Atlantic Tropical Action 2013

[am19psu]

I'm skeptical of the HWRF results. I've heard about improvements every year and then it still stinks. Maybe this will finally be the year they get it right, but I'm not going to use it to forecast until I see some decent operational results.

[HurricaneJosh]

I'm skeptical of the HWRF results. I've heard about improvements every year and then it still stinks. Maybe this will finally be the year they get it right, but I'm not going to use it to forecast until I see some decent operational results.

Well OK then.

[am19psu]

Well OK then.

[Ed Lizard]

I'm getting the feeling whatever happens weekend after next will be well South in the BoC, and thus with limited time over water, probably weak.  That is the trend with the reliable guidance.

 

But it is June, and I think I only had one storm this month anyway in the contest anyway.

 

Speaking of models, new improved Canadian still does weird things.  I've been watching it.  But maybe it does a great job predicting snow in far Northern climes.  By statistical modes, hey mean SHIPS and CLIPER?

[Srain]

Generally the globals and ensembles are in somewhat good agreement that the upper ridge will hold over the next 4-6 day across the Southern Plains and the SE US. Those models do suggest the ridge shifts a bit N and E next week and a surge of deep tropical moisture enters the NW Caribbean. Next week that increased deep tropical moisture does enter the Western Gulf as the monsoonal trough lifts N. What the globals are ‘sniffing’ is a monsoonal gyre that festers in the NW Caribbean/Yucatan/Bay of Campeche. This is a fairly typical pattern for June. As we move into the later part June/early July, that area will need to be watched for TC genesis. Some folks like to ‘dis’ the Bay of Campeche as a place for TC genesis, but that area is somewhat favored in the pattern ahead and my hunch is we’ll see a tropical cyclone develop be it a depression or TS over the next 10 days. The GFS and its ensembles are certainly keying in on that general location putting the Mexican Gulf Coast as well as Texas into Louisiana in a somewhat favorable location for landfall if anything develops. One thing I will add. We are not in a pattern where a prolonged drought across Mexico/Texas and Louisiana is conducive to a strong blocking upper ridge all season. Jorge has been getting pounded with storms and heavy rain in Monterrey and we here in Texas and Louisiana have seen plentiful storms as of late. Caribbean and Gulf action is looking more likely as we move ahead into the season, IMO.

 

[Ed Lizard]

^^ I'm not calling season cancel here, (it is June...)  just the ~Day 9 or 10 system is forecast way down in the BoC by GFS, esnembles and Euro, and will probably have limited time over water.

 

Right pattern, BoC can grow a Hurricane Bret.

 

After the day 9 system, 0Z ad 6Z GFS and 0Z ensembles are suggesting a Day 15 or 16 threat, but there is no point running a lowered resolution model out past two weeks.  IMHO.  No point running the GFS with a T number below 300, except for the cool softcore internet prawn.

[bluewave]

^^ I'm not calling season cancel here, (it is June...)  just the ~Day 9 or 10 system is forecast way down in the BoC by GFS, esnembles and Euro, and will probably have limited time over water.

 

Right pattern, BoC can grow a Hurricane Bret.

 

After the day 9 system, 0Z ad 6Z GFS and 0Z ensembles are suggesting a Day 15 or 16 threat, but there is no point running a lowered resolution model out past two weeks.  IMHO.  No point running the GFS with a T number below 300, except for the cool softcore internet prawn.

 

I think that the GEFS may be rushing the MJO a bit, but the Euro Ensembles look like they may get back to phase 1

near the end of the month or early July for more development potential.

 

 

[Mike.Ventrice]

Hi guys, 

 

The MJO tends to have a faster eastward propagation during boreal Summer. It's best to look at the upper-level circulation during boreal summer IMO instead of the standard real-time multivariate MJO indices. From my VP200 filtered MJO product, it suggests that the strongest MJO signal is currently over the Maritime Continent, and should continue to progress eastward across the Pacific and push back over the Atlantic/western Indian Ocean late June-early July. It almost hurts to say this, but I like the GFS forecast here. Dum dum dum!

