As Hurricane Florence was officially declared a Category 4 storm on Monday by the National Hurricane Center, weather experts warned people living in vulnerable areas in South Carolina, North Carolina, and Virginia that the intensification should not be ignored and to begin making preparations for what could be a devastating landfall later this week.

According to the noon-time update from the NHC, operated by the National Oceanic and Atmospheric Administration (NOAA), Florence currently has sustained winds of nearly 130 mph and has no become what the agency considers "a major hurricane."

Though no coastal advisories are yet in place, the update said that those warnings would likely be forthcoming. Now tracking in the Atlantic Ocean southeast of the U.S. mainland, "A turn toward the northwest is forecast to occur late Wednesday night," the latest NHC dispatch stated. "On the forecast track, the center of Florence will move over the southwestern Atlantic Ocean between Bermuda and the Bahamas Tuesday and Wednesday, and approach the coast of South Carolina or North Carolina on Thursday."

In response to the upgrade, meteorologists and weather-trackers warned people to pay attention to future developments.

"Folks, if you are in the Carolinas or Virginia -- this is a historic storm," declared Eric Holthaus, meteorologist and journalist who writes about extreme weather and climate change for Grist. "Take every available precaution. Help your neighbors. Do not underestimate this hurricane."

And Holthaus warned that Florence could well turn into a Category 5: