December/January 2019/20 Winter Speculation Thread

[John1122]

Euro gives a few flakes with the mid week system, mainly in elevated areas. By D10 a storm cut the Apps and gives some snow the northern part of the western forum areas. Big East based NAO at day 10 with some minor Alaska and West coast ridging tries to come around day 9 that appears to be beaten back quickly by another low in the Alaska area.  Hopefully the EPS carries into something favorable. An East based NAO with heights East of Greenland tend to promote cutters and miller Bs that bring snow to places like Indianapolis, St Louis, Columbus Ohio etc while not getting a lot done here.

[Carvers Gap]

As mentioned yesterday, the Euro op was likely in error in digging the trough into the West at d10.  (We won't know if that was an actual error until that time frame verifies of course)This morning it moved it right on through.    So far on modeling the trough is set to arrive around February 5th.  As I have mentioned ad nauseam, it will be tough for it to hold with no blocking over the Atlantic.  At this point the cold shot into NA is at d9, and we are not having to wait for d11-15.  JB mentioned last night that the cold source would likely be strong enough to press eastward(even if the trough centers in the front range eventually - even with varying degrees of SERs present on modeling.  The 6z GEFS has has muted the SER.   The EPS has has well but not to the GEFS' degree.  Right now, the GEFS is leading the way with the EPS again struggling with a pattern shift - that is a twist.  Will post more later.   The good thing is that the cold air shot is within d10 right now, so we should be able to get a better look at how it sets up(vs a washed out ensemble).  Two questions are in my mind now:

1.  How much, if any, blocking develops as it is now being hinted on modeling inside of d10?  That would fit with QBO understandings.  

2.  Does the Euro bend and head towards the MJO as it did in November?  In November, the Euro never caught up.

[Holston_River_Rambler]

7 hours ago, jaxjagman said:

Not sure if  it's going to do the trick,we was fooled earlier.Control don't show a split today

Yeah, I'm a little suspicious too, but the OP had triplets at the end of its run overnight:

GFS shows fraternal twins, but quickly reconsolidates:

Looks like most of it is form the bottom up too. If we can actually get the the point where it is stretched, will be interesting to see how all the extra ripples and turbulence play out. 

 

[Carvers Gap]

Personally, I don't think the PV splits quite yet.  Looks to me like modeling is bringing it back together after a strong disruption.  I also don't thing it was a head fake as the PV will be likely disrupted.  A TPV split is a "be careful what you wish for scenario."  Sometimes it really helps and sometimes it really hurts.  But still, I doubt this is completely worked out.  Great disco on the forum about it.  Certainly looks like some response from the troposphere may occur.

Also, do you all have the stats for the number of -NAO winters(DJF) that we have had during the past 10-15 years along with the dates?  I think it is seven of the last eight winters that we have not had Atlantic blocking.  I am going to examine whether the lack of Atlantic blocking is contributing to some of the less snowy winters that we have had recently.   

[Holston_River_Rambler]

Here's the best I got:

 

Pretty shocking to see it flip almost every year recently to a + state around what looks like the first of Dec. 

[Carvers Gap]

Also, I like the idea that a wave or area of slp could potentially run along the leading edge of a trough like the one modeled to come through next week.  Whether that happens remains to be seen.   The Euro has it at d10 which is a dubious range to refer to actual specifics I admit, but it does provide an example of what "could" happen.  That looks has also been on the GFS a few times which is dubious at most time ranges.  LOL.  Assuming next week's trough is legit, the way we score would likely be with energy on the front end, clippers, or energy as the SER slips underneath it.  Again, something to watch on ensembles is how much cold air will be available.  Looks like the trough will have moderate staying power of 4-5 days.  Could be less or more depending on your model of choice.  On some modeling the trough will lift out after one shot.  On others it gets a second shot of cold air that digs it further.  That second shot will likely decide how long the ridge holds as it could dig more into the West.  Right now(we have seen that change before), the cold looks substantial which means the cold could press into the SE despite the SER(reference to JB and just prior knowledge for that nugget) late in the run.  So now we wait, track some marginal events, and hang out on the forum.   Model mayhem is well underway.  Don't like what you see?  Just wait a run or two.  

[Carvers Gap]

2 hours ago, Holston_River_Rambler said:

Here's the best I got:

 

Pretty shocking to see it flip almost every year recently to a + state around what looks like the first of Dec. 

Which tells me that the lack of an Atlantic block is a problem.  Speaking for MBY in NE TN... 09-10 was a good winter and had a -NAO.  11-12 wasn't terrible as we had thunder snow here.  13-14 was a good winter and had a -NAO.  14-15 was a good winter and had a +NAO but I wonder if that was still a winter with good blocking in the AO region?   Seems like it had a -QBO as well.  I don't think the NAO is a "cure" for our winters as the Pacific is notable and important driver.  However, I can make a really good case that the lack of Atlantic blocking at this latitude has been a problem for several straight winters.  I think it is a problem especially for those on the eastern side of the forum as NW flow tends to modify by the time it gets here.  Need a block to actually bottle-up that cold air and keep it from sliding out.  All of that said, if we want a good February one path towards that is to see a -NAO develop and block the cold shot next week from leaving.  If it slides out, it is a textbook example of why some Atlantic blocking(even if weak) is important.  Without something to slow down system 50/50 low or a block, the cold slides out and is very dependent on timing as things are humming along.  The HB block has at least formed confluence near our area.

[Holston_River_Rambler]

Looking at the dates, I guess one of the reasons I've always favored the EPO, is because I can't really remember a consistent -NAO since I've been following all this, lol. I was still just watching Henry Margusity videos in 9 - 10. 

[Holston_River_Rambler]

But on the bright side, looks like we get a consistent period of - NAO every 10 or so years in winter, so maybe we're due soon. 

[Carvers Gap]

We have spoken about the QBO some.  Conversation has been spirited but constructive.  We are now in the easterly QBO descending phase(reference NASA) of the QBO which is also called negative.  As of January 26th, 30mb is roughly neutral, 40mb is negative, and 50mb is negative.  Below is the QBO chart developed by Barnston, Livezey, and Halpert.  D'Aleo shares a similar graphic from time to time.  He did again today and it is worth a share.  We are almost(if not there now) in the upper left hand quadrant of the graphic(East QBO and solar min).   When you look at both the 6z GEFS and 0z EPS, you see something very similar in modeling beginning about hour 330.  That tells me that the QBO is likely having more influence.  Notice the east based -NAO and the positive in the GOA.  Not a perfect fit, but pretty close.  Anyway, there is precedent within QBO understanding for the upcoming pattern.  It will be interesting if blocking continues to be shown at higher latitudes.

 

 

[Carvers Gap]

1 hour ago, Holston_River_Rambler said:

Looking at the dates, I guess one of the reasons I've always favored the EPO, is because I can't really remember a consistent -NAO since I've been following all this, lol. I was still just watching Henry Margusity videos in 9 - 10. 

During the social media era, the -NAO has been pretty lousy.  We have had a few winters with it during the past decade that have been stellar for sure.  I do think you make a good point that it will likely return.  Pretty much knew after that long stretch this past year that it was going positive this winter.  Problem with a -NAO during summer is that it has the opposite effect - hot.

[PowellVolz]

Ober’s web cam is showing snow is mixing in now. Temp has dropped from 40 to 35 there but my temp has gone from 38 to 40


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[Carvers Gap]

3 minutes ago, PowellVolz said:

Ober’s web cam is showing snow is mixing in now. Temp has dropped from 40 to 35 there but my temp has gone from 38 to 40
 

Cool.  Had a few wet flakes hit the windshield this AM, especially as we climbed away from the river.  Rates helped the mix.  Nothing major as it was still mostly rain.  OG has done fairly well with these elevation events lately, well compared to the rest of us.

[PowellVolz]

Cool.  Had a few wet flakes hit the windshield this AM, especially as we climbed away from the river.  Rates helped the mix.  Nothing major as it was still mostly rain.  OG has done fairly well with these elevation events lately, well compared to the rest of us.

If I’m reading this right, looks like melting is happening around 4K feet in the valley.



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[Carvers Gap]

***Heads-Up****

Looks like John has the Feb/March thread up and running.  So, I suggest we keep discussion for this week's marginal events in this thread(Dec/Jan) and then transition February discussion over to the the thread he created.  Looks like it is pinned to the top now.  

[Carvers Gap]

2 minutes ago, PowellVolz said:

 

If I’m reading this right, looks like melting is happening around 4K feet in the valley.



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Cold rain!  Great share.  Was/is definitely a marginal event.  

[Daniel Boone]

  Would be nice for the PV to split with 1 vort going into SE Canada while a - NAO forms between the 2 across Greenland into Baffin Islands. This in conjunction with a -EPO and active STJ would sure be a delight for snow lovers.

    To provide a little optimism,  this scenario is not far from being shown as being evolved per a couple model depictions. As of now it doesn't fall into the likely category,  just yet i.m.o..

    I think we need a PV split to help ignite a proper positioned -NAO, particularly if it stretches the direction the EC depicts. As John alluded to, an east based NAO won't help us but, will some of the areas that have been already getting their fair share of snow.