 

[Mike.Ventrice]

Hi guys,

 

I've updated my Kelvin-time lon plots with GFS forecast and have included a 200U anomaly filtered version. Strong CCKW pushing across S. America today. Some deep convection over S. America-central America in association to the more favorable atmosphere. Note that this is just a brief window for favorable conditions as the following suppressed phase of the CCKW will be pushing across the region in roughly 5-7 days..

 

[Ed Lizard]

While we wait for maybe something at the very end of June as suggested by a couple of recent GFS and GEFS ensembles, operating on the assumption late next week's system will be both weak and well surpressed in the By of Campeche, I think it is time for a mid-June "post your favorite hurricane YouTubes".

 

Bendy can delete if he thinks its inappropriate, I'll grumble, but not publically complain.

 

Warning for excited use of PG-13 language for our family audience.  Jim Leonard, Charley.

 

http://www.youtube.com/watch?v=xDNUSJ5bXjA

[TropicalAnalystwx13]

18z GFS had an intense tropical storm in the Bay of Campeche in a little over a week. Relatively inconsistent with this solution, but something to watch.

 

[thewxmann]

0Z GFS continues to have something pretty decent in the wrn Gulf around Day 8.

[HurricaneJosh]

Cool. Gettin' pretty yummyz.

Get it a little stronger and a little farther N, and we're in business.

[HurricaneJosh]

Maybe Adam'll comment this mornin' Re: Gulf prospects.

[am19psu]

Maybe Adam'll comment this mornin' Re: Gulf prospects.

Kelvin wave moving through early in the week will help the system organize and we've got a pretty decent shot of seeing something form, but I don't think it will be all that exciting, since the environment most likely won't be terribly conducive by the end of the week. Best guess is a weak to moderate TS somewhere north of Veracruz a week from now.

[bluewave]

I like the idea of the first strong tropical storm or hurricane of the season in early July.

The Euro Ensembles are hinting that we'll be in MJO 1 by early July. The last time

this happened we had  Bertha in 2008. It's still too far out to know what part of the

basin any system would develop in.

 

 

 

[Mike.Ventrice]

I like the idea of the first strong tropical storm or hurricane of the season in early July.

The Euro Ensembles are hinting that we'll be in MJO 1 by early July. The last time

this happened we had  Bertha in 2008. It's still too far out to know what part of the

basin any system would develop in.

 

ECMF_phase_MANOM_51m_full.gif

 

200807.phase.90days.gif

 

track.gif

 

I like the increased chances of an uptick in Atlantic TC activity developing during late june, early july. June 2008 is similar to this year in the sense of the intraseasonal state of convection in the tropics. It too had a good CCKW/MJO come through late June, early July:

 

 

But the ocean-structure in the equatorial Atlantic are different this year, such that we have a pretty anomalously strong cold tongue developing in the Gulf of Guinea = less genesis near West Africa and more genesis over the central MDR-Caribbean.

 

 

 

 

 

 

But I do have some confidence that we might see our rapid onset of the West African Monsoon into the "Sahelian Phase", or its mature summer-phase. Of course by July, the Atlantic should turn off again but as a result of intraseasonal type variability.

 

[bluewave]

I like the increased chances of an uptick in Atlantic TC activity developing during late june, early july. June 2008 is similar to this year in the sense of the intraseasonal state of convection in the tropics. It too had a good CCKW/MJO come through late June, early July:

 

 

But the ocean-structure in the equatorial Atlantic are different this year, such that we have a pretty anomalously strong cold tongue developing in the Gulf of Guinea = less genesis near West Africa and more genesis over the central MDR-Caribbean.

 

 

 

 

 

 

But I do have some confidence that we might see our rapid onset of the West African Monsoon into the "Sahelian Phase", or its mature summer-phase. Of course by July, the Atlantic should turn off again but as a result of intraseasonal type variability.

