What type of TAF forecast could indicate potential severe weather?

The choice indicating "IFR" – Instrument Flight Rules – is significant when discussing potential severe weather in TAF forecasts because IFR conditions generally arise from low visibility and/or low cloud ceilings, which can be associated with adverse weather phenomena such as thunderstorms, heavy rain, or significant turbulence.

When weather conditions deteriorate to IFR, it indicates that the visibility is less than 3 statute miles and/or the ceiling is below 1,000 feet above ground level, which can make flying extremely challenging. These conditions typically reflect a higher likelihood of severe weather effects, impacting flight safety and operational planning.

While VFR (Visual Flight Rules) signifies clear and favorable flying conditions, and MVFR (Marginal Visual Flight Rules) suggests some limitations in visibility and ceilings but not to the extent of IFR, they don't directly suggest the same level of severe weather potential. Even IFR forecasts without an indication of risk might not highlight the severity but can certainly point towards the likelihood of challenging flying conditions. Thus, the general indication of IFR conditions plays a crucial role in foreseeing severe weather developments.