Assuming you know your current (pre-Revaluation) tax expense, you need to figure out what your NEW tax expense will be. I cover how to do that here (if anything is unclear in the explanation I provided, please let me know).
Once you know your new, estimated tax expense, you can compare it to your pre-Revaluation expense to see if your taxes will go up or down.
A property revaluation is needed when market values start to change from assessed values. The purpose of the revaluation is to make assessed values equal to market values, so that everyone in the municipality is taxed fairly.
Jersey City is a case study of tax injustice that occur when a city fails to revalue when market values grow disconnected from assessed values. You can read more about the need for Jersey City to revalue here.
You will have to contact Appraisal Systems Inc. (the company that was hired by Jersey City to conduct the revaluation) and/or the Jersey City Tax Office to find this out.
Based on this November 2017 report in The Jersey Journal, the first round of new assessments may be mailed to homeowners as early as December 2017. I suggest reading The Jersey Journal and following Terrence McDonald for the latest updates.