Forecasts will always throw in everything including the kitchen sink.
The ICAO limitation for
only PROB30 or PROB40 makes a lot of it worthless. Basically if anything might even remotely happen (1% chance) it has to go in as a PROB30. A PROB40 is shorthand for "we think it will happen".
The best weather forecast is an IMCR or an IR
Then you have options..