 

 

Thanks for adding all that great detailed information to your post. I was using the analog

more for timing than for having such a strong early CV development. We might have a better

shot at something developing further west this time around since the Tropical Atlantic has

been on the stable side lately with more instability further west.

 

 

[Ed Lizard]

Short OT:  Bertha is such an awesome early season name. (Waiting on 2014)  I still fondly recall the 1996 Bertha, watching TWC's 'tropical update', it was almost a depression coming off the coast.  Double OT- the stuff Mike Ventrice posts on this forum is awesome.

 

 

ETA:  I'm getting the impression (please confirm) that a Kelvin wave has a shorter temporal span in which to help a disturbance become a TC as compared to an actual MJO.  As far as influence on OLR (which I can see without deep understanding), what are the relative strengths?

[Ground Scouring]

There is very little ground for supposing El Niño will emerge this year. The sudden June dip in Atmospheric Angular Momentum (AAM) shows that the global base-state is much more akin to that of a mild Niña than that of an emerging Niño: an above-average Central Indian monsoon, tropical forcing concentrated near Indochina, and a strongly negative but slowly rising Pacific Decadal Oscillation (PDO), among other indicators. Yes, there is warming occurring at the subsurface in the SW Pacific, but there is no real trend toward the surface—and certainly no strong atmospheric “smoking indicator” that would favor El Niño. I recently checked years that featured a strongly negative AAM in June and the two years that met the criterium, 1978 and 1988, both featured neutral-cool SSTA for the NINO zones in August-September, the real “meat” of the Atlantic season. In both years, the PDO was weakly negative or neutral by August-September, which also seems to fit this year's trend. So the chance of El Niño is probably less than 10%, at least in time for the peak of the season.

 

Now, let's talk about steering patterns.

 

As for the steering pattern, the high soil moisture from April-May in much of the southern Plains and the upper Midwest will negate the emergence of a persistent death ridge this summer. A check of the years with tropical forcing most analogous to this season's tends to favor a mean trough over the upper Midwest and the High Plains, probably centered around NE / IA, with a concurrent downstream ridge extending into the Mid-Atlantic and the Southeast. Furthermore, the East Pacific Oscillation (EPO) has shifted sharply from negative (≤ -.3) to positive (≥.3) in February-March 2013. A linear regression shows that the years which were most similar (1998, 2002) with respect to the EPO since 1995 correlated with a mean ridge over the Northeast. This fits well with the PDO trend in February-March; since 1995, the most similar years which initially featured a strengthening -PDO were 2009, 2011, and 2012. They correlated with above-average heights over the South Pacific between 180°-140°W and an easterly QBO in place, thus also favoring a west-based -NAO in August-September.

 

 

 

 

Years with February-March NAO values similar to 2013's ended up with the following August-September pattern:

 

 

The very positive +TNA trend in February-March 2013 also correlates to much weaker shear over the Gulf, the Caribbean, and the W Atlantic basin / MDR. In fact, the February-March +TNA was the most positive since February-March 2010.

 

 

As we know, such years as 2010 are characterized by much weaker shear that I mentioned:

 

Given the increased chance of a strong, west-based Bermuda High, I would say that numbers will not matter. Even a season with 14 named storms would likely feature a high ratio of strong / landfalling storms given the projected shear and the mid-level steering set-up in August-September 2013. The best track analogs which I have found seem to be 1926, 1960, 1998, 2002, and 2005, meaning an elevated risk of a major hurricane to the Central Gulf Coast (LA / MS) and SE FL.

 

Any comments on the steering this year?

