Re: Long Range Thread 12.0 (Split from original 12.0 Thread)

[Bobby Martrich EPAWA]

New update:

[Snow88]

Wow

Last week they had the MJO staying in the COD

This is most likely playing tricks with the models. The models are most likely getting colder because of the MJO.

[Frank_Wx]

Wow

Last week they had the MJO staying in the COD

This is most likely playing tricks with the models. The models are most likely getting colder because of the MJO.

To me the new update looks like more members staying in the COD than before

[amugs]

Looks good - hope it is not as transient - woudl like to see this extend over the top in a few more days but beggars can't be choosers - so much for shorts and tanks!

[amugs]

I cant post the gif - dont know how but the wave train in the NPAC oFf Asia is serious stuff into ALsaka with a stout - EPO and WPOthat is a game changer for a time frame come the end of Dec/ beginning of Jan - Trough builds into the East and and heights rise in NW CAN,
LP that is NW of Japan and Korean Penn is helping pump the Ridge over Alaska - Aleutians - is it what Scott so eloquently explained above ? Could very well be but it is 10000x better than what we were seeing a few days ago - shorter wavelengths as well.
Oh and this is the EURO depiction I am talking about. GEFS are on board as well - both 12Z suites showing this progression

[sroc4]

The MJO has had hints of it coming out several times in recent past only to see it fail.  Im still skeptical that it comes to fruition this time as well.  There may be a hint however at the convection that is present drifting slowly east as seen on the OLR maps.  There appears to be an intensity in the convection between 120E and 140E simliar to late October.  Same with East of 60W.  Combined with positive anomalies near 60E it has a definite La Nina look to it.  



It does look like the GFS forecasts the Easterlies, likely in response to the SOI spike occurring, are intensifying and pushing west over the next 10days.



 Both the westerlies and easterlies seem to be trending west below the black forecast line, so the convergent zone bewteen the two also would in theory shift westward if this verifies. This could be one reason why the latest MJO forecast is less likely to come out of the COD in 5-6 and propagate east, but instead the end of the LR MJO forecast is now pointing more towards phase 1-3 instead of 6-8.  Maybe Im reading this wrong however.  

Bobby.   I notice you posted the NCPE image and the ECMM from the CPC MJO site:



I wonder what you think of the NCPB image?  This one is supposed to the the Bias-Corrected Ensemble Global Forecast System.  



Watching these two over the past month I have notice there has been pretty big differences at times with regards to the LR forecast between the two only to see the NCPE trend towards the NCPB with time.  As you can see there currently are fairly significant differences.   

Vs the ECMF vs the ECMM which seem to be a little closer in LR forecast.  




IMHO the GFS corrected, NCPB, has been much more accurate in the overall verification as LR becomes reality.  Again Im skeptical that it makes it out of the COD.

[Bobby Martrich EPAWA]

Main takeaway and key takeaway isn't whether it remains in the circle of death or not, but the fact that it is moving the forcing away from the Maritime Continent.

And to answer your question, I think the bias corrected GEFS are probably a little bit more in line with the EPS, and probably a little bit more accurate. Although the mean stays in the circle of death, there are several spaghetti plots that are pointing toward a phase 1 look.

[sroc4]

Main takeaway and key takeaway isn't whether it remains in the circle of death or not, but the fact that it is moving the forcing away from the Maritime Continent.

[Bobby Martrich EPAWA]

I edited my previous comment response because I missed the part about what you wrote directly to me. Sorry about that. Getting torn in 10 different directions today.

[sroc4]

I edited my previous comment response because I missed the part about what you wrote directly to me. Sorry about that. Getting torn in 10 different directions today.

Unacceptable Bobby. JK thank you

[Bobby Martrich EPAWA]

Bit of a rex block showing up here which are difficult to break.



GEFS was also showing combo of -EPO and +SCAND D13-16, yet has SE ridge flex due to +NAO. Think it's overplaying ridge, and will adjust. They all will. First week of January will not be as previously advertised I'd be willing to bet. +SCAND although weak would combine with -EPO to promote EC troughiness, just don't think it's seeing yet. Still adjusting.



I think we'll continue to see changes in that first week of January look, may go back to near normal in these parts, but near normal for that time is mid-30s. Certainly cold enough to snow for at least interior.

EPS today not nearly as pronounced with that look, but with a -EPO I'll roll the dice and take my chances. I'd say below normal 12/30-1/2 and then near normal after that. Se ridge might be overkill here also with +NAO.

