Hi Jeffery!
Is there a way to limit Fog and Frost to a specified edit area?
No. The framework of ForecastBuilder, PoWT, used to work on edit areas, but FB does not. I'd really like if it did, but for now ForecastBuilder does not respect any active edit areas.
Have you considered using a different method for fog forecasting (i.e. UPS fog tool)?
I can't speak to any active development efforts, but personally I do not find much value in the default tool that runs for fog. There are a few alternatives available if you right-click on the PotFog grid - you should see a PoT_Fog_Opposite_Pop (not very useful), PoT_Fog_from_Model, and PoT_Fog_from_Visibility. The first is what is says it is - just opposite PoP grids. The second allows you to derive fog based on a model visibility. And the third lets you use your Visibility grid if you make such a grid. My personal method of PotFog creation is using a Weather Element Group to load all the model visibility, then use the Query tool to adjust the PotFog up and down. I sometimes use our Visibility grid (which we make for digital aviation), but sometimes this grid does not match my thinking and it's just easier to make my PotFog 'manually' using the Query tool.
There may be other tools other offices have developed or in development - hopefully the FB developers can respond when they return from furlough. (I'm not involved with FB, just a user!)
Finally, this is actually the "old" forum - you should post future questions in the "new" forum:
https://vlab.noaa.gov/group/forecastbuilder/discussions-forums-