[Mike.Ventrice]

There is very little ground for supposing El Niño will emerge this year. The sudden June dip in Atmospheric Angular Momentum (AAM) shows that the global base-state is much more akin to that of a mild Niña than that of an emerging Niño: an above-average Central Indian monsoon, tropical forcing concentrated near Indochina, and a strongly negative but slowly rising Pacific Decadal Oscillation (PDO), among other indicators. Yes, there is warming occurring at the subsurface in the SW Pacific, but there is no real trend toward the surface—and certainly no strong atmospheric “smoking indicator” that would favor El Niño. I recently checked years that featured a strongly negative AAM in June and the two years that met the criterium, 1978 and 1988, both featured neutral-cool SSTA for the NINO zones in August-September, the real “meat” of the Atlantic season. In both years, the PDO was weakly negative or neutral by August-September, which also seems to fit this year's trend. So the chance of El Niño is probably less than 10%, at least in time for the peak of the season.

 

Now, let's talk about steering patterns.

 

As for the steering pattern, the high soil moisture from April-May in much of the southern Plains and the upper Midwest will negate the emergence of a persistent death ridge this summer. A check of the years with tropical forcing most analogous to this season's tends to favor a mean trough over the upper Midwest and the High Plains, probably centered around NE / IA, with a concurrent downstream ridge extending into the Mid-Atlantic and the Southeast. Furthermore, the East Pacific Oscillation (EPO) has shifted sharply from negative (≤ -.3) to positive (≥.3) in February-March 2013. A linear regression shows that the years which were most similar (1998, 2002) with respect to the EPO since 1995 correlated with a mean ridge over the Northeast. This fits well with the PDO trend in February-March; since 1995, the most similar years which initially featured a strengthening -PDO were 2009, 2011, and 2012. They correlated with above-average heights over the South Pacific between 180°-140°W and an easterly QBO in place, thus also favoring a west-based -NAO in August-September.

 

 

 

 

Years with February-March NAO values similar to 2013's ended up with the following August-September pattern:

 

 

The very positive +TNA trend in February-March 2013 also correlates to much weaker shear over the Gulf, the Caribbean, and the W Atlantic basin / MDR. In fact, the February-March +TNA was the most positive since February-March 2010.

 

 

As we know, such years as 2010 are characterized by much weaker shear that I mentioned:

 

Given the increased chance of a strong, west-based Bermuda High, I would say that numbers will not matter. Even a season with 14 named storms would likely feature a high ratio of strong / landfalling storms given the projected shear and the mid-level steering set-up in August-September 2013. The best track analogs which I have found seem to be 1926, 1960, 1998, 2002, and 2005, meaning an elevated risk of a major hurricane to the Central Gulf Coast (LA / MS) and SE FL.

 

Any comments on the steering this year?

 

Thanks for your thoughts.. with regards to the state of ENSO, I'd be careful here. While the state of the MJO is to favor increased lower tropospheric easterly flow over the East Pacific which should force some upwelling in the East Pac and bring some colder waters to the surface, it will likely just be a sub-seasonal variation.  If you look sub-surface, a downwelling ocean Kelvin wave is currently bringing warm waters from the West Pac warm pool towards the East, acting to deepen the thermocline over the central Pacific. Much of the negative SST anomalies sub-surface have been erased and are trending warmer than average. Further, the current location of the MJO would favor enhanced low-level westerlies on the equator (>15 m/s totals!)  I'm expecting the warming trend to continue, and eventually bring some positive SST skin anomalies to the East Pacific with time.   There are often times where down-welling oceanic Kelvin waves couple with atmospheric convection and amplify the process. We are in a time where the atmosphere is superimposed with the downwelling oceanic Kelvin wave and could be one of those times where the ocean is talking with the atmosphere.

 

 

 

 

With regards to the current state of the Global Wind Oscillation, we did see a pretty good drop into negative AAM values, which is consistent with a La Nina type atmosphere. However, recently atmospheric angular momentum is back on the rise.  I'm not really sure if AAM will continue to trend up, or will plunge back down, but the downwelling oceanic Kelvin wave phased (temporarily) with the MJO suggests there is potential for the gradual increase of AAM. To be seen!

 

[HurricaneJosh]

Kelvin wave moving through early in the week will help the system organize and we've got a pretty decent shot of seeing something form, but I don't think it will be all that exciting, since the environment most likely won't be terribly conducive by the end of the week. Best guess is a weak to moderate TS somewhere north of Veracruz a week from now.

