Running a Weekly 13-Week Cash Forecast Review With a Fractional CFO

The cash forecast looked comfortable last Friday. This week, a customer payment has slipped, an annual software renewal has cleared, and the closing bank balance is lower than expected. Replacing the old numbers with the new ones produces an updated spreadsheet, but it does not explain what changed or help the team avoid the same surprise.

A fractional CFO can establish a weekly review that preserves the original forecast, reconciles actual cash, and turns differences into better assumptions. This guide focuses on maintaining a rolling 13-week forecast, rather than the wider first 90 days of a CFO engagement. The workflow and numerical example below are editorial illustrations that should be adapted to the business's payment patterns and reporting needs.

Decide what the forecast is meant to reveal

Define the decisions the forecast will support: scheduling an approved investment, understanding a seasonal cash trough, or identifying a collection issue early enough to address it. A model built for weekly cash visibility needs different detail from an annual budget or a financial statement forecast.

A 13-week horizon shows roughly a quarter in weekly intervals, but the useful level of detail varies. The next few weeks may be based on identified invoices and payment runs; later weeks may rely more on operating assumptions. Label that distinction instead of presenting every number as equally certain.

Deloitte's 13-week cash-flow forecasting overview describes a structured short-term forecasting process. Treat the horizon as a practical planning format, not a guarantee that every liquidity question can be answered by one spreadsheet. Where daily timing matters, add the necessary detail around the affected dates.

Establish a reliable opening balance

Agree the accounts included, the currency, and the precise cutoff time. Reconcile the opening cash balance to the relevant bank records. Explain pending transactions and separately identify money that cannot be used for ordinary operating needs. An unexplained starting difference can make every subsequent week appear inaccurate.

If the business uses several bank accounts, avoid treating a transfer between included accounts as new external cash. Where several currencies are involved, document the conversion assumption and distinguish cash movement from changes caused by translation. Ask the finance team to maintain the reconciliation rather than relying on the CFO's memory.

Assign an owner to each input. Collections staff may update expected customer receipts; procurement or operations may know about a changed supplier payment; payroll has its own payment calendar. Finance assembles the forecast, but the underlying facts often originate outside finance.

Forecast receipts and payments by expected cash date

An invoice date, a revenue recognition date, and a bank receipt date are different facts. For short-term cash planning, the expected cash date is the relevant input. Use known payment information where available and make assumptions visible where it is not.

For customer receipts, separate confirmed expectations from estimates based on normal payment behavior. A promise to pay is useful evidence, but it is still an expectation until the money arrives. Note disputes, missing approvals, or other dependencies that could move the date. Avoid counting both an open invoice and the same projected sale.

For outgoing cash, include recurring payments and irregular commitments. Payroll, supplier payments, rent, annual subscriptions, approved equipment purchases, and other scheduled obligations may follow different calendars. Use the company's approved payment and tax schedules; the forecast should reflect obligations accurately rather than quietly moving them to improve the picture.

Freeze a version before updating it

Save the forecast used for last week's decision before replacing estimates with actuals. Record the version date and the assumptions that matter. Without a stable reference, the team cannot distinguish a prediction error from a later change in the plan.

Compare actuals with the forecast made at a consistent lead time. A forecast prepared one day before a payment is not directly comparable with one prepared eight weeks earlier. Start with last week's committed view, then examine longer horizons when you have enough history to learn from them.

Keep corrections visible. If an opening balance was wrong or a payment was entered twice, classify the correction as a data issue. Do not rewrite the earlier version and then claim the forecast was accurate. A transparent error can lead to a better control; an erased error cannot.

Explain the variance before discussing actions

Use a small bridge from forecast closing cash to actual closing cash. Group differences by cause, then identify which ones change future weeks. Timing differences move cash between periods; permanent changes alter the expected total; data errors require correction of the model or source.

Illustration: one weekly cash bridge, in thousands of dollars. Positive values in the final column increase closing cash relative to forecast; negative values reduce it. Payments are shown as positive amounts in the forecast and actual columns.

The arithmetic is opening cash plus receipts minus payments. Here, actual closing cash is 100 + 65 - 95 = 70. The 20 difference consists of 15 fewer receipts and 5 more payments. That bridge explains the amount; the review still needs to explain why it happened.

Suppose the missing 15 receipt is expected next week and the extra 5 payment was an annual renewal omitted from the model. The first issue changes timing and needs a collection owner. The second reveals a missing commitment and needs a better payment calendar. Neither should be hidden inside a general “forecast adjustment” line.

Roll the forecast forward without double counting

Replace the completed week's estimates with reconciled actuals, make actual closing cash the next opening balance, and add a new week at the far end. Then update future receipts and payments using the latest evidence. Preserve the old version alongside the new one.

When a receipt slips, move the remaining expected amount rather than adding a new receipt while leaving the old one in place. When a supplier payment occurs early, remove or reduce the later scheduled amount. Check partial payments and split transactions carefully because they are common sources of duplicated cash.

Recalculate the lowest projected cash point, not just the balance at the end of week thirteen. A model can finish with a comfortable balance while showing a difficult week in the middle. The timing of that low point determines how much time management has to investigate and act.

Use scenarios to expose assumptions

Keep the main forecast distinct from alternative cases. A scenario might assume that a major customer pays two weeks later, a project starts later, or a planned purchase occurs on a different approved date. Change the affected inputs explicitly so the team can understand the resulting cash path.

Separate actions management controls from outcomes it merely hopes for. A customer payment date cannot be changed by editing a cell. An unapproved financing arrangement should not appear as dependable cash. Label dependencies and the evidence needed before an assumption can enter the main forecast.

Deloitte's discussion of sustainable cash forecasting emphasizes functional ownership, regular dialogue, and understanding the causes of weekly variances. Those principles support a review in which operational leaders explain their inputs instead of finance guessing for them.

Make the weekly meeting short and specific

Circulate the reconciled balance, the variance bridge, changed assumptions, and decisions required before the meeting. Discuss material exceptions first. Each action should have an owner, a date, and a clear next update. Set materiality thresholds that reflect the company's cash position rather than copying another business's numbers.

The CFO should challenge the explanation as well as the calculation. Repeatedly late receipts may indicate unrealistic assumptions, an unresolved billing problem, or a customer-specific issue. Each cause needs a different response. Record what evidence will distinguish them next week.

Avoid measuring success only through a single forecast-accuracy percentage. Large receipts and payments can cancel each other's errors. Review the main categories and recurring causes, and explain when a small cash base makes percentages misleading. The purpose is better decisions and fewer unexplained surprises.

Scope the fractional CFO's work clearly

A useful engagement includes the model, source ownership, a versioning process, a weekly review, and an internal handover. Agree who maintains the file between the executive's working days and who can authorize any resulting business action. Forecast ownership does not automatically grant authority to make payments or obtain financing.

Bring a recent forecast miss when you find a fractional executive. Ask candidates to show how they would investigate it and make the process repeatable. Browse fractional CFO providers and the CFO selection guide with that assignment in mind. The useful deliverable is a cash view the team can reconcile, explain, and update consistently.