Just tested on beta on a premade monk that has never been to Deepholm, and without the breadcrumb quest in my logs, I was able to access the first quests in Temple of Earth. So yes, this potion will let you cheat the travel to Orgrimmar and the fly in quest.
The Atlantic hurricane season is a time when most tropical cyclones are expected to develop across the northern Atlantic Ocean. It is currently defined as the time frame from June 1 through November 30, though in the past the season was defined as a shorter time frame.
(Check out sites like www.travelinsured.com or www.travelsafe.com for more information). As for hurricane season I would say things start to really pick up around mid to late August. It's really such a hit or miss when it comes to where or when a hurricane will hit. It's scary since the OBX hasn't had a major storm in the past couple of years, but I would say as a rule of thumb the later in the season the more likely the weather will get rough.