K. Thx.

[Mike.Ventrice]

Short OT:  Bertha is such an awesome early season name. (Waiting on 2014)  I still fondly recall the 1996 Bertha, watching TWC's 'tropical update', it was almost a depression coming off the coast.  Double OT- the stuff Mike Ventrice posts on this forum is awesome.

 

 

ETA:  I'm getting the impression (please confirm) that a Kelvin wave has a shorter temporal span in which to help a disturbance become a TC as compared to an actual MJO.  As far as influence on OLR (which I can see without deep understanding), what are the relative strengths?

 

Thanks Ed,

 

Yes, CCKWs provide a better estimate of when a TC will spin up in an active MJO signal. It usually takes about two days after the passage of a strong active phase of a CCKW superimposed with the MJO before a depression forms. Now it's not always exact, sometimes the CCKW can provide the necessary boost when superimposed with an easterly wave to spin up a cyclone over the ocean.  If you'd like some more info on this, here is a paper I wrote with regards to the CCKW-TC relationship and the large-scale environment over the Atlantic:

 

http://www.atmos.albany.edu/student/ventrice/documents/publications/Ventrice%20et%20al.%202012a.pdf

http://www.atmos.albany.edu/student/ventrice/documents/publications/Ventrice%20et%20al.%202012b.pdf

[Ground Scouring]

Thanks for your thoughts.. with regards to the state of ENSO, I'd be careful here. While the state of the MJO is to favor increased lower tropospheric easterly flow over the East Pacific which should force some upwelling in the East Pac and bring some colder waters to the surface, it will likely just be a sub-seasonal variation.  If you look sub-surface, a downwelling ocean Kelvin wave is currently bringing warm waters from the West Pac warm pool towards the East, acting to deepen the thermocline over the central Pacific. Much of the negative SST anomalies sub-surface have been erased and are trending warmer than average. Further, the current location of the MJO would favor enhanced low-level westerlies on the equator (>15 m/s totals!)  I'm expecting the warming trend to continue, and eventually bring some positive SST skin anomalies to the East Pacific with time.   There are often times where down-welling oceanic Kelvin waves couple with atmospheric convection and amplify the process. We are in a time where the atmosphere is superimposed with the downwelling oceanic Kelvin wave and could be one of those times where the ocean is talking with the atmosphere.

 

With regards to the current state of the Global Wind Oscillation, we did see a pretty good drop into negative AAM values, which is consistent with a La Nina type atmosphere. However, recently atmospheric angular momentum is back on the rise.  I'm not really sure if AAM will continue to trend up, or will plunge back down, but the downwelling oceanic Kelvin wave phased (temporarily) with the MJO suggests there is potential for the gradual increase of AAM. To be seen!

This is a good explanation, especially the bolded segment. It will be interesting to see whether the ECMWF, the CFS ensembles, and the UKMET accurately depict the magnitude of the atmospheric response to the warming. I do expect some fairly substantial warming through July and early August, but not enough to form a weak Niño in time for the peak of the season, though--now that I've looked more closely--I would tend to lean away from neutral-cool toward neutral-warm for the ASO period. If I am interpreting things correctly, 2004 seems to be a fairly good base analog based upon the tropical forcing currently in place, though the AAM was quite different in June 2004. There are few good analogs based solely upon AAM, so, as you mentioned, other factors need to be weighted in. But you seem to be suggesting that we may see weak Niño conditions by ASO and that the dynamical models have the best grasp of the evolving subsurface / atmospheric coupling.

