Hurricane Matthew is a monstrous storm unlike anything we’ve seen in the Atlantic Ocean in a long time. This morning, October 4, the Category 4 hurricane made landfall in Haiti, unleashing the brunt of its fury on the island nation—and it may soon do the same to Jamaica, Cuba, and the Bahamas. After that, the hurricane could either head out to sea or hit the U.S. East Coast head on. The hurricane is moving into a complicated weather pattern that the models are having a hard time figuring out, so we won’t know for a few more days what—if any—impacts Hurricane Matthew will have on the United States.

Data from the National Hurricane Center indicate that the storm currently has maximum sustained winds of 145 mph, ranking it as a Category 4 on the Saffir-Simpson Hurricane Wind Scale. The storm briefly reached Category 5 intensity this past weekend, making it the strongest storm we’ve seen in the Atlantic Ocean since Hurricane Felix in 2007 and one of a handful of storms in this part of the world to ever reach the top of the wind scale. It's also the first Category 4 hurricane to make landfall in Haiti in 52 years.

The National Hurricane Center’s forecast for Hurricane Matthew at 11:00 AM Eastern on October 3, 2016. Image credit: Dennis Mersereau

MODELING ITS POTENTIAL PATH

Hurricane Matthew’s worst winds are focused in a small part of the eyewall, but it still has a large shield of strong winds and extremely heavy rain that measures several hundred miles across. Forecasters expect deadly flash flooding and mudslides across Hispaniola, Jamaica, Cuba, and the Bahamas as Matthew passes through the area. Some parts of Haiti could see more than 2 feet of rain, leading to potentially devastating consequences. Already there are reports of deaths. The storm surge, or the flood of seawater pushed inland by the strong winds, could reach or exceed the height of a one-story house on the southern coasts of Haiti, Cuba, and some islands in the Bahamas.

The storm’s future is still an open question once it leaves the Caribbean. Some models steer the hurricane out to sea, while others bring it into the East Coast of the United States. The models are having a tough time determining how Matthew will interact with a ridge of high pressure over the Atlantic, which acts like a guard rail that keeps the storm from turning harmlessly out to sea. There’s also a trough of low pressure approaching the East Coast from the west that could catch the hurricane and drag it north, but the models disagree about that as well. The intricate play between Matthew and its environment will determine how much of a headache the storm will cause the United States in the next seven days. Data from extra weather balloon launches and persistent Hurricane Hunter missions into the storm will hopefully give weather models some extra information to work with so they can get a better handle on what will happen this week.

Everyone along the U.S. coast from Florida to Maine should keep an eye on the National Hurricane Center’s forecasts as Matthew draws closer to land. Any potential impacts to the U.S. will occur later this week or this weekend, so there are still a few days to make sure you’re prepared for a storm and its lasting effects in the event that it heads toward the coast. Either way, Matthew will generate powerful waves and rip currents at beaches up and down the eastern seaboard. Use extreme caution if you’re visiting the beach over the next week, and stay out of the water if conditions are too rough.

An infrared satellite view of Hurricane Matthew at peak strength on September 30, 2016. Image credit: NOAA/NASA

HOW IT GREW INTO A SCALE-TOPPING HURRICANE WITH ALARMING SPEED

Impacts aside, this hurricane is fascinating from a scientific perspective. Matthew grew from a small tropical storm into a powerful, scale-topping Category 5 hurricane with alarming speed. It took just 36 hours—between 11:00 a.m. EDT on September 29 to 11:00 p.m. EDT on September 30—for the storm’s winds to jump from 70 mph to 160 mph.

What’s even worse is that no human forecast or weather model expected Hurricane Matthew to turn into the monster it became. This hurricane is a prime example of how meteorology is still an inexact science. Matthew blew up over extremely warm waters, but it faced moderate wind shear that was expected to disrupt thunderstorms around the eye and keep it from strengthening as fast as it did.

Meteorologists have made great strides in improving hurricane track forecasts over the past couple of decades. They’re able to predict the location of most storms to within about 250 miles five days in advance—still a big margin of error, but much better than it was just a few years ago. While their track forecasts have improved, meteorologists still struggle with intensity forecasts, especially when rapid intensification occurs like we saw this weekend. There’s still a lot we don’t know about how hurricanes strengthen, and Matthew is proof of that struggle.

Hurricane Matthew is also odd because it didn’t look like a traditional Category 5 hurricane at its peak strength. The storm had an intense inner core with a weird, larger “blob” of convection to its east. The odd appendage was caused by easterly trade winds converging with Matthew’s winds circulating from the southwest. We normally don’t see that in the Caribbean because storms—especially strong ones—tend to keep moving west or northwest instead of stalling out and meandering for a few days.