December 2019 Med/Long Range Disco

[psuhoffman]

7 minutes ago, frd said:

Not sure how relevant, and to what latitude this might be targeted to , ie. DC , Philly or even NYC.,  but I read  that despite having a -AO in December, along with a  -NAO the most important indice to have in your favor during December for increased snowfall odds is a  +PNA.  I am beginning to believe that. You don't need the +PNA as much in J, F and M 

The +PNA does seem more important in reality versus the  -NAO/ Davis Straits block during December. 

Now for the records,  a MECS in December in the Northern Mid Atlantic, yes,  you need both. 

A lot of what I said here is from reading all the great posts and stats form Don S.  Love his stuff ! 

So next time you see a Greenland block you still need to check the Pac.  I know you know all this, LOL,  but some folks may not understand the importance of the Pac , especially this early in the season and for our hood especially .

Caveat mention here: as  @psuhoffman stated,   having this blocking in December may indeed be a positive sign for later in the season.  Especially seeing the NAO blocking a couple times so far. 

 

I saw that, and I also know the NAO is most correlated with cold in our region later in winter...so that does not shock me.  It also makes sense that in December when the depth of cold is not really established yet, and the warmer waters nearby still can make marginal setups difficult and promote southeast ridging... having a perfect mid latitude trough/ridge axis is probably the most important feature to overcome those issues.  But overall our december snow climo just sucks.  Its barely a snow month here.  We had a really nice run that was in the not so distant past and so its hard to think of it as NOT but in reality December is pretty hostile towards snow here.  

[Bob Chill]

4 minutes ago, BristowWx said:

So in a hostile PAC -NAO we are just muting what would be a real warm pattern into an AN one?  

The full latitude trough off the west coast down the line about a week or so looks to scour the entire continent of cold air and replace it with a massive slug of maritime air. The AO or NAO can't fight that off. This stuff happens so it's not shocking or anomalous. Let's assume it does happen.. it can either be transient or part of a longer term pattern. EPS/GEFS/GEPS all show it being transient. 12z EPS actually looks half decent by the end of the run and made a move towards the GEFS. 

[cbmclean]

GEFS shows MJO skipping the maritime area and looping back to 1.  Perhaps why it is not yet seeing the nasty Pacific.

 

EPS has a spaghetti bomb in the COD.

[frd]

10 minutes ago, psuhoffman said:

But overall our december snow climo just sucks.  Its barely a snow month here.  We had a really nice run that was in the not so distant past and so its hard to think of it as NOT but in reality December is pretty hostile towards snow here.  

We do better in March. I bet running the numbers it is remarkable how much more snow in this area the last 10 years during March versus December. 

Nothing new there, source regions still very cold, Atlantic SSTs colder, etc. 

 

[psuhoffman]

Just now, Bob Chill said:

The full latitude trough off the west coast down the line about a week or so looks to scour the entire continent of cold air and replace it with a massive slug of maritime air. The AO or NAO can't fight that off. This stuff happens so it's not shocking or anomalous. Let's assume it does happen.. it can either be transient or part of a longer term pattern. EPS/GEFS/GEPS all show it being transient. 12z EPS actually looks half decent by the end of the run and made a move towards the GEFS. 

And the see saw continues.  We are probably splitting hairs, but I doubt a prolonged true torch. I do think we will have to suffer a period of pacific air intrusion. Several days at least. But the mid latitude pattern has been progressive and fluid. It’s also quickly snapped back each time or deviated. I doubt a hostile regime locks in for a long time. I also like the fact we keep getting some kind of high latitude blocking the last 6 weeks. The tropical forcing has been a double edged sword. The standing wave in the Indian Ocean has muted attempts by waves to enter the hostile maritime continent region.  But it’s also kept forcing centered on a region not really great for us either. We’ve ended up stuck in meh. As that releases we may have to suffer a warm phase at some point but the SST configuration really does favor central pacific forcing and I have a hunch that we will spend at least some of core winter in favorable tropical forcing phases which should give us a decent pac pattern. If the propensity for occasions of high lat blocking continues I am banking we line this up at some point. All it takes are a couple hits to get us to climo. We can do that with a good 2 weeks!  That’s why I’m somewhat optimistic on things right now. 

[psuhoffman]

2 minutes ago, frd said:

We do better in March. I bet running the numbers it is remarkable how much more snow in this area the last 10 years during March versus December. 

Nothing new there, source regions still very cold, Atlantic SSTs colder, etc. 

 

I think some block out that fact because they don’t like March snow. I would prefer snow earlier in winter too. Ideally we get bombed around Xmas and it stays cold and on the ground for weeks. But I know my climo and I’ll taje March snow over no snow. 

