I understand that there is that chance of the jet stream forcing a curve toward the north, but we are dealing with a powerful (who knows what category in the open gulf) hurricane that wouldn't follow conventional wisdom and allow the jet stream to turn it towards the west-central coast. Also, that trough may yet be a factor when the system gets into the SE GOM. The NHC has taken these events into account in determining the impact they will have in 48 hours.
I would wait to see what the models' solutions will look like when Dennis enters the GOM.
There is little chance that meteorologists can solve the mysteries of weather until they gain an understanding of the mutual attraction of rain and weekends. ~Arnot Sheppard