The 4 p.m. advisory from the National Hurricane Center officially designates Bertha as the first major and only hurricane of the 2008 tropical season. Maximum winds in the storm are up to 115 mph, making it a category three (major) storm.
Forecasts over the weekend had Bertha slowly strengthening, over a span of several days, staying at category one strength. Monday morning's forecast introduced the first category two projections. And this afternoon, the storm was suddenly a major hurricane. The National Hurricane Center cites that "...Bertha's intensification to a major hurricane today highlights the difficulties of forecasting rapid intensity changes." It is important to note, however, that most global models did a fairly decent job at forecasting Bertha's development in advance.
It's still too far out to get a reasonable idea of who should be taking cover. High pressure over the Atlantic should eventually help steer the storm away from the U.S., however, the "cone of uncertainty" with the track is still wide enough to warrant close attention for those along the east coast of the U.S.
Official forecast do not have the storm intensifying beyond category three status.