Small-scale surface wind patterns may hold the key to predicting the kind of local showers that can surprise weather forecasters by forming without the usual early warning signs. A new prediction method being examined by NOAA is based on the fact that when moist, low-level winds converge over a specified area, the air has no place to go but up. Clouds and showers result.
The relationship between wind convergence and rainshowers has been recognized in a general way for years. But researchers recently had an opportunity to test this knowledge in an area surrounded by wind reporting stations. The research was conducted in southern Florida, in a 625-square-mile region with wind stations spaced about 4 miles apart around the perimeter. Researchers found that showers in the area were closely related to the surface winds measured along the area's perimeter.