ByJohn S. McClenahen Like Merrill Lynch & Co., New York-based securities firm UBS Warburg LLC is adjusting its GDP forecasts. Chief economist Maury Harris now predicts that -- adjusted for inflation -- the U.S. economy will grow 3% in 2003, down from his previous forecast of 3.4%. Merrill Lynch is forecasting real growth of 3.3% in 2003, down from its previous estimate of 3.7%. Harris suggests that U.S. economic growth in 2003 is going to come somewhat later in the year than originally thought because of a possible attack on Iraq and other "heightened near-term geopolitical uncertainties." Also a factor: The "still expected" recovery in capital spending "initially probably will be more modest than earlier forecast," Harris says.