Rob_M
Weather Hobbyist
Reged:
Posts: 60
Loc: Cary, NC
|
Discussion
Wed Jul 28 2004 06:42 PM
|
|
|
Unless the E GOM or W ATL areas pull a fast one, it looks like we'll end Jul with no TCs. Not to worry...the time will come. Perhaps sooner rather than later. Here's our latest discussion FWIW...
IWIC Atlantic Tropical Weather Discussion - 28 July 2004 - 1:20 PM EDT
For the most part, weather in the tropical Atlantic remains quiet. There are a few areas worth mentioning, however. Firstly, a strong upper level cyclone and associated surface trough are generating scattered convection from the Bahamas to 60ºW by strong diffluence. This disturbance has changed little over the past 24 hours and remains poorly organized. The only model that shows development of this system is the CMC. Considering that no other model is in agreement, plus the CMC's recent bias to over-amplifying lows in the subtropics, it is probably wise to disregard this solution. The entire model guidance indicates an upper level ridge will build over the Gulf of Mexico behind the current trough exiting the United States east coast in the next 2 to 3 days. Strong southerly shear over the western Atlantic will thus be enhanced and hinder any barotropic intensification from this system.
Another area worth watching is a weak area of convection along the remnants of a old frontal boundary in the eastern Gulf of Mexico. At the moment there is no low level center, but global model guidance does show increased low level cyclonic flow from this system over the next few days. A possible reason is the ridging progged to settle in the Gulf of Mexico as mentioned above. This will reduce shear values and aid evacuation aloft. Where any potential low will track is still in question, as models are a bit more diverged. Some lean towards a quasi-stationary motion in the eastern Gulf of Mexico, such as the GFS, whereas others take a possible low further west, such as the UKMET. Despite the favorable upper environment that may set in place, a classified tropical cyclone is still far-fetched at this point. The main reason being that, under normal circumstances, it will take more than a few days for a poorly organized area of showers along the tail of an old frontal boundary to organize into a strong enough low level pressure system. It will be an area to keep an eye on, but no tropical development is expected at this time.
In the Mean Development Region, Saharan Air and subsidence are suppressing the Intertropical Convergence Zone and traversing tropical waves. However, a high-amplitude tropical wave that just exited the western African coast will help clear the stable environment in place. Furthermore, over the African continent just north of the equator, several concentrated areas of convection have formed, possibly signalling the beginning of a tropical wave train. The operational GFS has now developed a tropical cyclone in the eastern Atlantic late in the forecast period for the past 5 runs, probably from one of these areas of convection over Africa. Although there is currently no support from other global models, this bears watching given the gradually improving Mean Development Region environment and the consistency in the GFS. To top all of that off, a dry Madden-Julian Oscillation that currently resides in the Atlantic Basin will move out of the area and be replaced by a wet phase by the middle of the upcoming month. So whether the exact tropical wave develops as the GFS shows or not, all indications point towards a significant increase in deep Atlantic tropical cyclone activity over the coming weeks as the peak of the season draws closer.
--------------------
Rob Mann
IndependentWx.Com
|
|
Previous
Index
Next
Flat
Edit
Reply
Quote
