Personal weather stations with the capability to interface with a computer have been around for a while now. However, this interface only operates in one direction.
I propose a hardware/software combo for providing better *local* weather forecasts.
The hardware feeds the usual variables (pressure,
temperature, humidity, wind speed and direction, cloud cover etc) to the computer which logs it in the usual fashion.
When the software detects that both the weather station is active and the computer is in use it flashes up a note at user-defined intervals requesting the current weather details.
The software would then compare the current data with the past record in order to provide a better, more personalised weather forecast for your locality.
At first the system would make its predictions based on the simplest assumptions (e.g. High Pressure = Low Cloud Cover). Even the smallest amount of data should improve accuracy, allowing the user to choose how much time to spend responding to the software's requests (i.e. you don't have to fill in every box on the form every time). Combining the data from users living in the same area via the internet should improve accuracy even further.