[Guest]

Bobby welcome. Cute kid in the picture!! If you keep posting at this rate you will surpass Jman by the time we get our first significant snowstorm!! Fella's for the sake of guys like me, every once in awhile translate all these SOI, MJO, Rosby wave whatever you wanna call it mumbo jumbo, into english for us mortals. Simple good ole fashioned city talk please.

[CPcantmeasuresnow]

Bobby welcome.  Cute kid in the picture!!  If you keep posting at this rate you will surpass Jman by the time we get our first significant snowstorm!!  Fella's for the sake of guys like me, every once in awhile translate all these SOI, MJO, Rosby wave whatever you wanna call it mumbo jumbo, into english for us mortals.  Simple good ole fashioned city talk please.

If I may add to this James as I did express similar thoughts to Mugs a couple of weeks ago.

A simple ending like, "This may be a positive for snow and cold", or "This is not a good look for snow and cold". Simple minds like mine need monarch notes.

I'm not sure anyone under 40 will get the monarch notes reference, but you get the idea.

[Bobby Martrich EPAWA]

Haha ok...

Well the most recent pictures I showed were from the GEFS and EPS, and are definitely a colder look from about the 30th through about Jan 2nd... after that the models are trying to pump up the SE ridge again from Jan 3rd onward, which I call BS on. This is a chart that I shared with the premium forum members today, that breaks down the periods ahead with cold/warm periods and confidence of that occurring. Might make it more simple. This area is for eastern half of PA, all of NJ, all of DE, and the northernmost counties in MD near PA/MD border, our coverage area.

[rb924119]

Bobby welcome.  Cute kid in the picture!!  If you keep posting at this rate you will surpass Jman by the time we get our first significant snowstorm!!  Fella's for the sake of guys like me, every once in awhile translate all these SOI, MJO, Rosby wave whatever you wanna call it mumbo jumbo, into english for us mortals.  Simple good ole fashioned city talk please.

The longer range, beyond the Christmas holiday, is looking more promising for, at the very least, equal amounts of cold and warm so that our region averages near normal through the same period that was supposed to be an all out torch a week ago. There are a couple signs that the cold may out duel the warmth and we could end up averaging slightly below normal temperatures, but whether they pan out remains to be seen. In terms of snowfall, nobody can say one way or the other, but if we end up averaging near normal temperatures we may end up seeing events similar to what we have so far; snow to to rain. If we average below normal temperatures, and we get timing right, we may be able to squeak out a snow event of some degree.

Better? Lol

[CPcantmeasuresnow]

Great stuff Bobby M, even I understood.

[Frank_Wx]

At this point I think it's kinda funny to see how much the models are struggling with seeing the convection in the western Pacific. Every single piece of guidance continues to forecast the MJO going into the COD. This is model error considering the wave causing this impulse still looks healthy as it propagates east.



The CFS is forecasting little to no CHI, or vertical velocity, heading into New Years. This could mean the pattern we're heading into the end of this month is a transient period rather than one that could sustain itself into January.



What we're likely to see is the return of the -WPO/-EPO ridge but this time there may be a +PNA ridge to accompany it. This would concentrate the cold on the east coast and be a pretty good set-up for a winter storm. The western ridge is key. 500mb vorticity would travel over this ridge and into the backside of the eastern trough. Storms are less likely to cut to our west in this set-up. The only issue is models show this feature flexing for just a day before it collapses and moves east. There are a series of Pacific waves crashing into the PAC NW around this time frame as well. Timing has to be just right. And unfortunately the NAO looks to remain positive too.



Models are already hinting at a possible winter storm in the 28th-31st time frame. Let's see if they hone in on a specific short wave in the next two days so we have an idea of what to keep an eye on.

[Frank_Wx]

00z GFS has the -EPO/+PNA spikes at D10 still. The lack of Atlantic blocking makes it hard for cyclogensis to occur off the coast. We need to see the short waves consolidate further west to sharpen the trough up. Time period is 28th-30th.

[rb924119]

00z GFS has the -EPO/+PNA spikes at D10 still. The lack of Atlantic blocking makes it hard for cyclogensis to occur off the coast. We need to see the short waves consolidate further west to sharpen the trough up. Time period is 28th-30th.

We need that Rex block out of the PNA region I think for this to happen, though. As much as we would like to see it there for more sustained cold in the East, it keeps the ridge too broad which forces the trough axis further east. A nice, tall and skinny ridge would be perfect, not a Rex block UNLESS it centers more over the west coast of North America, then we'd have a shot at the best of both worlds.

