Trending Data

Hi All,
I have a small task to complete which I have done but now I would like to make it a bit more hands off.

The scenario is this: I am to monitor a 2TB network drive for space and inform when there needs to be another 2TB drive created. Right now we are tearing thru these in about 1.5 months.

The data I collect is just the remaining freespace on the drive.

I do simple "yesterdays number minus todays number" to determine how many GB were consumed in 1 day.

I use the Trendline to forecast how long it will be until I am required to get another 2TB drive created but the forecasting is not as "hands off" as I would like.

When trending, I must tell excel how many forecasting periods I would like. What I want to do is get Excel to determine when my freespace gets to Zero (0) and don't trend past that date. I have already done the trend line intersect at Zero but thats not what I need, I want the trend to not show dates past when the trendline hits Zero.

Does that make sense?

The graph is a simple bar graph with GB on the the left side and dates along the bottom.

In the attached picture, you can see that I am forecasting 5 days past when the trendline hits Zero. If I want the trendline to fit nicely in the graph, I will have to manually go into the trendline and change the forecasting periods.