First of all...it's not a hurricane...its a tropical storm. Second...it's never NOT been moving westward (towards the W or WNW)...so there is no already turned west. Cape Verde storms that head towards the mainland ALWAYS head west...before they turn northward.
And it doesn't have to hit Tampa to be a mess. If it comes anywhere close (and is strong) the surge will be an issue...and coastal evacuations are the last thing you want during your convention.
The simple margin of error in both track and intensity forecasting, and the fact the convention area is mostly in a Category 1 evacuation zone, and the fact that evacuations have to start well in advance of a possible landfall, means I thin there actually is a pretty high probably they have to delay or cancel the convention.