[sroc4]

The ensembles cont to trend better for this time frame. Here are the last few runs of the EPS.  First two of which I used in my LR write up yesterday.  Ridging into the PNA region trends are better, ridging into the EPO region trending better, and the tough in the east trends better.   Just look at the evolution of the trough in the east.  Just like was said by many of us in the LR discussions from yestrday, more trough pulling back off the west coast with a piece breaking off and digging into the CONUS as it heads east compliments of the -EPO and +PNA ridging.  Ray rex block from this would be nice as there def looks like there will be some form of upper level LP in the SW.  Its on both GFS and Euro operational, and if you look close enough its even in the means of the ensembles.  Id like to see the trough cont to back up off the western coast a little more moving forward.  Def a time frame to watch.





I would imagine there is going to be a lot of model variations, esp in the operationals, as we cont to get closer to this time frame because we have to get past this on the 26th a mere 4 days or so, +/-, out ahead of it.  With such a dynamic system cutting up into the N plains Id imagine the upper level features beyond this time frame will cont to waffle.  





If you look at the LR beyond The new year If the height anomalies are true in the EPO region I expect a very similar trend as it gets closer IE: ridging into EPO region, +PNA with trough backing off west coast and piece breaking off and digging into CONUS.  troughs into the east come and go but the pattern may rinse wash repeat.  I stress MAY repeat.  





Simply stated, (CP), there may be several opportunities for snow, and the overall temp departures will likely not be too bad at all.

[sroc4]

Here is the trends GEFS for the same time frame 00z Dec 30th:
 

[amugs]

This is what we could be looking at with the Negative EPO - COLD!! WPO does some good but the EPO is much better

[algae888]

Scott I would add that the Atlantic side looks much better too. No raging positive Nao if you look at the EPS at our 216 and Beyond it looks like a transient negative Nao or neutral at least. We need to get the Western Atlantic Ridge to move north. Eps better than the GEFS on this. Not that I'm a huge fan of a negative nao but we need all the help we can get. So basically on the Pacific side it's a relaxation and a reload. I keep reading and hearing that once the ridge forms there that it likes to stay there. Hopefully this is true this winter so we'll have plenty of cold air to work with.

[sroc4]

Scott I would add that the Atlantic side looks much better too. No raging positive Nao if you look at the EPS at our 216 and Beyond it looks like a transient negative Nao or neutral at least. We need to get the Western Atlantic Ridge to move north. Eps better than the GEFS on this. Not that I'm a huge fan of a negative nao but we need all the help we can get. So basically on the Pacific side it's a relaxation and a reload. I keep reading and hearing that once the ridge forms there that it likes to stay there. Hopefully this is true this winter so we'll have plenty of cold air to work with.

Agreed on the NAO Al. The scandanavian ridge helps alot. I guess you canb argue for that being an East based block. In the images beyond the 10day I posted above show that block fading some, but my guess is that as we get closer and the wavelength shorten as the memebers come close together we see some form of blocking in this region, and or closer to greenland. A true -NAO west based im not so sure. I still think we can do ok without the NAO though if the pattern sets up like we have been discussing in the Pacific. This however would mean frequent over running or weak cyclogensis, without NA blocking. interesting none the less.

[rb924119]

Nice discussion, Scott! I don't disagree that the Rex block is a good thing: It will definitely get cold into the east. I'm just saying look at how expansive the positive height anomalies are in the west because of it; the ridge cannot sharpen because of the bowling ball beneath it. As a result, the height gradient becomes very tight over the southeastern CONUS because of the confluence created by the presence of the cutoff low beneath the ridge and trough to the east. In my opinion, that would not allow any significant storm to come up our way because it will not be able to "turn the corner"; the confluence with keep the flow too zonal and not allow it to be buckled more meridionally until it's too far offshore. One way to fix that is to either lose that cutoff low beneath the ridge and keep the ridge in place, which would then allow it to respond to upstream effects and possibly sharpen such that the downstream trough could sharpen. A second way would be to keep the Rex block in tact but shift it a bit more west than presently modeled, which even given the confluence would allow the flow to already oriented in a more south-north direction. If any energy dove down the backside of the trough, it would then have enough room to head our way in time. That's all I'm saying.

[amugs]

A scandinavian east based NAO buckles teh flow more - gives us secs and mecs events same set up we had in 13-14 and 14-15 (Feb - March)

Look at the EPO - all that warmth goes to the pole and we block over teh top and hopefully connect a bridge between the PAC and Atlantic

[rb924119]

SOI spike is now over as well. Today's value is just below zero. Now, can we get a rapid fall in response, further signaling the transience of the warmth like we are now seeing modeled and Bobby mentioned??? If we do, then the modeling we are seeing definitely holds merit with the "back and forth".

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