Lots to talk about...the Atlantic areas are probably being discussed more than they should be but we're bored...
http://www.independentwx.com/discussion.html
IWIC Worldwide Tropical Weather Discussion - June 20 2005 - 23:00 UTC
The area of disturbed weather and associated 1006MB low pressure near 13ºN and 97ºW in the eastern Pacific has slowly organized over the last 24 hours. Satellite imagery depicts a developing outflow pattern in response to a ridge of high pressure aloft. There is some potential of further development into a tropical depression within the next couple days. However, even if the low develops into a classified tropical depression or minimal tropical storm, significant or rapid intensification is not likely. The main low center is still moving west at a faster rate than the upper ridge aloft, and an upper trough to the west of the approaching system has put a cap on convection in its path. In summary, there is about a 50/50 chance of classification, and a hurricane is nearly out of the question. The low will remain on a westerly or wnw course and the threat to Mexico is minimal.
Beyond day five, several models are indicating the development of another tropical cyclone in the same general area. Given an already converging model consensus in the medium range, development is worth considering. If a tropical cyclone does form, a track away from Mexico is most likely, but it is too early to be certain. Finally, the long-range GFS develops yet another East Pacific system late next week. Specifics in the GFS that far out are worthless, but adds to the point that it appears the East Pacific is finally becoming active after a month-long lull. Climatology does show this basin tends to become more active around this time of the year and into July.
As noted in the previous discussion, the Atlantic could become a bit more active in the medium range. Today, the 00Z and 12Z model guidance is depicting a very confusing pattern across much of the basin. None of the models develop a tropical cyclone over the next six days, but each model is hinting at falling surface pressures in either the northwest Caribbean Sea, southern Gulf of Mexico, or western Atlantic. We begin with a mention of the tropical wave producing gusty winds and heavy rainfall over the southern half of the Lesser Antilles. This will be the first wave of energy that will be monitored. The wave will probably split with one half continuing on a westerly path towards the Yucatan Peninsula, and the other spreading northward into the western Atlantic.
Conditions are very hostile in the western Caribbean due to the upper level troughing over Florida and the Gulf. However, the upper trough will slowly lift northward while an upper level ridge attempts to develop over the Yucatan Channel. The southern end of the wave would certainly bear watching once in the western Caribbean or southern Gulf of Mexico if conditions do become more favorable as some of the models suggest. One caveat in this line of thinking is the potential tropical cyclone in the eastern Pacific around day six. The aforementioned favorable environment applies to the west side of Mexico as well, and currently all of the models are far more bullish with this system than any in the Bay of Campeche or northwest Caribbean. If cyclogenesis does occur in the Pacific at the end of the forecast period, the cyclone's poleward outflow channel would induce strong shear into the Gulf and western Caribbean Sea and thus counter any conducive environment in that region. Tropical development is not expected at this time, but our thinking may change as the technicalities of the pattern are worked out by medium range model guidance. Keep in mind, tropical storm Arlene developed in a similar patten. Also, none of the models, barring the GFS, indicated tropical cyclone development until 12 hours prior to the first signs of developing low pressure north of Honduras.
Meanwhile, the northern end of the wave will lift northward due to mid level ridging north of Puerto Rico. The Canadian is the most bullish model pertaining to the northern scenario, with weak surface low formation occuring east of the Carolinas by day six. Currently, the southeast is being dominated by an upper trough, which is inhibiting development near the East Coast due to shear. the main upper level low centered near southeast Tennesse will retrograde eastward, and will eventually become quasi-stationary near the coast. Hereafter, the low level energy associated with the approaching wave will become entwined within the aformentioned mid-level circulation envelope. Thus, any surface low would be aided by baroclinic forcing. Furthermore, mid to upper level southwest winds will also remain high, so even if a weak low were to form east of the upper low, it would likely be sheared apart. No development is expected in the western Atlantic within the next six to seven days.