Medium Range-Long Range thread

[tombo82685]

according to adam " the euro weeklies are -nao forever and ever"

[Porsche]

At what point do we even trust 10 + days out, I mean I've heard so many false alarms as to how things look good around a certain time period then 2 days later it doesn't pan out.  I know everyone talks about the NAO, PNA, AO, etc...... and it just doesn't seem to matter, I'm not throwing this week or the next out, but things don't look as promising.

[blinkers88]

At what point do we even trust 10 + days out, I mean I've heard so many false alarms as to how things look good around a certain time period then 2 days later it doesn't pan out.  I know everyone talks about the NAO, PNA, AO, etc...... and it just doesn't seem to matter, I'm not throwing this week or the next out, but things don't look as promising.

Just because conditions are favorable doesn't mean there has to be a storm

[Isotherm]

ECMWF ensemble mean for 120hrs, this Saturday.

NOT a conducive H5 synoptic set-up for east coast snowstorms. Monster trough in the Western US, SE ridge heights extending nwd into the Hudson Bay fake block, and low heights in Greenland.




Note the major changes by 240hrs. Height rises across the Arctic/NATL with more expansive/efficient blocking and consequently you've got the troughiness bellying underneath into the East. This is a set-up with loaded potential if it comes to fruition.


 

[tombo82685]

At what point do we even trust 10 + days out, I mean I've heard so many false alarms as to how things look good around a certain time period then 2 days later it doesn't pan out.  I know everyone talks about the NAO, PNA, AO, etc...... and it just doesn't seem to matter, I'm not throwing this week or the next out, but things don't look as promising.

This is my thoughts right now. Friday I think there will be some lgt snow or ice over the region, should be 3 inches or less for the places that stay snow. The weekend threat, has low potential. The problem with that setup is the low moving across the center of the country lifts north then gets blocked do to the block to the north. So it basically just rots there. While this is happening the 50/50 low is slowly lifting out. If you look on the h5 map you can see the ridge out ahead of the low that cuts to the north basically links up with the block over hudson bay. A hudson bay block to me isn't i deal, seems to far west for us. You want something that pushes into the davis straights.

The whole issue is the Pacific, which is supported by the mjo phases right now. The -pna setup allows the trofs to dive down in the western US. They then come out amplify and lift north which pumps up the se ridge. Now if you had a solid block that can mitigate that and cause it to push under it. Down the road if the mjo prospects are correct and it goes into the COD the influence of the mjo becomes limited. If the -nao prospects are correct we should see threats start appearing after the 27th storm. The -nao has the most influence in our pattern in the late winter. Should mention i wouldn't rule out wintry threats before that because models have a tough time with this blocky pattern. We have seen a good amount of times where they drive a storm up into for days but as we get closer it starts to catch onto things and adjust it south.

[CooL]

GEFS are mouth watering..There is a block on the maps right now but it's not locking in any confluence for us yet..That might come as we get into next week as the block gets refueled. We are going to have our chances

[Bobby EPAWA]

From GaWx in the SE US thread:  EPS weekly control for today - can we lock it up please?  lol...:

 

"Week #2 (2/25-3/3) confirms the cold coming in near 3/1 that is on just about all models now. Week #3 (3/4-10) is solidly cold (actually throughout nearly the entire country). Week #4 (3/11-17) is slightly colder than normal.

 

Precip.: week 2 wetter than normal. Weeks 3 and 4 near normal. Normal March rainfall is rather significant. So, near normal is rather wet. At the risk of being criticized, I'll mention that week #'s 3's precip. pattern showing slightly wetter than normal in the NE GOM (a precip. anomaly max) and then east of NC/VA in a long band as well as slight dryness in the Ohio Valley while it is solidly cold in the SE, at least suggests a chance for a Miller A SE snowstorm somewhere around 3/3-7. We'll see.

 

Pattern: Weeks 2-4 pretty strong west based -NAO. I have a feeling it will finally materialize (based on cold analogs).

Weeks 2-4 mostly a fairly weak -AO.

Weeks 2-3 nice +PNA. Week 4 pretty neutral PNA."

