Winter 2014-2015 Pattern Discussion Thread I

[griteater]

So what's the story with all the Tweets back and forth with HM today? We in trouble?

 

Sounds like at least some level of backing off on the strat progress, but that waxes and wanes....and it sounds like the nino is not acting like a west based nino...that's my best shot at trying to interpret those tweets.  I didn't see any winter cancels or uncancels

[Heisy]

I wouldnt get ahead of ourselves yet for the day 9-10 event on the EURO, today was first OP run that formed that 50/50 low which locks in the cold air. Just keep an eye out for next few days...

However the Xmas period is the time period I have much more confidence in, the EURO ens mean has been hinting at this time period for a while.

At least were looking at some potential tracking going forward

[deltadog03]

will post a new thread on it in here for those who want to watch the video.  

[RONALD B]

Sounds like at least some level of backing off on the strat progress, but that waxes and wanes....and it sounds like the nino is not acting like a west based nino...that's my best shot at trying to interpret those tweets.  I didn't see any winter cancels or uncancels

might be talking about this https://twitter.com/MJVentrice/status/543155406881947648/photo/1

[GaWx]

will post a new thread on it in here for those who want to watch the video.  

 

Will check it out later, Chris.

[GaWx]

might be talking about this https://twitter.com/MJVentrice/status/543155406881947648/photo/1

 

Whether or not we get a SSW is not at all necessary to get a cold winter or a strong -AO.  That being said, we may still get it.

[deltadog03]

Will check it out later, Chris.

Sounds good, Larry..TY!

[Webberweather53]

So what's the story with all the Tweets back and forth with HM today? We in trouble?

 

Nah, we were just chatting primarily about the "strange" behavior of this El Nino event... To briefly summarize, we touched base on how this El Nino in terms of the OLR which is directly related to its zonal circulation is most reminiscent to 2012, however, the extratropics are nothing like that winter & the Pacific's +PDO state will naturally resist any attempts at trying to build up a SE US ridge as was the case in Dec & Jan 2012-13. Thus of all regions of the US, the southeast should be well-protected even if the tropical forcing is similar to 2012 as it is at the current moment. The reason the El Nino is struggling stems from a weak & rather confused Walker Cell, where we're actually observing anomalous upper level convergence west of the international dateline, and by virtue of Dine's Compensation & mass continuity, this causes the air to sink & diverge near the surface, leading to overall downward motion which in this case greatly disrupted the MJO & along w/ the partial decoupling from the faster moving CCKW led to an overall de-amplificatin of the MJO as it started to encroach on the central Pacific (MJO phase 7).

 

You can easily pick out the anomalous "brick wall" in upper level convergence denoted by the bright band of westerlies orientated vertically sitting just to the west (left) of the International Dateline (180E).

(Blue= anomalous upper level easterlies, Yellow/Orange/Red= anomalous upper level westerlies) 

 

 

Sure, we can conclude that Mixed Rossby Gravity & Rossby Waves are contributing to these westerly winds here, but I think it has more to do w/ a fundamental problem that's been evident not just this year but over the last few decades or so, especially in following the "Super" El Nino of 1997-98. The westward propagating, near-just off equatorial Rossby Waves which carried the displaced warm water in the NINO region & returned it back to the West Pacific warm pool, but in doing so, some of the water is able to seep westward through relative "pores" in the loose conglomerate of landmasses that make up the Maritime Continent & emerge into the Indian Ocean through a process that is called Indonesian throughflow. This water is circulated throughout the global thermohaline circulation (that's based on differences in water density due to temperature & especially salinity) & thus ENSO, particularly on longer timescales does effect the overall oceanic heat conveyor system & can have some resonance on the longer term climate. Of course, I'm still unsure of what other physical mechanisms are promoting continued warming of the Indian Ocean, but the warm Indian Ocean is disrupting this El Nino event (& likely didn't help out w/ 2012 either) & is a primary reason why we are seeing the upper level convergence west of the Dateline in the Tropical Pacific. The warm SSTs in the Indian Ocean is promoting upward motion in this area of the world, & instead of a predominant wavenumber 1 (i.e. one area of upward & downward motion), the rising air over the IO is enforcing a less robust wavenumber 2 pattern, and because the scale of the equatorial region is finite, this causes a contraction of an already displaced & weakened Walker Cell, forcing upper level convergence that usually is found over the maritime continent to instead be shoved further east out into the Pacific because the ambient convective activity here w/ its associated upper level divergence (in relation to the Pacific, upper level westerlies) is counteracting/destructively interfering with the upper level easterlies that are originating from the east-central equatorial Pacific.

