Disturbance ten bound for Bay of Campeche
General outlook 1400Z 29th June 2013
Tropical disturbance ten is now centred just to the north of the Cayman Islands and producing an increase in thunderstorm activity across the northern half of the Caribbean, through the Yucatan Channel and into the Bay of Campeche. It is almost certain that this system will make a guest appearance in the Bay of Campeche early next week. Whilst the warm waters of the entire Gulf of Mexico are fertile for storm development, there is some upper level activity aloft that is hampering vertical organisation. Thus, the chances of this disturbance becoming much more than a fairly uninspiring tropical depression are slim. Irrespective of whatever this system does when it reaches the Bay of Campeche as far as strength is concerned, it is only likely to head ashore in Mexico rather rapidly. Like BARRY, this is likely to be a rainmaker.
Further to the east, tropical disturbance twelve is now around 12 hours steaming into the Caribbean and producing some very promising showers and thunderstorms with some quite stiff gusts in patches, however there are two factors which will spoil the party. First, the system has again accelerated to around 20 knots which does not permit a decent vertical heat and moisture chain from forming. In addition, there is an upper level low which is producing upper level shear, another passion killer I'm afraid.
As we reported earlier this week, satellite imagery is showing cloud systems which may be dragging Saharan air into the convergence zone. This is unlikely to continue for too long, but for now will severely inhibit the trans-Atlantic production line. The system we reported as leaving the African coast looks to have stalled, and may be a victim of dry and sandy air.