[HM]

Just a word of advice: The "MJO" right now is being analyzed in phase 4 but I don't think this represents the current situation well. It is another issue of KW activity muddying up the signal, similar to mid-late December. Keep this in mind for those of you using it to possibly forecast a return of a "-NAO/+PNA wintry pattern" in March, anticipating this thing simply propagates out of "phase 4-5-6" etc.<br /><br />It is quite possible the charts will show another "loop" as they try to resolve this KW/MJO interaction and the "MJO" stays in the "bad phases" through much of early-mid March.

[am19psu]

Just a word of advice: The "MJO" right now is being analyzed in phase 4 but I don't think this represents the current situation well. It is another issue of KW activity muddying up the signal, similar to mid-late December. Keep this in mind for those of you using it to possibly forecast a return of a "-NAO/+PNA wintry pattern" in March, anticipating this thing simply propagates out of "phase 4-5-6" etc.<br /><br />It is quite possible the charts will show another "loop" as they try to resolve this KW/MJO interaction and the "MJO" stays in the "bad phases" through much of early-mid March.

Nuh-uh. I heard it's going to Phase 8 next week!!!11!1

[famartin]

Nuh-uh. I heard it's going to Phase 8 next week!!!11!1

Go to the NYC subforum and tell them the bad news

[tombo82685]

Just a word of advice: The "MJO" right now is being analyzed in phase 4 but I don't think this represents the current situation well. It is another issue of KW activity muddying up the signal, similar to mid-late December. Keep this in mind for those of you using it to possibly forecast a return of a "-NAO/+PNA wintry pattern" in March, anticipating this thing simply propagates out of "phase 4-5-6" etc.<br /><br />It is quite possible the charts will show another "loop" as they try to resolve this KW/MJO interaction and the "MJO" stays in the "bad phases" through much of early-mid March.

How do you think march plays out? The weeklies were pretty bullish on the -nao as was stated by Adam. Do we wait till the mjo starts to cooperate or at least gets in the COD for its effects to be reduced?

[HM]

 

Nuh-uh. I heard it's going to Phase 8 next week!!!11!1

 

lol

Clearly the situation through the next week or so represents phase 3 more than anything (certainly hybrid and not clear-cut). Do we suspect the modeling will turn warmer in the extended once this KW--MJO situation becomes cohesive?

[am19psu]

  

lol

Clearly the situation through the next week or so represents phase 3 more than anything (certainly hybrid and not clear-cut). Do we suspect the modeling will turn warmer in the extended once this KW--MJO situation becomes cohesive?

That's what I keep saying, since there is usually a +NAO response to P4-P5, but it's obviously not showing up on the Euro weeklies, which are just -NAO forever and ever. Of course, it's just as possible that the weeklies are doing a poor job of responding the the KW activity.

 

P.S. That KW over the EPAC at 150W sure is energizing the southern stream, ain't it?

[NaoPos]

By the way, anyone have composites for march and MJO phases?

[am19psu]

By the way, anyone have composites for march and MJO phases?

http://raleighwx.americanwx.com/MJO.html

[HM]

 

How do you think march plays out? The weeklies were pretty bullish on the -nao as was stated by Adam. Do we wait till the mjo starts to cooperate or at least gets in the COD for its effects to be reduced?

 

It's not that simple; so, when you see others on the forum suggesting that, correct them immediately!

Sometimes the MJO goes into the COD because of conflicting waves, separating certain factors away from each other or broadening the signal. But that doesn't mean there isn't forcing/convection somewhere affecting the Mid Latitude pattern. I know I was a proponent of a -NAO but I didn't think it would last through mid-March either and still don't. Once the blocking breaks down in early March, I suspect we grow warm. I could see the first 10 days averaging like +2 or so and then taking off from there (exceeding +4). A possible +AO / unfavorable MJO juxtaposition may occur for a time mid-month but I don't think it will last long.

Until the blocking is dismantled, the risk for a coastal storm / wet snowstorm exists. Obviously, interior areas are most favored.

[tombo82685]

  

It's not that simple; so, when you see others on the forum suggesting that, correct them immediately!

