You heard it here first: The economy should grow about 3 percent in the second quarter of the year that ends June 30. Consider the source: Lawrence Yun, senior economist at the National Association of Realtors. Yun passed through town last week praising the prospects of the Tampa area housing market (improvement next year followed by a resumption of the boom within five years). Despite weak growth of 0.6 percent in the nation's gross domestic product in the first quarter, Yun predicted big improvement in the second. His explanation? The economy has negotiated the construction doldrums and shows more strength in areas like manufacturing.