Just before 9 a.m. on Monday Lt. Col. Jeff Ragusa briefed his crew at Keesler Air Force Base in Biloxi, Mississippi.

"The weather forecast is: hurricane."

Hurricane Dorian, then a Category 5 storm packing wind gusts of more than 200 mph, was over the Caribbean, threatening a swath of the East Coast from Florida to North Carolina. The Hurricane Hunters were about to fly directly into the storm. CNBC joined them on the flight.

Members of the Hurricane Hunters, the 53rd Weather Reconnaissance Squadron, have been flying on WC-130 Hercules aircraft, propeller planes specially outfitted to track weather and fly long missions, almost around the clock from the base in Biloxi into Dorian, as they do for other tropical cyclones.

These Air Force pilots, meteorologists, navigators and technicians, are tasked with collecting and transmitting data that will help federal forecasters advise countless other state agencies and businesses from airlines to hotels to retailers as they prepare for the projected the path of the storm, and if needed, evacuate.

"You have plenty of land observation," said Joel Cline, a meteorologist at the National Oceanic and Atmospheric Administration's National Weather Service. "With hurricanes if we wait to get land observations, it's a little bit late to be warning people."

The Hurricane Hunters' 10-hour mission, on Monday morning, their 32nd for this storm, included four passes through Dorian's 24-mile eye. The NOAA has its own storm-chasing team.

Weather technicians will request a path for pilots, helping them gather data, but they are careful to avoid tornadoes.

"People think Hurricane Hunters will do anything," said Ragusa. "We don't do tornadoes."

The task of predicting hurricanes remains remarkably difficult because of the number of variables that can affect a storm's path, such as winds and weather systems thousands of miles away.