Sometimes the MJO goes into the COD because of conflicting waves, separating certain factors away from each other or broadening the signal. But that doesn't mean there isn't forcing/convection somewhere affecting the Mid Latitude pattern. I know I was a proponent of a -NAO but I didn't think it would last through mid-March either and still don't. Once the blocking breaks down in early March, I suspect we grow warm. I could see the first 10 days averaging like +2 or so and then taking off from there (exceeding +4). A possible +AO / unfavorable MJO juxtaposition may occur for a time mid-month but I don't think it will last long.

Until the blocking is dismantled, the risk for a coastal storm / wet snowstorm exists. Obviously, interior areas are most favored.

 

So what you mean is if there are two waves present and one is in phase 4 and the other in phase 7, the mjo may go into the COD because they conflict each other? What would be the best way to determine that? Looking at roundy or where convection is firing? Is there any model that reduces that noises of conflicting signals?

[tombo82685]

http://raleighwx.americanwx.com/MJO.html

lol after looking at those we are basically looking right down the barrel of a flame thrower. Just need that person to pull the trigger..

[HM]

 

So what you mean is if there are two waves present and one is in phase 4 and the other in phase 7, the mjo may go into the COD because they conflict each other? What would be the best way to determine that? Looking at roundy or where convection is firing? Is there any model that reduces that noises of conflicting signals?

Mike's website has a large amount of data tackling this very issue. I sure hope he responds (if not go back and read his thoughts when the last conflict happened in late Jan). As for Roundy, he offers this filter for the MJO only (it's the link under the main link you probably usually click):

http://www.atmos.albany.edu/facstaff/roundy/waves/hovsdetmjo/7.5S_7.5N/2013.png

[tombo82685]

 

Mike's website has a large amount of data tackling this very issue. I sure hope he responds (if not go back and read his thoughts when the last conflict happened in late Jan). As for Roundy, he offers this filter for the MJO only (it's the link under the main link you probably usually click):

http://www.atmos.albany.edu/facstaff/roundy/waves/hovsdetmjo/7.5S_7.5N/2013.png

Thank you.. I always see you talking about kelvin waves. How do you understand kelvin waves and what not? How do you know that a kelvin wave is the noise and not the mjo and vice versa? What are the importance of kelvin waves to a pattern?

[HM]

 

That's what I keep saying, since there is usually a +NAO response to P4-P5, but it's obviously not showing up on the Euro weeklies, which are just -NAO forever and ever. Of course, it's just as possible that the weeklies are doing a poor job of responding the the KW activity.

 

P.S. That KW over the EPAC at 150W sure is energizing the southern stream, ain't it?

I feel the weeklies just run with a trend but I have no idea (I don't get them but hear about them). Do you feel this is a case of "ENSO modeling" where the shorter term trends dictate week 3-4?

[NJwinter23]

 

I feel the weeklies just run with a trend but I have no idea (I don't get them but hear about them). Do you feel this is a case of "ENSO modeling" where the shorter term trends dictate week 3-4?

 

I couldnt tell you for sure, but thats the reaction I had to the weeklies this morning as well. Many times this winter I can recall weeks 3 and 4 pretty much looking like shadows of the week 2 pattern.

[am19psu]

 

I feel the weeklies just run with a trend but I have no idea (I don't get them but hear about them). Do you feel this is a case of "ENSO modeling" where the shorter term trends dictate week 3-4?

In general, the Euro weeklies are the only dynamical model that even has a prayer of getting the MJO right past 7 days or so, due to the ocean-atmosphere coupling and superior tropical convection scheme. However, I have seen it get fooled in periods of strong Kelvin wave activity (hmmm...). If it gets the amplitude or wavelength of the KW wrong, it can screw up the whole forecast, imo. This is also why I don't usually believe the CFS forecasts, though since v2 came out, it's a lot better than it was.

[NaoPos]

lol after looking at those we are basically looking right down the barrel of a flame thrower. Just need that person to pull the trigger..

yeah ...phases 4-5-6 look like a furnace!

