This is not out of disk space ( memory card). This is runtime memory out of space. Typically when u see this kind of error, some code has allocated space for data, but didn’t free it ( over and over) when it was no longer needed. GC is garbage collection, which reclaims memory space no longer referenced.

I know this is old, but I was able to modify the forecast-io module to show weather alerts https://github.com/esmoyer/MMM-forecast-io