Atlantic Tropical Action 2012 - Part I

[Mike.Ventrice]

Mike,

Dr. Roundy's products are showing a Kelvin wave moving through 90-100W this weekend, which I assumed was the trigger for the potential cyclogenesis seen in the models. Over the last three years, since I started following Dr. Roundy's forecasts, these KW events have been able to overcome neutral, or even negative, MJO conditions. I'm not in the cyclogenesis camp right now, but the KW at least gives me pause. Since you are researching this stuff, I figured you might have a better idea than me.

P.S. I like the VP200 calculations. It's easier to diagnose than OLR.

Ah yes, Paul's analysis does show active convection associated with Kelvin wave propagating eastward across the East Pac-Carib. between June 13-19. The convectively active phase of a strong eastward propagating Kelvin wave can occasionally overcome the net suppressed phase of an MJO event for a period of a few days. While the chance of a developing tropical cyclone will increase with the passage of this Kelvin wave over the Eastern Pacific (since the East Pac is more of a favorable Basin for developing TCs than the Atlantic), it becomes less likely that this Kelvin wave will induce any developing disturbances over the Atlantic. The strongest convectively-coupled Kelvin waves are the ones that are in phase with convectively active MJO phase (i.e., RMM phases 1-3). The Atlantic tropical cyclogenesis-Kelvin wave relationship that I found over the Atlantic tends to hold true for times when the convectively active phase of the MJO is also located over the Atlantic. I illustrated this in a paper that is currently in the early-online-release state: http://journals.ametsoc.org/doi/pdf/10.1175/MWR-D-11-00305.1

[Mike.Ventrice]

Mike,

Dr. Roundy's products are showing a Kelvin wave moving through 90-100W this weekend, which I assumed was the trigger for the potential cyclogenesis seen in the models. Over the last three years, since I started following Dr. Roundy's forecasts, these KW events have been able to overcome neutral, or even negative, MJO conditions. I'm not in the cyclogenesis camp right now, but the KW at least gives me pause. Since you are researching this stuff, I figured you might have a better idea than me.

P.S. I like the VP200 calculations. It's easier to diagnose than OLR.

To further comment on Paul's statistical approach, a graduate student here at the University at Albany, Kyle McRitchie, has applied Pauls EEOF analysis on the CFS forecasts:

http://www.atmos.albany.edu/student/macritch/plotfilteredhovs_trans.php?lat=075N

The CFS does not identify any strong Kelvin waves to propagate across the Pacific in the upcoming week or two as Paul's analysis suggests. I'm not sure if I'd buy stock on it but it's just another piece of the puzzle to use!

[am19psu]

To further comment on Paul's statistical approach, a graduate student here at the University at Albany, Kyle McRitchie, has applied Pauls EEOF analysis on the CFS forecasts:

http://www.atmos.alb...ns.php?lat=075N

The CFS does not identify any strong Kelvin waves to propagate across the Pacific in the upcoming week or two as Paul's analysis suggests. I'm not sure if I'd buy stock on it but it's just another piece of the puzzle to use!

I don't know if you have time, but the Albany team is putting a lot of good products and I, at least, would benefit from having a sort of a webpage FAQ for the products that you guys are outputting. I know Paul's site and your site, but I haven't spent enough time with anything except Paul's forecasts to help with my operational TCG forecasts.

[Mike.Ventrice]

I don't know if you have time, but the Albany team is putting a lot of good products and I, at least, would benefit from having a sort of a webpage FAQ for the products that you guys are outputting. I know Paul's site and your site, but I haven't spent enough time with anything except Paul's forecasts to help with my operational TCG forecasts.

Interesting comment.. I'll talk to the IT guy about it- maybe we could have something relevant on the department home page... I'll have to get back to you!

[SquatchinNY]

I have heard on anouther forum that a kelvin wave can boost up ENSO.

[am19psu]

I have heard on anouther forum that a kelvin wave can boost up ENSO.

Different kind of Kelvin wave. Oceanic Kelvin waves are very important to ENSO forecasting (the "sloshing" that you sometimes read about is a Kelvin wave). We're talking about atmospheric Kelvin waves, though. Same mechanics, since the ocean and atmosphere are both fluids, but different results. It's like comparing apples and toasters.

[kylemacr]

Convectively coupled atmospheric Kelvin waves can indeed have an impact on El Nino, as can the MJO. As either of these modes passes through, we often get what's called a westerly wind burst (WWB), which is just a surge in the westerlies (reduction in the trades). Since the base state tends to keep warm water in the CPAC, these WWBs can advect the warm water eastward which can be very important in setting up an El Nino state.

