Does anyone use the "Complete this entry" button on the calorie tracker on myfitnesspal.com?
At the end of the day, it gives an estimate of what your weight will be in 5 weeks based on that days calories and exercise (i.e. net consumed after exercise). I never eat the same amount of calories a day and my exercise varies depending on the day too.
I never look ahead 5 weeks as it seems SO far away to me. But now I marked my calendar to see if it works out. (It says by March 7th I will be 213lbs which seems a bit of a reach but we'll see!)
I'd ask on MFP but their site isn't as good as this one.