Three components precede bad news: target, trigger and tweak. By recognizing these components, you can easily manage most of the bad news in your projects.
If the monthly target is $10K and the expenses are trending toward $40K for the next three months, then the potential overrun is a trigger that should prompt you to tweak the situation. Inform the project stakeholders but be careful not to cry wolf.
If you’re able to steer the project towards a more favourable outcome, then you can report the good news. If not, then the bad news will not be a surprise to the parties involved.
Take a look at your current targets—budget, schedule or objective—and identity triggers that will give you adequate room to tweak the circumstances if needed. It is better to pre-empt than to be held in contempt.