the for us to fail than score on the first chance after a shutout pattern. I'm very interested in how long the winter wx window lasts down the line. Is the whole setup just a transient shot of cold before a return to blah or will there be multiple shots at something before the wheels come off? 

GGEM has an even goofier setup than the GFS if that’s possible. I think right now we have an idea of the players that might/could/probably will be on the board. An arctic high and a strong southern stream s/w. That’s a good mix for a starting position. Lots of details to work out on positions and relative strength.

[MJO812]

55 minutes ago, Bob Chill said:

I'm shocked that the 1052hp on the 6z gfs disappeared. Much weaker cold push = blah

Check out the gefs. Bullish on the event. 

[WxUSAF]

Haven’t seen it yet, but @tombo82685 saying GEFS is liking the anafrontal event more this run.

[Bob Chill]

2 minutes ago, WxUSAF said:

Haven’t seen it yet, but @tombo82685 saying GEFS is liking the anafrontal event more this run.

Need to see the member solution but the mean is meh imo. Cold chasing precip. Def has the TN valley wave though...