In futurists' parlance a 'probable' future scenario -- as opposed to a 'possible' or 'plausible' one -- is a scenario that is intuitively anticipated from current conditions. It is usually an extrapolation of trends currently in evidence, with maybe a few guesses about how conflicting trends may shake out.
Probable scenarios are least risky but have correspondigly less potential strategic value. A probable scenario is also sometimes called a baseline scenario or, more playfully, "The Official Future". The probable future is the safest bet. Except when it turns out to be wrong.