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Atlantic Tropical Action 2013 - Part 2


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Feeling pessimistic about 93L...almost all models are now south of Tampico

 

Yep... and the closer to land the vorticity feature gets, the harder it will be to establish itself vs. the other different mesovorticies. I still think, however, there is a lot of uncertainty here given 93L is not quite well defined yet and won't be emerging into the BOC until tomorrow. 

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Yep... and the closer to land the vorticity feature gets, the harder it will be to establish itself vs. the other different mesovorticies. I still think, however, there is a lot of uncertainty here given 93L is not quite well defined yet and won't be emerging into the BOC until tomorrow. 

While I haven't had a ton of time to dig way into the data, my gut instinct from looking at some stuff this morning is the problem with 93L is that it's actually getting too organized too quickly.  Looking at visible imagery, it looks like there's already a pretty well organized vort center at 18.5N, 89W with decent banding.  It's motion would carry it back over water but way S in the deep BOC.  To me, when the GFS was showing something coming farther N it was because it took long enough for something to get concentrated in the gyre that the ridge to the N weakened and allowed everything to gain some latitude.  Now it is seeming more likely that assuming this is the main feature of interest it will tend to get trapped under the stronger ridging.

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 I'd pay a modest amount of attention to the area E of the Leewards if it can hold together somewhat. The reason is that the recurvature of it is very much in doubt as of now and the model consensus loosely suggests that some of its moisture/energy may be entrained into a developing cyclone (tropical or hybrid) in about ten days near the Bahamas or in the western Caribbean/E GOM. MJOwise, we're now and will (per the Euro) continue to be within the circle (for awhile), which has actually been relatively conducive for tropical genesis since 1995.

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While I haven't had a ton of time to dig way into the data, my gut instinct from looking at some stuff this morning is the problem with 93L is that it's actually getting too organized too quickly.  Looking at visible imagery, it looks like there's already a pretty well organized vort center at 18.5N, 89W with decent banding.  It's motion would carry it back over water but way S in the deep BOC.  To me, when the GFS was showing something coming farther N it was because it took long enough for something to get concentrated in the gyre that the ridge to the N weakened and allowed everything to gain some latitude.  Now it is seeming more likely that assuming this is the main feature of interest it will tend to get trapped under the stronger ridging.

There's something with the 850mb vorticity initialization in the 12z models...most of it is already in the BoC at hour 0...that would be 6 hours ago...as a consequence, they are too fast now with 93L, with no time to gain latitude. CIMSS shows that low level vorticity is still well inland, and what we are seeing in satellite imagery is even further east (mid level turning). Like Phil said, we still need to see where this thing develops first.

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 I'd pay a modest amount of attention to the area E of the Leewards if it can hold together somewhat. The reason is that the recurvature of it is very much in doubt as of now and the model consensus loosely suggests that some of its moisture/energy may be entrained into a developing cyclone (tropical or hybrid) in about ten days near the Bahamas or in the western Caribbean/E GOM. MJOwise, we're now and will (per the Euro) continue to be within the circle (for awhile), which has actually been relatively conducive for tropical genesis since 1995.

 

 Further to the above, the 12Z Euro is doing something similar to the 0Z Euro with a very slow moving tropical or hybrid cyclone forming near 70W E of the Bahamas on 9/19 with some of the moisture/energy seeming to originate with the entity that is now east of the Leewards. This forms underneath surface and upper ridging that then prevails over the far western Atlantic. Formation of surface lows below ridges like this is somewhat favored due to low level convergence below the high over warm water sometimes leading to homegrown surface lows in that area, especially from mid-Sep. to mid-Oct, when SST's are stlil quite warm and upper winds often still rather light. 1984's Diana comes to my mind to some extent.

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There's something with the 850mb vorticity initialization in the 12z models...most of it is already in the BoC at hour 0...that would be 6 hours ago...as a consequence, they are too fast now with 93L, with no time to gain latitude. CIMSS shows that low level vorticity is still well inland, and what we are seeing in satellite imagery is even further east (mid level turning). Like Phil said, we still need to see where this thing develops first.

That makes total sense, Jorge, thanks...

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While I haven't had a ton of time to dig way into the data, my gut instinct from looking at some stuff this morning is the problem with 93L is that it's actually getting too organized too quickly.  Looking at visible imagery, it looks like there's already a pretty well organized vort center at 18.5N, 89W with decent banding.  It's motion would carry it back over water but way S in the deep BOC.  To me, when the GFS was showing something coming farther N it was because it took long enough for something to get concentrated in the gyre that the ridge to the N weakened and allowed everything to gain some latitude.  Now it is seeming more likely that assuming this is the main feature of interest it will tend to get trapped under the stronger ridging.

 

I think you are overestimating how organized 93L is currently... the big blob of convection earlier was deceptive, as there is still no well defined llc. Decent mid-level vortex, but the surface obs suggest there isn't much of a surface reflection (yet)

 

1693t69.gif

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Getting sooooo sick of these BoC systems that are always just 10 mi offshore.

