This combination of accuracy, precision, resolution and all-weather operation can be of enormous value in forecasting severe storms, which are difficult to observe with spaceborne sensors. Moreover, balloons cannot be launched in a hurricane, ocean bouys and coastal sensors tend to get knocked out by them, inland sensors are far away, and few aircraft can venture in.  Shortly after Katrina hit, a forecaster at the National Hurricane Center in Miami noted, "It's almost as if we're forecasting blind" (Miami Herald, 8 Oct 05). GPS radio signals, however, cut deep into the storm, maintaining their accuracy and actually increasing their vertical resolution as they go down, exposing the critical temperature, pressure, moisture, and refractivity structure otherwise hidden from view.