Atlantic Tropical Action 2013 - Part 2

[Mike.Ventrice]

Convection is starting to wane over the East Pacific as upper-level wind pattern is beginning to transition... Finally not seeing strong influence from East Pacific on upper-air pattern o/ Atlantic... time for TCs to spin up!

 

 

 

[thewxmann]

Lol, the 0Z ECMWF doesn't take the next CV system past 40W. Good. Immediate recurve = No drama.

[HurricaneJosh]

Lol, the 0Z ECMWF doesn't take the next CV system past 40W. Good. Immediate recurve = No drama.

 

 It's like killing a suffering animal in the early stages.

[HurricaneJosh]

I stick to my guns-- that Cape Verde dreams this year will go unfulfilled.  Between TUTTs and SALs and big masses of dry air and East Coast troughs and everything else this year, hoping for a cyclone to make it across to North America is like hoping a little kitty will make it across a ten-lane highway.

 

We need home brews in the Gulf and W Cairbbean.

[H2O]

Good thing winter will be here soon to make up for this wretched tropical season

[HurricaneJosh]

Good thing winter will be here soon to make up for this wretched tropical season

 

Totally!  It will be fun to watch Mid-Atlantic icep*ssies once again pine away for snow events that never happen.  It's the perfect off-season pastime for us.

[Sunny and Warm]

Totally!  It will be fun to watch Mid-Atlantic icep*ssies once again pine away for snow events that never happen.  It's the perfect off-season pastime for us.

The best part of this is watching TWC grasping at any cloud structure in the Atlantic and following it for days.  My wife will ask about it, and I'll tell her they're doing it for ratings and to ignore.  Sure enough, a couple days later, they're on to some other pitiful, swirling clouds.

[HurricaneJosh]

The best part of this is watching TWC grasping at any cloud structure in the Atlantic and following it for days.  My wife will ask about it, and I'll tell her they're doing it for ratings and to ignore.  Sure enough, a couple days later, they're on to some other pitiful, swirling clouds.

 

[bluewave]

Any theory as to why this is happening has to  answer what began to change after

the 2005 season which resulted in a drierTropical  Atlantic and Caribbean with 

enhanced WPAC to IO convection. The last time we had a -PDO and +AMO from 

48-63 we did not observe this type of convective pattern. But there is more going on

this year to conspire to significantly enhance this recent background pattern. This

year is a more extreme version of strong African convection and more stable

Tropical Atlantic. 

 

 

 

 

 

[HurricaneJosh]

Any theory as to why this is happening has to  answer what began to change after

the 2005 season which resulted in drier Atlantic and Caribbean with enhanced

WPAC to IO convection. The last time we had a -PDO and +AMO from 48 to 63

we did not observe this type of convective pattern. But there is more going on

this year to conspire to significantly enhance this recent background pattern.

 

Did the problem for us start after 2005-- or later?  The 2007 and 2008 seasons produced multiple extremely-intense, Grade-A hurricanes.  I feel like things really went into the crapper starting 2009.

[bluewave]

Did the problem for us start after 2005-- or later?  The 2007 and 2008 seasons produced multiple extremely-intense, Grade-A hurricanes.  I feel like things really went into the crapper starting 2009.

 

The rainfall anomalies slowly began to shift after 2005, but it started becoming more evident with the falling instability

in the Tropical Atlantic and Caribbean since 2010. 

[HurricaneJosh]

The rainfall anomalies slowly began to shift after 2005, but it started becoming more evident with the falling instability

in the Tropical Atlantic and Caribbean since 2010. 

 

OK, I guess I'm just thinking solely about the end results-- and I found the 2007 and 2008 seasons to be totally satisfactory.  (2006 sucked, of course.)

[am19psu]

What jordanwx said. He supported it a lot better than I would have, too.

[Sunny and Warm]

Did the problem for us start after 2005-- or later?  The 2007 and 2008 seasons produced multiple extremely-intense, Grade-A hurricanes.  I feel like things really went into the crapper starting 2009.

not saying they are related (correlation does not necessarily equal causation), but the deeper than normal solar minimum started around that time.  The last minimum that deep was around 1910, give or take a few years.  That was also the era with no hurricanes for the entire season (if you believe pre-satellite records such as that).

 

Maybe it is strat related as said in passing yesterday.

[mappy]

Totally!  It will be fun to watch Mid-Atlantic icep*ssies once again pine away for snow events that never happen.  It's the perfect off-season pastime for us.

 

Ahem, not all of us Mid-atlantic people are ice******* my dear. Some of us have accepted the fact that our winters suck.

