How to manage an effective cash flow forecasting in a difficult business situation?

To successfully project cash flow, organisations look at their prior year’s checkbook (Bank Statements) as a basis of cash flow for the following year. Adjusting for any anticipated changes, this is often the more accurate way of projection. When looking over a previous year’s expenses, a company would then factor in changes like new pricing, program offerings, funding sources and interest rate changes etc.

However, the term used in your question "difficult business situation" is very subjective and could mean anything like new projects, deteriorating sales, increased expenses or vise versa. To incorporate these changes into the cash flow forecast the business needs to look for new contract or any cancelled contracts. 

As the year unfolds, a company then updates cash flow projections to adequately reflect recent developments in expenses and profits. Comparing budgeted cash flows to actual deposits and expenditures will help in more accurately projecting cash flow in the following months. Even the most practised of organisations find their forecasts change on a regular basis, thus prompting frequent revisiting.