TheStormExpert wrote::uarrow: A west-based season would also explain why most storms originating from AEW’s have struggled until they’re out of the MDR and north of 20°N. Could this have something to do with some of these waves being monsoon-like allowing them to take longer to get their act together? Of course being that this is looking more like a west-based season means more landfalls and land impacts.
There certainly is a connection between the lack of Eastern and Central Atlantic developing tropical cyclones and the heavily weighted concentration of T.S. developing and tracking west of 60W, but the very fact that this is occurring does not explain "why" most storms originating from AEW's have struggled. This west based season is more a "result of" rather then an explanation of. There are obviously particular dynamics which have/are contributing to very favorable conditions for initial cyclogenesis and pretty much causing any mass of convection (perhaps as small as most vehicles from any old Cheech & Chong movie

- if you laugh, then you're old lol). In spite these very favorable conditions however, lies one or two other variables that are not only restricting Eastern and Central Atlantic development, but are clearly hampering most T.D.s and T.S.'s from continuing to develop deeper and stronger core structures. It's interesting to note that the primary exception to this also happens to be the westernmost tropical cyclone to develop thus far (Hannah) in the Atlantic basin thus far. We largely anticipated a very active and moist Easterly trade regime that would result in robust tropical waves to enter the far Eastern Atlantic, and this has clearly verified. Surface and mid level heights might have restricted the easternmost ITCZ on occasion but that is seasonal and hardly explains why Central Atlantic MDR development would be hampered that much. Therefore it seems reasonable enough to assume that the increased strength of these easterly trades have been equally responsible for introducing an extent of SAL that has up to now broadly impacted relative humidity throughout the 400mb-850mb layer. I think this has been enough of an impediment to disrupt and choke off the otherwise rich rising column of convergent moisture from the surface. We all know how much more difficult it is for fast moving tropical waves or T.D. to develop a vertical LLC and MLC structure. Now add the additional complexity of suddenly introducing a "Teflon-like" variable that is working against and interrupting any continuous convective cohesion to maintain a CDO or convective banding within the forming cyclone's structure. The area's that appear least affected by this "salty" air would clearly seem to be those areas well to the south (i.e. south of 10N latitude), and perhaps the western-most reaches of the Tropical Atlantic such as the W. Gulf. When and how long will these hampering conditions continue is a fair question but I can only guess that like most seasons, it is an ongoing process and even now is slowly continuing to work it's way out. I think it's reasonable to assume that as time moves forward these mid atmospheric dry conditions will become at least somewhat less of a factor. I'd guess that September will bring improved enough conditions to be more conducive to Central Atlantic MDR development. I still have to think though, that those western regions of the basin (roughly west of 70W but especially the W. Caribbean & GOM) will be the quickest to recover and pose the greatest risk of Major Hurricane occurrences by middle September. I think that going forward the combination of all present (and improving) mid-level conditions along with a primarily strong West Atlantic mid level ridging pattern and mostly shallow retro-graded Great lakes long-wave pattern..... suggest to me that Central America, W. Cuba, and GOM from the North Texas coastline to Florida stand the greatest risk for 2-4 Major Hurricanes yet to occur.