 

The OLR over the last 60 days shows the Indian Ocean has been quite active of late & the region of +OLR in association w/ the large-scale upper level convergence in the West-Central Eq Pacific is also evident.

 

 

 

200mb VP. Lots of upper level divergence over the Indian Ocean & it is currently exhibiting a stronger signal than the eastern Pacific, which doesn't bode well for the ongoing El Nino, but we're at such a late stage that even if the El Nino tries to fade as rapidly as 2012-13 the lagged atmospheric response it's pretty much too late & we're stuck w/ this ENSO base state...

 

The entire general circulation is shifted to the east of what's typically observed in a more "typical" El Nino & downward motion is generally ongoing over the central Pacific, that's certainly not a modoki-look as some mets were blindly touting earlier this summer/fall

 

It's also obvious the El Ninos since the 1997-98 event have been hampered by the Indian Ocean, which as a whole like this year has expressed more dominant fingerprints in upper levels than the eastern Pacific, where as the pre 1997-era El Ninos were completely in control w/ a very robust upper level signature over the central-eastern Pacific & the Indian Ocean's influence was comparatively non-existent.

[deltadog03]

great post Eric!!

[Jon]

In other news the NAO goes negative on the 00z GFS run near Christmas, something we haven't really seen in the models yet if I recall. Most models and their ensemble means have been near neutral or slightly above for this time period. It will [most likely] change with the next run but what the hay.

 

Mean says no:

[burgertime]

In case no one had guessed the Euro just looked "meh" last night in the LR. As others have said there is no reason to get hung up on a 10 day forecast it will change. 

[beanskip]

Headed back up to N.C. Christmas week -- my excitement for a possible event is tempered by the reality that cold air will not be readily available. 

[Cold Rain]

Sounds like at least some level of backing off on the strat progress, but that waxes and wanes....and it sounds like the nino is not acting like a west based nino...that's my best shot at trying to interpret those tweets.  I didn't see any winter cancels or uncancels

 

 

Lots of stuff

Thanks guys. So, unraveling all of that, it sounds like for whatever reason, the Indian Ocean is interfering with the development of El Nino, and El Nino is not acting like a central based one...it's acting more east based.

Given that, should this negatively impact the overall expectation of a colder, stormier January and February?

Going from memory, an east based Nino is not as favorable as a west based or central based for the SE. However, in Eric's post, he indicated that the SE should not succumb to a SE ridge, so that sounded good.

[WidreMann]

In case no one had guessed the Euro just looked "meh" last night in the LR. As others have said there is no reason to get hung up on a 10 day forecast it will change.

We only say that when it shows something bad.

It's so weird to see that decently strong high pressure at the pole and yet such a crappy pattern over NA.

[burgertime]

We only say that when it shows something bad.

It's so weird to see that decently strong high pressure at the pole and yet such a crappy pattern over NA.

 

Well in my defense I do usually try to say when a threat is ten days away that it'll change.....but who wants to hear that. All aboard the snow train!!!!!11!!111!!!

 

I still think Christmas and beyond is the best bet....but it'll really suck if we get to Christmas and we're saying Jan 5th and beyond is when it will all start. 

[WSNC]

In case no one had guessed the Euro just looked "meh" last night in the LR. As others have said there is no reason to get hung up on a 10 day forecast it will change.

22 of the Euro ensemble members showed snow next weekend in Winston-Salem on the most recent 0z run vs zero from yesterday's 12z run where the op went wild.

[Cold Rain]

The 0z and 6z GFS ENS start to show the pattern change shortly after D10 and evolve to a nice PNA ridge/trough east by D15. Still showing a favorable look for cold. No helpful -NAO, though.

The D10 Euro ENS mean isn't far off from the 0z GFS mean. I can't see how it evolves after though. The 0z and 6z GFS Ops are a hot mess through the entire run, if you look at H5. The Euro at D10 still looks like trash too, if you're hoping for the favorable "teleconnection" pattern.