Just looking @ some of the GFS ensemble analogs on SV, they're pretty insistent on a pretty negative AO/-NAO(west based at that). 2m temps were below average as well. This was for the 6-10 day range, and 11-15 and 16-30 day outlook. They're also quite bullish with the -AO/-NAO strenghting big time in the 16-30 day range. Just throwing this out there for the disco. It seems like that would go against the MJO being in phases 4-5-6.

[HM]

 

Thank you.. I always see you talking about kelvin waves. How do you understand kelvin waves and what not? How do you know that a kelvin wave is the noise and not the mjo and vice versa? What are the importance of kelvin waves to a pattern?

A theoretical equatorial atmospheric KW has a certain wave number, amplitude and speed which differs from the MJO. Over a defined time, you can see which waves are what (and when you do this long enough, it becomes very easy to spot with a few maps). Mike has an excellent page for you to use to help you see them:

http://mikeventrice.weebly.com/tropical-waves.html

Here is an oldie:

http://cawcr.gov.au/staff/mwheeler/maproom/OLR_modes/

I would recommend you do the COMET Tropical Module because it goes over every type of wave.

[Mike.Ventrice]

  

It's not that simple; so, when you see others on the forum suggesting that, correct them immediately!

Sometimes the MJO goes into the COD because of conflicting waves, separating certain factors away from each other or broadening the signal. But that doesn't mean there isn't forcing/convection somewhere affecting the Mid Latitude pattern. I know I was a proponent of a -NAO but I didn't think it would last through mid-March either and still don't. Once the blocking breaks down in early March, I suspect we grow warm. I could see the first 10 days averaging like +2 or so and then taking off from there (exceeding +4). A possible +AO / unfavorable MJO juxtaposition may occur for a time mid-month but I don't think it will last long.

Until the blocking is dismantled, the risk for a coastal storm / wet snowstorm exists. Obviously, interior areas are most favored.

 

 

So what you mean is if there are two waves present and one is in phase 4 and the other in phase 7, the mjo may go into the COD because they conflict each other? What would be the best way to determine that? Looking at roundy or where convection is firing? Is there any model that reduces that noises of conflicting signals?

 

 

 

Mike's website has a large amount of data tackling this very issue. I sure hope he responds (if not go back and read his thoughts when the last conflict happened in late Jan). As for Roundy, he offers this filter for the MJO only (it's the link under the main link you probably usually click):

http://www.atmos.albany.edu/facstaff/roundy/waves/hovsdetmjo/7.5S_7.5N/2013.png

 

 

Thank you.. I always see you talking about kelvin waves. How do you understand kelvin waves and what not? How do you know that a kelvin wave is the noise and not the mjo and vice versa? What are the importance of kelvin waves to a pattern?

 

So many great topics! I will definitely share some thoughts when I have more time to compose them. For now, there is a clear-cut MJO (especially in 850 hPa velocity potential) signal that as HM states has CCKW contributions that is centered just west of 120E... so I believe we are currently in a wheeler and hendon phase 3 state, soon entering a phase 4 state. However, the extratropical circulation is not aligning properly (yet) with the current evolution of convection in the tropics. The GFS operation (at least) doesn't have a good handle on the eastward propagating signal at the moment.. which is contributing to some uncertainty in the northeast pacific ridge. However the past big snow storms we've seen over the north east U.S. (and just off the coast) really threw a good deal of mass towards the poles and built that strong -NAO blocking ridge west of Greenland. So to make matters worse than just model preditability issues, there could be issues with the atmosphere "memory" and our human brains (especially mine!) expecting that warm conditions should dominate early march. In agreement with HM, I feel that a warm northeast U.S. will materialize by the second week of March... But I am beginning to see some signs for a colder-than average April over much of the northeast... No real confidence in that yet of course but will update with time.

 

 

As for interpreting the real-time multivariate MJO indices being a true MJO, or noise produced by other features such as convectively coupled equatorial waves (most pronounced is the CCKW)... I will try to write up a brief post later in the afternoon. 

