(Adds new strength, changes dateline, previous MIAMI) HAMILTON, July 12 (Reuters) - Bermuda issued a tropical storm warning on Saturday as a weakening Hurricane Bertha came to a virtual standstill nearby, not close enough to bring significant winds but enough to whip up the surf. The tropical storm warning meant storm-force winds were expected to affect the mid-Atlantic British colony within the next 24 hours, the U.S. National Hurricane Center said. On Saturday morning though, the skies were clear and the sun bright as Bermudians went about their business paying little apparent heed to the hurricane 215 miles (345 km) to the southeast of the wealthy offshore finance center. Bertha, the first hurricane of the 2008 Atlantic hurricane season and a wake-up call to oil markets already nervous about crude supply, had barely moved for several hours, the Miami-based hurricane center said. At 2 p.m. EDT (1800 GMT) the storm's top sustained winds had slipped to 80 miles per hour (130 km per hour), according to data collected by a "hurricane hunter" aircraft sent into the hurricane. "Bertha has been meandering for the past several hours and little motion is expected today. However, Bertha should begin to move toward the north near 2 mph (4 kph) later tonight," the hurricane center said. "On this track, the center of Bertha is expected to slowly pass to the southeast and east of Bermuda, but the motion could occasionally be erratic." Bermuda has tough building codes and its 66,000 people are considered among the most storm-conscious in the region, meaning tropical storm conditions would be very unlikely to pose a threat to the territory, a major tourist resort. Bertha formed early in the hurricane season near the coast of Africa, giving some credibility to predictions that this year would be quite busy for storms. Hurricane activity does not usually get into high gear in the Atlantic until August. Energy markets pay close attention to Atlantic hurricanes because of their potential to wreak havoc among the oil rigs in the Gulf of Mexico that supply the United States with a third of its domestically produced crude. Bertha was never viewed as a threat to the Gulf but was briefly seen as a possible menace to the U.S. East Coast before the storm turned northward toward Bermuda. An average Atlantic storm season, which begins on June 1 and runs to the end of November, has around 10 tropical storms, of which six reach hurricane strength with winds in excess of 74 mph (119 kph). The record-busting 2005 season, which included Hurricane Katrina, spawned 28 storms. (Reporting by Lilla Zuill, Writing by Michael Christie, Editing by Jackie Frank)