 

[TropicalAnalystwx13]

BEGIN
NHC_ATCF
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INVEST, AL, L, , , , , 99, 2013, DB, O, 2013090506, 9999999999, , , , , , METWATCH, , AL992013
AL, 99, 2013090406, , BEST, 0, 215N, 917W, 15, 1013, LO, 0, , 0, 0, 0, 0, 
AL, 99, 2013090412, , BEST, 0, 215N, 926W, 15, 1013, LO, 0, , 0, 0, 0, 0, 
AL, 99, 2013090418, , BEST, 0, 215N, 934W, 15, 1012, LO, 0, , 0, 0, 0, 0, 
AL, 99, 2013090500, , BEST, 0, 215N, 940W, 15, 1011, LO, 0, , 0, 0, 0, 0, 
AL, 99, 2013090506, , BEST, 0, 215N, 944W, 20, 1010, LO, 34, NEQ, 0, 0, 0, 0, 1013, 180, 40, 0, 0, L, 0, , 0, 0, INVEST, S,

[CoastalWx]

I don't either. However, ENSO is neutral to La Nina, EPAC has been well below average in ACE, SSTs in the tropical Atlantic are above average, the African wave train has been healthier than normal, clearly there is a bigger problem. Personally, I think that problem is the subtropical SST profile. In fact, I think the subtropical SST profile is the single biggest reason this season has been a bust so far. Even if we don't finish with a bust, it is true that vertical instability and downward motion remained over basin through most of June-August. That has changed a bit recently with a strong return of the MJO, however. Anyway, on to the evidence. Below I have compared the SST anomaly over the subtropical Atlantic during the top 10 ACE years minus bottom 5 ACE years to SST anomalies this year so far:

 

SST Anomalies for Top 10 ACE Years Minus Bottom 5 ACE Years:

 

 

SST Anomalies for June-August 2013:

 

 

The first image tells us what kind of SST Anomaly profile we want for an active season -- warm tropical SSTs (obviously), warm SSTs around 30-50N between 40-15W and a block of cool SSTs extending off the east coast to about 40W from 30-50N. The second image shows us how SST Anomalies have been so far this season. The tropical Atlantic has been above average, but the region from 30-50N between 40-15W has been much colder than average (where we want it warm) and the region off the east coast has been much warmer than average (where we want it cold).

 

So there you have it, the subtropical SST profile is completely out of wack. Looking at 500mb height anomalies, this has pushed the subtropical ridge further north than normal (broadening Hadley cell) and also brought anomalously high pressure from 30-50N.

 

 

What do you get underneath that anomalous ridging? Convergent flow, how's 500mb omega looking south of the anomalous ridging (~35N)?

 

Sure enough, downward motion starts just on the southern periphery of that anomalous ridging (i.e. that strong band of positive anomalies extending across the entirety of the Atlantic between 30-25N). Further down south in the MDR we have even more downward motion...as previously mentioned subtropical SSTs likely playing a big part in the meridional overturning within the Atlantic, causing upward motion in the deep tropics to suffer. Forcing from strong upward motion over adjacent regions (epac and african continent have both been experiencing strong upward motion) is also hurting the Atlantic (through simple conservation of mass).

 

I don't disagree with the physical mechanisms what you said, but again these didn't occur overnight and we've had a SST profile not ideal, yet never this boring of a season. There are likely other issues going on that are just enough to tip the delicate convection scheme to very unfavorable. I think there is more to it then some warmer water broadening the Hadley cell. There has been a band of higher than normal H5 anomalies circling the globe. Definitely a little different with the AO remaining + this year vs the last what...5 or 6 seaons. I've heard your theory and various others as well. Nice work BTW.

[am19psu]

I don't disagree with the physical mechanisms what you said, but again these didn't occur overnight and we've had a SST profile not ideal, yet never this boring of a season. There are likely other issues going on that are just enough to tip the delicate convection scheme to very unfavorable. I think there is more to it then some warmer water broadening the Hadley cell. I've heard your theory and various others as well. Nice work BTW.

What other things affect the global tropics? I honestly can't think of any, which is why I keep coming back to the Hadley Cell argument.

[Mike.Ventrice]

Guys,

I'm starting to see signs of a developing system over the western Caribbean in 120-150 hour time that could track towards the northwest over the Gulf of Mexico... This is being advertised in over half of the GFS enKF ensemble members in this mornings 00Z forecast and poses an immediate threat to the Gulf States. With the cold air surge (or edge wave) propagating down the lee of the Andes in South America, the southern Caribbean will likely become pretty unstable over the next few days... 

 

[am19psu]

It's weakly there in the op GFS and Euro ensembles, too. Heads north from the Bay of Campeche toward CRP in both models, imo.

[CoastalWx]

What other things affect the global tropics? I honestly can't think of any, which is why I keep coming back to the Hadley Cell argument.

