However , the return of dry air and upwelling of cooler waters caused Causation the system to deteriorate into a tropical storm .

Dry air , westerly wind shear , and upwelling of cold waters prevented Preventing_or_letting further intensification over the next 24 hours .

As a result of its slow motion , the storm Catastrophe caused Causation significant upwelling Motion , leading to Causation a marked decrease Cause_change_of_position_on_a_scale in convection , and weakening Cause_change_of_strength accordingly .

However , due Causation to its slow movement , the storm causing Causation upwelling , which decreased Cause_change_of_position_on_a_scale sea surface temperatures ( SST 's ) , weakening Cause_change_of_strength Leslie back to a tropical storm on September 7 .