Could Hurricane Polo be a Category 6? Officially, absolutely not. But after Polo exploded into one of the most intense hurricanes ever measured in the eastern Pacific, the question doesn’t sound quite as ridiculous as it normally would. Polo peaked Tuesday at 180 mph sustained winds and a central pressure of 892 millibars, according to NOAA Hurricane Hunters. That pressure made it the second-most intense eastern Pacific hurricane on record, similar in scale only to Hurricane Patricia’s staggering 872 mb in 2015. By Thursday morning, Polo had fluctuated between Categories 4 and 5 and was listed at 155 mph by the National Hurricane Center. Category 5 begins at 157 mph. There is no official Category 6; everything above that threshold remains a five. That’s the point raised by independent forecasters now arguing that storms like Polo are beginning to stretch the usefulness of the current scale. Scientists have actually explored that idea.…