ATL: GABRIELLE - Remnants - Discussion

['CaneFreak]

Looks like a slowly developing disturbance to me. Don't think the chances will go up much at 8 pm. Maybe back up to 40 % or something in 48 hours and likely to stay the same or slightly increase at 50 or 60 % probabilities in 5 days. Looks like we are back where we were Sunday at this time. Needs to continue the increase in convection for 12-24 hours before any upgrade occurs.

[CronkPSU]

I am surprised this thread isn't busier considering the ramp up today and everyone dieing to track something

looks pretty good right now, bears watching

[gatorcane]

I am surprised this thread isn't busier considering the ramp up today and everyone dieing to track something

looks pretty good right now, bears watching

Look at all the convection, saved loop:

[jlauderdal]

I am surprised this thread isn't busier considering the ramp up today and everyone dieing to track something

looks pretty good right now, bears watching

Floridians and islanders, that it for this one

['CaneFreak]

Latest vorticity maps just came in and they indicate a significant battle is likely to take place in the coming days between the lower level circulation to the north and the lower level circulation to the south (i.e. 97L). A significant increase in organization of the northern lower level vort leads me to believe that there might be some Fujiwara swirling of the two disturbances given the close proximity. Not something you want to see if you are looking for a significant storm to develop.

Edit: However, a significant storm could develop once this gets north of Hispaniola provided that there is still some significant lower level vorticity left to work with.

http://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor&zoom=&time=

[caneman]

Latest vorticity maps just came in and they indicate a significant battle is likely to take place in the coming days between the lower level circulation to the north and the lower level circulation to the south (i.e. 97L). A significant increase in organization of the northern lower level vort leads me to believe that there might be some Fujiwara swirling of the two disturbances given the close proximity. Not something you want to see if you are looking for a significant storm to develop.

Edit: However, a significant storm could develop once this gets north of Hispaniola provided that there is still some significant lower level vorticity left to work with.

http://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor&zoom=&time=

The models seem to indicate so. Looks to be coming together. Interesting times ahead. MAy be the only big thing we get this year.

[ozonepete]

I am surprised this thread isn't busier considering the ramp up today and everyone dieing to track something

looks pretty good right now, bears watching

A lot of us have to work all day and can't get to a computer or would get fired for being on storm2k at work, lol.

[tailgater]

This GOMer thinks it should be 50 % if it continues to organize, low level really improved today and convection seems to following, all we need IMHO is a little more organization of convection and we should see pressures starting to drop farther, to become a TD.
.

[HurricaneDREW92]

I am surprised this thread isn't busier considering the ramp up today and everyone dieing to track something

looks pretty good right now, bears watching

A lot of us have to work all day and can't get to a computer or would get fired for being on storm2k at work, lol.

Ozonepete, any chance if this develops more we get a TD at 11pm? Thanks in advance

[ozonepete]

Dare I say remember it is in the East Caribbean.

While the Caribbean low level jet can increase low level divergence and cut down on genesis, it's really more of a feature of the early season. Once you get to September, the Eastern Caribbean sees formation on par with the rest of the basin, and in the late season, is even proportionally a little higher.

So, like many things on the board, this is something that has some truth to it, but gets overused and beaten into the ground.

This paper is technical, but since it's in BAMS, is written to be a little more accessible: http://journals.ametsoc.org/doi/pdf/10. ... BAMS2822.1

I'm not disputing that however I saw a formation chart for early September on TWC last night that shows the opposite. Also, don't forget that each individual year affects the process and this year has been unquestionably unfavorable.

I'd even add that yesterday's low level cloud formation in the east Caribbean showed a streaky, striated appearance with higher speed while the low level clouds above the Antilles showed a more even, slower pattern. This itself is a visual clue of the effect.

True is right here. You have to look at all of the factors and I agree that the "east Caribbean graveyard" idea is too often way overused here. Every year is different as you said, sanibel, but this year has been different because the conditions have been more favorable in the eastern Caribbean than usual. It is high shear through the mid to upper levels, not fast low level winds alone, that traditionally make the eastern Caribbean a hostile place until September. But shear has actually been often lighter in the eastern Caribbean this season than normal. Much of the unfavorable conditions so far this season have been due to dry, stable air, especially due to a lot of SAL. And fast low-level winds only tell you about the lowest levels; they don't give you a picture of the total shear at all. Chantal still developed while low level winds were really fast because it had a really fast forward speed which negated the effect. Each case is different and you can't use climatology when the current conditions don't agree with climatology. The NHC has said consistently over the past few days that shear is not a problem and upper winds are favorable for development of this system. So we can ignore that part of the climatology for this storm for now.

[Dean4Storms]

I have the center of the overall rotation near 64W 15.8N moving due west, is that about what everyone else is seeing?

[HurricaneDREW92]

I have the center of the overall rotation near 64W 15.8N moving due west, is that about what everyone else is seeing?

I believe so, yes.