A post by Paul Roundy talks about this if you're interested: http://blog.timesuni...a-cake-pan/872/. It's written for the layman, but it's still quite informative.

[am19psu]

Convectively coupled atmospheric Kelvin waves can indeed have an impact on El Nino, as can the MJO. As either of these modes passes through, we often get what's called a westerly wind burst (WWB), which is just a surge in the westerlies (reduction in the trades). Since the base state tends to keep warm water in the CPAC, these WWBs can advect the warm water eastward which can be very important in setting up an El Nino state.

A post by Paul Roundy talks about this if you're interested: http://blog.timesuni...a-cake-pan/872/. It's written for the layman, but it's still quite informative.

I see what you are saying, but atmospheric Kelvin waves generally aren't of a large enough spatial or temporal magnitude to have a large effect on the interseasonal variation of ENSO.

[kylemacr]

Multiple successive events can be, though.

[Mike.Ventrice]

I see what you are saying, but atmospheric Kelvin waves generally aren't of a large enough spatial or temporal magnitude to have a large effect on the interseasonal variation of ENSO.

This would be true for your typical 16-20m/s eastward propagating convectively coupled atmospheric Kelvin wave (CCKW). However, you occassionaly see very strong CCKWs over the Warm Pool regions (IO and West Pac). There, these CCKWs can propagate as slow as 6-7m/s with equivalent depths approaching 5m! These CCKWs are the ones that float along the "gap" between the MJO and CCKWs on symmetric space-time spectrum diagrams. So what Paul is discussing in that article are most likely these strong, or "super" CCKWs, (these waves have also been called "super cloud clusters" by Takayabu and Murakami 1991). These are strong CCKWs that are associated with westerly wind bursts that could produce enough stress on the ocean surface to develop a downwelling oceanic Kelvin wave (downwelling oceanic Kelvin waves are are commonly associated with eastward phase speeds of 2-4m/s and bring warm waters from the West Pac Warm Pool eastward across the Pacific).

These strong CCKWs that have been called "super cloud-clusters" are usually the ones that bring the Wheeler and Hendon (2004) RMM phase space out of the inner-core and suggest there is a robust MJO at that time. While most MJOs are composed of one of these strong CCKWs, that's research for another day

And as Kyle pointed out, multiple, consecutive CCKWs could produce a WWB, which are commonly seen in the active phase of the MJO.

[phil882]

Great discussion guys! Mike, I always enjoy comparing your graphics to CPC's interpretation Wheeler and Hendon's RMM plot (without removing the interannual signal) to see if there are any outstanding differences. Looks like your RMM plot is at the borderline of phase 3/4 vs. phase 5 from the CPC's RMM. Its interesting to look at the outstanding differences since I know your RMM plot uses velocity potential and zonal winds. vs. zonal winds and outgoing longwave radiation (OLR) like that used in WH's RMM space.

[wxmx]

Great discussion guys! Mike, I always enjoy comparing your graphics to CPC's interpretation Wheeler and Hendon's RMM plot (without removing the interannual signal) to see if there are any outstanding differences. Looks like your RMM plot is at the borderline of phase 3/4 vs. phase 5 from the CPC's RMM. Its interesting to look at the outstanding differences since I know your RMM plot uses velocity potential and zonal winds. vs. zonal winds and outgoing longwave radiation (OLR) like that used in WH's RMM space.

Most models are now hinting at a quite quick transit trough phases 5-6-7 and amplifying a bit in it's journey toward phase 1. That would probably mean an enhanced probability of cyclogenesis in the EPac and Atlantic around the 20th and the next ~10 days after that.

[Mike.Ventrice]

Most models are now hinting at a quite quick transit trough phases 5-6-7 and amplifying a bit in it's journey toward phase 1. That would probably mean an enhanced probability of cyclogenesis in the EPac and Atlantic around the 20th and the next ~10 days after that.

