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Medium Range-Long Range thread


NaoPos

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This week- cold, Stormy on the 25th. 

Next week- Slow warm up

Week of Feb 4- cold

Week of Feb 11- slightly below normal, back and forth

Week of Feb 18-  normal to slightly above normal, SE ridge, dump of cold into west. 

 

quite a bit of storminess as well. 

thanks mitchell i appreciate it. Looks like the weeklies are matching up well with the mjo. As adam said looks like 2nd half of february will get warmer as the mjo progresses into warmer phases.

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Looks like many of the MJO models are reacting to the stratospheric warming HM was talking about pushing it into Phase 8. Example - 

 

I don't think they are picking up on that as much as the situation described for the last two weeks (MJO against stagnant walker).

 

The MJO should ultimately get back to phase 1 as we close January. There is a very strong amount of westerlies being added to the system right now with the ridiculous west pac anticyclone being replaced with a cyclone finally. The anticyclone has been successfully shoved east toward Hawaii. The stratosphere/30mb level remains warmer than normal over the W PAC / Indonesia but all other regions have cooled due to the stratospheric warming.

 

I still like where we stand for early Feb in terms of the Tropical Pacific. What I don't like are the trends in the polar stratosphere to reorganize the potential vorticity over the North Atlantic in 10 days.

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I don't think they are picking up on that as much as the situation described for the last two weeks (MJO against stagnant walker).

 

The MJO should ultimately get back to phase 1 as we close January. There is a very strong amount of westerlies being added to the system right now with the ridiculous west pac anticyclone being replaced with a cyclone finally. The anticyclone has been successfully shoved east toward Hawaii. The stratosphere/30mb level remains warmer than normal over the W PAC / Indonesia but all other regions have cooled due to the stratospheric warming.

 

I still like where we stand for early Feb in terms of the Tropical Pacific. What I don't like are the trends in the polar stratosphere to reorganize the potential vorticity over the North Atlantic in 10 days.

what do you mean by that? Are you saying that they are showing the pv shifting to unfavorable position?

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what do you mean by that? Are you saying that they are showing the pv shifting to unfavorable position?

 

Yes.

 

The good news is that downward momentum from the westerly jet stream in the stratosphere is not going to be at t=0 because of the recent SSW. We can still get a tropospheric -NAO response in early Feb, due to the Tropical Pacific junk. It would just be a lot easier if we didn't have a PV trying to reconsolidate in the North Atlantic up above.

 

Ultimately, it will get a tropospheric response and most likely end our winter stretch, as Adam already stated in the thread. However, it probably isn't the end of winter (like last year ended up) either. Although, admittedly, I am a little more concerned today than I was in the past 2 weeks about March.

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You're more of a stratopsheric expert than I am, but isn't there a concern for an early final warming (and therefore warm early spring) given the massive PV disruption we've had this year?

 

If that's true, then we are all marooned. lol

 

It's not the early final warming that's the impetus for a warm March as much as it is the PV reload after the mid-winter SSW. The exact way the SSW manifests and how slowly the breakdown is will determine how early the FW will be (usually they come early during winters that lack early to mid winter disturbances but there is also decadal variability too that has to be factored in). So the last couple of years have been classic because you had early and/or mid winter warmings and then a strengthening from top-down of the positive NAM. This usually leads to a +AO tendency and peak leading up the FW date (as you saw from the blog article). You also knew from other factors that the stratosphere would do this too (QBO, ENSO, SOLAR states).

 

This year isn't as clear cut actually. There is still a downward -QBO shear stress working on the Tropics, neutral ENSO with a possible el nino-like intraseasonal state starting now and a weak solar state. The SSW was stronger this year with a u-wind response but the effects have been immediate in the troposphere and PV anomalies have been hanging on. We are also seeing the top rebuild. What we need is continued warming disturbances, albeit subtle, to continue getting -AO periods through March; otherwise, the PV may rebuild and take control of the NAM for March.  

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So the last couple of years have been classic because you had early and/or mid winter warmings and then a strengthening from top-down of the positive NAM. This usually leads to a +AO tendency and peak leading up the FW date (as you saw from the blog article). You also knew from other factors that the stratosphere would do this too (QBO, ENSO, SOLAR states).

Gotcha. This is the process I was thinking about

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MJO models are now pretty definite about going into phase 8. It was only a little while ago when the models were predicting a loop in Phase 6 and 7 and then a crash into the circle of death.. Hope it produces a significant storm early February.

Which is why you shouldn't rely on dynamical models for MJO forecasts

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Which is why you shouldn't rely on dynamical models for MJO forecasts

Basically I have been following them for only a short period but I know the models are only as good as the number of variables included and the quality of real time data allow. It will be interesting to see a fairly impressive impulse make it into Phase 8 and see if it has the correlated affects in the east CONUS as advertised..

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Basically I have been following them for only a short period but I know the models are only as good as the number of variables included and the quality of real time data allow. It will be interesting to see a fairly impressive impulse make it into Phase 8 and see if it has the correlated affects in the east CONUS as advertised..

the roundy one has nailed the the cycle around. Granted the strength of the wave was off but it showed a complete cycle around to phase 2-3

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the roundy one has nailed the the cycle around. Granted the strength of the wave was off but it showed a complete cycle around to phase 2-3

But, at the same time, it's why you shouldn't rely on statistical models alone, either. As with anything else, just popping up one particular solution and leaning on it will get you in to trouble. I obviously had some skepticism last week about the MJO progression after the models showed what they showed.

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But, at the same time, it's why you shouldn't rely on statistical models alone, either. As with anything else, just popping up one particular solution and leaning on it will get you in to trouble. I obviously had some skepticism last week about the MJO progression after the models showed what they showed.

So what approach do you take then? Do you just pull up the daily maps in the tropics and see how strong the wave is?

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So what approach do you take then? Do you just pull up the daily maps in the tropics and see how strong the wave is?

I use everything I can (dynamical models, statistical models, theory, AAM, strat temps when I remember). Nothing really forecasts the MJO well, so it's one of the places where you can add a lot of value

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Well this was definitely an example of using both your "chops" and the tools available. The KW analysis by Mike was good and recognizing that the easterly propagation is usually underdone, especially in a year like this one, on the modeling. At the same time, this is quite a battle going on with the old walker regime and stratosphere, so you knew there was something to the dynamical forecasts, but just that they were too extreme.

 

A compromise of those thoughts would give you what we are seeing on the charts this week and the wild weather pattern next week. The great news is that some wintry octants are on the way as we end the month and start Feb.

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so in summary it looks like brief warm-up next week before cold makes a return heading into Feb.

 

D6.gif

 

 

D10.gif

Yeah, its been kind of consistent for a while with both ends of the solution. I would imagine that this afternoon or tomorrow, the NAEFS week 2 cold probabilities will join the party and the bike will get stuck in the icy mud again.

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