how wide of an area is used to test against the predictions? I notice he calls out local weathermen, well a thirty percent chance of rain given out by the TV gu

how wide of an area is used to test against the predictions? I notice he calls out local weathermen, well a thirty percent chance of rain given out by the TV guys for the metro Atlanta area is either dead accurate or dead wrong depending what part of metro Atlanta I am in. It would be really cool to see weather forecasts done up like topography maps, with +/- symbols denoting changes in precip and the like