[tombo82685]

 

A theoretical equatorial atmospheric KW has a certain wave number, amplitude and speed which differs from the MJO. Over a defined time, you can see which waves are what (and when you do this long enough, it becomes very easy to spot with a few maps). Mike has an excellent page for you to use to help you see them:

http://mikeventrice.weebly.com/tropical-waves.html

Here is an oldie:

http://cawcr.gov.au/staff/mwheeler/maproom/OLR_modes/

I would recommend you do the COMET Tropical Module because it goes over every type of wave.

Lol why when i read that stuff or look at it i feel like banging my head against a wall. You guys are going to have to dumb it down for me and I assume others who want to learn to figure this out. Which map on Mike's page shows the kelvin waves? I see the phase diagram map for kelvin waves under that. Is There a particular phase that leads to something of importance to us or what not?

[HM]

 

So many great topics! I will definitely share some thoughts when I have more time to compose them. For now, there is a clear-cut MJO (especially in 850 hPa velocity potential) signal that as HM states has CCKW contributions that is centered just west of 120E... so I believe we are currently in a wheeler and hendon phase 3 state, soon entering a phase 4 state. However, the extratropical circulation is not aligning properly (yet) with the current evolution of convection in the tropics. The GFS operation (at least) doesn't have a good handle on the eastward propagating signal at the moment.. which is contributing to some uncertainty in the northeast pacific ridge. However the past big snow storms we've seen over the north east U.S. (and just off the coast) really threw a good deal of mass towards the poles and built that strong -NAO blocking ridge west of Greenland. So to make matters worse than just model preditability issues, there could be issues with the atmosphere "memory" and our human brains (especially mine!) expecting that warm conditions should dominate early march. In agreement with HM, I feel that a warm northeast U.S. will materialize by the second week of March... But I am beginning to see some signs for a colder-than average April over much of the northeast... No real confidence in that yet of course but will update with time.

 

 

As for interpreting the real-time multivariate MJO indices being a true MJO, or noise produced by other features such as convectively coupled equatorial waves (most pronounced is the CCKW)... I will try to write up a brief post later in the afternoon. 

Mike thanks for the information. Looking forward to the post later today. Is it possible the extratropical circulations are not aligning properly due to the KW issues we've described? I feel like the off-equatorial, antisymmetric RW/MRG waves are through the roof along with the KW issues.

[HM]

 

Lol why when i read that stuff or look at it i feel like banging my head against a wall. You guys are going to have to dumb it down for me and I assume others who want to learn to figure this out. Which map on Mike's page shows the kelvin waves? I see the phase diagram map for kelvin waves under that. Is There a particular phase that leads to something of importance to us or what not?

Kelvin Waves are faster and shallower than the MJO but occasionally can overlap in things like power spectrum etc. (they also both are easterly waves while things like RWs propagate toward the west). But they both operate similarly in what to look for on a map during enhanced phases (low level convergence / upper level divergence / convection). Currently there is a KW about to enter the IO from Africa. There is also a coherent MJO signal in the eastern IO. Active MJO waves will tend to excite and slow down an oncoming KW, esp. in the IO. This KW will affect Mid Latitude circulation, similiarly to the MJO, through outflow wind / latent heat release and residual tropical cyclonic anomalies (time scale just may be briefer than a typical MJO).

Since the IO will become excited by this over the next week, the Mid Latitude circulation may appear more like a hybrid (phase 3-4 type of look) before possibly settling comfortably into the phase 4-5 look in March.

On Mike's site, you want to go to the diagrams that plot KW waves (dashed blue or black lines for CCKW) to see how they propagate and interact with the MJO. You can also use his filter VP maps to see each type of wave.

For example, here is just h2 VP anomalies for KW, only, showing the African wave and leading W PAC wave:

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/vp.filt.anom.90.5S-5N.png

Here is how the total VP picture is broken down by each wave (third image is KW):

http://www.atmos.albany.edu/student/ventrice/real_time/maps/waves/global/28.gif

You should give this a read too, if you have the time:

http://www.atmos.albany.edu/facstaff/roundy/kelvinmod.pdf

[CooL]

 

I feel the weeklies just run with a trend but I have no idea (I don't get them but hear about them). Do you feel this is a case of "ENSO modeling" where the shorter term trends dictate week 3-4?

 

Any thoughts about the early March potential?