[SnowGolfBro]

15 minutes ago, psuhoffman said:

I think some block out that fact because they don’t like March snow. I would prefer snow earlier in winter too. Ideally we get bombed around Xmas and it stays cold and on the ground for weeks. But I know my climo and I’ll taje March snow over no snow. 

Prime time For snow around DC and burbs is Christmas to PD.  Sure we score in December and March but it’s not nearly as common and requires a lot more to go right for the snow to fall and stick.  I won’t start getting bitter about warm air until it starts eating into January.  But with a week in Canaan over New Years i should at least see some snow.  I hate missing a hometown storm.

[WxUSAF]

@psuhoffman our thoughts are very similar. The Pac flood continues to get can kicked, muted, and washed out. Good trends for high latitude blocking so far. It’s just hard to overcome a meh Pac in the early season. Much more feasible in JF. I’m impatient as we all are, but I’m still objectively optimistic on the winter .

[JakkelWx]

24 minutes ago, cbmclean said:

GEFS shows MJO skipping the maritime area and looping back to 1.  Perhaps why it is not yet seeing the nasty Pacific.

 

EPS has a spaghetti bomb in the COD.

If the euro MJO progression verifies, any warm ups projected on it will probably be muted/transient for the next 2 weeks. Both ens really.

[SnowGoose69]

32 minutes ago, Bob Chill said:

The full latitude trough off the west coast down the line about a week or so looks to scour the entire continent of cold air and replace it with a massive slug of maritime air. The AO or NAO can't fight that off. This stuff happens so it's not shocking or anomalous. Let's assume it does happen.. it can either be transient or part of a longer term pattern. EPS/GEFS/GEPS all show it being transient. 12z EPS actually looks half decent by the end of the run and made a move towards the GEFS. 

All it really can do is prevent a massive SER from developing so you probably won’t see a 570dm ridge with a high of 75 as you might see if the AO and NAO were strongly positive 

[HighStakes]

4 minutes ago, WxUSAF said:

@psuhoffman our thoughts are very similar. The Pac flood continues to get can kicked, muted, and washed out. Good trends for high latitude blocking so far. It’s just hard to overcome a meh Pac in the early season. Much more feasible in JF. I’m impatient as we all are, but I’m still objectively optimistic on the winter .

I'm optimistic as well. This just doesn't have the feel of dud winter where we're stuck in a hostile shutout pattern being tortured for weeks trying to chase a change to something favorable. I see no indication that we all don't reach our annual averages and accompanied by a few rather cold periods.

[Ralph Wiggum]

2 hours ago, Maestrobjwa said:

And again, why does it keep going bad in mid/late December every single year? Smh Can we just assume it'll do that every mid/late December from here on?

I dont doubt it. We used to have the dreaded January Thaw....and that was a legit real thing. We could count on it almost every single year. This appears no different. 

[Ralph Wiggum]

Maybe some snow squalls Wednesday behind the system.

[CAPE]

22 minutes ago, losetoa6 said:

A bit better blocking for the day 8/9 storm . ..at  192 . Not sure it will matter yet 

It wont matter. That's a rainstorm. And that is not blocking- it is a fairly transient upper ridge. In order to overcome a hostile Pac, a legit block that actually extends into the NA for multiple days, with a quasi-stationary 50-50 low stuck underneath, would give us a fighting chance.  Bootleg stuff- an h5 ridge near GL with a blue ball racing northeastward through the 50-50 region, is a thread the needle deal, and indicative of a lack of  true blocking. Outside of perfect timing/a lot of luck, that likely wont work out well for the majority of our region, esp when the EPAC is hostile.

[BristowWx]

Many different versions of the same look..the influx of PAC air as we head to Xmas...lets get it over with like Bob said..hope for better set up later. 

[Bob Chill]

6 minutes ago, BristowWx said:

Many different versions of the same look..the influx of PAC air as we head to Xmas...lets get it over with like Bob said..hope for better set up later. 

Yea, the beginning of the invasion starts in about 5 days so we can't call it fantasy range anymore. Interestingly, the lr 18z gfs shows a sensible wx version of what both the gefs and eps are showing irt turning cold again. If we can see the way out before we even get in I don't worry much. 

[CAPE]

Just now, BristowWx said:

Many different versions of the same look..the influx of PAC air as we head to Xmas...lets get it over with like Bob said..hope for better set up later. 

I honestly don't see a "torch", but ofc that is relative. There will probably be a week or so centered on Xmas of temps generally in the 45-50 degree range at worst. But yeah, wrt to snow potential, that is a virtual shutout. Even on the EPS, looking at the last 4-5 runs, there are indications this will be transient and the pattern may evolve to a more favorable look as soon as the last few days of the month.

