Oil prices rose again in morning trade here, moving towards 60 usd a barrel, sparked by worries that two tropical storms could hit US crude production in the Gulf of Mexico, dealers said. Persistent concerns that refineries may struggle to meet demand during the fourth quarter as the northern hemisphere winter bites are also bolstering prices, they said. At 11:50 am, New York's main contract, light sweet crude for August delivery was up 27 cents at 59.86 usd a barrel from its close of 59.59 usd in the United States yesterday. "Certainly the market has a bullish tone about it," said Mark Pervan, a commodities analyst with Daiwa Securities in Melbourne, Australia. "The market is very news-sensitive especially to (possible) supply disruptions ... the cyclone news from the US will keep the bullish sentiment intact," he said. The US National Hurricane Center issued advisories Tuesday for tropical storm Cindy, located in the central Gulf of Mexico, and tropical storm Dennis, in the eastern Caribbean Sea. Tropical storms often develop into hurricanes. In September 2004, a series of hurricanes devastated Gulf of Mexico production, causing prices to rise sharply. The 2005 Atlantic Ocean hurricane season lasts from June 1 through November 30. New York crude futures struck an all-time high of 60.95 usd on June 27, on concerns of a possible global supply shortage. Prices then eased after an unexpected rise in US crude inventories last Wednesday and analysts said this week's US government report on oil stocks will be a major factor as to whether oil breaches 60 usd a barrel again.