Arthur is "not a bellwether," said Dennis Feltgen, spokesman for the National Hurricane Center. "We are not forecasting it to be a major hurricane."
Arthur as of 8:50 a.m. PST was expected to become a Category 2 storm, Feltgen told the Los Angeles Times. Winds, at 90 mph, were expected to surpass 96 mph, he said.
In May, the National Oceanic and Atmospheric Administration predicted a slow Atlantic hurricane season, with eight to 13 named storms and one to two major hurricanes. Hurricanes -- measured from 1 to 5 on the Saffir-Simpson Hurricane Wind Scale -- are not considered major until hitting Category 3, when winds reach 111 to 129 mph, "well-built framed homes may incur major damage ... many trees will be snapped or uprooted, blocking numerous roads" and electricity and water are unavailable for days to weeks after the storm passes, according to the hurricane center.
Arthur's nothing to sneeze at, however.
The tropical storm graduated to hurricane status early Thursday. At Category 1, a hurricane's winds are from 74 to 96 mph. Category 2's "extremely dangerous winds" can reach 110 mph and could cause major roof damage to homes, uproot some trees and cause extensive power outages, according to the National Weather Service.
Feltgen told the Los Angeles Times that storms that form in June and early July are not indicative of what will occur in the rest of the hurricane season, which heats up from mid-August to late October.
North Carolina, where the worst blow is expected as Arthur continues up the East Coast, is bracing now for the storm, with residents and tourists clearing out of Hatteras Island on Thursday. The barrier island is under a mandatory evacuation order.
North Carolina, as the state Department of Public Safety notes, is vulnerable to hurricanes. From 1851 to 2005, the state experienced 47 hurricanes, with a dozen of those Category 3 or higher. The state maintains a list of hurricanes and tropical storms that have hit North Carolina from 1954 to 2011, and there are only two other hurricanes that occurred in that time period as early in the season: Hurricane Bertha on July 12, 1996, and a tropical storm on June 20 in the same year -- also called Arthur.
Astronauts on the International Space Station took a photo of Arthur as it was forming on Tuesday, above. From space, the tropical storm was a majestic swirl of white. Read more about Arthur.