[Bob Chill]

Just now, C.A.P.E. said:

I honestly don't see a "torch", but ofc that is relative. There will probably be a week or so centered on Xmas of temps generally in the 45-50 degree range at worst. But yeah, wrt to snow potential, that is a virtual shutout. Even on the EPS, looking at the last 4-5 runs, there are indications this will be transient and the pattern may evolve to a more favorable look as soon as the last few days of the month.

I've been specifically talking about mid level temps with reference to warmth or torch. This is a legit shot of maritime air as it covers nearly the entire continent. It may never hit 60 degrees the rest of the month but it's no doubt at least a temporary shutout. At least a week from how it looks now but not much longer (hopefully)

[Ralph Wiggum]

 

7 minutes ago, Bob Chill said:

Yea, the beginning of the invasion starts in about 5 days so we can't call it a fantasy range anymore. Interestingly, the lr 18z gfs shows a sensible wx version of what both the gefs and eps are showing irt turning cold again. If we can see the way out before we even get in I don't worry much. 

Agreed Bob. This has the makings of a muted and transient moderation as the pattern reloads. We are likely going to see this every so often this winter, tho overall I do believe we will avg colder than normal, so any panic shouldn't be warranted at this point. Now if this PAC puke had staying power thru the waning days of Dec into early Jan and we needed to waste an additional 10-12 days reestablishing the cold in Canada then another 5 days to a week to deliver said cold into the lower 48, then frustration would certainly be warranted. I dont think you nor I nor anyone else that posts in this forum is seeing such a thing at this time. 

[poolz1]

10 minutes ago, losetoa6 said:

HH Gefs has a pretty big coastal signal now for day 8-10. A few biggies in the mix

Thought it was interesting that there was only one member that had a forum wide rain event...every other member that had the storm had frozen in some part of the area.  Western areas favored obviously.  Didnt look at member h5 but I am curious what the snowy ones show as a lead up to the storm.

[Bob Chill]

17 minutes ago, losetoa6 said:

HH Gefs has a pretty big coastal signal now for day 8-10. A few biggies in the mix

Def uptick in # of solutions that deliver at least some frozen. More have frozen than all rain by 2:1. Of course the existence of the storm itself is very much in question. Something to watch before we close the blinds for a spell. 

18z gefs also had a splattering of events in the d13+ range. A good sign that we get cold again sooner rather than later. 

[Maestrobjwa]

Hey @Bob Chill (or somebody else who may know)...I'm trying to remember...was the awful Dec 2010 nina-induced miss the last time we didn't have to deal with a hostile pac to end the month?

[CAPE]

Not a bad looking HH GEFS snowfall map. Almost all of that is from the 20th through the 29th in our region.

[jewell2188]

Can we all agree at least we are not starved for moisture!? After the mini drought we had, we have rebounded nicely regardless if it’s frozen precip or not. 

[frd]

19 minutes ago, Bob Chill said:

Def uptick in # of solutions that deliver at least some frozen. More have frozen than all rain by 2:1. Of course the existence of the storm itself is very much in question. Something to watch before we close the blinds for a spell. 

Several,  if not more , very interesting solutions with what looks like impressive wrap around snows and deepening lows, some tracking South of us too. Not a bad run. But like you said Bob, so much is still a question mark about this period.   

[Bob Chill]

11 minutes ago, Maestrobjwa said:

Hey @Bob Chill (or somebody else who may know)...I'm trying to remember...was the awful Dec 2010 nina-induced miss the last time we didn't have to deal with a hostile pac to end the month?

2013 was pretty good after the heatwave before Christmas. It was a good month in general with a reloading -epo to start and end the month. 

[frd]

2 minutes ago, Bob Chill said:

2013 was pretty good after the heatwave before Christmas. It was a good month in general with a reloading -epo to start and end the month. 

HM really thinks deep arctic air will return when the West Pac re-sets. The re-set will assist in the EPO and WPO regions, says the worse is yet to come.

I say Bring it !!! I would love to see a -WPO and a -EPO.   

[Bob Chill]

@C.A.P.E. This panel is encouraging. Not that I think it's some sort of storm window or anything but you can see the spread favoring cold or snow/mixed versus warm rain. If the Pac was likely to lock in and screw up the rest of the month we wouldn't see panels like this. 

[Ralph Wiggum]

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

Not a bad looking HH GEFS snowfall map. Almost all of that is from the 20th through the 29th in our region.

Isnt that our moderation/closed blinds period? GEFS either blinked or the cave is starting. Wouldnt be the first or second time this monh.

[cbmclean]

33 minutes ago, Maestrobjwa said:

Hey @Bob Chill (or somebody else who may know)...I'm trying to remember...was the awful Dec 2010 nina-induced miss the last time we didn't have to deal with a hostile pac to end the month?

Depends on what you mean by hostile.  Right at Christmas 2017 the weather turned chilly, then cold then bitter.  I think that was a +EPO cold dump.  But it was bone dry