[Mike.Ventrice]

This is a good explanation, especially the bolded segment. It will be interesting to see whether the ECMWF, the CFS ensembles, and the UKMET accurately depict the magnitude of the atmospheric response to the warming. I do expect some fairly substantial warming through July and early August, but not enough to form a weak Niño in time for the peak of the season, though--now that I've looked more closely--I would tend to lean away from neutral-cool toward neutral-warm for the ASO period. If I am interpreting things correctly, 2004 seems to be a fairly good base analog based upon the tropical forcing currently in place, though the AAM was quite different in June 2004. There are few good analogs based solely upon AAM, so, as you mentioned, other factors need to be weighted in. But you seem to be suggesting that we may see weak Niño conditions by ASO and that the dynamical models have the best grasp of the evolving subsurface / atmospheric coupling.

 

I'm thinking a warm-neutral ENSO state is likely, with relatively small influence to extratropical circulation at low frequency timescales. WOH I'm not sure if dynamical models will be able to handle the oceanic Kelvin wave/atmospheric coupling!!  If I would have to think of one, maybe the CFS could do the job but would likely overamplify the low-freq convection signal.

[Ed Lizard]

Mike-

 

Trying to understand the basics of this as an interested amateur-

 

The OLR minima lags (considerably) the low level convergence maxima of the CCKW?  I'm assuming the low level convergence maxima is considered the 'peak' of the CCKW?  Is the CCKW, looking at the diagram below, in any way like an MCS that forms an MCV in the stratiform region?  (Also thinking of non-tropical origin systems I distinctly remember, like Danny 1997).

 

 

Also, are you suggesting the decay of the MJO triggers Atlantic CCKWs (and thus the utility of tracking MJO phase in the Indian and Pacific Ocean is actually in the fact they'll produce CCKWs)

 

Lastly, speaking of the Kelvin filter, the OLR maps from the CPC MJO page aren't the best way to track CCKWs, I assume.

 

Thanks.

[TropicalAnalystwx13]

The CFS agrees on nothing less than dramatic warming during weeks 3 and 4 across the equatorial Pacific.

 

[wxmx]

The CFS agrees on nothing less than dramatic warming during weeks 3 and 4 across the equatorial Pacific.

 

 

Although weeks 1 & 2 will probably show some cooling across 3.4 and 4...so net warming would probably prove moderate at most. I still think probabilities of weak El Niño are still relatively low.

[Srain]

The reliable models are beginning to converge on a solution that bring a robust easterly tropical wave into the Bay of Campeche next Wednesday into Thursday. The GFS suggests the disturbance will stay further S near the Veracruz Region while the Euro brings the disturbance further N and just offshore of Tampico. Regardless of any development, increasing deep tropical moisture from the Caribbean above 2 standard deviations of normal for this time of year may well spread across Coastal Texas with heavy tropical rains in S Texas on up to the Middle and Upper Texas Coast where lesser amount may develop. Should this disturbance become better organized, higher rainfall amounts are possible and may extend further N or inland. The upper air pattern appears somewhat favorable as the upper ridge weakens and moves W and a weakness develops across the Western Gulf into NE Mexico and Texas.

[Ed Lizard]

The reliable models are beginning to converge on a solution that bring a robust easterly tropical wave into the Bay of Campeche next Wednesday into Thursday. The GFS suggests the disturbance will stay further S near the Veracruz Region while the Euro brings the disturbance further N and just offshore of Tampico. Regardless of any development, increasing deep tropical moisture from the Caribbean above 2 standard deviations of normal for this time of year may well spread across Coastal Texas with heavy tropical rains in S Texas on up to the Middle and Upper Texas Coast where lesser amount may develop. Should this disturbance become better organized, higher rainfall amounts are possible and may extend further N or inland. The upper air pattern appears somewhat favorable as the upper ridge weakens and moves W and a weakness develops across the Western Gulf into NE Mexico and Texas.

 

I believe the blob in the SW Caribbean is he beginning of the disappointingly weak and suppressed system.  But it is only June.  So I can only be so disappointed, and I believe the long term average is only a shade over 1 system June and July combined, so if it can struggle to Barry-hood, we'll be above normal.  The Barry thing is iffy  A closed low looks iffy.  Unless the NavGem scores a major coup.