The green Potential bar on the Sales & Re-Order Opportunities dashboard chart is an estimated number based on the aggregate 6-month history of sales across all accounts for that user. It is estimating, based on historical sales, how much potential you have for re-orders for the remainder of the month. As the month continues to move forward and accounts order more wine against their 6-month average, it will count down the Potential bar.

You can see those actual account-level numbers in the chart just below the dashboard bar chart. It breaks down each account with their average/month, how much they have spent so far this month, and then what their potential is.