Short answer: Choose two to four external forces that could decide the year, cross them into three or four named scenarios, and test the business plan against each one. A good scenario is not a forecast. It is a framework you can act within, equipped with leading indicators that signal it is materializing.
The longer view
The common mistake is to write an "optimistic", a "base" and a "pessimistic" scenario. Those are not scenarios; they are the same plan with different multipliers. A real scenario is built from driving forces. For Israel in 2027, for example: the state of the maritime straits and seaborne trade, the reconstruction and funding mechanism in Gaza, the race between regional trade corridors, and the price of capital and energy. Each combination of forces produces a different world, with a name every member of the executive team understands.
Once the scenarios exist, ask three questions of each: what in our plan breaks in it, what opens up in it, and which decision would we make today if we knew it was coming. The answers accumulate into a short list of robust decisions, correct in most scenarios, and a list of scenario-dependent decisions, for which you set decision points in advance.
This is a reading through the seven layers of The Blue Pumpkin, the method of Dr. Bella Barda-Bareket.
What to do tomorrow morning
Schedule a half-day executive workshop around four defined scenarios, and leave it with three robust decisions and three dated decision points.