For work I was just chatting to the Met office (flood forecasting).
Their models have been really struggling this week and into the weekend which is poss why MWIS has been getting it wrong.
It will be very wet Friday in Lochaber worst in the afternoon, much better day Saturday and dry through the night but then deterioration again from early Sunday, currently heavy showers but may form a more consistent band of rain throughout the day.
Should be warmish throughout. Midges were pretty bad in the woods last weekend in Argyll, so a headnet and Smidge are recommended!
HTH