Perhaps you would know what the VFR, MVFR, EFR, etc. represents under the Aviation | Flight Categories tab?
Enjoy,
Paul
VFR, "Visual flight rules", this is what most GA (general aviation, little guys) pilots fly when out for fun, it means "see and be seen".
MVFR is "marginal VFR conditions" which is wx conditions close to, but at or above a cloud ceiling of 1000ft and flight visibility of 3 statue miles, but close to it and IFR (Instrument flight rules, when you don't ever have to technically look out the window, except landing) are possible at any time.
EFR, no idea, I never used it.