While this may verify, it is important to put into context the recent skill (or lack there of) of all the global models assessing the current state of the MJO. Most models have been doing a very poor job of representing the MJO in the past week, and especially the past two weeks!! The first plot is verification from week 1, the second is week 2:

The model anomaly correlations have been abnormally low over the past month:

To compare with past year:

But to credit your point: I am also thinking we will see a tropical cyclone over the East Pacific towards the end of June once the low-level westerly phase of the MJO is over the Western Hemisphere

[wxmx]

While this may verify, it is important to put into context the recent skill (or lack there of) of all the global models assessing the current state of the MJO. Most models have been doing a very poor job of representing the MJO in the past week, and especially the past two weeks!! The first plot is verification from week 1, the second is week 2:

The model anomaly correlations have been abnormally low over the past month:

To compare with past year:

But to credit your point: I am also thinking we will see a tropical cyclone over the East Pacific towards the end of June once the low-level westerly phase of the MJO is over the Western Hemisphere

Another point about verification...mostly from observation. Models verification is usually poorest during weak/slow waves and they get a lot better when they forecast quick/high amplitude waves (with the exception of the Canadian ens, with it's squished spider solutions which verify better in slow moving waves) , which several of them are now forecasting...though they are usually a tad too fast.

[Eyewall2005]

Were are those cooler sst's across the atlantic?

[kylemacr]

Some food for thought...

The CFS is forecasting a fairly strong convectively inactive phase of the MJO to develop in the coming weeks. You can see that by clicking the MJO box on my hovmoller page: http://www.atmos.albany.edu/student/macritch/plotfilteredhovs_trans.php?lat=75S75N

My page uses Paul Roundy's diagnostic algorithm to separate the modes and applies it to the CFS 90 day forecast. Separating the modes out of the total CFS forecast is great because it reduces a lot of the noise and lets you get right toward the signal you're looking for.

I have been calculating the anomaly correlations for the various modes, which you can see on my horizontal map page: http://www.atmos.albany.edu/student/macritch/plotfilteredhovs_trans.php?lat=75S75N . Notice how much higher the ACCs for the individual modes are than the total OLR field! Slower modes are, in general, better forecast in advance... the low frequency ENSO component is a great example (bottom panel).

The strong suppressed MJO is forecast for about 10 days out from now. The average ACC for 10 day forecasts for the MJO mode has been above 90% since March of this year when I started calculating them (which, admittedly, isn't very long). This gives me some confidence in the forecast.

[Mike.Ventrice]

Some food for thought...

The CFS is forecasting a fairly strong convectively inactive phase of the MJO to develop in the coming weeks. You can see that by clicking the MJO box on my hovmoller page: http://www.atmos.alb....php?lat=75S75N

My page uses Paul Roundy's diagnostic algorithm to separate the modes and applies it to the CFS 90 day forecast. Separating the modes out of the total CFS forecast is great because it reduces a lot of the noise and lets you get right toward the signal you're looking for.

I have been calculating the anomaly correlations for the various modes, which you can see on my horizontal map page: http://www.atmos.alb....php?lat=75S75N . Notice how much higher the ACCs for the individual modes are than the total OLR field! Slower modes are, in general, better forecast in advance... the low frequency ENSO component is a great example (bottom panel).

The strong suppressed MJO is forecast for about 10 days out from now. The average ACC for 10 day forecasts for the MJO mode has been above 90% since March of this year when I started calculating them (which, admittedly, isn't very long). This gives me some confidence in the forecast.

Kyle, I am all aboard on the strong suppressed MJO phase developing in the convective fields over the Indian Ocean-West Pac region in the up coming two weeks! According to the time-longitude filtered 200 hPa Velocity Potential plot (shading are unfiltered VP200 anomalies; black contours are Kelvin filtered VP200 anomalies; red-bold contours are MJO filtered VP200 anomalies; green are ERWs), this suppressed MJO phase is currenlty located over the Western Hemisphere (90-60W). More importantly, this is the SAME suppressed MJO phase that was associated with all MJO events since late January! While the MJO convective signature is strongest over the Warm Pool regions, the upper-level wind signature (illustrated in the VP200 field) just keeps going round and round and round! This is what Kathy Straub was arguing in her talk at this past AMS tropical conference (https://ams.confex.com/ams/30Hurricane/webprogram/Paper204880.html).

For the time-longitude plot of VP200 unfiltered and filtered anomalies:

Dashed contours are negative filtered VP200 anomalies (anomalous upper-level divergence, or a crude proxy of the convectively active phase).

[Ed Lizard]

GFS and Euro both suggest EastPac action week to ten days, with some suggestions it might cross into the BoC.

Maybe its a little weenie to be fixating on models over a week out, but the thought of Josh and Jorge and video, and my natural glass half full optimism, it is something I'll be watching.

