To prepare for the most powerful Atlantic tropical storm since 2007, you're going to need to grab your umbrella and some facts. NBC News reported that Hurricane Matthew is now being characterized by the National Hurricane Center as a Category 4 storm as of 11 a.m. this morning.Matthew has reached sustained winds of 145 mph, but that's not its only notable claim to fame. Here's what we know so far. According to the Weather Channel , the eye of the storm made landfall in the southwestern portion of Haiti, including the town of Les Cayes, Tuesday morning. There is already significant flooding in this area of the country, and the Weather Channel reports that Haiti could get up to 20 inches of rain in lower elevations and up to 40 inches in the mountains. CNN reported that last Wednesday, a teenage boy was killed in a landslide caused by Hurricane Matthew in St. Vincent and the Grenadines. In Haiti, a fisherman drowned Sunday, and another fisherman is presumed dead, though his body has yet to be recovered. The NHC predicts that Cuba should expect between eight and 12 inches of rain in most areas. Jamaica and the Dominican Republic will also be significantly affected. The Weather Channel reports that mountainous areas could get over a foot of rain, though, which could lead to dangerous flash flooding and mudslides. Eastern Cuba will have the greatest chance of seeing the strongest winds, according to the Weather Channel.The Weather Channel reports that Hurricane Matthew could take three or four days to clear the Bahamas. According to NBC News, a 10-to-15-foot storm surge is predicted here.A large portion of the East Coast will certainly be affected by at least a tropical storm, according to the Weather Channel. As of Monday evening, the NHC said, "While there remains significant uncertainty in the track of Matthew in the long range, the threat to Florida and the southeastern U.S. coast has increased."According to NBC News, on Monday, both Florida and North Carolina have activated states of emergency. Included in that are 66 of 100 counties in North Carolina and all counties in Florida. NBC meteorologist Bill Karins predicts that Hurricane Matthew will still be a Category 3 or 4 hurricane by the time it reaches Florida on Thursday.We'll keep you updated as we learn more.