Posting here in case anyone else has the same problem. It seems Google shut down their weather API. Since the Weather & Toggle Widget appears to no longer be available or have a developer, it's unlikely that the widget will be updated to use another source for weather info. As a result, the weather app appears to be useless. That's a bummer since I paid for the forecast add-on.
I've switched to Fancy Widgets which is still being developed and allows the user to choose between Google and Accuweather as a weather source. Accuweather is working on Fancy Widgets while Google weather does not currently work, but the dev may fix this in the future.
See this discussion for more info: Weather Widget not working - xda-developers