I'm just a 23 year old with an ardent passion for weather. I first became aware of this interest after Tropical Storm Isidore struck my area in 2002.
By: KoritheMan , 12:43 AM GMT on July 31, 2010
A strong tropical wave, dubbed "Invest 90L" by the National Hurricane Center, has become less organized throughout today. This isn't due to unfavorable atmospheric conditions. Rather, it is due to interaction with a larger tropical wave to the east, near the Cape Verde Islands. I suspect that this wave will continue to gradually ingest Invest 90L, and will likely be designated "Invest 91L" tomorrow morning. This system is very poorly organized, with shortwave infrared satellite animations indicating very little in the way of shower activity, much less any cyclonic vorticity. I can detect a faint, very weak and rapidly dissipating spin from 8 to 9°N and along 34 to 32°W. The rest of the convection in the area is associated primarily with the ITCZ, not the wave.
Figure 1. Latest infrared satellite image of Invest 90L.
Latest CIMSS wind shear analysis from University of Wisconsin CIMSS depicts only 5-10 kt of northeasterly shear impinging upon the system. However, again, because of dangerously close proximity to the aforementioned tropical wave to the east, I am not expecting significant development of Invest 90L. Obviously though, it would be rather foolhardy for anyone to take their eyes off the system until the system completely loses its identity.
The Cape Verde wave should move W over the next couple of days, with a more WNW motion occurring in 60-72 hours as a shortwave trough weakens the ridge to the north. This system may pass north of the Leeward Islands and Puerto Rico in about five to seven days, but it is uncertain if this system will be able to recurve out to sea entirely. This system may be a long-range threat to the southeast or northeastern United States, but this is highly speculative, and residents living in those areas should not be overly concerned. Upper-level winds favor development over the next several days, but as the wave approaches the Lesser Antilles, strong westerly shear associated with the TUTT will return once again, which will make additional development or intensification highly improbable, and the system may even destroyed at that point.
Should it remain farther south, however, and enter the Caribbean, upper-level winds greatly favor intensification. This scenario is possible, given the large size of the system, which means it could take awhile to consolidate.
Eastern Caribbean tropical wave
A tropical wave located across the eastern Caribbean Sea continues to produce disorganized convection. Upper-level winds are currently unfavorable for development. This, along with the wave's fast forward speed, 20 to 25 mph (which is expected to continue for the next couple days, by the way), should prevent any appreciable organization from occurring until the system nears Central America in about two to three days. At that point, upper-level winds will also relax, and the system will have a small window of opportunity in which to become a tropical cyclone. I am not expecting this to happen, however.
Also, I still fully anticipate an active season. I cannot stress this enough. This season will be active -- in 1998, the most similar year to this one that I can find, the second named storm did not occur until August 20. That season ended up producing 14 named storms, 10 hurricanes, and 3 major hurricanes, and, most remarkably, four simultaneous hurricanes existed in the basin on September 25 -- Georges, Ivan, Jeanne, and Karl. The season also had three hurricanes impact the United States mainland: Bonnie, Earl, and Georges.
Lastly, it featured the mighty Hurricane Mitch, which killed anywhere from 11 to 20,000 people across portions of Central America due to days of prolonged torrential rainfall, which produced flash flooding and mudslides across mountainous areas.
While I'm not saying we're necessarily going to see an exact repeat of 1998, I do not want anyone to be foolish enough to drop their guard by thinking that the season is over. Most parameters still point to a sharp upswing in overall activity beginning the second week of August.
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