Mountainous terrain will have an impact on two types of storms in particular: those with small inner cores and those that are relatively weak. The terrain causes all sorts of disruptions in the low-level flow, where the strongest part of a hurricane's circulation is found. This is above and beyond the normal effects of friction over flat land.

As noted in the revised first post, recon found a pressure of 938mb and flight level winds of 136kt in the southeast quadrant. They are on their way to the northeast quadrant and, given that data and the absolutely remarkable appearance on satellite imagery, I believe they may well find even stronger winds up there. We'll know by 11am, but Dennis is well on its way to potentially becoming a category 5 hurricane before making landfall once again in Cuba. The satellite appearance this morning is textbook -- though you may notice a slight elongation towards the north in later frames -- and the waters in that part of the basin just south of Cuba are the warmest and deepest in the entire Atlantic basin.

Needless to say, this storm is going to pack quite a fury for central Cuba later on today, and we can only hope that the trek over land -- and later, the trek to the north -- causes it to weaken and not maintain (to later strengthen over water).

To answer any potential follow-up question: no, I don't know of any category 5 hurricanes in July. I'm not saying this storm will become one, but it may be closer than we think and has the potential to do so in the next 6 hours or so before its rendezvous in Cuba.