12/20 was the first target date. That will be a fail.

12/25 up next.

[SnowNiner]

The 0z and 6z GFS ENS start to show the pattern change shortly after D10 and evolve to a nice PNA ridge/trough east by D15. Still showing a favorable look for cold. No helpful -NAO, though.

The D10 Euro ENS mean isn't far off from the 0z GFS mean. I can't see how it evolves after though. The 0z and 6z GFS Ops are a hot mess through the entire run, if you look at H5. The Euro at D10 still looks like trash too, if you're hoping for the favorable "teleconnection" pattern.

12/20 was the first target date. That will be a fail.

12/25 up next.

 

Well, I've always justed hoped to see it on the models within 10 days on 12/20 then I'm straight.  If not, then I'll be inconsolable.  I can't believe we had 3 pages of posts on one run of the 10 day EURO op. 

[Brick Tamland]

I was hoping we would have something to track for next weekend. Funny how things change in less than a day. Still a lot of time to change again. But maybe it will just set the stage for something around Christmas. I have read so many folks say there is a strong signal for a good storm the week of Christmas. I think everyone is really anxious to see a viable threat to track.

[metwannabe]

The 0z and 6z GFS ENS start to show the pattern change shortly after D10 and evolve to a nice PNA ridge/trough east by D15. Still showing a favorable look for cold. No helpful -NAO, though.

The D10 Euro ENS mean isn't far off from the 0z GFS mean. I can't see how it evolves after though. The 0z and 6z GFS Ops are a hot mess through the entire run, if you look at H5. The Euro at D10 still looks like trash too, if you're hoping for the favorable "teleconnection" pattern.

12/20 was the first target date. That will be a fail.

12/25 up next.

The NAO looks to dip negative around christmas

[Southern Track]

PNA is a gamer still, the AO is mocking us, and the NAO will never go negative in DJF while I'm alive.

 

[franklin NCwx]

Euro ensembles look pretty good.

[buckeyefan1]

 

 

Thanks guys. So, unraveling all of that, it sounds like for whatever reason, the Indian Ocean is interfering with the development of El Nino, and El Nino is not acting like a central based one...it's acting more east based.

Given that, should this negatively impact the overall expectation of a colder, stormier January and February?

Going from memory, an east based Nino is not as favorable as a west based or central based for the SE. However, in Eric's post, he indicated that the SE should not succumb to a SE ridge, so that sounded good.

To the first bolded......This seems to be the theme for this decade      

To the second bolded.....indeed     

[Bob Chill]

12/20 was the first target date. That will be a fail.

12/25 up next.

I suppose it depends on how you look at it. 12/20 is still spot on for beginning of ridging building in the west and getting the hideous vortex out of the GOA. That's the single most important thing to not fail and it's becoming fairly certain that it's going to happen and be on time. Considering how hostile of a snow pattern we're in, it's going to take some time to reshuffle things.

Looks like 2 storms will affect the east coast during the 12/20-25 time frame (and probably another 1 or 2 during the 25-31st). I look at the first 2 like bonus opportunities because you can't rule snow out with the setup and neither of our regions do particularly well when transitioning from a crappy pac air pattern. Just a hunch but one of these storms this month is going to push the NAO over the edge into neg territory.

We should be loving the southern track going on right now. We haven't seen anything like it since 09-10 (not an analog. lol).

[buckeyefan1]

I suppose it depends on how you look at it. 12/20 is still spot on for beginning of ridging building in the west and getting the hideous vortex out of the GOA. That's the single most important thing to not fail and it's becoming fairly certain that it's going to happen and be on time. Considering how hostile of a snow pattern we're in, it's going to take some time to reshuffle things.

Looks like 2 storms will affect the east coast during the 12/20-25 time frame (and probably another 1 or 2 during the 25-31st). I look at the first 2 like bonus opportunities because you can't rule snow out with the setup and neither of our regions do particularly well when transitioning from a crappy pac air pattern. Just a hunch but one of these storms this month is going to push the NAO over the edge into neg territory.

We should be loving the southern track going on right now. We haven't seen anything like it since 09-10 (not an analog. lol).