 

I've seriously forgotten what it's like to track a healthy Caribbean Cruiser with nothing but warm water and low shear ahead of it.  It just seems like the NATL forgot that recipe.

 

Well again there is a ton of uncertainty with 93L. The 18z GFS is bringing back the small intense TC solution from the looks of it early on...

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I think you are overestimating how organized 93L is currently... the big blob of convection earlier was deceptive, as there is still no well defined llc. Decent mid-level vortex, but the surface obs suggest there isn't much of a surface reflection (yet)

 

 

Yeah, I hope I wasn't implying that it was like about to be a TC, LOL - more just that it had more vorticity and organiziation than it seemed as if the models had been implying a day or two ago. As wxmx says, the 12Z GFS was too far W with its initialization of the vorticity, and now that it is better analyzed, seems to have trended back toward the more robust, somewhat farther north idea.

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Well again there is a ton of uncertainty with 93L. The 18z GFS is bringing back the small intense TC solution from the looks of it early on...

 

I'm not saying it's dead. I mean I'm just weary of these borderline situations where the difference between it being an intense hurricane a or a depression is 10 miles and 6 hours.  It's just boring after a while.  Remember when we had 'canes like Dean and Felix just barreling across the Caribbean, moving in a straight line, getting crazy-intense, for days?  Can't remember that feeling.  Now it's this spinning-up-ten-miles-offshore crap.  Even Baby Ernie last year-- which was awesome and a cool chase-- was the same d*mn thing--  it played games until the end and only became a strong cyclone two hours before landfall.

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One bit of housekeeping:  thread owners should be better about updating the thread titles.  Gabrielle has been a TS for a couple of days now, and Humberto has a been a hurricane since this morning.  If the thread owners don't do it, the mods should, I think.

I made Humberto's thread but apparently don't have the power to update it.

 

18z GFS:

 

73wMI1f.png

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I'm not saying it's dead. m I mean I'm just weary of these borderline situations where the difference between it being an intense hurricane a or depression is 10 miles and 6 hours.  It's just boring after a while.  Remember when we had 'canes like Dean and Felix just barreling across the Caribbean, moving in a straight line, getting crazy-intense, for days?  Can't remember that feeling.  Now it's this spinning-up-ten-miles-offshore crap.  Even Baby Ernie last year-- which was awesome and a cool chase-- was the same d*mn thing--  it played games until the end and only became a strong cyclone two hours before landfall.

 

Well from a forecasting perspective these are the interesting ones because there is so little margin for error. Storms like Dean and Felix are very rare and the mid-2000s had an abnormal stretch of these types of systems. 

 

2001 Iris

2004 Ivan

2005 Dennis, Emily

2007 Dean, Felix

2008 Gustav

 

prior to this period there was no Caribbean cruser (defined as a Major Hurricane that undergoes genesis in the Eastern Caribbean or MDR then moves into the Caribbean) since 1988, so you can go a decade or more without seeing one of these particular types of storms.

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I'm not saying it's dead. I mean I'm just weary of these borderline situations where the difference between it being an intense hurricane a or a depression is 10 miles and 6 hours.  It's just boring after a while.  Remember when we had 'canes like Dean and Felix just barreling across the Caribbean, moving in a straight line, getting crazy-intense, for days?  Can't remember that feeling.  Now it's this spinning-up-ten-miles-offshore crap.  Even Baby Ernie last year-- which was awesome and a cool chase-- was the same d*mn thing--  it played games until the end and only became a strong cyclone two hours before landfall.

 

One thing I recall is the lack of northward motion in this area since around 2005. Think of all the BOC straight into Mexico storms we've had since then.

 

Bret '05

Gert '05

Jose '05

Lorenzo '07

Marco '08

Hermine '10

Karl '10

Arlene '11

Nate '11

Helene '12

 

With the exceptions of Lorenzo, Karl and Nate none of them became hurricanes and only Hermine had a northwest component to it's track.

 

I do recall back as a kid in the 1990s many more fronts and thunderstorms which would equate to much more back and forth movement of the high pressure domes that protected the Gulf Coast. You had more Opal and Bret situations rather than what we've seen the last few years.

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18z GFS is back a bit north...and a lot stronger...don't mind the MSLP in the model...the 850mb vorticity is the strongest of any run so far...it's a very smal cyclone and it goes thru the warm eddy east of Tampico full length wise .

 

It maxes the vorticity scale

 

post-29-0-99416300-1378939107_thumb.png

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Getting sooooo sick of these BoC systems that are always just 10 mi offshore.

 

I've seriously forgotten what it's like to track a healthy Caribbean Cruiser with nothing but warm water and low shear ahead of it.  It just seems like the NATL forgot that recipe.

 

True, the Caribbean really started getting drier after after the 2007 season with Dean and Felix.

 

 

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