 

I think that is part of it for sure, but haven't we had SST profiles like this before and still a half decent tropical season? Is the QBO having a say? What about all the rising air in the EPAC. I know it's not extreme, but could sinking air from that be just enough to throw it off? The rather stout AO and higher band of height anomalies circling the globe? Maybe a combo of several factors...I mean you of all people know that if one little thing is thrown off...it causes TC genesis to be difficult. We don't have QG forcing like we do in the mid latitudes so the atmosphere better be in top shape to support rising air in the subtropics. Perhaps it is mostly the Hadley argument, but did the SST profile give you guys a concern in June? It sounded like people were still bullish back in June. This is the attached SST profile from June 1-July 31. Did that warmer water really adjust the Hadley Cell that much? Is the warmer water more of a product of its environment and perhaps feeds back to helping the ridge develop and broaden? Again, in my limited tropical experience I agree with the physics behind what Jordanwx said. He did a nice job on that. I just wonder how much of that contributed. 

 

[am19psu]

I mean, the Hadley Cell is affected by more than just SSTs. The amount of wave breaking across the mid-latitudes plays a major role, too, as does other things like the QBO. But I can tell you, I wish I'd have given more credence to it back then when the HC hit almost 60N in July. That strikes me as unusually broad. So, my argument is the weak, broad Hadley Cell is the main reason the tropics have sucked this year and SSTs help modulate the strength of the Hadley Cell, but it's not just as simple as this SST pattern -> tropics suck.

[HurricaneJosh]

Guys,

I'm starting to see signs of a developing system over the western Caribbean in 120-150 hour time that could track towards the northwest over the Gulf of Mexico... This is being advertised in over half of the GFS enKF ensemble members in this mornings 00Z forecast and poses an immediate threat to the Gulf States. With the cold air surge (or edge wave) propagating down the lee of the Andes in South America, the southern Caribbean will likely become pretty unstable over the next few days... 

 

 

Hawtest post on this forum in weeks.  Now we're talkin'.

[CoastalWx]

I mean, the Hadley Cell is affected by more than just SSTs. The amount of wave breaking across the mid-latitudes plays a major role, too, as does other things like the QBO. But I can tell you, I wish I'd have given more credence to it back then when the HC hit almost 60N in July. That strikes me as unusually broad. So, my argument is the weak, broad Hadley Cell is the main reason the tropics have sucked this year and SSTs help modulate the strength of the Hadley Cell, but it's not just as simple as this SST pattern -> tropics suck.

 

It's a head scratcher and I imagine it makes you want to pull your hair out...lol.  I agree about the Hadley cell and subsidence...I guess what I meant is that what factors are causing it (Hadley cell issue) and could this have been seen. 

 

Do you agree about having a late run perhaps given the western carb is on fire?

[Floydbuster]

We've always had to deal with dry air occasionally. I remember in 2004, Hurricane Ivan weakened from 115 kt to 90 kt east of the Windward Islands because dry air got into it's core. Of course it mixed it out, came back and then some. But in the last six-seven years, we've dealt with this super dry ill-defined waves with slopgyres and reforming centers and storms with 935 mb pressure but 95 kt winds (an exaggeration but you know what I'm talking about).

 

We've had to deal with the Fays and the Isaacs which both could have been Charleys and Ivans.

 

What the hell? I mean...really? What the hell?

[Ed Lizard]

If only 99L had 96 hours more time over the BoC before Tampico...

[Superstorm93]

If only 99L had 96 hours more time over the BoC before Tampico...

 

Ugh...12z guidance shows 18-24 hours until landfall. If this had more time, it could definitely spin up into a tight-core cane. 

 

2. OUTLOOK FOR SUCCEEDING DAY:

A. FIX MISSION AT 05/1800Z NEAR 19.5N 68.5W IF SYSTEM

DEVELOPS.

B. POSSIBLE LOW LEVEL INVEST IN THE BAY OF CAMPECHE NEAR

20.0N 94.5W AT 05/1730Z. 

 

Tis the season for another crappy storm. 

 

[Derecho!]

If only 99L had 96 hours more time over the BoC before Tampico...

 

 

It's interestng that the CLIPER track is due North  - I wouldn't have thought that was the climo track for a BoC Storm this early in the season. So by all rights this should have been interesting, but isn't.

[wxmx]

People is too focused with the wave entering the Caribbean (justifiably), but I think the next named system might come from the wave currently approaching the Yucatan peninsula. It looks like a Fernand redux, but a tad north...the MJO wave strongest effects are crossing that area and we are very close to climo peak. Models are showing a surface trough or weak TD/TS at most, but this area usually outperforms a bit.

Gabrielle and it's 15 minutes of fame trolled this post, but otherwise it looks that it was a decent prognosis. TD to weak TS looks like a good bet before landfall around the Tampico area tomorrow morning.

[Amped]

It's not just the Atlantic thats struggling, all three basins in the nh have well below normal Ace. This might point to some issues with the stratosphere or glaam balance causing as a partial culprate.