The lack of activity projected by models next two weeks shouldn't be too surprising.
*All* of the years since 1995 with a strong W African monsoon saw little significant activity (i.e hurricanes) in the MDR starting from Aug 1 through most of the month, until either the last week of Aug or early Sep.This includes 1999, 2003, 2008, 2010, 2012, 2016, 2017 and 2018.
Main reason has been discussed here by Cyclonicfury and others- when the W African monsoon is strong, rainfall in Sahel and the ITCZ are displaced north of climo, and the climo ITCZ position in Aug is already the northernmost of any month in hurricane season. This generally means tropical waves come off the African coast at too high a latitude to develop, encountering too much dry air and cool SSTs.
Even Irma and Florence, which broke the exended spell of no MDR development in the past two years, came off at an unusually high latitude for a developing Cape Verde TC.
LarryWx wrote:
My interpretation of the 12Z Euro ensembles (50+ members) is that all the way through day 15 (the above discussed link stops at day 10) it is a much quieter than average run for the climo relatively busy 8/12-27. Out of these 50+ members, there's hardly even a minimal hurricane through the entire 15 days! This is amazingly quiet, folks, for mid to late August! If one wants a busy August, this is not what one should want to see.
I apparently overlooked the current indicators are signaling shear dropoff down there. We will see if that lasts. These assessments can change. Personally, I hope that shear remains strong in the Caribbean in that it will keep down the number of damaging tropical cyclones from impacting areas down there and the CONUS. Shear levels are not crippling as they were in other years right now, but the Dry air really has been the major problem in the MDR and Caribbean.
