Plot weather model winds in GUI prior to a simulation

[nwagenbrenner]

This is something we could consider doing. Sometimes it's handy to know what the weather model forecast looks like before a simulation, for example if you are comparing between a few weather models or want to know what the flow features look like in the weather model output before you start a mass and momentum run. We already have stand alone executables that convert the 10 m winds from weather model output to a KMZ file (e.g., wrf_to_kmz and hrrr_to_kmz). This same idea could be implemented into GUI/API code that allows plotting of downloaded forecasts. We can support all the models we download, plus wrfout NetCDF files. A possible workflow:

1. User downloads a forecast file
2. Once a supported forecast is detected on disk, the a "View weather model winds" button is enabled
3. If the user clicks the button a kmz file is written to disk and displayed on the map

We would need to account for whether or not the KMZ has already been written if a WindNinja run is then initialized with that forecast and the "write weather model outputs" is selected -- we don't want to generate the same KMZ twice. This might be more easily handled once the casefile is implemented.