Irma is the second most powerful hurricane ever recorded–so far. Hurricanes get their power from a heated surface; if the warm surface layer is shallow, they can deplete this heat source quickly–but in Irma’s case, the warm water goes deeper than usual. Wind shear can break up the vertical structure of a hurricane–those towering funnels– but wind shear is currently low. Such factors, plus the wind circulation above between high and low pressure areas, determine when Irma turns north–and thus what path it takes near Florida. The temps shown range from about 82F white to 87+deg F red. WHC
