JANUARY SAIL -- Windsurfing on the high seas hasn't been a typical scene during the first month of 1993. Calm sunny weather had been the norm until yesterday when winds increased to more than 30 knots and seas offshore reached heights of 18 feet. This lone sailboarder braved the rough seas for an exciting ride at Horseshoe Bay. US NAS forecaster Petty Officer Mark Vandever said the outlook was for an improvement today.