Model Divergence

Just wondering if some of you weather gurus out there could shed some light on why the models are drastically divergent at present, even in the short to medium term forecasts of 3-5 days out, let alone the long term forecasts (7+ days).

Is it due to a rather active and unusually late monsoon trough stretching across the top of the continent and out into the Coral Sea/Tropical South Pacific?

I just can't recall the models being this divergent (particularly in the short to medium term) for some time.