ATL: Invest 97L in Central Atlantic

[Cyclone1]

Well, convection has increased considerably since just this mornng, which is impressive given the dry air and time of day

[wzrgirl1]

what do you all think about the loop scenario I suggested above?

A loop could happen if a system gets pulled N by a weakness (e.g. from a short-wave trough) but the trough does not completely catch the system and a ridge builds in from the NW behind the trough pushing the system west again.

I see no evidence of such a situation with 97L and even so its so long out (like 7-10 days) and so many IFs (like will 97L even develop) that I haven't thought much about it. Are you seeing something with the long-range synoptics that may suggest a loop?

Actually gator I haven't really seen anything....only looking at the models and towards the end of the runs it seems as if they are in the beginnings of a possible loop, but I haven't studied the environment in the long range as of yet....

http://www.wunderground.com/tropical/tr ... model.html

[RL3AO]

Its probably close to meeting the definition of a tropical depression. Doesn't mean the NHC will upgrade anytime soon.

[cycloneye]

The latest ATCF Best Track at 18:00 UTC:

AL, 97, 2008072518, , BEST, 0, 183N, 422W, 25, 1010, DB, 34, NEQ, 0, 0, 0, 0, 1012, 120, 25, 0, 0,

[cycloneye]

The latest pic:

[Recurve]

Obviously not much coverage but it looks like there's inflow from everywhere, if those are low clouds.

[gatorcane]

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Here is a good loop for members to look at as to why the forecast reasoning is for a recurve:

http://www.ssd.noaa.gov/goes/east/natl/loop-wv.html

Check out the deep trough digging down at around 50W as a powerful Northern Atlantic Low spinning on the top of the screen is pushing south. That should be enough to deflect 97L out to sea ultimately.

There is also a stationary ULL low parked just SSE of Bermuda also. Even if 97L were to head more W it would be running into hostile Upper-Level winds.

I expect 97L to slide inbetween the ULL and the trough digging south and bend NNW around 50-55W again well NE of the Leewards and out of harms way.

[HURAKAN]

[RL3AO]

Nice look at the exposed center.

[cycloneye]

I see a circulation at 17.8n-42.5w.

[Thunder44]

:uarrow: I see a circulation at 17.8n-42.5w.

I think you see a smaller circulation to north of the one I saw earlier at 14.5N. They both actually seem to be rotating around broader center in between. Still a disorganzied system.

[Ed Mahmoud]

Double Post Alert:

This wave seems to extend all the way to the ITCZ, with an enhancement of activity just South of 10ºN

The most prominent apparent circulation closer to 18ºN seems part of a looser elliptical circulation extending SSW from the 18º circulation that seems to suggest fairly low level West winds down to about 13ºN, with a lesser maximum, or "pole", of the elliptical circulation near 15ºN, 44ºW.

The more convectively active part of the circulation could break off and try to develop, leaving the Southern end of the wave to continue on a more Westward path.

Perhaps the models are picking up on that with a fairly quick recurve of the partially exposed circulation closer to the convection.

The 12Z GFS quickly develops the Northernmost vorticity, and pulls the Southernmost 850 mb vort max into it, but notice it initializes the Southern vort max stronger.



I'm not convinced the 18ºN will overcome dry air and shear to develop. However, if it does, I'm not sure part of the wave won't continue Westward, and may become active in the Caribbean or Pacific.

[gatorcane]

looks like the "LLC" at 17.9N is moving due west at the moment while the convection is getting sheared off to the NE. That may give an appearance it is moving WNW already when indeed the swirl continues moving west.

http://www.ssd.noaa.gov/goes/east/tatl/loop-vis.html

[HURAKAN]

[KWT]

Whilst the convection is obviously displaced it is closer to being a system then before anyway given we at least now do have some convection at least!

I'm not expecting this to become too strong if it does get going but still too early to tell I suppose.

[HURAKAN]

[GeneratorPower]

Nothing more than an ACE booster if it develops. Sounds good to me!

[cycloneye]

Nothing more than an ACE booster if it develops. Sounds good to me!

If it develops looks like a 45 ACE for the season when its done.Its 37.1 now.

[fasterdisaster]

I wouldn't COMPLETELY rule out a hit on the Carolinas but it does look likely this will be a fish.

[HURAKAN]

Loop: http://rammb.cira.colostate.edu/ramsdis ... is_floater

Convection detaching from circulation.