An economic report released Thursday provided some good news for grape growers still recovering from a rain-soaked spring. Global wine prices, including local markets on the North Coast, are continuing to strengthen as the economy recovers and consumers sip their way through the surplus of wine, according to the Rabobank Wine Quarterly report. “There is an improving picture,” said Stephen Rannekleiv, a co-author of the report. “Things seem to be getting slowly better.”