The U.S. economy slowed drastically in the first three months of the year as a harsh winter exacted a toll on business activity. The slowdown, while worse than expected, is likely to be temporary as growth rebounds with warmer weather. Growth slowed to a barely discernible 0.1 percent annual rate in the January-March quarter, the Commerce Department said Wednesday. That was the weakest pace since the end of 2012 and was down from a 2.6 percent rate in the previous quarter. Many economists said the government’s first estimate of growth in the January-March quarter was skewed by weak figures early in the quarter. They noted that several sectors — from retail sales to manufacturing output — rebounded in March. That strength should provide momentum for the rest of the year. More