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August 2012

TD 5 Forms, not a Big Deal for Now, but Could Become One Later

   Posted by Levi at 2:19pm on August 2, 2012

Invest 99L developed into Tropical Depression #5 yesterday, and has maintained about the same intensity since then. Thunderstorm activity partially covers the center, but is still clearly being limited by wind shear being imposed on the northern side of the circulation by an upper low over the central Atlantic. This wind shear will continue to be a moderate issue for TD 5 over the next few days as the upper trough expands westward a bit to the north of the big Caribbean islands, following TD 5 as it too moves westward. The bigger issue for TD 5 though will be the strong trade wind flow that it is entering. The depression is now moving at 21mph, indicating the increasing flow that it is becoming embedded in, which will make it difficult for its circulation to survive and for thunderstorms to develop over it. This is a typical pattern for the eastern Caribbean that makes this region unfavorable most of the time for developing tropical systems, but especially during El Nino years like this one. Due to this pattern, I don’t expect TD 5 to really strengthen at all for the next 3-4 days. It may get named Ernesto, but should remain a very weak tropical storm for the time being, and could even degenerate back into an open wave at some point if it loses the westerlies on the southern side of its circulation. The lesser Antilles will get minimal tropical storm conditions from this starting tomorrow, but not a big deal there.

However, TD 5’s best days may lie well ahead of it. If TD 5’s circulation survives as a defined entity until it reaches Jamaica, the pattern starts to turn in its favor. Right now there is an upper trough over the northwest Caribbean that won’t be moving much over the next 7 days, and neither will the upper trough over the central Atlantic. As TD 5 moves westward, the NW Caribbean upper trough will start backing away to the southwest in front of TD 5, a situation that is almost always favorable, since it allows upper-level ridging to expand over the system and cause light wind shear and divergence aloft that promotes convection and lowering of pressures. The positioning of the TUTT-like trough to the northeast of TD 5 at that time would further improve ventilation of the area in general. The GFS ensemble mean supports this, as I show in the video. Such a pattern could rapidly become conducive for significant strengthening if TD 5 is organized enough to take advantage down the road in the northwest Caribbean and quite possibly the Gulf of Mexico.

As far as the future track goes, much will still depend on how strong TD 5 can get west of Jamaica if it is still alive, but some general ideas can be discussed. The GFS specifically and now the ECMWF have been leaning northwestward with TD 5’s track in the long term, and it is worth investigating whether this could make sense. I show in the video how the typhoon pattern in the western Pacific looks like it is connected with this idea, causing amplification in the pattern that ripples downstream and strengthens a trough over the eastern U.S. in 7-10 days that may break down the ridge over the Gulf of Mexico and allow TD 5 to turn northwestward towards the gulf. The strengthening of the eastern trough also looks like it could force the Texas heat ridge far enough back into the Rockies that Texas itself could be open to a hurricane hit in this kind of a situation, but such a pattern leaves everywhere from central America to Louisiana open to a hit, and specifics cannot be known this far in advance.

Overall, TD 5 is no big deal in the near term, and will be directly affecting only the Lesser Antilles as a tropical depression or minimal tropical storm tomorrow and Saturday. Jamaica and the rest of the NW Caribbean may have to deal with TD 5 in 4-6 days, possibly as a restrengthening system of higher caliber than it is now if it survives the trip through the Caribbean and is able to take advantage of what should be a much more favorable pattern for intensification in that area. Interests in the NW Caribbean, central America, and the Gulf of Mexico should keep a wary eye on this situation due to its possible long-range implications.

We shall see what happens!




  • Anonymous says:

    So if this lives this whole process and heads into the gulf of mexico, where do you think it will hit?

    • Peter says:

      Did you ever feel like you could never get over a broken heart and that the pain would go on fovreer? A woman?I know feels like this and I am so sad for her. She is 27. How did you get over it and what can a person say to help her?

  • Anonymous says:

    So if this lives through this whole Process and heads into the gulf of Mexico, where do you think it will hit?

    • Zach says:

      I believe he answered that pretty clearly in the video brotha – too far in the future to predict. It would be pure speculation. He said the entire gulf should monitor it, especially in 5-7 days. If it is the surf you are trying to forecast, then just wait and see like Im gonna have to.

      • Joshua says:

        Yes it is good that he has held them to account, HOwever $20 Billion droalls is a pittance in the ocean. It is nothing compared to the magnitude of the damage done to our world.. a damage that NEVER could be fixed, a permanent damage to the ecosystem the wildlife and our world. These sorts of accident have to be minimised BEFORE they happen. Is America concerned only with the money?? or with the state of the natural world?? This is going to impact on other seas and other countries ( the world is round) and America is not an Island separated from the rest of the planet.. Money is NOT everything.. but sure it is good that he held them to account. I would have liked to have seen BP dissolved completely and all it’s assets given to better causes like green peace and conservation programs.

    • Karen says:

      counseling and a good divorce sproupt group. time can heal but its’ what you do in that time. sometimes folks end up hurtnig for years and years but it’s cause they didnt do anything constructive during that crucial time. one day you’ll get to a point where you love him, and yet you can start your life again. good luck!

  • Anonymous says:

    Really appreciated the detailed explanation of the “ripples” caused by the typhoons. Mother Earth just amazes me when you can take a top-down view and watch how everything affects everything.

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