[ozonepete]

I am surprised this thread isn't busier considering the ramp up today and everyone dieing to track something

looks pretty good right now, bears watching

A lot of us have to work all day and can't get to a computer or would get fired for being on storm2k at work, lol.

Ozonepete, any chance if this develops more we get a TD at 11pm? Thanks in advance

I don't think so. I think the earliest is tomorrow sometime. This just looks like a slow developer. It's still fighting with the disturbance to the northeast for control, although it appears to finally be winning. But we need to see the convection with that one to the northeast collapse more - it is also probably feeding some dry air into the western one. It sure looks like it will be a TD tomorrow though.

Btw someone mentioned Fujiwhara effect earlier. That's a really smart idea to suspect it, but these are too weak for that to happen. These are currently just two very weak disturbances that are entwined together in one broad low. The one that develops more convection and holds it for many hours will be the one that takes control. While visually it's getting pretty obvious which one will win, the northeastern disturbance hasn't collapsed yet. One interesting sign is that the 500 mb vorticity is starting to consolidate over the western disturbance and convection is really increasing over it even though we are near DMIN time. So this might be a sign that this is ready to take off betwen now and tomorrow. But not by 11PM I wouldn't think.

[Alyono]

wouldnt that other disturbance be sheared badly by this system's upper high?

Not sure the models are capturing that aspect

[HurricaneDREW92]

A lot of us have to work all day and can't get to a computer or would get fired for being on storm2k at work, lol.

Ozonepete, any chance if this develops more we get a TD at 11pm? Thanks in advance

I don't think so. I think the earliest is tomorrow sometime. This just looks like a slow developer. It's still fighting with the disturbance to the northeast for control, although it appears to finally be winning. But we need to see the convection with that one to the northeast collapse more - it is also probably feeding some dry air into the western one. It sure looks like it will be a TD tomorrow though.

Btw someone mentioned Fujiwhara effect earlier. That's a really smart idea to suspect it, but these are too weak for that to happen. These are currently just two very weak disturbances that are entwined together in one broad low. The one that develops more convection and holds it for many hours will be the one that takes control. While visually it's getting pretty obvious which one will win, the northeastern disturbance hasn't collapsed yet. One interesting sign is that the 500 mb vorticity is starting to consolidate over the western disturbance and convection is really increasing over it even though we are near DMIN time. So this might be a sign that this is ready to take off betwen now and tomorrow. But not by 11PM I wouldn't think.

Thank you for your input, ozonepete . Personally feel they'll go conservative at the 8pm TWO at 50/70%, but we could see a code red then, too.

[HurricaneDREW92]

TWC met said, "A Major Threat AnyWhere From Miami to Nova Scotia" hasn't even developed yet!

[TJRE]

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http://www.nrlmry.navy.mil/

Latest BD

Hello to the crew!!!

[ozonepete]

wouldnt that other disturbance be sheared badly by this system's upper high?

Not sure the models are capturing that aspect

One would think so. But this is a truly complex situation. If you look at the charts (such as CIMSS) each disturbance has their own closed area of upper divergence but they still share a common area of lower convergence. I would say in fairness that the models haven't done too badly so far because they haven't reconciled the problem and neither can we so far, lol. But the general model consensus has the western one winning out and then a good possibility of development. Visually this seems to be playing out, albeit at a very slow speed.

UPPER DIVERGENCE


LOWER CONVERGENCE

[sfwx]

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
342 PM EDT TUE SEP 3 2013

.DISCUSSION...


FOR LATER THIS WEEK AND WEEKEND...THE AXIS OF HIGHER SURFACE PRESSURE THAT
SETS UP ACROSS THE FLORIDA PENINSULA WILL STEADILY WEAKEN THROUGH THE
UPCOMING WEEKEND THANKS TO LOW PRESSURE THAT WILL BE EXTENDING
NORTHWARD FROM THE NORTH/NORTHEASTERN CARIBBEAN. THERE IS STILL
PLENTY OF UNCERTAINTY AS TO THE EXTENT OF THE STRENGTH OR POSITION OF
ANY POTENTIAL TROPICAL SYSTEM EMANATING FROM THIS AREA. GFS GRAPHICAL
GUIDANCE HAS BEEN THE MOST CONSISTENT WITH A MORE DISCREET AND
STRONGER SYSTEM...REMAIN WELL EAST OF THE KEYS. OTHER RELIABLE GLOBAL
MODELS MOVE A FASTER WAVE WELL TO OUR SOUTH. AT THIS POINT...IT IS
STILL PRUDENT TO KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH
THOSE LATE PERIODS...AND NOT MAKE RADICAL CHANGES TO OUR WIND LOCAL FIELD.

[ozonepete]

Thank you for your input, ozonepete . Personally feel they'll go conservative at the 8pm TWO at 50/70%, but we could see a code red then, too.

While they might do the code red at 8PM, I'm pretty sure they'll do it by 2 AM.