Not a lot of heat potential off Mexico on the happy side of 100ºW yet, but remembering the happy example of Alex in 2010, although obviously the end of June, not the middle, feeds my glass half full sunny nature...

[Riptide]

More fuel for the the fire regarding an active hurricane season. It appears a good portion of the 2012 tropical season will occur during ENSO-neutral conditions, with a 50% chance of el nino development after September.

EL NIÑO/SOUTHERN OSCILLATION (ENSO)

DIAGNOSTIC DISCUSSION

issued by

CLIMATE PREDICTION CENTER/NCEP

and the International Research Institute for Climate and Society

7 June 2012

ENSO Alert System Status: El Niño Watch

ENSO-neutral conditions prevailed in May 2012, following the dissipation of La Niña in April. Sea surface temperatures (SSTs) are currently near average across most of the equatorial Pacific Ocean, and above-average in the far eastern Pacific (Fig. 1). The Niño 4 and Niño 3.4 indices were near zero during most of May, while the Niño 3 and Niño 1+2 indices remained positive (Fig. 2). The oceanic heat content (average temperature in the upper 300m of the ocean) anomalies became more strongly positive in May (Fig. 3), as above-average sub-surface temperatures became established across most of the central and eastern equatorial Pacific (Fig. 4). The low-level trade winds and convection over the central equatorial Pacific were near average during May, although convection remained enhanced over portions of the western Pacific (Fig. 5). Collectively, these oceanic and atmospheric patterns indicate ENSO-neutral conditions.

The extensive volume of above-average sub-surface water temperatures indicates that the tropical Pacific SST anomalies will likely warm further in the coming months. A majority of models predict ENSO-neutral to continue through the June-August (JJA) season (Fig. 6). Thereafter, most of the dynamical models predict El Niño to develop during JAS, while the statistical models tend to favor the continuation of ENSO-neutral. Thus, there remains uncertainty as to whether ENSO-neutral or El Niño will prevail during the second half of the year. The evolving conditions, combined with model forecasts (Fig. 6), suggest that ENSO-neutral and El Niño are roughly equally likely during the late northern summer and fall. The CPC/IRI forecast calls for ENSO-neutral conditions through JAS, followed by an approximately 50% likelihood for El Niño during the remainder of the year (see CPC/IRI consensus forecast).

http://www.cpc.ncep.... ... odisc.html

[QVectorman]

Mike and Kyle I see you guys don't post much I would like to say thanks so much for the great posts. Hopefully you two will continue posting in the upcoming months and continue to share your knowledge!

[phil882]

Were are those cooler sst's across the atlantic?

The 10-20 day potent -NAO and -AO episode has really helped the Atlantic warm back up above normal basin-wide. However, it should be noted that these Oceanic heat content (OHC) are still much lower than 2005, 2010, and quite comparable to last year, so just because we aren't below normal anymore shouldn't be a huge indication we are likely to have a hyperactive season such as 2005 or 2010. The big wild card continues to be what is going to happen with ENSO, and I'm wondering if the forthcoming MJO episode is finally going to produce the westerly wind burst WWB we have been waiting for to shift the thermocline further eastward. There are plenty of warm waters sub-surface, so it won't take a major shift to case a significant warming in SSTs across the center and east Pacific.

[Superstorm93]

Pretty much a 50/50 shot in either basin.

[Srain]

Pretty much a 50/50 shot in either basin.

Monsoonal Trough ftw...

[U_Thant]

Monsoonal Trough ftw...

SLOPGYRE ™, anyone?

[am19psu]

SLOPGYRE ™, anyone?

As modeled, looks more like an Alma/Arthur situation to me.

[U_Thant]

As modeled, looks more like an Alma/Arthur situation to me.

ECM looks more like a Cosme/Allison '89 displaced a little farther east, but not as far as the '65 no-name. Haven't quite figured out the GFS - looks like dueling cyclone spinups straddling CENTAM on days 7-9.

[Srain]

ECM looks more like a Cosme/Allison '89 displaced a little farther east, but not as far as the '65 no-name. Haven't quite figured out the GFS - looks like dueling cyclone spinups straddling CENTAM on days 7-9.

Adam and I have a running joke re: Allison. See his avatar. I do agree that a Cosme/Allison 89 redeux, but a tad further E does seem plausible. Regardless, it looks like a sheared mess with the Western Trough established during the 7-10 day range.

[Scott747]

Heh

[am19psu]

Heh

[Eyewall2005]

06z GFS ensembles fom earlier this morning..