I agree(as if you didn't know that already   )   ...........Preach it Bob   

[Cold Rain]

The NAO looks to dip negative around christmas

So here are three charts right at Christmas:

The first is the 6z GFS ENS Mean at 324. It shows maybe a slight bit of ridging near Greenland, but the H5 look says +NAO. Numerically, I'm not sure what the output is, but there is no helpful -NAO effect from that look:

The second image is the 6z GFS Op at 324. It's not too dissimilar. Again, no helpful -NAO effect which could act to slow down the jet:

Lastly, here is the 6z GFS Op at 384. You can see a north Atlantic ridge. I think numerically, it would qualify as a -NAO. But as we continue to observe year after year, this type of -NAO (which is the only one that shows up in the winter time), isn't very helpful to us:

This chart might look like a step in the right direction, but I would rate the actual value secondary to the H5 look:

[Cold Rain]

I suppose it depends on how you look at it. 12/20 is still spot on for beginning of ridging building in the west and getting the hideous vortex out of the GOA. That's the single most important thing to not fail and it's becoming fairly certain that it's going to happen and be on time. Considering how hostile of a snow pattern we're in, it's going to take some time to reshuffle things.

Looks like 2 storms will affect the east coast during the 12/20-25 time frame (and probably another 1 or 2 during the 25-31st). I look at the first 2 like bonus opportunities because you can't rule snow out with the setup and neither of our regions do particularly well when transitioning from a crappy pac air pattern. Just a hunch but one of these storms this month is going to push the NAO over the edge into neg territory.

We should be loving the southern track going on right now. We haven't seen anything like it since 09-10 (not an analog. lol).

I almost posted the 12/20 maps. Still a bit of work to be done to get the ridge up, but I can see what you're saying about that being the beginning of the process. My target dates were mostly in jest. It is still clear on virtually all of the guidance that I saw that the ridging idea is still fully a go. I agree, it's the most important piece of the puzzle right now. We've got to halt the Pac jet.

[Shawn]

from 00z Euro: 8 members for rock hill & 12 for GSP have wintry weather.  Only two for KCAE.. so there is still some hope for some further North than my back yard possibly.

[Southern Track]

I suppose it depends on how you look at it. 12/20 is still spot on for beginning of ridging building in the west and getting the hideous vortex out of the GOA. That's the single most important thing to not fail and it's becoming fairly certain that it's going to happen and be on time. Considering how hostile of a snow pattern we're in, it's going to take some time to reshuffle things.

Looks like 2 storms will affect the east coast during the 12/20-25 time frame (and probably another 1 or 2 during the 25-31st). I look at the first 2 like bonus opportunities because you can't rule snow out with the setup and neither of our regions do particularly well when transitioning from a crappy pac air pattern. Just a hunch but one of these storms this month is going to push the NAO over the edge into neg territory.

We should be loving the southern track going on right now. We haven't seen anything like it since 09-10 (not an analog. lol).

Thanks Bob,  I need all the love I can handle.

[Jon]

So here are three charts right at Christmas:

The first is the 6z GFS ENS Mean at 324. It shows maybe a slight bit of ridging near Greenland, but the H5 look says +NAO. Numerically, I'm not sure what the output is, but there is no helpful -NAO effect from that look:

gfs-ens_z500_mslp_nhem_55.png

The second image is the 6z GFS Op at 324. It's not too dissimilar. Again, no helpful -NAO effect which could act to slow down the jet:

gfs_z500_mslp_nhem_44.png

Lastly, here is the 6z GFS Op at 384. You can see a north Atlantic ridge. I think numerically, it would qualify as a -NAO. But as we continue to observe year after year, this type of -NAO (which is the only one that shows up in the winter time), isn't very helpful to us:

gfs_z500_mslp_nhem_49.png

This chart might look like a step in the right direction, but I would rate the actual value secondary to the H5 look:

nao_sprd2.gif

Good post.

 

The 06z GEFS actually shows a -NAO after Christmas, but I know what you mean by looking at the H5.

 

This will keep going from negative to neutral to negative to neutral until we get closer. The 0z GFS OP was a -NAO I don't know if you saw that, but the mean was slightly positive.

 

You can see from the 06z GEFS output a lot of the members go neutral to negative around Christmas

 

 

It's splitting hairs really until we get a constant progged -NAO showing up and that won't happen probably until after mid month but I like what I see.